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Title: Hydrilla management in Florida: a summary and discussion of issues identified by professionals with future management recommendations
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Title: Hydrilla management in Florida: a summary and discussion of issues identified by professionals with future management recommendations
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Creator: Hoyer, M. V.
Netherland, M. D.
Allen, M. S.
Canfield, D. E. Jr.
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Publication Date: 2005
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Table of Contents
    Title Page
        Page 1
    Table of Contents
        Page 2
    The situation
        Page 3
    Introduction
        Page 4
    Synopsis of introductory presentations
        Page 5
        Page 6
    Summary of presentations
        Page 7
    Critical issues identified in the workshop
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
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        Page 31
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    Reference
        Page 38
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        Page 40
        Page 41
        Page 42
    Workshop participants
        Page 43
    Minutes and notes from the workshop
        Page 44
        Page 45
        Page 46
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        Page 48
        Page 49
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    Florida statutes and Florida administrative codes
        Page 51
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Full Text












Hydrilla Management in Florida: A Summary and Discussion of
Issues Identified by Professionals with Future Management
Recommendations



Final Document



June 14, 2005


M. V. Hoyer
Department of Fisheries and Aquatic Sciences
Institute of Food and Agricultural Sciences
University of Florida

M. D. Netherland
U.S. Army Engineer Research and Development
Center, Vicksburg, MS
Center for Aquatic and Invasive Plants
University of Florida

M. S. Allen, and D. E. Canfield, Jr.
Department of Fisheries and Aquatic Sciences
Institute of Food and Agricultural Sciences
University of Florida




Funded by: Florida LAKEWATCH, Department of Fisheries and Aquatic Sciences, University
of Florida/IFAS.










Table of Contents

The Situation -------------------------------------- --------------------------- 3

Introduction------------------------------------ ---- -- ------------------4

Synopsis of Introductory Presentations -------------------------------------- ----------- 5

"Hydrilla Management Before Fluridone", by Dr. Bill Haller, UF/IFAS Center for
Aquatic and Invasive Plants ------------------------------------------------ 5

"Recent Challenges and Current Viable Options for Hydrilla Management in
Florida", by Dr. Mike Netherland, USA ERDC/Center for Aquatic and Invasive Plants 5

"Current Florida DEP Management Strategies for Hydrilla in Florida", by Jeff Schardt,
FL Department of Environmental Protection------------------------------ 6

"Water Management Schedules and Hydrilla Management", by Susan Sylvester,
U. S. Army Corps of Engineers, Jacksonville District -------------------------------------- 6

Summary of Presentations ------------------------------------------------------- 7

Critical Issues Identified in the Workshop---------------------------------------- 7

Integrated Plant Management ----------------------------------------------- 7

Triploid Grass Carp ------------------------------------------------------- 11

Current and Future Chemical Management Practices for Hydrilla ---------------------- 14

Water Regulation Schedules and the Use of Fluridone ------------------------------ 24

Wildlife and Fisheries Management--------------------------------------------- 33

Florida Statute and Florida Administrative Code-----------------------------------------34

References --------------------------------------------------------------------38

Appendix I Workshop Participants ------------------------------------ -------------43

Appendix II Minutes and Notes from the Workshop ---------------------------------------44

Appendix III Florida Statutes and Florida Administrative Codes ------------------------------ 51












The Situation


Following the introduction of hydrilla (Hydrilla verticillata L.f. Royle) into Florida's waterways
in the late 1950's, it has spread throughout the state. The ability of this plant to occupy nearly the
entire water-column of small lakes and thousands of contiguous acres of large lakes has resulted
in the expenditure of millions of state dollars on an annual basis for control efforts. Through the
1990's the herbicide fluridone was used to selectively and economically control hydrilla,
particularly in large Florida lakes. By maintaining low concentrations (5-10 ppb), fluridone
offered selective treatment for large acreages of hydrilla at a relatively low cost compared to
other methods such as contact herbicides and mechanical harvesting. Hydrilla control with
triploid grass carp would also be cost effective but offered limited plant selectivity and grass carp
add the risk of complete removal of all submersed habitat that is so important to the largemouth
bass fisheries of large lakes. Nevertheless, triploid grass carp are stocked for hydrilla control in
more than 70 public lakes. Research during the last several years revealed that several
populations of hydrilla, particularly in large Central Florida lakes, have become resistant to low
concentrations of fluridone. Fluridone will still control hydrilla at higher, sustained doses (15-40
ppb) but these high doses impact non-target native aquatic macrophytes and maintaining greater
concentrations significantly increase the cost of control. There are no other registered herbicides
available with comparable environmental, cost, and application characteristics to replace
fluridone, placing management agencies in the difficult situation of trying to balance cost and
selectivity as they attempt to manage hydrilla in Florida lakes.

There were several lines of discussion from the workshop that are pursued in this document, and
these include the following: 1) Hydrilla is an exotic plant that can cause numerous problems with
the intended use of Florida's aquatic systems. In recognition of the historical problems caused
by hydrilla, Florida State law mandates management of hydrilla to the lowest feasible level. 2)
The selective management of hydrilla is difficult and expensive and has become further
complicated by the development of increased resistance to fluridone, our most cost-effective
treatment 3) Using current control methods, hydrilla cannot be selectively eradicated from the
waters of Florida. 4) There are some recognized benefits of hydrilla to fish and wildlife;
however, maintaining optimal coverage levels that do not impact other uses of the water body
over an extended period of time has proven to be very difficult in most aquatic systems. 5)
Given the funding constraints and the lack of cost-effective or selective controls, we are faced
with the reality that in some water bodies we may have to live with the presence of expanding
hydrilla populations for one or more seasons. Current technology and funding will dictate the
lowest feasible level of hydrilla until new and more effective management techniques become
available. 6) When possible, efforts should be focused on reducing hydrilla coverage to the
lowest feasible level and encouraging the re-establishment and proliferation of native submersed
vegetation.

The purpose of this document is to summarize the current issues associated with hydrilla control,
outline the pros and cons of current control technologies, and discuss issues that impact or are
impacted by current management options. Recommendations will also be made for developing
lake-specific management strategies and for future research needs.
3










In discussing hydrilla and hydrilla management, one issue that is often overlooked is the
temporal nature of how we view hydrilla and management results. A small-scale infestation
today may cause no problems, but may lead to a system-wide infestation within one or two
growing seasons. Likewise, a system that is completely infested with hydrilla today may be
subjected to a severe disturbance (e.g. the impact of the 2004 hurricanes on large Central Florida
Lakes) that greatly reduces the biomass for one or more seasons. When assessing the impacts of
grass carp, one must view the management over a fairly long period, because at some point in
time, the fish have likely reduced the hydrilla and left native plants at a level that would lead one
to consider the stocking a success. From the standpoint of hydrilla providing valuable fish and
wildlife habitat, certain levels of hydrilla likely provide good habitat quality without impacting
other uses of the lake. Nonetheless, this situation has rarely been static, and history suggests that
hydrilla will often expand and interfere with other uses of the water body. In these cases, by
allowing hydrilla to aggressively expand, subsequent large-scale management efforts are often
required. Efforts to bring hydrilla back under control can require multiple treatments that will
extend over more than one season. In the end, it is difficult to say when and where hydrilla will
manifest itself as a problem, and once it does become a problem, it is difficult to say how long
the extensive infestations will remain. One must keep in mind that this is a plant with a six-
decade history of expansion that has withstood our most vigorous efforts of control.
Management efforts should be viewed on a lake-by-lake basis, and what works for one lake or
chain of lakes, may not be appropriate for another lake or group of lakes.

Introduction

Due to the above-mentioned new challenges, researchers from the University of Florida
sponsored a workshop on December 6 and 7, 2004 to identify issues related to the management
of hydrilla in Florida. The workshop included over 40 experts from county, state and federal
agencies that have professional experience with water resource management (see Appendix I).

The workshop began with a series of introductory presentations, followed by a session to identify
and prioritize the current issues related to hydrilla management. In this document, we
summarized the proceedings of this workshop, and the critical issues identified and prioritized by
the assembled experts (see Appendix II). Following the workshop, the authors met in late
December 2004 and discussed how to proceed with this document. It was decided that a
comprehensive literature review of all the issues identified at the workshop would serve
primarily to reiterate the knowledge and background already held by the panel of experts
attending the workshop. Therefore, in this document, we briefly summarized the literature for
each issue and made management recommendations that reflected the workshop proceedings and
conventional wisdom from the literature. The management recommendations were provided to
all workshop participants for comment, followed by revision. This final document is intended for
distribution to a broader audience and can be used by each appropriate county, state and federal
resource management agency (if they choose) to help with their management decisions regarding
hydrilla. We recognize that increased stakeholder involvement and public education will be
important components of moving forward with future hydrilla management programs.











Synopsis of Introductory Presentations


"Hydrilla Management Before Fluridone", by Dr. Bill Haller, UF/IFAS Center for Aquatic
and Invasive Plants


-Hydrilla introduced into Florida in 1958-1960
-Control measures included mechanical, biological, chemical measures
-Problems with all of these strategies
-Grass carp symposia in 1976 and 1994
-Fluridone approved for use in 1980
-Cost of hydrilla control with Fluridone much lower than other herbicides
-Mike Netherland noted hydrilla resistance to Fluridone in 1999
Where to go from here
-Current herbicides that gain USEPA approval have a single, simple, mode of action
-Such herbicides are prone to resistance development,
-Similar to agricultural herbicide uses, we need several different compounds to

-However, the aquatic herbicide market is very small compared to agricultural
Markets, lowering the incentive to develop new compounds
-Use of grass carp, as a management tool is likely to increase
-State and federal agencies may need to incur the cost of developing and testing
New aquatic herbicides (third party registrations)
-We need research and development of compounds with more than one mode of action


"Recent Challenges and Current Viable Options for Hydrilla Management in
Florida", by Dr. Mike Netherland, US Army Engineer Research and Development Center
/Center for Aquatic and Invasive Plants

-Management of hydrilla should include an evaluation of the relative benefits
and harm in doing so
-Hydrilla has some benefits as habitat to fish and wildlife when it is present at low
densities, but high densities can have detrimental properties
-1990s is when hydrilla spread throughout the Kissimmee Chain of Lakes and
Lake Istokpoga, where most control budget is currently spent
-We may need to realize that current management strategies such as whole-lake
reductions may not be compatible with current realities of viable options
-Control of the spread of hydrilla across lakes has been unsuccessful
-Compared to other regions, shallow lakes and warm temperatures in Florida
cause hydrilla to potentially occupy a large portion of lake surface area,
which is the problem.
-Prior to resistance, Fluridone was a low-cost option to reduce large acres of
hydrilla in large lakes, with little impact on native plants
-Resistance to Fluridone was inevitable, and it developed simultaneously in
5









several locations in Florida
-With resistant hydrilla, it has been difficult to maintain contact times at high
concentrations of Fluridone due to water management schedules, flushing
rates, and bacterial breakdown of Fluridone
-The primary issue with resistance is selectivity, because non-target impacts of
herbicide use are certain to increase with Fluridone resistant hydrilla
-The Kissimmee Chain and Lake Istokpoga present the major challenges due to
resistant hydrilla and importance of native plants to those ecosystems,
causing high risk of non-target impacts
-We need to know if high coverage of hydrilla is a flood control threat in these
lakes


"Current Florida DEP Management Strategies for Hydrilla in Florida", by Jeff Schardt,
FL Department of Environmental Protection

-Management of hydrilla has reduced the total acres from 140,000 to 110,000,
and the total number of water bodies from 280 to 186
-Large-scale hydrilla control has been ineffective with mechanical removal or
use of insects
-Fluridone and Endothall are the two chemicals currently available for use
on large systems
-Grass carp remove hydrilla but are nonselective for other native plants
-Fluridone most effective in January-May due to low rainfall increasing
contact time, and lower light availability for growth
-Fluridone tolerant hydrilla and microbial breakdown of the compound have made
long contact times necessary for control difficult to obtain
-65% of hydrilla control total budget is spent on Lake Istokpoga and the
Kissimmee Chain of Lakes
-Lake stage and flow greatly influence the cost of Fluridone treatments, with
high lake Kissimmee stage (e.g., 55 ft MSL) costing over four times the amount
that a low stage (e.g., 49 ft MSL) would cost
-Hydrilla control will require cooperation among all state and federal agencies
involved in large lakes in Florida

"Water Management Schedules and Hydrilla Management", by Susan Sylvester,
U. S. Army Corps of Engineers, Jacksonville District

-USACOE managed lakes in Florida are operated using regulation schedules for
flood control, navigation, and water supply for agriculture and
downstream flow
-The regulation schedules have reduced variation in water levels compared to
historic hydrologic regimes
-Temporary deviations from the schedules have been used to aid hydrilla
treatments, but they require planning and multi-agency input
-Impacts of hydrilla on flood control in large lakes has not been evaluated











Summary of Presentations


The introductory presentations confirmed that viable management options for hydrilla in Florida
are changing. Use of Fluridone as a long-term control measure for hydrilla on large lakes is
currently a much less viable and cost-effective option than it was in the 1990s, and non-target
plant impacts are likely to be significant for lakes with Fluridone-tolerant hydrilla. New
compounds are needed, and third-party registrations may be required to invoke the resources
necessary to develop these compounds. Water regulation will continue to play an important role
in management options for hydrilla.


Critical Issues Identified in the Workshop

Although many issues were discussed, we provide a brief literature summary of the following
top five issues identified by the participants in the workshop and make recommendations
regarding the issues:

Integrated Plant Management
Triploid Grass Carp
Current and Future Chemical Management Practices for Hydrilla
Water Regulation Schedules and the Use of Fluridone
Wildlife and Fisheries Management

Neither the issues identified nor the recommendations provided should be considered as having
any particular ranking within this document.

An additional section describing the Florida Statutes and Florida Administrative Codes
pertaining to management of aquatic plants in Florida is added to clarify the laws relating to
aquatic plant management in Florida and what agencies are responsible with what legislative
authority.

Integrated Plant Management

In the final phase of the Hydrilla Issues Workshop held December 7, 2004 the participants listed
Integrated Aquatic Plant Management as one of the top five issues. Integrated Aquatic Plant
Management is the process of evaluating all available tools and then using the appropriate tools
in a combination that will achieve the management objectives for a given aquatic system and a
given budget. There are several written descriptions in reports and manuscripts that describe this
management strategy. The following summary outlining Integrated Aquatic Plant Management is
from the North American Lake Management (NALMS)/Aquatic Plant Management Societies'
(APMS) aquatic plant management manual (Hoyer and Canfield 1997):

A successful integrated aquatic plant management plan is built on six main principles: (1)
identify the uses of the water body and determine if any of these uses are impaired or benefited
7











Summary of Presentations


The introductory presentations confirmed that viable management options for hydrilla in Florida
are changing. Use of Fluridone as a long-term control measure for hydrilla on large lakes is
currently a much less viable and cost-effective option than it was in the 1990s, and non-target
plant impacts are likely to be significant for lakes with Fluridone-tolerant hydrilla. New
compounds are needed, and third-party registrations may be required to invoke the resources
necessary to develop these compounds. Water regulation will continue to play an important role
in management options for hydrilla.


Critical Issues Identified in the Workshop

Although many issues were discussed, we provide a brief literature summary of the following
top five issues identified by the participants in the workshop and make recommendations
regarding the issues:

Integrated Plant Management
Triploid Grass Carp
Current and Future Chemical Management Practices for Hydrilla
Water Regulation Schedules and the Use of Fluridone
Wildlife and Fisheries Management

Neither the issues identified nor the recommendations provided should be considered as having
any particular ranking within this document.

An additional section describing the Florida Statutes and Florida Administrative Codes
pertaining to management of aquatic plants in Florida is added to clarify the laws relating to
aquatic plant management in Florida and what agencies are responsible with what legislative
authority.

Integrated Plant Management

In the final phase of the Hydrilla Issues Workshop held December 7, 2004 the participants listed
Integrated Aquatic Plant Management as one of the top five issues. Integrated Aquatic Plant
Management is the process of evaluating all available tools and then using the appropriate tools
in a combination that will achieve the management objectives for a given aquatic system and a
given budget. There are several written descriptions in reports and manuscripts that describe this
management strategy. The following summary outlining Integrated Aquatic Plant Management is
from the North American Lake Management (NALMS)/Aquatic Plant Management Societies'
(APMS) aquatic plant management manual (Hoyer and Canfield 1997):

A successful integrated aquatic plant management plan is built on six main principles: (1)
identify the uses of the water body and determine if any of these uses are impaired or benefited
7










by aquatic vegetation; (2) understand plant ecology and the ecology of the water body; (3) set
management goals; (4) consider all management techniques and select for use those that are most
appropriate for the defined problems; (5) develop an action plan and a program to monitor the
success or failure of management activities; (6) establish a long-term aquatic plant management
education program.

The Department of Environmental Protection and other agencies charged with the management
of aquatic plants generally follow the above procedures with some exceptions that came out in
the Hydrilla Issues Workshop.

Throughout the workshop it became obvious that for the above Principle (4) the number of tools
that are available for aquatic plant management is declining, especially for large lakes with
abundant hydrilla that is resistant to low concentrations of fluridone. This hinders the ability to
use fluridone for the selective control of hydrilla and enhancement of native plants. Fluridone
provides short-term control of resistant hydrilla at higher use rates, but at an increased risk of
killing non-target plants and at a significantly higher cost. Thus, to maintain some level of
control, other management methods like contact herbicides and/or mechanical harvesting will
have to be used, understanding that the total area of hydrilla control will be much less for
equivalent expenditures. More information and some recommendations to alleviate this problem
will be made in the section on herbicides.

The workshop participants strongly felt that the above noted procedures need to be followed
working toward the development of lake management plans making sure to involve all
stakeholders. Developing individual lake management plans by incorporating stakeholder input
can be accomplished (e.g., Tsala Apopka Chain of Lakes, Hoyer et al. 1999). However, this is
time consuming and requires dedicated financial resources.

Integrating Mechanical or Biological Control Methods

While this document provides detailed discussions and recommendations for grass carp,
chemical use, and water level deviations, there is limited mention of mechanical and classical
biological control approaches. Workshop participants suggested that moving towards an
integrated management approach was the number one issue and priority, yet there was little input
regarding how to incorporate mechanical or biological control methods with the current
management techniques. Both mechanical and biological control were noted as tools that may
be used for hydrilla control, yet both options have been available for many years and
technological advances that demonstrate methods for improved use of these tools are limited.

The lack of discussion on mechanical harvesting likely reflects the fact that there have been
limited advances in technology over the past several decades (Haller 1996). While mechanical
harvesting can provide immediate relief from hydrilla, the typical cost of control ($500 to $1,200
per acre), limited capacity to address large-scale infestations, and rapid re-growth of hydrilla
have greatly limited the use of harvesting as a primary tool for hydrilla control. It should be
noted that as the potential for integration of mechanical harvesting is discussed, in-lake disposal









methods could significantly increase efficiency and reduce costs by up to 50% compared to
standard trucking and disposal methods (Sabol 1981). While recent evaluation of a machine
called the Kelpin harvester provided hydrilla control at approximately $200 per acre (Haller
1996), these large machines can be difficult to move from site to site, and the upfront costs for
building the number of machines necessary to integrate this technology into a statewide program
would be substantial. Lastly, a significant increase in the use of harvesting suggests the issue of
non-target organism mortality as described by Haller et al. (1980) would need to be revisited.
While mechanical harvesting represents a tool that could be immediately integrated into the
larger state hydrilla control program, issues such as cost-effectiveness, use patterns and
efficiency, non-target impacts, and disposal methods would require further discussion prior to
embarking on a large-scale mechanical control effort.

Classical biological control has a much better chance of providing a long-term and highly
selective tool for hydrilla control; however, overseas exploration for new organisms has been
very limited over the last decade. The Hydrellia flies Hydrelliapakistanae and Hydrellia
balciunasi have been released in Florida for the control of Hydrilla. H. pakistanae became
established, while H. balciunasi has not. While research with H. pakistanae continues, there is
limited evidence that demonstrates presence of the hydrellia fly provides a consistent and
quantifiable level of control that is compatible with an operational management program.
Hydrellia flies are already present in many lakes throughout Florida, and their effectiveness is
related to the ability to build up a threshold population density (Wheeler and Center 2001). Fly
populations are impacted by both winter weather patterns as well as the nutritional value
(nitrogen) of the hydrilla, with damage typically noted in the top 20 cm of the hydrilla canopy
(Wheeler and Center 2001). Lake Seminole on the border of Florida and Georgia does represent
a site where H. pakistanae populations are thought to have increased to a level that provided a
large-scale, but short-term reduction in hydrilla biomass (Grodowitz et al. 2003b). Nonetheless,
at the current time, the presence or absence of the hydrellia fly within a waterbody has little
bearing on the hydrilla management approach taken by resource managers in Florida. From an
integrated plant management standpoint, the presence of hydrellia flies is likely having some
level of impact on hydrilla growth potential (Doyle et al. 2002), and therefore, where present, the
hydrellia fly would already be considered part of an integrated management program.

The operational use of this tool as a primary means of managing a hydrilla infestation remains a
significant question. There has been a recent research emphasis on mass rearing and release of
hydrellia flies to provide a more pro-active approach to hydrilla management, and these results
are being analyzed. Results from laboratory and the field indicate that herbivory by Hydrellia
spp. can impact hydrilla by reducing photosynthesis, thereby impacting biomass production and
tuber formation. This research suggests that sustained herbivory, even at relatively low levels
(i.e., 15% to 30% leaf damage) may reduce the competitive advantage of hydrilla over native
species allowing native species to compete more favorably (Doyle, et al. 2002, Grodowitz et al.
2003 and Grodowitz and Smart et al. 2003).

Researchers from the U. S. Army Engineers Engineer Research and Development Center
(ERDC), Vicksburg, MS have continued work with H. pakistanae in the laboratory and field and
they have developed mass rearing capabilities. Mass rearing allows introduction or
augmentation of Hydrellia sp.. Researchers with the ERDC are currently working with the









Florida DEP regarding permits for releasing Hydrellia flies into selected Florida Lakes. In
addition to releasing the flies, there are plans for follow-up monitoring of hydrellia fly
populations and their impact on hydrilla. It should be noted that it might take a number of years
and a number of fly introductions for impacts to be seen and documented.
As research with the hydrellia fly continues, aquatic resource managers in Florida should pay
close attention to results that provide a quantifiable demonstration of the effects of site
augmentation with the flies.

Due to the limited number of classical biological control options available, aquatic resource
managers within the state of Florida should encourage interested agencies (FLDEP, USACOE,
University of Florida) to meet and discuss the feasibility, advisability, and target countries for
renewing overseas searches for biological control organisms on hydrilla. While the performance
of the upcoming hydrellia fly augmentation releases will be monitored, to date, H. pakistanae
has not been indicative of an organism that will provide a predictable level of hydrilla control
necessary to relieve pressure on aquatic managers.

Recommendations

Recommendation 1: Florida Department of Environmental Protection (FDEP) should begin
establishing for each lake/aquatic system receiving significant State of Florida aquatic plant
management funds an initial working group composed of senior FDEP and Florida Fish and
Wildlife Conservation Commission (FWC) staff that is charged with developing a preliminary,
written, aquatic plant management plan. Other appropriate state and federal agencies will be
notified of the formation of this working group and those agencies will be allowed to determine
whom among their staff are best qualified to provide input on the development of the plan. The
plan must consider the principal or planned use of the water body, the optimum sustained use by
the public of the water body's living aquatic resources, and/or sound biological management
principals. The working group must utilize stakeholder input throughout the development of lake
management plans. Finally, the working group shall also determine the historical level of
hydrilla infestation, current status of the hydrilla, and technologies and funding available for
control when determining the minimum feasible level of hydrilla. This must be done with the
recognition that protection of human health, safety, and recreation are mandated by the Florida
legislature when determining minimum feasible levels of hydrilla.

Justification: The Florida Department of Environmental Protection and the Florida Fish and
Wildlife Conservation Commission are the two entities charged by the Legislature to manage
aquatic plants throughout the state of Florida. Senior staffs from these two groups know the
lakes, have extensive experience, and know other pertinent players at each lake. Senior staff of
these agencies in conjunction with appropriate representatives from other local, state, and federal
agencies has the best chance of coming up with a temporary yet workable lake management plan.
These individuals also know the consequences of failure (i.e., legislative involvement) to their
programs. Both the FLDEP and FWC have statewide responsibilities regarding hydrilla
management, therefore, these two groups will be the most knowledgeable regarding the need for
including Water Management Districts, the US Army Corps of Engineers, US Fish and Wildlife
Service, County cooperators, and other groups with a stake in management policies regarding
hydrilla.










Triploid Grass Carp


Throughout the Hydrilla Issues Workshop the use of grass carp as a tool for controlling hydrilla
was mentioned many times. All participants were aware that grass carp are used extensively in
Florida, but some felt it was necessary to reevaluate their use, especially in some of Florida's
larger public lakes (e.g., KCOL) containing abundant populations of Fluridone resistant hydrilla.
This concern was largely driven by the reality that Fluridone resistant hydrilla is consuming a
large portion of the management budget. As these fluridone resistant plants spread they will
consume larger portions of the budget and therefore the need to consider the cost-effectiveness of
grass carp balanced with the potential environmental impact.

Diploid grass carp arrived in Florida and other parts of the country in the early 1970s. Their
arrival caused an explosion of research on their use as an aquatic plant management tool. Today
only sterile triploid grass carp can be used for aquatic plant control. An excellent summary of the
majority of grass carp research for aquatic plant management can be found in the Proceedings of
the Grass Carp Symposium held in Gainesville, Florida (U. S. Army Corps of Engineers 1994).
There were two major consensuses that came from the grass carp symposium that were also
parallel from participants in the Hydrilla Issues Workshop: 1) when stocked in sufficient
densities at a large enough size to avoid predation (approximately > 12 in) grass carp are very
efficient at controlling all submersed aquatic vegetation, and 2) when grass carp are stocked into
a lake at densities high enough to control all submersed aquatic vegetation they are extremely
hard to remove from a system. Thus, if the elimination of submersed aquatic plants is an
acceptable management objective for a lake system, then grass carp are an efficient cost effective
means of aquatic plant control.

Less clear from the Proceedings of the Grass Carp Symposium (U. S. Army Corps of Engineers
1994) and the Hydrilla Issues Workshop is the potential for grass carp to be used after herbicides
have decreased aquatic plant biomass to selectively control regrowth of hydrilla and maintain
moderate levels of native aquatic vegetation. Florida lakes Deer Point, Miccosukee, and Conway
have all been used as success stories at maintaining some submersed vegetation with low levels
of carp controlling hydrilla. However, with the exception of Lake Conway (Leslie et al 1994)
there has not been consistent evaluations and publication of data confirming the successes of
these examples. With a quick literature review we found some more current evidence suggesting
that stocking low levels of grass carps can achieve control of palatable problem species while
maintaining moderate levels of native aquatic vegetation in ponds (Pipalova 2002) and small
impoundments (Blackwell and Murphy 1996).

Contrary to the above findings, Hanlon et al. (2000) examined long-term macrophyte control in
38 Florida lakes using triploid grass carp and found an apparent break point suggesting an all or
nothing control response. These efforts suggest that stocking grass carp between 25 to 30 grass
carp per hectare of vegetation can result in a lake having some plants left (Hanlon et al. 2000).
However, the remaining vegetation will be unpalatable submersed, floating leaf, and emergent
vegetation. Hanlon et al. (2000) also noted that while stocking rates based on the amount of
submersed vegetation provides a "narrow window of opportunity" to control nuisance vegetation
like hydrilla while maintaining some submersed plants it is extremely difficult to achieve a










stocking rate of 25 to 30 grass carp per hectare of vegetation. These rates are difficult to maintain
in individual lakes because of varying grass carp mortality rates, fish mobility, and changing
limnological conditions. When grass carp were stocked at densities greater than 25 to 30 fish per
vegetated hectare the complete control of aquatic vegetation was achieved and lakes stocked
with less than 25 to 30 fish per vegetated hectare tended to have the same or higher amounts of
aquatic vegetation as when the lake was originally stocked. Similar results were found in
Washington State when Bonar et al. (2002) evaluated grass carp stocking in 98 lakes and ponds.
Nineteen months after stocking in the Washington lakes and ponds, submersed macrophytes
were either completely eradicated or not controlled at all with a small percentage (18%)
maintaining an intermediate level of submersed aquatic vegetation. Bonar et al. (2002)
recommended against stocking grass carp in lakes where eradication of submersed vegetation
cannot be tolerated.

Grass carp have been used to control hydrilla in several large systems including Lake Conroe in
Texas (Klussmann et al. 1988), Santee Cooper Reservoir in South Carolina (Kirk et al. 2000),
and Lake Guntersville in Alabama (Webb et al. 1994). In lakes Conroe and Santee Cooper
almost complete control of all submersed aquatic plants was achieved while in Lake Guntersville
hydrilla was reduced for a one to two year period while maintaining moderate levels of other
submersed plants. In Florida, Lake Istokpoga (surface area approximately 12,100 ha) was
stocked with 125,000 grass carp with little or no impact on the abundance of aquatic
macrophytes. The hypothesis is that the grass carp left Lake Istokpoga through outlet canals
before they could impact the hydrilla in the system, however insufficient data were collected to
support this hypothesis. Lake Yale is another large Florida lake (surface area approximately
1,635 ha) where grass carp were used in an attempt to control hydrilla. Initially, the carp were
stocked at low levels (approximately 7/ha or 3/acre) but additional stocking brought that density
to approximately 17/ha (7/acre) where the consumption rate of the carp exceeded the growth rate
of the submersed vegetation. The final result was the complete elimination of submersed and
emergent vegetation (primarily grasses) for several years. It took 4 to 5 years of intense electro-
fishing and other carp removal strategies to bring carp densities to a level where revegetation
efforts once again established littoral vegetation. The cost of these efforts was high and would
suggest that current technologies for grass carp removal are not cost-effective or practical. Thus,
the large lake case histories show a similar trend to the pond and lake studies listed above. Some
large lakes experienced total elimination of submersed aquatic vegetation, some had no reduction
in aquatic plants and there was limited evidence that some level of temporary hydrilla control
can be achieved while maintaining other species of submersed aquatic vegetation.

With little hard evidence that submersed aquatic plant control can be achieved with low density
stocking of grass carp while maintaining some submersed aquatic vegetation, a common warning
in the grass carp literature is the statement that "unless complete elimination of submersed
aquatic vegetation can be tolerated, grass carp stocking is not recommended." Thus, the key to
universal use of grass carp for plant management is to have the ability to develop a cost-effective
strategy to remove the fish from a system if the amount of plant control exceeds target amounts.
Historically, managers have experimented with several methods for removing grass carp from
lake systems including: herding, angling, attracting, use of lift nets, and toxic fish baits
(Schramm and Jirka 1982; Bonar et al. 1993; Mallison et al. 1994). Unfortunately, all techniques










used in the removal studies were time consuming, labor intensive, sometimes quite expensive
and in each case failed to remove a major portion of the carp population. This is especially
important in light of evidence suggesting that it may take only 0.5 carp per acre to maintain
complete control of submersed vegetation regrowth after complete control of submersed
vegetation is achieved (Moxley et al. 1993).

Recently, grass carp have been trained experimentally to come to sound (Willis et al. 2002) and
then after training placed in ponds to evaluate recapture after attracting with sound (Duncan
2002). Another new method for the removal of grass carp from lake systems is the use of
biodegradable capsules containing fish toxicant that could be implanted in the carp and used to
euthanize the fish after a given period of time (Thomas 2004). These and other new methods for
manipulating carp densities could make the grass carp a more useful and acceptable aquatic plant
management tool.

Much more could be written on the volumes of grass carp literature that exists but the brief
summary above covers the major issues brought up at the Hydrilla Issues Workshop.


Recommendations

Recommendation 2: Throughout the literature review, Grass Carp Symposium and the Hydrilla
Issues Workshop it is clear that if there was some cost-effective and selective method of
removing grass carp from a lake system before complete eradication of submersed aquatic
vegetation was accomplished then triploid grass carp would be an excellent method of hydrilla
control for large and small lakes. Therefore, we recommend making funds available for more
research on new techniques for removing grass carp from lakes. Research on this and other
methods may be expensive but a successful method would pay great dividends to aquatic plant
management in Florida lakes.

Comments on the first draft of this report echoed warnings from previous studies suggesting that
if total elimination of aquatic vegetation is unacceptable then the use of grass carp to control
vegetation in large or small lakes should not be considered. However, if research provides an
efficient method to remove grass carp from a lake then it is recommended that this method be
evaluated in a Florida lake requiring aquatic plant control.

Justification: With the onset of resistant hydrilla there are limited tools with which to manage
large infestations of hydrilla that are cost effective and selective. Thus, increased use of grass
carp will likely be a major alternative. Because of the fear of complete removal of submersed
aquatic plants from lake systems, it is imperative that some means of predictably removing grass
carp from systems be obtained.










Current and Future Chemical Management Practices for Hydrilla


The impetus for organizing the Hydrilla Issues Workshop revolved around the phenomenon of
fluridone resistance. As a result much of the dialogue focused on the challenges associated with
managing fluridone-resistant hydrilla (FRH). Discussion related to this issue included current
and past chemical alternatives, as well as the potential for developing new products. In this
section we address current and future chemical management practices, and identify the strengths,
weaknesses, and issues associated with these management strategies. We conclude by making
specific recommendations related to future chemical control efforts.


A Basic Understanding Fluridone Resistance

Within the aquatic plant and resource management communities the challenges associated with
managing FRH have not been well understood. In order to provide background information to a
broad range of resource managers a Symposium on Herbicide Resistance in Aquatics was held at
the Aquatic Plant Management Society Meetings in Tampa, FL in July 2004. The recent Hydrilla
Issues Workshop in December was organized to specifically focus on hydrilla management and
fluridone resistance issues. While there remains much to learn regarding hydrilla and fluridone
resistance, the following statements provide an overview of our current understanding of this
issue:

1. Formerly sensitive populations of hydrilla have developed increased resistance to low
levels of fluridone in numerous Florida lakes. Despite a similar genetic origin for hydrilla
throughout Florida (Madiera et al. 1997), the majority of lakes with "resistance issues" have
a history of fluridone management. While literature is sparse regarding hydrilla and fluridone
resistance, recent publications describing this phenomenon have become available
(MacDonald et. al 2002, Michel et al. 2004, Arias et al. 2005).

2. Fluridone resistance is caused by various point mutations at site 304 in the phytoene
desaturase (PDS) gene, and each point mutation has a different impact on the response of
hydrilla to fluridone (Michel et al. 2004). The fact that adjoining lakes support hydrilla with
different mutations indicates that fluridone resistance has evolved independently at different
sites.

3. The development of fluridone resistance was not predicted by the scientific community
based on the asexual nature of dioecious female hydrilla, and the lack of previous evidence of
resistance to PDS inhibitors such as fluridone. In fact, hydrilla is the first example of a
somatic mutation leading to development of widespread resistance in the field.

4. FRH is currently widespread with populations dominating the Kissimmee Chain of Lakes,
Lake Istokpoga, several Polk County Lakes, and numerous other public and private water
bodies throughout the state. Resistant biotypes of hydrilla are present in lakes that contain
well over 100,000 surface acres of water, and as the critical mass of FRH infestation
increases the threat for continued inter-lake spread of these plants is greatly increased.










5. It has been suggested that it took approximately 14 years for hydrilla to develop resistance
to fluridone. This scenario is based on the registration of fluridone occurring in 1986 and the
documentation of resistance in the year 2000. Evidence from research ponds and various
lakes suggest that selection of resistant biotypes can occur in a much shorter period of time.
For example, large-scale fluridone treatments on Lake Cypress, FL were not initiated until
1996 and the entire 4000-acre lake contained a tolerant biotype by 2000. The complete
dominance of resistant plants on Lake Cypress within 4 years of an initial treatment would
suggest that fluridone resistant strains were established in the lake within a couple of years of
the initial large-scale treatment. While rapid selection for resistant biotypes was inevitable,
the subsequent dominance of these resistant biotypes was likely accelerated by successive
treatments with sub-threshold fluridone concentrations.

6. There is currently no evidence of a "fitness penalty" for the development of fluridone
resistance. This means that FRH is likely to be just as competitive and aggressive as the
sensitive biotypes. Therefore, once resistant plants become established and produce tubers, it
is unlikely that active management, lack of management, or intra-specific competition
between the biotypes will remove the resistant plants from the system.


Use of Fluridone for Control of Resistant Biotypes of Hydrilla

For those individuals with a peripheral involvement in hydrilla management, one of the more
difficult questions to address is why aquatic plant managers continue to use fluridone after
resistance has developed. First and foremost, the number of tools available for hydrilla control is
quite limited, and fluridone and triploid grass carp remain the only tools currently proven to
provide cost-effective control of large-scale hydrilla infestations. In addition, the slow plant
death following a fluridone application is a desirable trait that is often overlooked, and yet from a
wildlife and fisheries, and water quality standpoint, the incremental loss of dense hydrilla over
several months may be one of the most important characteristics of any fluridone treatment,
whether for susceptible or resistant biotypes.

The level of fluridone resistance can vary considerably and therefore, while the term resistance
connotes a qualitative character (i.e. a population is or is not resistant), it is the quantitative
determination of the level of resistance that is more critical to issues such as treatment cost, non-
target plant impacts, and long-term efficacy. Quantifying the sensitivity of a hydrilla population
to fluridone can be determined through intensive sampling and laboratory assay to assist aquatic
managers in determining treatment strategies.

The most resistant strain of hydrilla characterized to date, remains sensitive to fluridone well
within the label's maximum allowable use rate of 150 ppb. One of the key attributes of fluridone
has been its specificity for plants and hence its wide margin of safety for non-target organisms
(invertebrates, fish, and wildlife) up to the maximum use rate. There are also no fishing,
swimming, or potable water use restrictions associated with the use of fluridone up to the
maximum rate of 150 ppb. Therefore, increasing traditional use rates of fluridone from 5 to 10
ppb by 3 to 5 times, while certainly changing the economics of hydrilla control, is not expected










to have a direct adverse impact on invertebrates, fish, wildlife, or recreational uses of the water
body. There will, however, still be indirect impacts because of loss of fish and wildlife habitat.

While resistance has greatly impacted the economics of fluridone treatments, fluridone costs
remain competitive and are generally lower than costs of other chemical techniques when one
considers control on a per vegetated acre basis. Nonetheless, this comparison may not be
appropriate as contact herbicides tend to be applied directly to a densely vegetated priority area,
and therefore control is generally limited to the immediate vicinity of the treatment zone. In
contrast, fluridone tends to be quite long-lived in the water column and will disperse well beyond
the treatment site. This has allowed the use of fluridone to control hydrilla in large areas
throughout a water body. The need to maintain a long-term concentration in the water column
regardless of the plant distribution or density is both a strength and weakness of fluridone.
Fluridone is the only chemical tool that can be used in a cost-effective manner to prevent hydrilla
expansion when plants are widely distributed on a large water body. In contrast, when resistant
hydrilla is concentrated within an area of a large water body, dispersion of residues to areas
without hydrilla or into sites dominated by native vegetation reduces either the cost-effectiveness
or selectivity of the treatment.

The reality of managing resistant hydrilla has greatly reduced the expected longevity of control
following a fluridone treatment. As a result, yearly applications of fluridone have been
conducted since the late 1990s to suppress hydrilla growth during the spring and summer months
in the Kissimmee Chain of Lakes. The greatest challenge in developing treatment strategies is
related to the need to maintain a fluridone concentration above a target threshold for an extended
period of time (Netherland and Getsinger 1995). Initial water levels and water level schedules
can have a dramatic impact on the cost and effectiveness of treatments in large flowing lakes
such as the Kissimmee Chain or Lake Istokpoga. Under the best of conditions (sites with limited
or no flow) the ability to maintain fluridone residue thresholds for over 100 days when targeting
a resistant biotype has proven challenging (see the following section).

Selectivity Concerns

In addition to the significant cost increase and reduced longevity of control created by hydrilla
resistance, adverse impacts to non-target vegetation have also been noted as the use rates have
increased. While the lower use rates of fluridone for control of susceptible hydrilla had minimal
impacts to important native submersed (e.g. vallisneria, Illinois pondweed) and emergent (e.g.
bulrush, knotgrass, maidencane, water lily, spatterdock) vegetation, the higher use rates
necessary to control FRH have shown potential to result in significant injury to several native
species. Unfortunately, the vast majority of published literature regarding the selectivity of
fluridone has been conducted in the northern tier states with an emphasis on submersed aquatic
species (Getsinger et al. 2002). Due to the whole-lake use patterns of fluridone, non-target plant
injury is a significant issue, and the desire to protect native vegetation will likely result in a
practical upper limit on fluridone residues depending on the native communities present in a
given water body. The availability of an accurate immunoassay test for fluridone analysis
(Netherland et al. 2002) has greatly facilitated hydrilla management, and similar sampling
protocols could be used to determine the relation between field residues and non-target impacts.










One of the major concerns regarding fluridone selectivity is based on repeated applications and
increasing use rates of fluridone. Fluridone impacts plants in a unique way, and the bleaching
symptoms tend to be highly visual for the more sensitive emergent species. Intense bleaching at
the new growing points is a symptom of exposure, yet these symptoms do not indicate that plant
death is imminent. While fluridone is often referred to as a systemic herbicide, it is not
translocated in the phloem like glyphosate or 2,4-D (e.g. Rodeo, Weedar), and therefore a long-
term aqueous exposure to fluridone is required to kill even the most sensitive emergent plants. A
short-term exposure to high fluridone residues can result in a severe but temporary bleaching of
new growth that is followed by rapid recovery. In contrast, long-term exposure to near threshold
concentrations can greatly reduce the growth of non-target plants and may eventually result in
death of established emergent plants. While investigations are ongoing, the area of fluridone
selectivity definitely requires further research attention.

It should be noted that regardless of the fluridone use rate, it is unlikely that treatments would
result in a complete loss of vegetation. Higher use rates would likely alter plant competition and
result in a significant shift in the vegetation community from a dominance of native grasses,
lilies, or submersed macrophytes to more tolerant plants such as pickerelweed, smartweed, or the
macrophytic algae Chara or Nitella.

Endothall as a Chemical Alternative

With the onset of fluridone resistance, use of the aquatic herbicide endothall has significantly
increased over the past several years. Endothall has been used for hydrilla control for over 30
years, and unlike fluridone it requires only hours to a few days of exposure to provide control of
hydrilla. Typical use rates for endothall are in the range of 3000 ppb and, therefore, while the
exposure time is greatly reduced, use volumes are in the range of 100 times greater than
fluridone on a per acre basis. The increased volume requirement presents practical limitations to
the amount of Endothall that can be applied. Product volumes, product costs, rapid control of
vegetation, and a 3-day fishing restriction have typically limited the use patterns of endothall to
smaller treatment areas. While endothall provides a strong benefit in small treatment blocks,
there is ongoing discussion of increasing the size of treatment blocks to manage larger
contiguous areas of hydrilla. Regardless of the size of the treatment block, the concentration and
exposure time of endothall in the treatment area remains a critical element in achieving the
desired level and longevity of hydrilla control (Netherland et al. 1991). Endothall currently
represents the key chemical alternative to fluridone in preventing the establishment of new
infestations of hydrilla. In addition, the practice of integrating endothall into fluridone treatments
for control of FRH has enhanced the efficacy of both compounds.

At the present time endothall is typically viewed as a product that provides several weeks to a
few months of relief from hydrilla. _Research is ongoing to improve the longevity of endothall
treatments for use on shoreline strips, boat trails, and large contiguous blocks of hydrilla. With
the spread of FRH, endothall is an indispensable tool for creating access or open water in the
midst of large hydrilla infestations. Despite a significant increase in endothall use for hydrilla
control during the past several years, the literature is sparse regarding improving methods,
treatment timing, or use rates for hydrilla control. The recent development of an immunoassay










for endothall detection in the water column has greatly facilitated both laboratory and field
research efforts. Monitoring treatment timing, formulation differences, and various use rates in
the field is currently ongoing.

Two of the major concerns associated with endothall use are the requirement for posting a 3-day
fishing restriction (fluridone has no use restrictions), and the potential for a rapid decay of plant
biomass that could reduce dissolved oxygen to levels that could result in a fish kill. In December
2004, the registrant submitted data to the USEPA requesting that the 3-day fishing restriction for
Aquathol be removed from the label. While fish kills in association with herbicide applications
on large public water bodies have been rare, a cautious approach is still warranted. The timing of
application (e.g. water temperature) and the density of the target vegetation at the time of
treatment are likely the most significant variables that will determine if there is a potential for
significant oxygen depletion. Reduced efficacy of endothall over time has also been noted as a
significant concern. While these observations remain anecdotal research into potential tolerant
strains of hydrilla and enhanced environmental degradation are ongoing.

In regards to plant selectivity, the nature of endothall degradation and the use patterns favor the
selective use of this product. While endothall use rates are typically in the range of 3000 ppb, the
molecule is rapidly degraded by microbial action. In addition, use patterns typically result in the
treatment of smaller areas within large lake systems. Rapid dispersion and degradation result in
minimal exposure of plants outside of the treatment zone. Submersed applications of endothall
do not tend to have impacts on emergent vegetation (Skogerboe and Getsinger 2001). Vallisneria
and macrophytic algae tend to thrive following endothall applications, while Illinois pondweed
and naiads tend to be fairly sensitive.

Contact Treatment Strategies

Within the Harris Chain of Lakes (Griffin, Eustis, Harris), the Saint Johns Water Management
District, Lake County Mosquito and Aquatic Plant Management, and the FDEP have
implemented an intensive surveillance and spot treatment strategy with endothall to prevent
hydrilla from expanding within these systems. The recent expansion of hydrilla in these large
lakes has been attributed to improved water clarity. The management response has been to
greatly increase surveillance using a variety of people (agency personnel, contractors, and the
public) to locate and map new hydrilla infestations. Spot treatment strategies are rapidly
implemented to prevent further spread, and follow up visits are made to insure treatment
efficacy. This approach has been effective for these systems; however, there may be unique
features of these lakes that favor this strategy.

Hydrilla within the Harris Chain of Lakes represents small pioneer infestations that may be
deterred from rapid expansion by the shading activities of intense phytoplankton blooms.
Recovery of hydrilla following the small contact herbicide operations is likely hindered by the
reduced water clarity provided by these blooms. Furthermore, the plants in the Harris Chain of
Lakes are susceptible to fluridone, so any large-scale recovery of hydrilla could be set back using
a low rate and cost-effective fluridone treatment. In contrast, hydrilla growing in the Kissimmee
Chain of Lakes or Lake Istokpoga is widespread and past growth has not generally been










constrained by phytoplankton blooms. In these systems water quality conditions following a
contact treatment are often favorable for rapid recovery of any plant tissue that survives the
initial herbicide application. In addition, this hydrilla has an increased resistance to fluridone,
and the inability to manage growth with contacts through the spring could lead to a situation of
widespread hydrilla coverage and inability to implement whole-lake management strategies
under conditions of high biomass and high precipitation and flow during the summer months.

It is interesting to note that through the spring of 2005 hydrilla infestations on the Kissimmee
Chain of Lakes, Lake Istokpoga, and Lake Weohyakapka are greatly reduced following the
intense disturbance from hurricanes in the summer of 2004. This has led to the suggestion that a
greater emphasis should be placed on surveillance and spot control for hydrilla management on
these sites. In addition, the current situation of highly colored water on these lakes is a strong
deterrent to hydrilla recovery due to markedly reduced light penetration into the water column.
The combination of highly stained water and low hydrilla biomass in the spring of 2005 may
allow for the successful implementation of the surveillance/spot treatment strategy through the
summer and fall of 2005. While a surveillance and spot treatment strategy may represent a
sound management program as long as current low biomass and water clarity conditions exist,
most aquatic managers recognize that these conditions can change rapidly. As water clarity
improves and sprouting hydrilla tubers survive over thousands of contiguous acres, maintaining
hydrilla control with a surveillance/spot treatment strategy will be greatly complicated. The
current example illustrates that need for aquatic plant managers to use prevailing conditions to
their advantage when implementing hydrilla control strategies.

Current State Policy on the Use of Copper-based Products

In the late 1980s and early 1990s the State of Florida began moving away from the use of
copper-based products for hydrilla control in natural water bodies throughout the state. A policy
was implemented regarding copper use in manatee aggregation areas, but this soon became the
standard for the majority of natural water bodies. While copper use has not been banned as part
of the state program, its use is generally limited to urban and artificial water bodies that are
considered degraded. Within the state program, copper is sometimes used in combination with
diquat in areas around boat ramps where retention time is often very limited due to the small size
of the treatment. Despite considerable debate regarding the fate and toxicology of copper that is
bound to the bottom sediments, it is not disputed that each application results in further
accumulation of copper in the sediment. A 1992 workshop held at the University of Florida was
organized to present information on the bioavailability and toxicity of copper (Joyce 1992).
Several opposing viewpoints were expressed regarding copper toxicity to non-target organisms
and the bioavailability of copper bound to sediments. Despite the passage of over 12 years, the
major issues associated with copper use remain largely unchanged.

FDEP has taken the stance that copper should not be used if reasonable alternatives exist. The
major concern expressed over the use of copper was the need for multiple treatments and hence
an impact on the accumulation of copper in the sediments. Given the recognition that FRH has
become widespread, there is some question as to whether the state should consider the use of
copper on a limited basis as a rotation tool for endothall. The combination of diquat and copper










has been a standard treatment for hydrilla in other parts of the country, and the efficacy of this
combination is not in question. The amount of copper necessary to enhance diquat activity is
currently not well defined, and studies along these lines could prove valuable in allowing
recommendations of reduced copper rates for improved hydrilla control. This approach would
seek to use the minimal amount of copper necessary to control hydrilla. It should be noted that
low rates of copper might also enhance the activity of endothall or fluridone.


Potential Development of Alternative modes of action

During the course of the Hydrilla Issues Workshop, the need for development of alternative
modes of action was discussed. While many in attendance viewed this as an industry
responsibility, two alternatives were presented that would allow state and federal agencies and
university personnel to become more integrally involved in the process of registering products
for aquatic use. The two alternatives proposed included cooperation with the USDA IR-4
program and the potential for a state agency within Florida to explore a third party registration.

The USDA IR-4 program was initiated in response to the loss and lack of products available for
minor use markets (e.g. vegetables, horticulture). While industry was generally averse to
investing extra money to develop products in these niche markets, they were willing to move into
these markets. With the consent of an industry partner, the IR-4 program helped to develop data
requirements that would support a new product use in minor markets. These data were then
submitted to the Environmental Protection Agency for registration of the product in the minor
use market. The end-user benefited as a new tool became available for their industry. It is worth
noting that in several cases, IR-4 has helped to develop new tools in response to resistance issues
in minor use markets. Current discussions are ongoing within the IR-4 program on how best to
include the field of aquatic plant control.

One area where IR-4 could be particularly helpful would be in the development of food crop
tolerances (i.e. the maximum amount allowed in commodities) that would reduce the restrictions
on new and existing aquatic products. For example the irrigation restrictions on the recently
registered products triclopyr and imazapyr are largely driven by a lack of tolerances in food
crops. Development of these tolerances would be aligned with the IR-4 mission, and would
provide greater flexibility for use of chemical tools in aquatics.

Third party registration would involve the FDEP or another governmental agency becoming
involved in registering a product for their exclusive use for hydrilla control. While close
cooperation with Industry would be required, precedent for this arrangement has been set by the
Florida Fruit and Vegetable Growers Association (they have several third party registrations),
and by the Florida Tropical Fish Farmers Association. This approach could provide an incentive
for evaluating off-patent compounds. At the present time there is little incentive for researchers
to screen off-patent herbicides, as it is very unlikely that industry would be willing to consider
investing several million dollars in such a project. While this would be a non-traditional
approach, there are numerous scenarios where private industry and government could work
together to develop new tools for the aquatic market.










One of the greatest challenges to the research community and industry is identifying desirable
attributes for a new product in the aquatic market. Despite the large number of products available
in terrestrial agriculture, there are actually very few herbicides that would have a good fit within
the aquatic market. Some of the key attributes that have been identified include the following:

1. A compound must have a very strong toxicology package for mammalian, bird, fish, and
invertebrate organisms. This requirement eliminates many families of herbicides from
consideration. Water use restrictions (e.g. fishing, drinking water, etc.) are generally
undesirable and are largely based on the toxicological properties of the compound.

2. A compound must provide a high level of selective control for hydrilla.

3. A compound with a long residual in the water column and an alternate site of action
compared to fluridone represents a strong candidate.

4. A compound with a short residual in the water column and systemic activity on hydrilla
would be highly desirable.

5. Products that result in a slow pattern of plant death (e.g. like fluridone) would be
beneficial from a water quality standpoint.

6. The product should be easy to apply, cost-effective, safe for applicator handling, and
preferably used at low volumes.

The Development of Acetolactate Synthesis inhibitors as an alternative to Fluridone

There was considerable interest expressed at the workshop regarding the development of new
herbicides for aquatic use. Acetolactase synthesis (ALS) inhibitors currently show strong
potential to control hydrilla at low use rates. These compounds block the formation of essential
branched-chain amino acids in plants. The ALS enzyme system is unique to plants, therefore
non-target toxicity of these compounds is very low. Preliminary evaluations indicate that several
ALS inhibitors are active on hydrilla at rates in the low part per billion ranges. Due to the low
use rates, activity on a specific plant enzyme, and impact on the new growth of hydrilla it is
likely that ALS chemistry would have a very similar use pattern to fluridone. The maintenance of
low concentrations over a long period of time will be critical to the efficacy of an ALS inhibitor.
While the issues of potential resistance development and use of water for irrigation have been
discussed, the need to evaluate new modes of action is deemed the more critical issue at this
point in time. In regards to the selectivity of ALS chemistry, research is ongoing at the
greenhouse and field scale. The herbicides penoxsulam and imazamox recently received
Experimental Use Permits from the EPA for up to 500 acres of water in Florida. Both
compounds are expected to provide good control of hydrilla at low use rates. Several use sites
have been identified for evaluation in the spring and summer of 2005.










Recommendations


Recommendation 3: Based on the extent of Fluridone resistant hydrilla (FRH), the
identification and development of new herbicides for hydrilla control is critical. FDEP should
immediately re-invigorate Florida's chemical research programs for aquatic plant management
programs. FDEP should lead by obtaining needed state and federal funding (goal 10% of State of
Florida's existing activities budget), and entering into agreements with universities, federal
agencies or private entities for research and the development of new or improved aquatic plant
control methods. In addition to the USEPA data requirements for the registration of a new
product, a thorough evaluation of the efficacy and selectivity of a new herbicide will be critical
prior to recommending its use on large public water bodies.

Justification: The inability to develop new tools for hydrilla control will result in further spread
of FRH and this will greatly compromise the ability of the FDEP and its cooperators to manage
hydrilla throughout the state. The best strategy for resistance management is the development of
multiple tools that can be rotated. To conduct the appropriate research, funding is needed. FDEP
provided research funding in the 1980s (FS 369.20(4)(b)) and the State of Florida got a good
return on investment. Therefore, a good argument can be made to the Florida Legislature for
increased research funding. As the largest purchaser of aquatic herbicides in the world, the FDEP
and other end-users should make it clear to Industry that new tools would be welcomed and
integrated in to their existing program. The increased reliance on endothall as the sole chemical
alternative to fluridone may result in future problems with endothall efficacy. Finally, the
addition of new aquatic products could provide enhanced benefits to the state for control of
aquatic invasive species other than hydrilla.

Recommendation 4: There is a strong need to improve our ability to quantify the impact that
fluridone or other lake management techniques are having on key non-target plant species.
Methodologies for collecting reliable and useful field data need to be worked out between
responsible agencies so results can be compared across both managed and unmanaged water
bodies and sites treated at different fluridone use rates.

Justification: While increasing fluridone use rates does not pose a direct threat to non-plant
organisms, the potential loss or severe reduction of a key individual plant species is a legitimate
concern that requires improved data collection to support future decision-making. The bleaching
symptoms following a fluridone application are quite visual, and conclusions on the ultimate
impact to these native plants are often anecdotal and based on a bias regarding fluridone use for
whole-lake management. There has been little or no quantitative assessment of the impact to
native submersed and emergent vegetation following increased use rates of fluridone. While
laboratory and mesocosm data for non-target native plants are currently being generated, these
data need to be put in the context of actual field results. The FWC has conducted some initial
field monitoring, but these efforts have generally been limited and have remained internal.

Recommendation 5: For sites where the hydrilla remains susceptible to fluridone, consecutive
year applications are discouraged. It is also crucial that resistance management strategies be
developed to prevent FRH from developing a dual resistance to another mode of action.










Justification: Fluridone has proven its utility in providing large-scale hydrilla control, and a
successful treatment should greatly reduce the need to conduct an application the following the
year. In situations where adequate control is not achieved, aquatic managers need to determine
the basis for this reduced efficacy (e.g. increased herbicide resistance, loss of residues to flow,
enhanced degradation). Based on the widespread coverage of FRH on the Kissimmee Chain of
Lakes and several other large lake systems, it is apparent that sequential applications of fluridone
can ultimately facilitate the lake-wide expansion of resistant biotypes.

ALS chemistry represents a potential new tool that could be rotated with fluridone for control of
susceptible hydrilla. In the case of FRH, management with an ALS herbicide will be
complicated the fact that managers will be treating plants that have already developed a
resistance to one mode of action. For sites already dominated by FRH, management strategies
need to be considered to prevent development of a dual resistance to both fluridone and ALS
inhibitors. This issue suggests that more than one new mode of action is needed for the long-term
control of hydrilla.


Recommendation 6: In addition to considering rotation schemes with fluridone, aquatic
managers also need a contact product that can be rotated with Aquathol. There are currently no
new contact products being considered for registration. In order to provide a new tool that
would be available for immediate use of combinations of products should be further evaluated. .
We recommend that copper only be considered for hydrilla control when used in combination
with the herbicide diquat or other registered herbicides. Research should be conducted to
determine if low rates of products such as the dimethyalklyamine formulation of endothall or
hydrogen peroxide can enhance the activity of diquat or endothall for spot control of hydrilla..
As the treatment of new infestations is the top FDEP priority for hydrilla control, addition of a
new contact product would provide a highly useful tool to address this priority.

Justification: Endothall is the only contact product in wide-scale use in Florida public waters,
and this complete reliance on a single contact herbicide does not represent a good resistance
management strategy. There are many cases where multiple applications of endothall are being
applied in the same areas. In lieu of waiting for a new contact herbicide registration (this could
be years away), aquatic managers are encouraged to support research that evaluates the use of
combination products to provide enhanced control and the ability to rotate products.

Recommendation 7: When possible, intense but small-scale management of hydrilla is
preferable to large-scale whole-lake management efforts. In the case of larger lakes, this requires
a considerable commitment to surveillance, sound reporting of the exact locations and size of
hydrilla infestations, rapid action, and aquatic managers who can make decisions on the optimal
treatment recommendations for insuring that small infestations are not allowed to spread. This
recommendation fits with the current priority list of the FDEP regarding intense management of
new finds, and this strategy should be employed to delay the spread of hydrilla, especially
resistant strains.










Justification: When practiced properly, this form of management most resembles the highly
successful water hyacinth maintenance control program and it represents the best use of limited
state resources and manpower. Preventing the establishment and dominance of hydrilla in water
bodies with abundant native vegetation is the best management practice both in terms of cost-
effectiveness and selectivity. If hydrilla can no longer be controlled in this manner, then whole-
lake options should be considered. Experience suggests that once hydrilla has been allowed to
cover a water body, it is likely that whole-lake management will be required for multiple years to
keep the plants under control. This increases both the long-term cost and the likelihood of
resistance development.

Water Regulation Schedules and the Use of Fluridone

Water regulation schedules for the Kissimmee Chain of Lakes (Lake Tohopekaliga, Lake
Cypress, Lake Hatchineha, and Lake Kissimmee) and Lake Istokpoga received considerable
attention at the Hydrilla Issues Workshop. This discussion was based on the direct linkage
between water levels and release schedules, and the cost-effectiveness and overall efficacy of
fluridone when managing FRH. It is important to note that the issue of regulation schedules and
deviation requests is currently unique to fluridone applications, as other management practices
are not typically impacted by regulation schedules. The participation of state and federal water
managers with engineering backgrounds greatly facilitated the discussion addressing water
regulation schedules and issues related to hydrilla and hydrilla control at the Workshop. The
interaction of the engineers with field biologists, researchers, and resource managers focused
mainly on the large flood control lakes noted above. In this section we provide an overview of
the situation, describe issues associated with fluridone use and water schedules, discuss hydrilla
in relation to flood control, and provide recommendations for future work in this area.

The Kissimmee Chain of Lakes (KCOL) often refers to the lakes regulated by the seven existing
regulation schedules for lakes upstream of the S-65 structure on Lake Kissimmee. The following
lakes are regulated under these seven regulation schedules in the Kissimmee River Lake
Istokpoga Basin Water Control Plan:
a. Lakes Kissimmee, Hatchineha, and Cypress
b. Lake Tohopekaliga
c. East Lake Tohopekaliga, Fell's Cove, and Lake Ajay
d. Lakes Hart and Mary Jane
e. Lakes Joel, Myrtle, and Preston
f. Alligator Chain of Lakes (Alligator, Brick, Lizze, Coon, Center, and Trout)
g. Lake Gentry.

The vast majority of hydrilla problems, large-scale fluridone treatments, and issues with FRH
have occurred on Lakes Tohopekaliga, Hatchineha, Cypress, and Kissimmee. Yet the proximity
of lakes that contain FRH to upstream sites that are regulated by control structures is a cause for
concern. In addition to the potential spread of FRH into these upstream lakes, water flows
through these lakes can have a strong impact on downstream whole-lake herbicide applications.
For brevity, subsequent reference in this section to the Kissimmee Chain of Lakes will be limited
to the four large lakes noted above.










Large Lake Situations


Lakes Tohopekaliga, Cypress, Hatchineha, and Istokpoga have shown the capacity to support
thousands of contiguous acres of hydrilla, with historic infestation levels from the late 1980s to
the 2000s noted as high as 60 to 90 percent of the surface acreage on individual water bodies. In
response to the potential for hydrilla to overwhelm these systems, management on these multi-
purpose use lakes represents a large percentage (up to 65%) of the FDEP aquatic plant
management budget. The increased reliance on fluridone for use on the KCOL and Istokpoga in
the 1990s was a function of the magnitude of the hydrilla problem, increased funding availability
to the FDEP, public pressure to greatly reduce the hydrilla, and early success with several large-
scale applications. It is now documented that each of these lakes is dominated by FRH, and this
has greatly increased the costs and technical challenges of managing hydrilla in these systems. If
left unmanaged, there is a high likelihood that some or all of these lakes could support sustained
and dense infestations of hydrilla that would have detrimental impacts on recreational use, access
for navigation, tourism, real estate values, native plant communities, water quality, fisheries, and
flood control. Given the history of dense hydrilla coverage on these lakes, some level of hydrilla
management is necessary if these systems are to serve their multi-purpose functions.

The relationship between water regulation schedules and the management of FRH has become a
complex topic that could, and probably will, justify its own workshop. As the authors of this
document all have biology/limnology backgrounds, we will not make any recommendations
regarding water schedules, as our suggested changes would likely have unforeseen impacts on
other important uses of the water. We have therefore chosen to focus on the two major areas of
debate that came out of the recent workshop. It is important that the readers of this document
distinguish between 1) the issue of hydrilla control as it relates to regulation water schedules, and
2) the presence of dense hydrilla as a potential threat to flooding and flood control structures.

It is instructive to use the circumstances of 2004, to highlight how management philosophies
impact different views of hydrilla control on the KCOL. After lowering the lake levels due to
implementation of the Lake Tohopekaliga extreme drawdown,, a significant fluridone treatment
(low water levels and low flow), and three successive hurricanes that impacted the KCOL in
2004, it is apparent that the current level of hydrilla biomass is much lower than recent historical
levels. While hydrilla can be found throughout the lakes, it is sparse, and could hardly be
considered problematic at the end of 2004. The length of time it will take to become problematic
again cannot be predicted. There is one management viewpoint that says now is the time to take
advantage of the low biomass and prevent the hydrilla from recovering. Another management
viewpoint suggests that given the current level of infestation, large-scale management is not
justified. These are honest differences of opinion; however, it is important that each group seeks
to understand the other's point of view. With or without management, it is apparent that hydrilla
will continue to persist and cause problems in the KCOL for the foreseeable future. Therefore
we are forced to debate the optimal amount of hydrilla and management effort that allows these
lakes to serve their multi-function purpose.










Hvdrilla Control in Relation to Regulation Schedules for Water


Based on comments of various agency personnel participating in this meeting, water regulation
schedules are based on the multi-purpose function of these lakes and they encompass a wide
range of uses including flood control, irrigation, downstream water delivery to the Kissimmee
flood plain, habitat for fish and wildlife, and endangered species issues. One of the major
concerns voiced by many participants was the increased frequency of deviation requests to
support fluridone applications in the KCOL and Lake Istokpoga. Requests for deviations have
become a yearly event, and they have coincided with the spread of FRH in these systems.

The current practice of FDEP requesting temporary water schedule deviations to reduce water
levels and flow on the Kissimmee Chain or Istokpoga has strong merit when viewed solely in the
context of improving the cost-effectiveness and efficacy of a fluridone treatment for hydrilla
control (Table la and lb). Due to the need to "maintain" much higher residues than in the past,
this table reflects only the initial cost of treatment, and not the additional applications needed to
sustain a target concentration.

It has been suggested that timing of the fluridone treatments be changed to increase compatibility
of the treatments with regulation schedules. Regardless of the susceptibility of the hydrilla, it is
well established that late winter or early spring is the optimal time to initiate fluridone
applications. This treatment timing coincides with a period of low initial biomass and rapid
growth as the plants start to emerge from the cool water temperatures and short days of the
winter. Initiation of deviations will therefore typically be desired during the months of January
through April, and limiting discharges from lakes may be desired as late as July. Requests to the
US Army Corps of Engineers for a deviation should be made from several months to a year prior
to the desired deviation start date in order to allow time for the proposed deviation to be
developed, coordinated, and evaluated. Based on experience with attempting to control dense
stands of hydrilla on other systems, initiating large-scale fluridone treatments outside of the time-
frames noted above are not recommended regardless of the water level and flow conditions. In
situations where hydrilla biomass is low and active growth is occurring, treatment timing is not
as critical.



Table la. The impact of initial water levels on the amount of fluridone required to achieve an
initial target concentration on West Lake Tohopekaliga.


West Lake Number of Lbs of ~ Initial
Tohopekaliga Acre- Feet Fluridone to Product Cost to
Achieve an Achieve 30 ppb
initial 30 ppb
Full Volume 151,000 12,292 $3.0 Million
-1.0 Ft. Volume 131,000 10,664 $2.6 Million
-2.5 Ft. Volume 102,000 8,303 $2.0 Million










Table lb. The impact of water discharge rates on the amount of fluridone lost from Lake
Tohopekaliga on a daily basis. The cost and lbs of fluridone loss values are approximate.

West Lake Discharge of Discharge of Discharge of Discharge of
Tohopekaliga 100 CFS 250 CFS 500 CFS 1000 CFS
Lbs of 16 lbs / Day 40 lbs /Day 80 lbs /Day 160 lbs / Day
Fluridone Loss/
Day
Cost / Day $4000 $10,000 $20,000 $40,000
Lbs of 480 lbs/ Mo. 1200 lbs/ Mo. 2400 lbs/ Mo. $4800 lbs/Mo.
Fluridone Loss/
Month
Cost/ Month $120,000 300,000 $600,000 $1,200,000


Prior to the onset of FRH, management of susceptible strains of hydrilla, although complicated
by high water levels and flow, was technically feasible due to the ability to maintain threshold
concentrations over a long period of time. The following graph illustrates why FRH presents a
significant technical and economic challenge in comparison to previously susceptible strains of
hydrilla (Figure 1). The maintenance of threshold concentrations of fluridone for controlling
FRH is greatly complicated by high initial water levels, and inflow and outflow through the lake.
While improved control of FRH would result if water levels and flow were optimal, there is no
indication that such treatments would provide long-term control (greater than 1 season) of
hydrilla. The continued use of fluridone on these systems also increases the risk of selecting for
hydrilla biotypes with an even greater level of resistance.

As noted above, the onset of FRH has resulted in a significant decrease in the longevity of
hydrilla control following fluridone applications. For example, while control efforts on Lake
Istokpoga used to be conducted every other year, fluridone treatments have been initiated for the
past 3 consecutive years due to the quicker recovery by the FRH. The resistance issue has
created a cycle that has resulted in reduced long-term efficacy, and yet the need for more
frequent treatments at higher rates is necessary to achieve FDEP program goals of managing
hydrilla to the lowest feasible level. While this presents a conundrum, it is obvious from the
Workshop that current alternative tools are either limited in their ability to provide cost-effective
control on a large scale, or they are not proven to provide selective control on a large-scale basis.

The issue of what new regulation schedules may be implemented in the future to facilitate
hydrilla control is beyond the scope of this document. Currently it is expected that revised
regulation schedules for some or all of the lakes of the Kissimmee Chain will be developed
through the KCOL Long-Term Management Plan, and that these revised schedules may be
implemented in late 2007 or later. The need for control of hydrilla should be considered in
developing some or all of the revised schedules. Before new regulation schedules for
Kissimmee Basin lakes are implemented which adequately facilitate hydrilla treatments, the
choice facing plant managers would seem to be one of changing management tools and learning
















35

30

- 25
0.
o.
20

*- 15

. 10


Profile of Multiple Fluridone Applications
For Control of a Resistant Strain of Hydrilla


0 14 28 42 56 70 84 98 112 126 140 154 168 182 196 210

Profile of Multiple Fluridone Applications
for Control of Sensitive Hydrilla


0 14 28 42 56 70 84 98 112 126 140 154 168 182 196 210


Days After Treatment


Figure 1. Hypothetical Fluridone treatment scenarios for control of a resistant and susceptible population of
hydrilla. Yellow shaded areas represent concentration thresholds below which fluridone is no longer phototoxic to
hydrilla. The large X's represent additional bump treatments required to maintain residues above thresholds.



to live with more hydrilla, requesting temporary deviations to facilitate hydrilla treatments,
increasing funds available to compensate for high water and flow, or living with the control that
is achievable with a fixed budget and existing regulation schedules. Stakeholder comments will
be an important part of this process.










It is important to note, that as future new chemistries are developed, there is a good possibility
that some of these products will require a prolonged exposure period to provide optimal control
of hydrilla. Therefore, while the current issue of water regulation schedules is unique to
fluridone, water regulation management in relation to new products may be a topic for future
discussion. It is therefore important that upcoming discussions and long-term management plans
regarding regulation schedules be broadened beyond the issue of fluridone.

Lake Specific Issues

Topics that deserve special note include the impacts of hydrilla management on endangered
species (specifically snail kites), the use of water for irrigation from Lake Istokpoga, and the
potential for enhanced degradation of fluridone. The snail kite and irrigation issues are tied to
water regulation schedules and deviation requests to support fluridone treatments. Enhanced
degradation has not been a common observation, but it is a new phenomenon that has been
observed to negatively impact some fluridone applications.

Large-scale hydrilla control efforts can include the potential for indirect adverse effects to the
endangered snail kite (Rosthamus sociabilisplumbeus). These impacts are largely related to
water deviation requests that can impact nesting success of the snail kite. Lowering water levels
at a different rate at certain times of the year can cause nests to collapse. In the Kissimmee
Chain of Lakes nests are more frequently constructed in herbaceous vegetation that is more
susceptible to collapse. Snail kites must nest over water to help support the vegetative structure
below the nest and to reduce predation of the nests by terrestrial predators. Another potential
indirect impact results from the actual herbicide application activities. Snail kite biologists and
aquatic plant managers have recently begun coordinating to exchange information on the
location of active nests in order to create buffer zones that prevent disturbance of the nest. From
a longer-term perspective, the use of higher rates of fluridone could impact the composition of
emergent vegetation in the littoral zone of lakes. However, it is not known if these impacts
would have a negative or positive effect in terms of snail kite habitat.

Although non-target plant injury has become a greater long-term concern, there is no evidence of
emergent plants rapidly succumbing to fluridone treatments early in the course of an application
when snail kites are beginning to establish nests. While improved data regarding non-target
species susceptibility, rapid collapse of emergent plants is inconsistent with the use of fluridone.
The issue of the impact of sustained dense infestations of hydrilla on organisms such as the snail
kite, apple snail, and native vegetation, while important, did not generate much discussion in the
Workshop.

Concerns with snail kite nesting on Lake Istokpoga are minimal, yet there is fairly extensive use
of Istokpoga water for irrigation of crops. With presence of FRH in some sections of Istokpoga
requiring higher fluridone use rates for control, it has become increasingly important for
management plans with fluridone in Istokpoga to address potential exposure of certain sensitive
crops to herbicide residues in irrigation water above the 1 ppb limit described on labels for
fluridone herbicides. There have been no irrigation problems reported with the past use of
fluridone in Lake Istokpoga, yet the increasing use rates due to the presence of FRH can cause a










potential conflict between fluridone residues necessary to control hydrilla, and residue levels that
could result in phytotoxicity to sensitive crops. Treatments conducted in the spring of 2005
resulted in fluridone residues in the outlet canal water that feeds an extensive irrigation network.
In response, the FLDEP used large quantities of powder activated carbon applied from a boat and
drip system to reduce these residues in the irrigation canal water. The rapid degradation of
fluridone following the spring 2005 treatments in Lake Istokpoga and decisions to halt further
treatments, prevented any further potential issues with fluridone residues in irrigation source
water. This situation did point out that Lake Istokpoga is an important source of agricultural
water, and any future treatment recommendations need to consider this critical use of the water.

In the last three years, there have been sporadic events of rapid loss of fluridone in an isolated
number of Florida lakes treated for control of FRH. While fluridone loss is often influenced by
typical environmental variables such as flow and water quality, studies have determined a factor
in this phenomenon is enhanced degradation of fluridone by a microbial agentss. Since this
discovery, investigations have been ongoing to determine the causative agents) responsible for
enhanced degradation and the environmental factors that trigger such events. While research
efforts by industry and government scientists have provided some understanding of this
phenomenon and informed managers on potential improved strategies for fluridone use, results
to date have demonstrated that the processes involved are complex and difficult to study under
laboratory and field conditions. Ongoing research continues to examine processes affecting
fluridone dissipation and potential mitigation techniques to address confirmed events of
enhanced microbial degradation.

Fluridone treatments conducted in the spring of 2005 resulted in a rapid loss of residue in both
the Kissimmee Chain of Lakes and Lake Istokpoga. Operational plans called for several split
applications to maintain a target threshold of fluridone on the lakes; however, residues dropped
rapidly and the ability to maintain these thresholds was compromised by the rapid half-lives
observed early in the treatment cycle. Due to the rapid loss of fluridone in these systems,
additional treatments were halted. There are numerous variables that contribute to fluridone
dissipation/degradation, yet the enhanced loss of fluridone residues in the Spring of 2005 is still
under investigation.

Hydrilla as a Threat to Flood Control

There was considerable debate at the Hydrilla Workshop regarding the potential for hydrilla to
threaten the flood control function on the KCOL and Lake Istokpoga. While there was a strong
divergence of opinion regarding the nature of this threat, it was apparent that there are more
unknowns than knowns. When the structures were placed on the KCOL and Lake Istokpoga,
these lakes did not support hydrilla, and it was likely unforeseen by resource managers that
hydrilla could occupy thousands of contiguous acres on these lakes. The potential threat, if any,
that hydrilla poses to flood control problems is a key question, as one of the main justifications
for the intense management of hydrilla on the KCOL and Lake Istokpoga is largely predicated on
the potential of dense hydrilla to pose an increased threat of flooding. The need to manage
hydrilla on a large scale obviously ties back in to the requests for water schedule deviations on
an annual basis.










In regards to hydrilla and flood control, there were two major questions posed to the engineers
that attended the workshop. First, at what level of infestation would hydrilla potentially pose a
threat to the ability to move water downstream, and hence the flood control function on the
KCOL or Lake Istokpoga? The second question involved the dense growth of hydrilla near the
structures, and the threat of a large mass of plants jamming against structure. There were no
definitive answers to either of these questions, although there were several lines of interesting
discussion both within and outside of the formal session. The following issues were discussed:

1. Within the KCOL, Lake Tohopekaliga and Kissimmee contain water control structures
while Lakes Cypress and Hatchineha do not have water control structures associated with
them. Should we view these lakes differently in terms management practices and the
threat of hydrilla to impact flood control?

2. The potential for placing a structure between Lake Hatchineha and Lake Kissimmee
was discussed. This structure would allow increased latitude to manipulate water levels
on individual lakes and could facilitate and isolate the impacts of future fluridone
treatments as well as drawdowns.

3. There are contingency plans in place to remove debris that may become lodged against
structures on Lake Tohopekaliga and Kissimmee. There was discussion as to whether
these plans are adequate in terms of a severe hydrilla infestation.

4. While it is well documented that submersed plant growth in canals create resistance to
water flow and thereby increase the chance of flooding, it was unclear if this principle
applies to larger lakes. Given the large size of Lake Tohopekaliga, Kissimmee, and
Istokpoga in relation to the small structures, it was asked if plants could create enough
resistance to flow to prevent downstream water movement?

5. It was noted during the Workshop that there is not an extensive history of submersed
plants impacting structures (flood control, bridges) in the State of Florida. While floating
plants have impacted structures, there is not sufficient experience with submersed plants
to make a definitive statement regarding the threat they pose.

The only engineering opinion that presently exists regarding the potential impact that rooted
aquatic plants could have on flood control was conducted for Lake Istokpoga and was authored
by Howard L. Searcy consulting engineers in July 1993 (Contract # C-3019 for the South Florida
Water Management District). The authors ran simulation models (FEMA/SURGE model) that
included the presence of two different levels of hydrilla infestation. The model represented
rooted macrophytes for potential friction losses, modified bathymetry, partial blockages, or total
blockage. The worst-case plant scenario was a 50% lake infestation of 13,000 acres, and the
other scenario included hydrilla occupying up to 2000 acres of Lake Istokpoga. The model
results indicated that the higher levels of hydrilla could nearly double the flooding threat in
comparison to the lower density hydrilla from 3.4 to 7.1 feet above regulation following a 100-
year flood event. This differential was reduced from 3.2 to 5.3 feet for a 50-year event, and
further reduced from 1.9 to 2.3 feet for a 10-year event. The model would suggest that the










increased flooding threat posed by a 100-year storm is significant in comparison to the relatively
minor threat for a 5 or 10-year flood. The validity of this model is not well known, and it will be
the topic of future discussions. Future modeling will need to take into account a much greater
range of hydrilla acreage (2000 to 25,000 acres), as well as location of the infestations within the
lake. The conclusions from this model would tend to support both intense management based on
the 100-year flood risk, as well as reduced management based on the 10-year flood risk.

Recommendations

Recommendation 8: A formal request will be made to appropriate Water Management
Districts for a detailed response as to the threat hydrilla causes to flood control. This inquiry
should include all water bodies where FLDEP Aquatic Plant funds are likely to be spent to
reduce hydrilla. The response should include an engineering assessment of the amount and
locations of hydrilla that could create an increased risk of flooding. Once such a response is
formulated, aquatic plant managers can develop plans to insure that hydrilla is managed in
critical areas that represent an increased risk of flooding.

Justification: It was apparent from the workshop that the threat hydrilla poses to the flood
control function of these lakes is not well understood. For FDEP to consider changing
management practices on these lakes, there needs to be a clear understanding of the implications
of leaving high levels of hydrilla in the system. While it was noted that mechanical measures are
in place to deal with plants becoming lodged in the structure (track hoes or draglines), it was
unclear if these plans take into account a large infestation.

Recommendation 9: As it is likely that new herbicides may require an extended exposure
period, it is recommended that an assessment of regulation schedules take into account the
improved economics and efficacy that reduced water levels and flow can afford. In lieu of
deviation requests on a yearly basis, the impact of deviation requests every two or three years
should be studied, including the impacts to fish and wildlife. The seasonality of treatments may
be adjusted based on the ability to manipulate water levels/flow during various times of the year.

Justification: Resistance management plans will likely prevent sequential or back-to-back use of
new products within these lakes. Therefore, when treatments are initiated, it is likely that we will
be dealing with a significant hydrilla infestation, and it is important to provide optimal
conditions to allow extended control of the hydrilla.

Recommendation 10: With the long-range viability of fluridone in large lakes with FRH in
doubt, the FDEP, FWC and South Florida Water management District (SFWMD) need to
develop long-term aquatic plant management plans for how, when, and where to manage hydrilla
on the large flood control lake systems.

Justification: If the hydrilla infestations become more severe on these systems, increasing
fluridone rates may not be a feasible option. It is important that priority zones for access,
navigation, and habitat improvement are included in a lake management plan that does not
include the use of fluridone.










Wildlife and Fisheries Management


Like all submersed aquatic macrophytes, hydrilla can provide habitat, food resources, and
refugia for fish and wildlife. For fishes, a number of studies have evaluated the value of hydrilla
as habitat. Intermediate coverage of hydrilla has been associated with quality largemouth bass
(Micropterus salmoides) populations, causing high production of young fish (Colle and
Shireman 1980; Maceina et al. 1995; Hoyer and Canfield 1996; Miranda and Pugh 1997; Tate et
al. 2003), and quality fisheries (Moxely and Langford 1985; Maceina and Reeves 1996).
However, high hydrilla coverage (> 85%) can reduce fishing effort due to difficulties in angler
access (Colle et al. 1987), may cause fish growth rates to decline (Colle and Shireman 1980), and
represents a risk to fish populations due to low oxygen and potential fish kills.

In the 1980s, FDEP funded a multi-year research project to address relations between aquatic
plants and the limnology (i.e., water quality and fisheries) of Florida lakes (Canfield and Hoyer
1992). This research demonstrated that fish populations only had a chance of being negatively
impacted when aquatic plant coverage was less than 15% or more than 85%. These findings
suggested aquatic plant control programs have a broad window of plant coverage that they could
work within, without causing major negative changes in water quality and/or fisheries (Canfield
and Hoyer 1992). An important issue when controlling submersed aquatic plants, however, is
that that the significance of hydrilla for quality largemouth bass fisheries may be related to lake
size (Hoyer and Canfield 1996). Small lakes have relatively high littoral area to surface area
ratios, possibly allowing adequate habitat for sport fish even in absence of submersed
macrophytes. In large lakes, submersed plants such as hydrilla may substantially increase the
available habitat over that which is provided by littoral areas (Hoyer and Canfield 1996). Thus,
hydrilla management strategies for fishery benefits should consider lake size and the other
available habitat present at each lake.

Considering wildlife, hydrilla provides a food resource for some aquatic birds including
waterfowl. Johnson and Montalbano (1984) found 12 species of waterfowl consuming, and
preferring, hydrilla while over-wintering in Florida. Similarly, Montalbano et al. (1979) found
hydrilla to be the most common plant food found in the esophagi of ducks and coots in two
Florida lakes. Esler (1990) reported that total bird use in experimental plots in a Texas reservoir
was substantially greater with the presence of hydrilla than without the plant. Examining aquatic
bird data on 46 Florida lakes, Hoyer and Canfield (1994) showed that bird abundance and
species richness remain relatively stable as macrophyte abundance increases, but birds that prefer
open water habitats (e.g., double-crested cormorant, Phalacrocorax auritus) are replaced by
species that use macrophyte communities (e.g., ring-necked duck, Athya collaris). Additionally,
some species require certain types of emergent vegetation to be present regardless of the total
lake-wide coverage of aquatic plants (e.g., least bittern, Ixobrychus exilis). Thus, for aquatic
plant management some judgments have to be made regarding the positive and negative impacts
on habitat preferences for aquatic bird species.

Some strategies for managing hydrilla with Fluridone have included temporary deviations of lake
level regulation schedules and these associated changes in water level could influence habitat
availability for several bird and fish species. Participants in the Hydrilla Issues Workshop noted










that manipulated low water used for hydrilla control should be considered in the context of
available basin-wide habitat for birds rather than lake-specific habitat considerations (Appendix
II). Wading bird densities in Florida generally decline with increases in water levels (Breininger
and Smith 1990; David 1994), and thus, temporary declines in water levels for hydrilla control
could increase wading bird habitat.

There is no evidence that hydrilla directly influences habitat quality for the endangered snail kite
Rostrhamus sociabilis. However, low water levels have been associated with poor nest success
(Beissinger and Snyder 2002) and lower juvenile survival (Dreitz et al. 2004) for snail kites.
Changes to lake regulation schedules therefore may influence habitat quality for snail kites and
should be considered in the plans. Dreitz et al. (2001) contended that relatively few adult snail
kites might exhibit low nest success during low water due to their ability to select alternative
locations when water levels decline. Nevertheless, hydrilla management strategies that include
changing water levels should obviously consider habitat for wading birds and the snail kite in the
context of regional habitat availability.


Recommendations

Recommendation 11: Hydrilla management actions should aim to keep non-target impacts to a
minimum because non-target impacts of hydrilla control measures on native plant abundance
could greatly reduce available fish and wildlife habitat. Where control of resistant hydrilla is
limited because of budgetary considerations and/or insufficient selective management tools and
where hydrilla coverage is not impacting the designated uses of a lake, FDEP should consider
allowing some hydrilla to persist. Where water level manipulations are needed to improve the
efficiency of hydrilla control with Fluridone, aquatic plant management plans should consider
the impacts of water level changes on fish and bird populations.

Justification: Research has found no evidence that a wide range of hydrilla coverage (15% to
85% coverage) represents a threat to wildlife and fisheries, and in most cases, hydrilla even
provides beneficial habitat. However, high hydrilla coverage (> 85%) can cause problems for
fisheries and hydrilla coverage greater than 40% to 50% generally cause problems with
recreational activities. Water-level manipulations in lakes have been shown to significantly
influence bird and fish populations.



Florida Statute and Florida Administrative Code

Aquatic plant managers in the state of Florida must manage aquatic plants so as to protect human
health, safety and recreation and to the greatest degree practicable prevent injury to non-target
plants, animal life, and property. Any modifications of plant control activities by the Florida
Department of Environmental Protection (FDEP), however, are guided by Florida Statute (FS
369.20-369.255) and the Florida Administrative Code (FAC 62C-20). Both documents are
attached in Appendix III so all participants in the workshop have access and can read them.










Prior to the recognition of hydrilla resistance, Fluridone was the only available herbicide that
might offer the ability to eradicate hydrilla from an aquatic system. Initially, aquatic plant
managers under the jurisdiction of FDEP may have performed many of their activities under the
Florida Statute's and the Florida Administrative Code's definition for an Eradication Program
(FS 369.22(2)(e) and FAC 62C-20.0015(11)). "Eradication program" was defined as a method
for the control of non-indigenous aquatic plants in which control techniques are utilized in a
coordinated manner in an attempt to kill all the target aquatic plants on a permanent basis in a
given geographical area. With the continued re-growth of hydrilla it became obvious that aquatic
plant managers were actually working in more of a maintenance control direction. A
"maintenance control program" is defined as a method for the control of non-indigenous aquatic
plants in which control techniques are utilized in a coordinated manner on a continuous basis in
order to maintain the plant population at the lowest feasible level as determined by the
department (FS 369.22(2)(d)). The Florida Administrative Code also clearly directs the
department that "lowest feasible level" is the level of plant control permitted by funding and
technology (FAC 62C-20.0015(13)). Now with the development of fluridone resistance (see
Herbicide Section), the probability of eradication by fluridone will be zero, and maintenance
control will continually push the target of lowest feasible level higher. Thus, the loss of a cost-
effective herbicide like fluridone does not affect FDEP's ability to manage plants, but severely
limits the acreage of control due to cost and selectivity considerations of other management
tools. The spread of fluridone resistant hydrilla also means that managers may have to allocate
funds in such a manner that minimal or no hydrilla control activities can be implemented on a
given system for one or more growing seasons. Given the current funding and technologies, we
may have to accept an increased level of hydrilla in a given aquatic ecosystem. So as identified
by the experts in attendance at the Hydrilla Issues Workshop, FDEP will have to establish how
much hydrilla will be left in a given system given public use, environmental and budgetary
considerations.

The Legislature has also established that the FDEP shall supervise and direct all maintenance
programs, excluding the authority to use fish as a biological control (FS 369.22(4). Because
aquatic plants can be important in lakes, it would greatly assist FDEP's maintenance
management efforts if comprehensive lake management plans were developed for the lakes
requiring major expenditures for aquatic weed control. The importance of having a
comprehensive management plan was clearly identified by the experts attending this issues
workshop. However, the development of such plans will cost money and time. Until plans are
developed, FDEP will have to expand existing plant management techniques (i.e. contact
herbicides and mechanical harvesting) within their budget to achieve maintenance plant levels.

Deciding how many plants should be left in a lake can be difficult, but the Florida Legislature
provides guidance in statute ((FS 369.20(2)). The Florida Aquatic Weed Control Act states it
shall be the duty of FDEP to manage plants so as to protect human health, safety, and recreation.
In Florida, the lack of flood control represents the greatest human health and safety concern.
Consequently, FDEP staff in attendance had questions regarding the impact of dislodged hydrilla
on water control structures. The current response to the potential threat of vegetation clogging a
structure is for water management agencies to station or have nearby mechanical devices (e.g.,
track hoes or draglines) at each structure to remove plants accumulating in front of structures in









emergency situations. As this workshop made clear, there is a strong potential for increased
hydrilla coverage on those flood control lakes that contain structures (Lake Tohopekaliga,
Kissimmee, and Istokpoga). Therefore, it is up to the SFWMD to insure that current response
measures are adequate given different densities of hydrilla. With the exception of lakes
containing flood control structures, the major issue regarding hydrilla management for FDEP
will, therefore, be recreation. Recreation for most lake users will translate to access and fishing.

Some participants at the issues workshop believe it is possible to use grass carp in a maintenance
program and help reduce aquatic plant control costs. Florida statutes, however, are clear that use
of fish such as the grass carp is not under the control of FDEP (FS 369.20(2)). Use of Grass carp
is under the control of the Fish and Wildlife Conservation Commission (FWC) and their
regulation is detailed in the Florida Administrative Code (FAC 68A-23.088; see Appendix III).
Pertinent to any discussion about using grass carp in a maintenance program is the FWC's
authority to deny any permit to stock triploid carp in any water body, other than private ponds, if
such proposed stocking is inconsistent with the principal or planned use of the water body, the
optimum sustained use by the public of the water body's living aquatic resources, or sound
biological management principals (FAC 68A-23.088 (3) (d)). FDEP, however, is charged with
the guidance and coordination of all plant management activities of all public bodies, authorities,
agencies, and special districts (FS 369.20(3)). Thus, FDEP and FWC must work together to
determine how best to use grass carp as a tool for aquatic plant management in the state.

Because issues requiring research have been raised concerning the use of grass carp, FDEP must
recognize that it has the statutory authority to promote, develop, and support research activities
directed toward the more effective and efficient control of aquatic plants (FS 369.20(4)). If a
research project involving barriers to carp movement is advanced (see grass carp section), FDEP
also is charged with the authority to construct, acquire, operate, and maintain facilities and
equipment (FS 369.20(4)(c)).

Recommendations

Recommendation 12: FDEP and cooperators shall consider implementing a maintenance
program using registered contact herbicides and/or mechanical harvesting on water bodies with
fluridone resistant hydrilla. The initial focus shall be on public and private access points and
trails to maintain recreational use. If there are funds available after access allocations, FDEP will
set as the working objective of maintaining submersed plant coverage above 15% of the water
body's surface area. FDEP unless advised differently by the working group establishing the lake
management plan shall not attempt to manage submersed vegetation coverage below 15% of the
water body's surface area, especially on large lakes where the submersed vegetation is the vast
majority of fish habitat. In many aquatic systems hydrilla constitutes the vast majority of
remaining submersed vegetation. Therefore, while goals are to maintain native submersed plants
above a certain percentage, aquatic managers will often be faced with recognizing hydrilla as a
constituent of the submersed vegetation community.

Justification: The Florida Aquatic Weed Control Act states it shall be the duty of FDEP to
manage plants so as to protect human health, safety, and recreation. Access and fishing are two
important issues in each category mentioned by the Legislature. Access and fishing are also two









areas that can draw public ire if not managed properly. Research has shown the probability of
encountering an impacted fish population increases when aquatic plant coverage is below 15% or
greater than 85%, thus providing a wide "window of opportunity" for managing plants and
fishing. This is critical because with the development and spread of hydrilla resistance to
fluridone, the existing funding and technology means fewer acres of hydrilla can be managed.
Implementing a maintenance program as recommended can buy time until improvement in
technology and funding can be achieved.

Recommendation 13: FDEP work with their cooperators (i.e., become the lead agency) to seek
funding for the establishment of a comprehensive aquatic plant management plan at each lake
requiring major amounts of state dollars for weed control. These planning efforts should directly
incorporate stakeholder concerns and directions for management.

Justification: Participants in the Hydrilla Issues Workshop acknowledged throughout the
meeting that what is "done" depends upon having a lake management plan. FDEP is mandated
by the Florida Legislature to guide and coordinate weed control activities on all public waters
(FS 369.20(3)). Because aquatic plants affect water quality and FDEP works with FWC on
plant/fish management problems, FDEP is a logical state agency to lead the long-term effort to
get a workable lake management plan for each lake requiring aquatic plant management. FDEP
is also the state agency best positioned with the Legislature to ask for funds for the development
of a comprehensive aquatic plant management plan because FDEP and the water management
districts have developed similar surface water improvement plans (SWIM) for Florida.











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Appendix I Workshop Participants


NAME Agency/Affiliation
Chris Horton Bass Anglers Sportsman's Society/ESPN
Dean G. Barber Florida Department of Environmental Protection
Matt Phillips Florida Department of Environmental Protection
David Demmi Florida Department of Environmental Protection
Joe Hinkle Florida Department of Environmental Protection
Ed Harris Florida Department of Environmental Protection
Jess Van Dyke Florida Department of Environmental Protection
Judy Ludlow Florida Department of Environmental Protection
Jeff Schardt Florida Department of Environmental Protection
Terry Sullivan Florida Department of Environmental Protection
Bill Torres Florida Department of Environmental Protection-BIPM
Jim Estes Florida Fish and Wildlife Conservation Commission
Bill Johnson Florida Fish and Wildlife Conservation Commission
Steve Rockwood Florida Fish and Wildlife Conservation Commission
David Eggeman Florida Fish and Wildlife Conservation Commission
Joe Benedict Florida Fish and Wildlife Conservation Commission
Vicki Pontius Highlands County
Keshav Setaram Orange County
Dean Jones Polk County
Mike Bodle South Florida Water Management District
Bob Howard South Florida Water Management District
Dan Thayer South Florida Water Management District
Brian Nelson Southwest Florida Water Management District
Wayne Corbin St. John's River Water Management District
Steve Miller St. John's River Water Management District
Mike Netherland U.S. Army Engineer Research and Development Center
Cathy Byrd U.S. Army Corps of Engineers Jacksonville District
Kamili Hitchmon U.S. Army Corps of Engineers Jacksonville District
Adam Stuart U.S. Army Corps of Engineers Jacksonville District
Susan Sylvester U.S. Army Corps of Engineers Jacksonville District
Charles E. Ashton U.S. Army Corps of Engineers Jacksonville District
Bob Pace U.S. Fish and Wildlife Service
Art Roybal U.S. Fish and Wildlife Service
Mike Allen University of Florida
Mark Hoyer University of Florida
Patrick Cooney University of Florida
Christy Horsburgh University of Florida
Julie Terrell University of Florida
Bill Haller University of Florida
Karl Havens University of Florida
Dan Canfield University of Florida
Will Strong University of Florida











Appendix II Minutes and Notes from the Workshop


These notes are organized according to each issue identified.


Integrated Plant Management

Art Roybal: Have we taken an integrated approach? It is a management approach on the
ecosystem and changing the condition with multiple methods of attack. We have used grass carp,
chemicals, and physical control, but sometimes this doesn't work. Maybe we should use different
methods of control at the same time.

Jess Van Dyke: We need applied research on grass carp combined with low rates with of
herbicides. Compare costs, efficacy, and containment.

Brian Nelson: The major question we are facing is: How do you manage hydrilla with contact
herbicide if you loose sonar?

Dean Barber: We can manage with Grass Carp and herbicide. We need to look at water shed
management with this fish. We have been too conservative with research and stocking in large
scale systems.

Terry Sullivan: We need to look at an integrated approach. Look at whole lake approach with
sonar, contact herbicide, and grass carp.

Jeff Schardt: DEP needs to look at its policy for copper use. Look at its inside policy to
integrated approach. Research on better ways to get native plants in the system if we are getting
hydrilla out of systems. What are the best native plants to plant in the system? Talk at the
beginning of Kiss restructuring.. .Hatchineha and Kissimmee structure that is missing.....is it
cost keeping that out.....could we get coordinated funding to get that structure in place. Also
develop a habitat drawdown schedule in that plan....maybe we can rotate storage of water to help
with hydrilla control.

Dave Eggman: We need to have management plans based on specific lake needs. Need to get to
not only the uses but have a plan on each of the lakes.

Bob Pace: There needs to be flexibility with climactic changes (in case of wet winter or
hurricane), and flexibility with funding (able to move money from one project or carry over from
one year to next).

Steve Rockwood: For water fowl species, hydrilla is a beneficial plant. Presence of hydrilla can
mitigate the loss of habitat for water fowl. Should we set lake by lake priorities based on the
need of plants for waterfowl? Maybe treat after the migration waterfowl.










Bill Haller: We don't need to allow high levels of hydrilla in lakes because it will happen
without us trying. We need more tools to control hydrilla. The pressure of stocking carp is going
to rapidly increase, and we need to have more tools to utilize with grass carp to control hydrilla.

Bill Johnson: If you aren't able to maintain high enough concentration of herbicide at every sprig
of hydrilla, then the use of herbicide is not effective.

Dave Eggman: We stocked carp in lakes in the 80's at very high density, so we backed off with
sonar. Then we lost sonar's effectiveness, so we have picked back up on carp in public lakes. We
will probably try and increase. We have an issue group next week to address how to handle carp
in lakes, which will include such issues as: where do we put barriers, who will maintain them.

Brian Nelson: There is a lot of integration of control methods on the smaller lakes, it is just not
on the big lakes.

Dean Jones (Polk): As we move forward from here, please don't forget about the people doing
the spraying. Think about the men putting it out....resources of people putting it out.
Recourses/time allocation to application feasibility.

Patrick Cooney: Would you be stretching yourselves too thin both financially and in personnel
by creating lake by lake management goals that would need to be altered frequently, depending
on user wants and needs? Won't it just end up with people fighting for the same limited
resources of money and personnel to carry out the management plan on one lake just to fail in
another? It seems like a statewide goal is more attainable than specific lake by lake goals with
the current resources available.

Jeff Schardt: What is integrated plant management? What are you going to tell me that I don't
know? We have used every tool we have to control, and I can't do it. So you spend a lot of time
telling me to do it. You won't help me. Don't tell me to integrate. Tell me how to integrate. We
need the focus on refining the methods of what we already have. Tell me how it works and when
it works and when it doesn't and why. This doesn't help me with the big five. I won't be able to
use grass carp on the those lakes. The fish will just escape. I need management techniques for
these big 5 lakes. Kissimmee chain of lakes and Istokpoga. We walked away from walk in
water....but still spend over million dollars on contact.

Grass Carp

Jess Van Dyke: We need applied research on grass carp: low rates of carp with low rates of
herbicides. Compare costs, efficacy, and containment.

Dean Barber: We can manage with Grass Carp and herbicide-need to look at water shed
management with this fish. We have been too conservative with research and stocking in large-
scale system.









Jeff Schardt: There has been discussion about carp in lakes. If we think about putting carp in big
lakes, we need barriers. Whose responsibility is it to build, establish, and maintain electric
barrier?

Dave Eggman: Look at barrier stuff when you look at research for carp. I know how to stock
fish....but we need barrier design.

Water Level Regulations

Jeff Schardt: Big 5 lakes (Kissimmee Chain and Lake Istokpoga): We need research to determine
hydrilla levels on the impact of flood control. This is the most important thing. Review policies
on water level lowering...we need to do something now for this. COE and WMD looking at the
schedules for hydrilla control. Temporary deviations. We also need to revise the way the
temporary deviations are put into place. We need all agencies at the table at the start. We need
money-especially from the federal level. If we can't get the water level down....can the feds
make up the $ from the different water levels.

Wayne Corbin: The geographical location of lakes undergoing drawdowns for hydrilla control
concern the wildlife...the locations next to that are then limited because wildlife is disturbed. We
need to figure out ways to rotate drawdowns.

Steve Miller: Snail Kites...the real issue is snail kites. Gave a history of snail kites. Kiss and
Toho chain is key to snail kites...it is a non viable population. Wants to drawdown his area but
put it off last year because of Toho. Now needs to drawdown kiss .....but there is talk about
Toho getting drawn down again....we need kiss down. Need to take a region wide perspective
when doing water level drawdowns and not just a lake system.

Steve Miller: Structure integrity-what distance to keep...Mike N: need control research of
resistance/friction of the mass with water flow is this a problem or is the problem only if the
mass breaks free. How far in front of structure do we need to control?

Adam Stuart: Temporary water level deviations can be used on a yearly basis until 2008 on the
Kissimmee chain. We need to be talking earlier. Once the sonar is in the water, is it better to
manage for a certain level and try to keep this. Or do we not do any discharges and just realize
we will have more water if it rains. Balancing contact time with water levels....is it better for
contact time (water levels) or flow?

Herbicides

Ed Harris: More research for herb development. Adding aquatic labels. Either with state
university level. Label extensions.

Matt Phillips: We are increasing concentration of sonar to combat resistant hydrilla-but, we
don't have a good handle on the susceptibility of native plants. Knot grass is affected at 20
ppb.....but what about lilies? We are seeing damage and loss of native plants. More research to
find susceptibility of native plants to increased sonar levels. Grass carp may be a good alternative









if we have to use high levels of sonar which will kill everything-we are losing many stands of
native plants. Needs the research quickly.

Dave Eggman: We need research (collect data) in field to determine selectivity

Dean Barber: We need another herbicide product. We need to stimulate aquatic interest via a 3rd
party. It is necessary to have multiple site inhibitors or multiple modes of actions (MOA). If this
is a significant problem. They are doing this on terrestrial side.

Bill Haller: We won't find a herbicide with multiple MOA. We will need to register many
herbicides with different MOAs.

Vicki Pontius: Research issue-agriculture and non target impact of sonar.

Mike Netherland. Should we distinguish hyd and hyd tolerant sonar when developing a plan?

Mike Allen: Well if you have hyd and use sonar you have hyd tolerant sonar type.

Mike Netherland: It hasn't happened everywhere....if it is a new infestation, we might be able to
control.

Brian Nelson: Hydrilla tolerant to sonar is a big issue because you can't meet goals of minimum
feasible levels.

Bill Haller: The problem is that everyone is talking about plans of controlling hydrilla, but we
don't have the tools to manage hydrilla in some lakes. There are some lakes we can't buy enough
sonar to control hydrilla. What about contact herbicide....we don't have enough $.

Wayne Corbin: pleading/afraid to get the encourage the scientist/nasty chemical groups to get a
new compound-need a letter of concern addressed.

Mike Netherland: we already did a search-get rid of 90% of them. We have found about 4 or 5
compounds. But each will create resistance....how do we use these compounds to delay the
resistance....it will happen but you can get a few more years. In terms of managing susceptible
hydrilla, we can allow these plants to expand, as it is much easier to control a susceptible lake
with topped out hyd. We should use these treatments sparingly and should never treat back to
back with susceptible hyd. But tolerant hyd.....spend $ on this while it is low.

Dean Jones: Reviewing and considering more increase of copper uses.

Brian Nelson: Haller painted a pessimistic picture about getting a new herbicide
regulated... getting short-term solutions. And if we get one it will be short lived also.












Wildlife Fisheries Management


Jeff Schardt: Research has issues of drawdown due to Apple Snails on the timing and the extent
and the speed of the water. Also AVM is an issue-killing off eagles and coots in the Carolina.
Also, with snail kites we've had suggestion of setting crews back from active snail kite
nests....how far of a set back needed). Need an enforceable set back area for tour boats also.

Wayne Corbin: The geographical location of lakes undergoing drawdowns for hydrilla control
concern the wildlife...the locations next to that are then limited because wildlife is disturbed. We
need to figure out ways to rotate drawdowns.

Steve Miller: Snail Kites...the real issue is snail kites. Gave a history of snail kites. Kiss and
Toho chain is key to snail kites...it is a non viable population. Wants to drawdown his area but
put it off last year because of Toho. Now needs to drawdown kiss .....but there is talk about
Toho getting drawn down again....we need kiss down. Need to take a region wide perspective
when doing water level drawdowns and not just a lake system.

Bob Pace: Need to know how far from birds nest herbicide applicators must maintain.

Structure

Steve Miller: Structure integrity-what distance to keep...Mike N: need control research of
resistance/friction of the mass with water flow is this a problem or is the problem only if the
mass breaks free. How far in front of structure do we need to control?

Adam Stuart: Structural stability via mat of hydrilla or tussock? Need investigations. Even if the
structural stability isn't an issue what about clogging the gates. System performance also needs
to look at. What is the effect of lake volume of stage if the lake is covered with hydrilla? May
just be ballpark numbers....

Jeff Schardt. Need to have emergency procedures to get hydrilla off the structures.

Brian Nelson: How does hydrilla effect sedimentation rates?
Minimum Feasible Levels

Jeff Schardt: Needs agency commitment for invasive species management. Needs an agency
policy because of the people changing within the agencies-once we get some understanding
with a personnel then they move on and we have a new person. Coordinated response from
agencies for hydrilla control (within and between).

Matt Phillips: What is more important controlling hyd or maintaining native plants? It depends
on the lake. We need a more lake-by-lake decision process rather than blanket statement for state
due to differences in user groups.










Dave Eggman: Need to have management plans based on specific lake needs. Need to get to not
only the uses but have a plan on each of the lakes. Right now, if you have money and you find
hydrilla, you control.

Jeff Schardt. We need to redefine the lowest feasible level of hydrilla ($, tech, and uses).

Mark Hoyer: Legislature set up for DEP to set the lowest feasible levels.

Jim Estes: Funding comes from DEP, so DEP sets priorities. They need to set purposes of
hydrilla control when decisions are made to control. Set priorities based on objectives.

Jeff Schardt. Agrees with Jim, but feels that there needs to be concurrence from the FWC. It is
necessary to get things worked out between FWC and DEP.

Chris Horton: If you keep the public involved in the decision of a lake by lake basis it will be
easier to go to the legislature to get funding

Jeff Schardt: We don't have time nor personnel to create a plan for every lake....so what we did
is put a website out there...We got more help from the web page....we don't have time to get
together every year for 350 lakes with a staff of 2. some can take months. We are excited that
BASS is coming to FL. Maybe BASS can help us in an effort to set individual plans for several
lakes with angler interests.

Brian Nelson: Hydrilla tolerant to sonar is a big issue because you can't meet goals of minimum
feasible levels.

Biocontrol

Jeff Schardt: Renew bio control on hydrilla research.

Personnel

Joe Hinkle: More involved in sonar treatment-more help in our section. More staff-man
power.

Jeff Schardt: We don't have time nor personnel to create a plan for every lake....so what we did
is put a website out there...We got more help from the web page....we don't have time to get
together every year for 350 lakes with a staff of 2. some can take months.

Public Involvement

Mike Bodle: This issue is beyond the general public...local agencies need to address public
awareness to include the public and get their support because this topic is getting complicated.
Public education needed at the agencies. Wants the public involved prior to crisis.









Chris: Anglers aren't screaming in FL-we are fortunate. Bass anglers perspective want
habitat/structure. Can help educate the public. Need public buy in... it is key to make sure the
public is involved or well informed. In the name of progress....make sure the public is involved.

Water Quality

Steve Miller: Water quality issues-stick marsh. Pollution load reduction goals. It is a good
water quality if you get rid of hyd you will loose our capabilities.










Appendix III Florida Statutes and Florida Administrative Codes


The 2004 Florida Statutes

Title XXVIII
NATURAL RESOURCES; CONSERVATION, RECLAMATION, AND USE
Chapter 369
CONSERVATION
View Entire Chapter


PART I

AQUATIC PLANT CONTROL

369.20 Florida Aquatic Weed Control Act.--

(1) This act shall be known as the "Florida Aquatic Weed Control Act."

(2) The Department of Environmental Protection shall direct the control, eradication, and
regulation of noxious aquatic weeds and direct the research and planning related to these
activities, as provided in this section, excluding the authority to use fish as a biological control
agent, so as to protect human health, safety, and recreation and, to the greatest degree
practicable, prevent injury to plant and animal life and property.

(3) It shall be the duty of the department to guide and coordinate the activities of all public
bodies, authorities, agencies, and special districts charged with the control or eradication of
aquatic weeds and plants. It may delegate all or part of such functions to the Fish and Wildlife
Conservation Commission.

(4) The department shall also promote, develop, and support research activities directed toward
the more effective and efficient control of aquatic plants. In the furtherance of this purpose, the
department is authorized to:

(a) Accept donations and grants of funds and services from both public and private sources;

(b) Contract or enter into agreements with public or private agencies or corporations for research
and development of aquatic plant control methods or for the performance of aquatic plant control
activities;

(c) Construct, acquire, operate, and maintain facilities and equipment; and

(d) Enter upon, or authorize the entry upon, private property for purposes of making surveys and
examinations and to engage in aquatic plant control activities; and such entry shall not be
deemed a trespass.










(5) The Department of Environmental Protection may disburse funds to any special district or
other local authority charged with the responsibility of controlling or eradicating aquatic plants,
upon:

(a) Receipt of satisfactory proof that such district or authority has sufficient funds on hand to
match the state funds herein referred to on an equal basis;

(b) Approval by the department of the control techniques to be used by the district or authority;
and

(c) Review and approval of the program of the district or authority by the department to be in
conformance with the state control plan.

(6) The department shall adopt rules pursuant to ss. 120.536(1) and 120.54 to implement
provisions of this section conferring powers or duties upon it and perform any other acts
necessary for the proper administration, enforcement, or interpretation of this section, including
creating general permits and exemptions and adopting rules and forms governing reports.

(7) No person or public agency shall control, eradicate, remove, or otherwise alter any aquatic
weeds or plants in waters of the state unless a permit for such activity has been issued by the
department, or unless the activity is in waters expressly exempted by department rule. The
department shall develop standards by rule which shall address, at a minimum, chemical,
biological, and mechanical control activities; an evaluation of the benefits of such activities to
the public; specific criteria recognizing the differences between natural and artificially created
waters; and the different amount and quality of littoral vegetation on various waters.
Applications for a permit to engage in aquatic plant control activities shall be made to the
department. In reviewing such applications, the department shall consider the criteria set forth in
subsection (2).

(8) As an exemption to all permitting requirements in this section and ss. 369.22 and 369.25, in
all freshwater bodies, except aquatic preserves designated under chapter 258 and Outstanding
Florida Waters designated under chapter 403, a riparian owner may physically or mechanically
remove herbaceous aquatic plants and semiwoody herbaceous plants, such as shrub species and
willow, within an area delimited by up to 50 percent of the property owner's frontage or 50 feet,
whichever is less, and by a sufficient length waterward from, and perpendicular to, the riparian
owner's shoreline to create a corridor to allow access for a boat or swimmer to reach open water.
All unvegetated areas shall be cumulatively considered when determining the width of the
exempt corridor. Physical or mechanical removal does not include the use of any chemicals or
any activity that requires a permit pursuant to part IV of chapter 373.

(9) A permit issued pursuant to this section for the application of herbicides to waters in the state
for the control of aquatic plants, algae, or invasive exotic plants is exempt from the requirement
to obtain a water pollution operation permit pursuant to s. 403.088.
(10)









History.--ss. 1, 2, ch. 70-203; s. 3, ch. 80-129; s. 32, ch. 85-81; s. 1, ch. 89-151; s. 187, ch. 94-
356; s. 2, ch. 96-238; s. 2, ch. 97-22; s. 75, ch. 98-200; s. 91, ch. 99-245.

Note.--Former s. 372.925.

369.22 Nonindigenous aquatic plant control.--

(1) This section shall be known as the "Florida Nonindigenous Aquatic Plant Control Act."

(2) For the purpose of this section, the following words and phrases shall have the following
meanings:

(a) "Department" means the Department of Environmental Protection.

(b) "Aquatic plant" is any plant growing in, or closely associated with, the aquatic environment
and includes "floating," "emersed," submersedd," and "ditch bank" species.

(c) "Nonindigenous aquatic plant" is any aquatic plant that is nonnative to the State of Florida
and has certain characteristics, such as massive productivity, choking density, or an obstructive
nature, which render it detrimental, obnoxious, or unwanted in a particular location.

(d) A "maintenance program" is a method for the control of nonindigenous aquatic plants in
which control techniques are utilized in a coordinated manner on a continuous basis in order to
maintain the plant population at the lowest feasible level as determined by the department.

(e) An "eradication program" is a method for the control of nonindigenous aquatic plants in
which control techniques are utilized in a coordinated manner in an attempt to kill all the aquatic
plants on a permanent basis in a given geographical area.

(f) A "complaint spray program" is a method for the control of nonindigenous aquatic plants in
which weeds are allowed to grow unhindered to a given level of undesirability, at which point
eradication techniques are applied in an effort to restore the area in question to a relatively low
level of infestation.

(g) "Waters" means rivers, streams, lakes, navigable waters and associated tributaries, canals,
meandered lakes, enclosed water systems, and any other bodies of water.

(h) "Intercounty waters" means any waters which lie in more than one county or form any part
of the boundary between two or more counties, as determined by the department.

(i) "Intracounty waters" means any waters which lie wholly within the boundaries of one county
as determined by the department.

(j) "Districts" means the six water management districts created by law and named, respectively,
the Northwest Florida Water Management District, the Suwannee River Water Management
District, the St. Johns River Water Management District, the Southwest Florida Water

53









Management District, the Central and Southern Florida Flood Control District, and the Ridge and
Lower Gulf Coast Water Management District; and on July 1, 1975, shall mean the five water
management districts created by chapter 73-190, Laws of Florida, and named, respectively, the
Northwest Florida Water Management District, the Suwannee River Water Management District,
the St. Johns River Water Management District, the Southwest Florida Water Management
District, and the South Florida Water Management District.

(3) The Legislature recognizes that the uncontrolled growth of nonindigenous aquatic plants in
the waters of Florida poses a variety of environmental, health, safety, and economic problems.
The Legislature acknowledges the responsibility of the state to cope with the uncontrolled and
seemingly never-ending growth of nonindigenous aquatic plants in the waters throughout
Florida. It is, therefore, the intent of the Legislature that the state policy for the control of
nonindigenous aquatic plants in waters of state responsibility be carried out under the general
supervision and control of the department, and that the state itself be responsible for the control
of such plants in all intercounty waters; but that control of such plants in intracounty waters be
the designated responsibility of the appropriate unit of local or county government, special
district, authority, or other public body. It is the intent of the Legislature that the control of
nonindigenous aquatic plants be carried out primarily by means of maintenance programs, rather
than eradication or complaint spray programs, for the purpose of achieving more effective
control at a lower long-range cost. It is also the intent of the Legislature that the department
guide, review, approve, and coordinate all nonindigenous aquatic plant control programs within
each of the water management districts as defined in paragraph (2)(j). It is the intent of the
Legislature to account for the costs of nonindigenous aquatic plant maintenance programs by
watershed for comparison management purposes.

(4) The department shall supervise and direct all maintenance programs for control of
nonindigenous aquatic plants, as provided in this section, excluding the authority to use fish as a
biological control agent, so as to protect human health, safety, and recreation and, to the greatest
degree practicable, prevent injury to plant, fish, and animal life and to property.

(5) When state funds are involved, or when waters of state responsibility are involved, it is the
duty of the department to guide, review, approve, and coordinate the activities of all public
bodies, authorities, state agencies, units of local or county government, commissions, districts,
and special districts engaged in operations to maintain, control, or eradicate nonindigenous
aquatic plants, except for activities involving biological control programs using fish as the
control agent. The department may delegate all or part of such functions to any appropriate state
agency, special district, unit of local or county government, commission, authority, or other
public body. However, special attention shall be given to the keeping of accounting and cost data
in order to prepare the annual fiscal report required in subsection (7).

(6) The department may disburse funds to any district, special district, or other local authority
for the purpose of operating a maintenance program for controlling nonindigenous aquatic plants
and other noxious aquatic plants in the waters of state responsibility upon:

(a) Receipt of satisfactory proof that such district or authority has sufficient funds on hand to
match the state funds herein referred to on an equal basis;










(b) Approval by the department of the maintenance control techniques to be used by the district
or authority; and

(c) Review and approval of the program of the district or authority by the department to be in
conformance with the state maintenance control plan.

(7) The department shall submit an annual report on the status of the nonindigenous aquatic
plant maintenance program to the President of the Senate, the Speaker of the House of
Representatives, and the Governor and Cabinet by January 1 of the following year. This report
shall include a statement of the degree of maintenance control achieved by individual
nonindigenous aquatic plant species in the intercounty waters of each of the water management
districts for the preceding county fiscal year, together with an analysis of the costs of achieving
this degree of control. This cost accounting shall include the expenditures by all governmental
agencies in the waters of state responsibility. If the level of maintenance control achieved falls
short of that which is deemed adequate by the department, then the report shall include an
estimate of the additional funding that would have been required to achieve this level of
maintenance control. All measures of maintenance program achievement and the related cost
shall be presented by water management districts so that comparisons may be made among the
water management districts, as well as with the state as a whole.

(8) The department shall have the authority to cooperate with the United States and to enter into
such cooperative agreements or commitments as the department may determine necessary to
carry out the maintenance, control, or eradication of water hyacinths, alligator weed, and other
noxious aquatic plant growths from the waters of the state and to enter into contracts with the
United States obligating the state to indemnify and save harmless the United States from any and
all claims and liability arising out of the initiation and prosecution of any project undertaken
under this section. However, any claim or claims required to be paid under this section shall be
paid from money appropriated to the nonindigenous aquatic plant control program.

(9) The department may delegate various nonindigenous aquatic plant control and maintenance
functions to the Fish and Wildlife Conservation Commission. The commission shall, in accepting
commitments to engage in nonindigenous aquatic plant control and maintenance activities, be
subject to the rules of the department, except that the commission shall regulate, control, and
coordinate the use of any fish for aquatic weed control in fresh waters of the state. In addition,
the commission shall render technical and other assistance to the department in order to carry out
most effectively the purposes of s. 369.20. However, nothing herein shall diminish or impair the
regulatory authority of the commission with respect to the powers granted to it by s. 9, Art. IV of
the State Constitution.

(10) The department is directed to use biological agents, excluding fish, for the control of
nonindigenous aquatic plants.

(11) The department shall adopt rules pursuant to ss. 120.536(1) and 120.54 to implement the
provisions of this section conferring powers or duties upon it and perform any other acts









necessary for the proper administration, enforcement, or interpretation of this section, including
adopting rules and forms governing reports.

(12) No person or public agency shall control, eradicate, remove, or otherwise alter any
nonindigenous aquatic plants in waters of the state unless a permit for such activity has been
issued by the department, or unless the activity is in waters expressly exempted by department
rule. The department shall develop standards by rule which shall address, at a minimum,
chemical, biological, and mechanical control activities; an evaluation of the benefits of such
activities to the public; specific criteria recognizing the differences between natural and
artificially created waters; and the different amount and quality of littoral vegetation on various
waters. Applications for a permit to engage in aquatic plant control activities shall be made to the
department. In reviewing such applications, the department shall consider the criteria set forth in
subsection (4).

History.--ss. 1, 2, ch. 74-65; s. 4, ch. 80-129; s. 33, ch. 83-218; s. 16, ch. 84-254; s. 2, ch. 89-
151; s. 188, ch. 94-356; s. 76, ch. 98-200; s. 92, ch. 99-245.

Note.--Former s. 372.932.
369.25 Aquatic plants; definitions; permits; powers of department; penalties.--

(1) As used in this section, the term:

(a) "Aquatic plant" means any plant, including a floating, emersed, submersed, or ditch bank
species, growing in, or closely associated with, an aquatic environment and includes any part or
seed of such plant.

(b) "Department" means the Department of Environmental Protection.

(c) "Nonnursery cultivation" means the tending of aquatic plant species for harvest in the natural
environment.

(d) "Noxious aquatic plant" means any part, including, but not limited to, seeds or reproductive
parts, of an aquatic plant which has the potential to hinder the growth of beneficial plants,
interfere with irrigation or navigation, or adversely affect the public welfare or the natural
resources of this state.

(e) "Person" includes a natural person, a public or private corporation, a governmental entity, or
any other kind of entity.

(2) No person shall engage in any business involving the importation, transportation, nonnursery
cultivation, collection, sale, or possession of any aquatic plant species without a permit issued by
the department or the Department of Agriculture and Consumer Services. No person shall
import, transport, nonnursery cultivate, collect, sell, or possess any noxious aquatic plant listed
on the prohibited aquatic plant list established by the department without a permit issued by the
department or the Department of Agriculture and Consumer Services. No permit shall be issued









until the department determines that the proposed activity poses no threat or danger to the waters,
wildlife, natural resources, or environment of the state.

(3) The department has the following powers:

(a) To make such rules governing the importation, transportation, nonnursery cultivation,
collection, and possession of aquatic plants as may be necessary for the eradication, control, or
prevention of the dissemination of noxious aquatic plants that are not inconsistent with rules of
the Department of Agriculture and Consumer Services.

(b) To establish by rule lists of aquatic plant species regulated under this section, including those
exempted from such regulation, provided the Department of Agriculture and Consumer Services
and the Fish and Wildlife Conservation Commission approve such lists prior to the lists
becoming effective.

(c) To evaluate an aquatic plant species through research or other means to determine whether
such species poses a threat or danger to the waters, wildlife, natural resources, or environment of
the state.

(d) To declare a quarantine against aquatic plants, including the vats, pools, or other containers
or bodies of water in which such plants are growing, except in aquatic plant nurseries, to prevent
the dissemination of any noxious aquatic plant.

(e) To make rules governing the application for, issuance of, suspension of, and revocation of
permits under this section.

(f) To enter into cooperative agreements with any person as necessary or desirable to carry out
and enforce the provisions of this section.

(g) To purchase all necessary supplies, material, and equipment and accept all grants and
donations useful in the implementation and enforcement of the provisions of this section.

(h) To enter upon and inspect any facility or place, except aquatic plant nurseries regulated by
the Department of Agriculture and Consumer Services, where aquatic plants are cultivated, held,
packaged, shipped, stored, or sold, or any vehicle of conveyance of aquatic plants, to ascertain
whether the provisions of this section and department regulations are being complied with, and
to seize and destroy, without compensation, any aquatic plants imported, transported, cultivated,
collected, or otherwise possessed in violation of this section or department regulations.

(i) To conduct a public information program, including, but not limited to, erection of road
signs, in order to inform the public and interested parties of this section and its associated rules
and of the dangers of noxious aquatic plant introductions.

(j) To adopt rules requiring the revegetation of a site on sovereignty lands where excessive
collection has occurred.









(k) To enforce this chapter in the same manner and to the same extent as provided in ss.
403.121, 403.131, 403.141, and 403.161.

(4) The department shall adopt rules which limit the sanctions available for violations under this
act to quarantine and confiscation:

(a) If the prohibited activity apparently results from natural dispersion; or

(b) If a small amount of noxious aquatic plant material incidentally adheres to a boat or boat
trailer operated by a person who is not involved in any phase of the aquatic plant business and if
that person is not knowingly violating this act.

(5)(a) Any person who violates the provisions of this section is guilty of a misdemeanor of the
second degree, punishable as provided in s. 775.082 or s. 775.083.

(b) All law enforcement officers of the state and its agencies with power to make arrests for
violations of state law shall enforce the provisions of this section.

History.--s. 1, ch. 69-158; ss. 14, 26, 35, ch. 69-106; s. 4, ch. 70-203; s. 1, ch. 70-439; s. 350, ch.
71-136; s. 2, ch. 71-137; s. 140, ch. 77-104; s. 1, ch. 77-174; s. 23, ch. 78-95; s. 1, ch. 84-120; s.
1, ch. 92-147; s. 189, ch. 94-356; s. 93, ch. 99-245; s. 1, ch. 2000-146; s. 1, ch. 2001-258.

Note.--Former s. 403.271.
369.251 Invasive nonnative plants; prohibitions; study; removal; rules.--

(1) A person may not sell, transport, collect, cultivate, or possess any plant, including any part or
seed, of the species Melaleuca quinquenervia, Schinus terebinthifolius, Casuarina equisetifolia,
Casuarina glauca, or Mimosa pigra without a permit from the department. Any person who
violates this section commits a misdemeanor of the second degree, punishable by fine only, as
provided in s. 775.083.

(2) The department shall study methods of control of plants of the species Melaleuca
quinquenervia, Schinus terebinthifolius, Casuarina equisetifolia, Casuarina glauca, and Mimosa
pigra. The South Florida Water Management District shall undertake programs to remove such
plants from conservation area I, conservation area II, and conservation area III of the district.

(3) The department has authority to adopt rules pursuant to ss. 120.536(1) and 120.54 to
implement the provisions of this section. Possession or transportation resulting from natural
dispersion, mulching operations, control and disposal, or use in herbaria or other educational or
research institutions, or for other reasons determined by the department to be consistent with this
section and where there is neither the danger of, nor intent to, further disperse any plant species
prohibited by this section, is not subject to the permit or penalty provisions of this section.

History.--s. 1, ch. 90-313; s. 190, ch. 94-356; s. 77, ch. 98-200.
369.252 Invasive exotic plant control on public lands.--The department shall establish a program
to:










(1) Achieve eradication or maintenance control of invasive exotic plants on public lands when
the scientific data indicate that they are detrimental to the state's natural environment or when the
Commissioner of Agriculture finds that such plants or specific populations thereof are a threat to
the agricultural productivity of the state;

(2) Assist state and local government agencies in the development and implementation of
coordinated management plans for the eradication or maintenance control of invasive exotic
plant species on public lands;

(3) Contract, or enter into agreements, with entities in the State University System or other
governmental or private sector entities for research concerning control agents; production and
growth of biological control agents; and development of workable methods for the eradication or
maintenance control of invasive exotic plants on public lands; and

(4) Use funds in the Invasive Plant Control Trust Fund as authorized by the Legislature for
carrying out activities under this section on public lands. Twenty percent of the amount credited
to the Invasive Plant Control Trust Fund pursuant to s. 201.15(6) shall be used for the purpose of
controlling nonnative, upland, invasive plant species on public lands.

History.--s. 3, ch. 96-238; s. 1, ch. 97-38; s. 21, ch. 99-205; s. 30, ch. 99-247; s. 4, ch. 99-312; s.
62, ch. 2000-152.
369.255 Green utility ordinances for funding greenspace management and exotic plant control.--

(1) LEGISLATIVE FINDING.--The Legislature finds that the proper management of
greenspace areas, including, without limitation, the urban forest, greenways, private and public
forest preserves, wetlands, and aquatic zones, is essential to the state's environment and economy
and to the health and safety of its residents and visitors. The Legislature also finds that the
limitation and control of nonindigenous plants and tree replacement and maintenance are vital to
achieving the natural systems and recreational lands goals and policies of the state pursuant to s.
187.201(9), the State Comprehensive Plan. It is the intent of this section to enable local
governments to establish a mechanism to provide dedicated funding for the aforementioned
activities, when deemed necessary by a county or municipality.

(2) In addition to any other funding mechanisms legally available to counties and municipalities
to control invasive, nonindigenous aquatic or upland plants and manage urban forest resources, a
county or municipality may create one or more green utilities or adopt fees sufficient to plan,
restore, and manage urban forest resources, greenways, forest preserves, wetlands, and other
aquatic zones and create a stewardship grant program for private natural areas. Counties or
municipalities may create, alone or in cooperation with other counties or municipalities pursuant
to the Florida Interlocal Cooperation Act, s. 163.01, one or more greenspace management
districts to fund the planning, management, operation, and administration of a greenspace
management program. The fees shall be collected on a voluntary basis as set forth by the county
or municipality and calculated to generate sufficient funds to plan, manage, operate, and
administer a greenspace management program. Private natural areas assessed according to s.
193.501 would qualify for stewardship grants.










(3) This section shall only apply to counties with a population of 500,000 or more and
municipalities with a population of 200,000 or more.

(4) Nothing in this section shall authorize counties or municipalities to require any
nongovernmental entity to collect the fee described in subsection (2) on their behalf.

History.--s. 12, ch. 97


CHAPTER 62C-20 AQUATIC PLANT CONTROL PERMITS


62C-20.0011 Program Policies. (Repealed)
62C-20.0015 Definitions.
62C-20.002 Permits Applications.
62C-20.0025 Types of Permits. (Repealed)
62C-20.0035 Waters Exempt from Permitting.
62C-20.0045 Criteria for Issuing, Modifying or Denying Permit Applications.
62C-20.0055 Management Method Criteria and Standards, Operations and Reporting
Requirements.
62C-20.0075 Penalties.

62C-20.0015 Definitions.
(1) "Aquatic plant" means any plant, including a floating, emersed, submersed, or ditchbank
species, growing in, or closely associated with, an aquatic environment, and includes any part or
seed of such plant.
(2) "Aquatic plant management" means an activity designed to control the growth of aquatic
plants so as to protect human health, safety and recreation and, to the greatest degree practicable,
to prevent injury to non-target plants, animal life, and property.
(3) "Beneficial aquatic plants" mean indigenous aquatic plant species that provide fish and
wildlife habitat, water quality protection, and shoreline stabilization.
(4) "Bureau" means the Bureau of Aquatic Plant Management, an administrative subdivision of
the Department of Environmental Protection, located at 2051 E. Dirac Dr., Tallahassee, Florida
32310-3760, telephone (850) 488-5631.
(5) "Classes of Surface Water" means the classification of surface waters as defined by the
Department of Environmental Protection, pursuant to Rule 62-302.400, F.A.C.
(a) "Class I Public Water Supplies" means surface waters designated for human consumption.
(b) "Class II Shellfish Propagation or Harvesting" means surface waters where shellfish are
grown or harvested for human consumption.
(c) "Class III Recreation, Propagation and Maintenance of a Healthy, Well-Balanced
Population of Fish and Wildlife" means all surface waters of the state of Florida, which are not
included in Class I, II, IV or V.
(d) "Class IV Agricultural Water Supplies" means secondary and tertiary canals within
agricultural areas.









(e) "Class V Waters Navigation, Utility and Industrial Use" means waters designated for such
use.
(6) "Collection" means the removal or gathering of any aquatic plant, including any part or seed
thereof, from the place in which it is growing in the natural environment.
(7) "Connection" means any depression, ditch, canal, culvert, pipe, or any other natural or man-
made conveyance, whether permanent or intermittent, which joins the surface water of one
waterbody to the surface water of another waterbody in such a manner as to allow the
interchange of water between the waterbodies. Waterbodies with conveyances which are subject
to man-made controls, including but not limited to dams, weirs, water control gates, and valves
which are preventing the interchange of water between waterbodies at the time of the use of an
herbicide for aquatic plant management activities, and throughout any water use restriction
periods required by the herbicide product label, shall not be considered to be connected.
(8) "Control area" means an area of water containing the aquatic plant management site within
which opportunity exists for the mixture of water temporarily degraded by management activities
with receiving or adjacent waters. This includes the area of water in which the use of a herbicide
or mechanical aquatic plant management activity is undertaken.
(9) "Department" means the State of Florida Department of Environmental Protection.
(10) "Ditchbank species" means those plants usually growing not directly in water but near
water's edge at normal water level.
(11) "Eradication program" means a method for the control of non-indigenous aquatic plants in
which control techniques are utilized in a coordinated manner in an attempt to kill all the target
aquatic plants on a permanent basis in a given geographical area.
(12) "Herbicide" means any chemical product used to chemically control or regulate aquatic
plant growth.
(13) "Maintenance program" means a method for the management of aquatic plants in which
techniques are used in a coordinated manner, on a continuous or periodic basis, in order to
maintain the target plant population at the lowest feasible level funding and technology will
permit, as determined by the department.
(14) "Manatee aggregation site" means a specific area within a waterbody or canal system where
manatees periodically congregate, as identified by the bureau in consultation with the U.S. Fish
and Wildlife Service and the department's Office of Protected Species Management.
(15) "Natural waters" means those surface waters created through geological and biological
processes whether or not subsequently modified by man.
(16) "Noxious aquatic plant" means any part, including but not limited to seeds or reproductive
parts, of an aquatic plant which has the potential to hinder the growth of beneficial plants, to
interfere with irrigation or navigation, or to adversely affect the public welfare or the natural
resources of this state.
(17) "Outstanding Florida Waters" means waters designated by the Environmental Regulation
Commission as worthy of special protection because of their natural attributes as listed in Rule
62-302.700, F.A.C.
(18) "Permit" means a license issued by the department, pursuant to this chapter.
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(19) "Person" means individuals, children, firms, associations, joint ventures, partnerships,
estates, trusts, business trusts, syndicates, fiduciaries, corporations, and all other groups or
combinations.









(20) "Regional biologist" means a biologist employed by the bureau who is located in a region of
the state designated by the bureau, and whose duties are to carry out the responsibilities of the
bureau within the region as assigned.
(21) "Riparian owner" means a person who possesses fee title to property that extends to the
ordinary high water mark of navigable waters, or to the bottom.
(22) "Sovereignty lands" means, pursuant to Article X, Section 11, Constitution of the State of
Florida, the title to lands under navigable waters, within the boundaries of the state, which have
not been alienated, including beaches below mean high water lines, is held by the state, by virtue
of its sovereignty, in trust for all the people.
(23) "Waters" or "Waters of the State" means rivers, streams, lakes, navigable waters and
associated tributaries, canals, meandered lakes, enclosed water systems, and all other bodies of
water.
(24) "Waters of Special Concern" means Class I and II waters, Outstanding Florida Waters, and
waters designated by rule as a fish management area by the Florida Game and Fresh Water Fish
Commission.

Specific Authority 370.021, 369.20, 369.22, 369.251 FS. Law Implemented 369.20, 369.22,
369.251, 403.088 FS. History-New 2-9-82, Amended 7-9-85, Formerly 16C-20.015, 16C-
20.0015, Amended 5-3-95.

62C-20.002 Permits Applications.
(1) No person shall attempt to control, eradicate, remove, or otherwise alter any aquatic plants in
waters of the state, including those listed in Section 369.251, F.S., except as provided in a permit
issued by the department unless the waters in which aquatic plant management activities are to
take place are expressly exempted in Rule 62C-20.0035, F.A.C.
(2) Permits issued pursuant to this chapter are not intended to allow for the collection and
subsequent use of the removed plants, unless specifically provided for in the permit conditions.
(3) Application format and requirements:
(a) All applications for new permits or modifications to existing permits shall be submitted in
accordance with the requirements of this rule.
(b) All application documents shall be submitted in an 8 1/2 by 11 inch format and be of good
quality and clearly legible.
(c) Each application shall be submitted on DEP form 50-032(16) (Aquatic Plant Management
Application, effective date 5-3-95, which is hereby incorporated by reference), and is available at
no cost from the bureau.
(d) All applications, except for those from government agencies, research institutions, and
wastewater treatment facilities approved by the Department of Environmental Protection, shall
be in the name of and signed by the riparian owner who shall, upon request, provide proof of
riparian ownership. An application may be submitted by an agent of the riparian owner provided
that the name, address, telephone number, signature of the riparian owner, and agent is provided
on the application. Persons representing multiple riparian owners such as, but not limited to,
governmental agencies and officers of homeowners associations may submit an application
without the name, address, telephone number, and signature of all riparian owners. However, the
name, signature, address, and telephone number of the contact person must be shown.









(e) As part of the application, the applicant shall provide the name of the waterbody, if it is
named, and a map with directions to the proposed management site using county, state, and U.S.
highway names and route numbers.
(f) As part of the application the applicant shall provide a detailed diagram of the proposed
management site which shall contain at a minimum the following information:
1. 1. Riparian owner's property boundaries, including dimensions.
2. 2. Approximate water's edge at the time of the proposed application.
3. 3. All prominent features such as docks, fences, trees, etc., located near the water's edge.

4. All aquatic plant communitieslocated at the site identified by name or symbol, with a clear
depiction of the aquatic plants proposed for control including the dimensions of the control area
and the vegetation not to be controlled.
5. The proposed control method to be used.
2. 6. Type of public notification to be used when applying herbicides with water use restrictions
required by the herbicide product label.

7. Legends thatexplain all symbols and patterns used.
.(g) Each applicant shall submit one complete application bearing original signatures and two
copies of the complete application to the appropriate regional biologist.
.(4) The regional biologist shall review and determine the completeness of each application and
may conduct an on-site inspection.
.(5) Final agency action on permit applications.
.(a) Allconditions of the permit shall be stated on the permit.
.(b) Permits shall be effective for a period of three years from the date issued.
.(6) Permit amendments:
.(a) The permitted may request an amendment subject to the procedures and review criteria of
this chapter.
.-69
.(b) Following notice to the permitted, the department is authorized to amend a permit issued
pursuant to this chapter during the term of the permit to restrict or limit the scope of the
permitted activity. This shall be done if necessary to ensure the protection of human health,
safety, recreation, plant and animal life, and property.
.(c) A permit issued pursuant to this chapter may be transferred at the written request of a new
owner or assignee of the permitted property when accompanied by written consent from the
permit holder. If any changes, additions, or modifications to the permit are requested, an
application for a new permit must be filed for processing.
.(7) It shall be the responsibility of the permitted to submit a renewal application 45 days prior to
the expiration date of the permit.
.(8) When a person enters into a contract with the department to conduct aquatic plant
management for research purposes or pursuant to an eradication or maintenance program
initiated under Chapter 62C-52, F.A.C., or Chapter 62C-54, F.A.C., the execution of the contract
shall constitute the department's permit for aquatic plant management.

Specific Authority 370.021, 369.20, 369.22, 369.25, 369.251 FS. Law Implemented 369.20,
369.22, 369.25, 369.251, 403.088 FS. History-New 5-8-77, Amended 2-9-82, 7-9-85, Formerly
16C-20.02, 16C-20.002, Amended 5-3-95.










62C-20.0035 Waters Exempt from Permitting.
.(1) No aquatic plant management permit is required by the department for the following waters:
.(a) Waters wholly owned by one person, other than the state, provided there is no connection to
Waters of Special Concern.

.(b) Class IV waters or artificially created waters used exclusively for agricultural purposes,
provided there is no connection to Waters of Special Concern.
.(c) Electrical power plant cooling ponds, reservoirs, or canals unless used as or connected to
waters designated by the department as manatee aggregation sites.
.(d) In waters of 10 surface acres or less provided there is no connection to Waters of Special
Concern. The acreage of waters in systems with any connections shall be calculated for each
individual water rather than collectively as a system. Natural connections between non-exempt
waters shall be considered part of those waters.
.(e) In that specific area of a waterbody where a dredge and fill activity is permitted by the
Department of Environmental Protection and aquatic plants are removed as a part of the
permitted activity.
.(2) Although certain waters are exempt from the department's permit requirements, all aquatic
plant management activities shall be conducted in a manner so as to protect human health, safety,
recreational use, and to prevent injury to non-target plant and animal life, and property, to the
greatest degree practicable. When applying a herbicide in exempt waters, all persons shall
comply with label rates, instructions, cautions, and directions, and shall follow the public notice
requirements of paragraph 62C-20.0055(2)(c), F.A.C. No aquatic plant management activity
using herbicides or mechanical harvesting equipment shall be conducted when manatees are in
the control area in exempt waters. Copper-based herbicides shall not be used in any exempt
waterbody connected to any natural waterbody designated as a manatee aggregation site without
a permit from the department.

Specific Authority 370.021, 369.20, 369.22, 369.251 FS. Law Implemented 369.20, 369.22,
369.251, 403.088 FS. History-New 2-9-82, Amended 7-9-85, Formerly 16C-20.035, 16C-
20.0035, Amended 5-3-95.

62C-20.0045 Criteria for Issuing, Modifying or Denying Permit Applications.
.(1) The department recognizes the varied human and environmental concerns for Florida's
waters. Aquatic plant management permits shall be issued to allow persons reasonable access to,
and use of, these waters while maintaining sufficient native vegetation to provide for
environmental concerns such as the impact upon fish, wildlife, water quality, and shoreline
stabilization. Native aquatic plant species in natural waters will not be considered for control
unless the native species alone, or when intermingled with nonindigenous species, have become
noxious.
(2) In determining whether a permit shall be issued for aquatic plant management purposes, the
department shall consider the following criteria:
(a) The noxious aquatic plant species present and the potential of the target plants to create
adverse effects.
.(b) The amount and quality of the aquatic plants within the waterbody and the proposed
management site, and their importance to biological communities that are utilizing them.










(c) The positive or adverse impacts of the aquatic plant management activities on public interest
considerations such as:
1. 1. Health and safety of the public.
2. 2. Navigation.
3. 3. General public's access to, or use of, the waterbody.
4. 4. Riparian property owners' access to, or use of, the waterbody.
5. 5. Swimming, fishing or other recreational activities.
6. 6. Water flow or the potential for flooding.

(d) The positive or adverse impacts of the aquatic plant management activities on fish and
wildlife considerations such as:
1. Endangered or threatened species, species of special concern, or their prey species and habitat.
2. The potential of the management activities to improve habitat for the production of fish and
wildlife, including non-game species.
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3. The potential of the plant management activities to increase or improve native aquatic plant
species diversity.
(e) The positive or adverse impacts of the proposed aquatic plant management activities on water
quality considerations such as:
1. 1. Native plant coverage which may protect or improve water quality.
2. 2. Native plant coverage which may prevent or reduce shoreline erosion and runoff.

3. Nutrient levels, dissolved oxygen levels, deposition of organic matter, herbicide residues or
other impacts on water quality outside of the control area designated by the department.
.(f) The protection of the receiving waterbodies consistent with the classes of surface waters
established pursuant to Chapter 62-302, F.A.C.
.(g) The potential of the proposed activity tospread noxious aquatic plants, or to promote the
survival and growth of native aquatic plants.
.(3) The department will not issue more than one permit for the same activity at the same site, at
the same time, in the behalf of a riparian owner.
.(4) The removal, cutting, collecting, or altering in any way of mangroves, mangrove seeds
(fruits) or propagules, or plants restricted by Rule 46-42.001, F.A.C., are not regulated by this
chapter and, therefore, shall not be permitted pursuant to Chapter 62C-20, F.A.C.
.(5) If after review of a complete application the department determines that the proposed
activity does not conform to the criteria as established in Rule 62C-20.0045, F.A.C., the
department shall deny the permit.

Specific Authority 370.021, 369.20, 369.22, 369.251 FS. Law Implemented 369.20, 369.22,
369.251, 403.088 FS. History-New 2-9-82, Formerly 16C-20.045, 16C-20.0045, Amended 5-3-
95.

62C-20.0055 Management Method Criteria and Standards, Operations and Reporting
Requirements.
.(1) Management Method Criteria and Standards
.(a) Herbicide control activities:










1. Allherbicide control activities shall be in conformity with label requirements of the product to
be used.
1. 2. Herbicides that require water use restrictions when used according to label requirements,
and do not indicate a potable water intake setback distance on the label, must not be used to
manage floating plants within 0.5 miles of a functioning potable water intake in a lake or within
two miles upstream or 0.5 miles downstream of a functioning potable water intake in a river
system.
2. 3. When used to manage aquatic vegetation other than floating plants, herbicides that require
water use restrictions when used according to label requirements, and do not indicate a potable
water intake setback distance on the label, must not be used within two miles of a functioning
potable water intake in a lake or within two miles upstream or 0.5 miles downstream of a
functioning potable water intake in a river system.
3. 4. When management activities, using a herbicide without a potable water setback distance,
are to take place within two miles of a functioning potable water intake in a lake, or within two
miles upstream or 0.5 miles downstream of a functioning potable water intake in a river system,
written notice by certified mail must be given to the operator of the water treatment plant and to
the bureau at least one week prior to the treatment activity, unless an alternative notification
system has previously been approved by the department.
.5. When more than one herbicide is registered for use in an aquatic site, the department shall
require the use of the herbicide which it determines has the least adverse effect upon human
health, safety, recreational uses, non-target plants, fish, and wildlife. In determining which
herbicide shall be used, the following criteria shall be considered:
.a. Which herbicide will provide the greatest protection to human health, safety, and recreational
uses.
.b. Which herbicide will provide the greatest protection to non-target plant and animal life.
.c. Which herbicide will be most effective at controlling the targeted species.

1. 6. Noherbicide shall be permitted for use in violation of label requirements as registered by the
Department of Agriculture and Consumer Services or the United States Environmental
Protection Agency.
2. 7. Application of herbicides shall be conducted at all times in a manner to cause the least
possible adverse effect on human health, safety, recreational uses, non-target plants, fish, or
wildlife.
3. 8. Management activities using herbicides shall not be permitted in manatee aggregation sites
when manatees are present except when automatic herbicide spreaders operating on timing
devices have been authorized by a permit.
4. 9. In order to protect the welfare, safety, and health of manatees, when manatees are sighted in
a control area, all herbicide control operations must cease immediately (except when automatic
herbicide spreaders operating on timing devices have been authorized by a permit), and shall not
be resumed until all manatees have left the control area of their own volition. No manatee may
be herded or harassed into leaving the control area.
5. 10. Proposed herbicide treatments that may cause the rapid decay of aquatic vegetation and
possible oxygen depletion, shall be required to be staggered or conducted in stages to allow time
for recovery and stabilization of oxygen levels between treatments.









(b) Mechanical and Physical Control Activities:
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1. 1. Mechanical aquatic plant management operations shall be conducted in a manner which will
not cause further significant spread of noxious aquatic plant species. All cut or harvested aquatic
vegetation shall be deposited as prescribed in the permit. No substrate is authorized to be
recontoured or removed under an aquatic plant management permit.
2. 2. When manatees are sighted within 50 feet of mechanical operations, all operations must
cease immediately and shall not be resumed until all manatees have left the mechanical
operations area of their own volition. No manatees may be herded or harassed into leaving the
control area.
3. An aquatic plant management permit is required to fluctuate water levels when the primary
purpose is for aquatic plant management. A permit to fluctuate water levels may also be required
from the appropriate water management district.
(c) Biological Control Activities:
3. 1. The use of fish as a biological control for aquatic plants requires a permit from the Fish and
Wildlife Conservation Commission which has statutory authority for the regulation of the use of
fish.
4. 2. All other biological control agents shall be used only if approved for general release by the
U.S. Department of Agriculture and the Florida Department of Agriculture and Consumer
Services.

(2) Operations Requirements:
.(a) All persons conducting aquatic plant management activities shall remove from the site and
properly dispose of, in accordance with label instructions, all herbicide containers which result
from aquatic plant management activities.
.(b) All persons conducting aquatic plant management activities shall allow employees of the
department to conduct inspections, sample waters in management sites, observe control activities
at management sites, and review records required by; subsection 62C-20.0055(3), F.A.C., of this
chapter in order to determine compliance with the terms of this chapter and permit conditions. In
addition, all persons shall allow employees of the department, acting as agents of the Department
of Agriculture and Consumer Services, pursuant to an interagency memorandum of
understanding (effective date 22 May 1985, which is hereby incorporated by reference and is
available from the bureau) to remove samples from spray tanks to ascertain compliance with the
terms of this chapter, and permit conditions.
.(c) Prior to undertaking herbicide control activities, each permitted shall notify potential users
of waters, subject to or affected by the aquatic plant management activities, if there are use
restrictions on the herbicide label for treated waters. The permitted must use one or more of the
following methods of notice, which shall be stated on the permit, for posting water-use
restrictions to properly notify the affected public:
1. 1. The posting of signs at access points.
2. 2. The publication of notice in a newspaper of general circulation in the affected area.
3. 3. The placement of notices at the management site.
4. 4. The establishment of a signal or marker system.
5. 5. Giving notice at established point of contact.
6. 6. Other methods, approved in advance by the department, designed to reach the affected
public.









.(d) The notice shall include, at least, the types of activities which will be temporarily
prohibited, or restricted, and the dates for which these prohibitions, or restrictions, are applicable.
The notice must remain posted during the period for which any use restrictions are in effect.
.(e) Any person engaged in aquatic plant management must have a copy of the aquatic plant
management permit when conducting control activities, unless activities are being undertaken
pursuant to Chapter 62C-54, F.A.C.
.(f) If the department finds that immediate, serious danger to the public health, safety, or welfare
requires emergency action, it is authorized, to suspend, restrict, or limit the scope of the
permitted activity by emergency order. Any emergency action taken pursuant to this rule shall be
promptly reported to the Governor as agency head.
.(3) Reporting Requirements:
.(a) Eachpermittee shall maintain records of herbicide use conducted pursuant to this chapter on
DEP Form 50-031(16) (Aquatic Plant Management Annual Operations Report, effective date 5-
3-95, which is hereby incorporated by reference and is available from the bureau). An equivalent
report may be used provided it is approved in advance by the bureau.
.(b) The Operations Report Form, or other approved equivalent form, shall be sent to the bureau
each year within 30 days following the anniversary of the issue date or the expiration date of the
permit.
.(c) Subsequent permits will not be issued or renewed until the Operations Report is received. A
permit is subject to revocation if the Operations Report is not received within the required time
frame.

Specific Authority 370.021, 369.20, 369.22, 369.251 FS. Law Implemented 369.20, 369.22,
369.251, 403.088 FS. History-New 2-9-82, Amended 7-9-85, Formerly 16C-20.055, 16C-
20.0055, Amended 5-3-95.

62C-20.0075 Penalties.
.(1) Following proper notice, the department is authorized to modify, revoke, suspend, annul, or
withdraw any permit granted by it, or deny or modify any permit request, if the department
determines that the following actions were committed by the permitted or applicant:
.(a) Submission of false or inaccurate information in the permit application, requests for
amendments or renewals, or records maintained pursuant to subsection 62C-20.0055(3), F.A.C.
.-72
.(b) An unresolved violation of a permit, permit conditions, this chapter, or Florida Statutes
relating to aquatic plant management activities.
.(c) Failure to file an operations report within the specified period of paragraph 62C-
20.0055(3)(b), F.A.C.
.(2) Violators of this chapter involving the use of herbicides are subject to penalties as provided
in Sections 403.141 and 403.161, F.S.

Specific Authority 370.021, 369.20, 369.22, 369.251 FS. Law Implemented 369.20, 369.22,
369.251, 403.088, 403.141, 403.161 FS. History-New 2-9-82, Formerly 16C-20.075, 16C-
20.0075, Amended 5-3-95.




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