Shellfish aquaculture research...
 Thermal tolerance of triploid...
 Design and management of reefs...
 Florida ecosystems in the...

Group Title: Waterworks
Title: Waterworks. October 2007.
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00067314/00016
 Material Information
Title: Waterworks. October 2007.
Series Title: Waterworks
Physical Description: Serial
Language: English
Creator: Institute of Food and Agricultural Sciences
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Publication Date: October 2007
 Record Information
Bibliographic ID: UF00067314
Volume ID: VID00016
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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Table of Contents
    Shellfish aquaculture research and extension
        Page 1
    Thermal tolerance of triploid clams
        Page 2
    Design and management of reefs for fisheries
        Page 3
    Florida ecosystems in the spotlight
        Page 4
Full Text


Newsletter of the UF/IFAS Department of Fisheries and Aquatic Sciences October 2007

The Shellfish Aquaculture Extension
Program (SAEP) works with research
faculty in the Department of Fisheries and
Aquatic Sciences (FAS) to develop and
implement applied research and extension
educational projects for the state's shellfish
aquaculture industry. In collaboration with
industry, institutional, and agency stake
holders, these projects are focused on four
major areas: (1) genetic stock improvement;
(2) water quality monitoring; (3) animal
health and (4) production technologies.

G enetic Stock Improvement Using
federal and state funds, SAEP and
FAS faculty conduct applied research
to help develop a hardier clam strain
through breeding techniques that improve
survival during prolonged hot summers. A
combination of high water temperature,
reduced oxygen and high clam
metabolism may contribute to increasingly
high summer mortalities observed in
Florida hard clams. A Florida Sea Grant-
funded project is evaluating the use of
triploidy to enhance clam production.
Results from field trials conducted with
industry partners and laboratory studies
conducted by Dr. Shirley Baker and her
graduate students will determine if triploid
clams have greater resistance to summer
environmental stressors through reduced
gametogenesis. The use of hybrids between
the hard clam Mercenaria mercenaria and
southern quahog clam M. campechiensis
for increasing survival and production
is being examined with USDA special
research grant funding procured through
the efforts of the Cedar Key Aquaculture
Association. Triplicate families of each,
and their reciprocal hybrids, are being
produced this fall by Dr. John Scarpa at

the FAU Harbor Branch Oceanographic
Institution and will be evaluated under
commercial conditions during 2008-09.

W after Quality Monitoring SAEP
has developed a partnership with
federal and state agriculture agencies for
continued operation of water quality and
weather monitoring stations to provide
data for a decision support tool used by
the clam industry. Currently, stations
are located at 7 high-density lease areas
in 5 coastal counties. These stations
provide timely continuous information
to clam growers, allowing them to make
informed management decisions based on
temperature and salinity measurements.
This program, however, does not allow for
an in-depth understanding of the influence
oftemperatureon clam production. Smaller
data loggers (that can fit inside clam bags)
were recently purchased with Hatch
funding, and will allow for greater spatial
resolution and broader data coverage.
This summer clam growers are deploying
these units at multiple lease sites so that
temperature variability can be related
to water depth, substrate characteristics,
currents and other parameters.

Animal Health In 2003, FAS and
SAEP faculty conducted a preliminary
health assessment of cultured clams by
examining samples from several growing
areas. No serious disease-causing agents
were detected. However, there is a
concern regarding the health of stocks as
growers report crop losses during summer.
Pathology may be exacerbated by stressors
or high stocking densities. With Hatch
funding, a more thorough examination of
stocks prior, during and after the summer

months by Dr. Denise Petty will help
determine if environmental diseases or
disease pathogens are present. In addition,
low larval survival has been reported in
Florida hatcheries in recent years and
has impacted clam seed production.
Therefore, site visits by Dr. Petty will
include assessment of hatchery protocols
and health of larvae and post-set seed. The
goal is to reveal practices that are limiting
to seed production.

reduction Technology Diversifying
the hard clam culture industry by
developing farming technology and
markets for other bivalve species would
increase economic stability and growth.
Florida Sea Grant is funding a project
where faculty from SAEP, FAS, Food and
Resource Economics Department and
FAU Harbor Branch will develop and
demonstrate biological and technical
procedures for spawning and culturing the
sunray venus clam Macrocallista nimbosa.
The sunray venus is an attractive venerid
clam distributed from South Carolina to
Florida and the Gulf states. Commercial
fishermen targeted the large 4-7 inch
clam in the late 1960s off the northwest
Florida coast for the chowder market but
the erratic size of the fishing grounds
precluded large-scale exploitation of this
fishery. Recent growth experiments, using
marked individuals, suggest that these
popular clams can attain a length of 3
to 12 inches in just 12 months, similar
to market size of hard clams in Florida.
The existence of a prior fishery, market
potential and growth rate, along with it
being a native species, make the sunray
venus a logical choice as a new species
to diversify the shellfish aquaculture
industry. Broodstock have been selected
and spawned and the juveniles are being
culutred by industry parnters in land-based
nurseries and commercial leases.
Leslie Sturmeris a multi-county shellfish
aquaculture extension agent and faculty
member in the Department of Fisheries
andAquatic Sciences
Contact the Author:
LNST@ufl.edu or (352) 543-5057


Student Spotlight

The northern hard clam (Mercenaria
mercenaria) has been a popular seafood
item for many years, and is an important
aquaculture crop along the eastern
seaboard. Aquaculture of the northern
hard clam became prevalent on the
west coast of Florida in the 1990s after
a retraining program was initiated for
fishermen impacted by poor oyster harvests
and Florida's gillnet ban. Clam farming has
been a success story for Florida's coastal


In this photo, Elise is examining a group of triploid
clams that were grown at a particular water
temperature for their viability

fishermen, where the warm plankton-rich
waters allow clams to reach market size
in 12 to 18 months, faster than other areas
along the east coast. With a net profit of
10.7 million dollars in 2005, the Northern
hard clam is one of the most economically
important aquaculture species in Florida's
marine waters.

In recent years, clam farmers on the West
coast have reported lower than average
survival and crop losses during the long
hot summers. This has been attributed to
higher than average water temperatures
combined with fluctuating salinities, low
dissolved oxygen levels, and potentially
lower food availability. In addition to
stressful environmental conditions, the
hard clam loses a significant amount of
energy reserves to reproductive activity
during the spring in Florida, leaving them

more susceptible to
poor conditions.

Clam farmers met
with scientists,
managers and
extension agents to
discuss concerns
with the high clam mortalities. Triploidy
was suggested as a possible solution, since
triploid bivalves have been shown to have
reduced reproduction, which could then
be realized in additional energy stores
available during summer months. Hard
clams are diploid in nature, meaning
they have 2 sets of chromosomes per cell,
whereas triploid organisms have three sets
of chromosomes. Triploid and diploid
hard clams were produced at FAU Harbor
Branch Oceanographic Institution.

As part of my master's thesis, I conducted
laboratory experiments to assess the value
of triploidy for hard clam aquaculture. I
challenged two sizes of clams to a range of
water quality conditions and assessed their
survival. I tested growout-size seed clams
(20 mm average shell-length) and pasta-
size clams (46 mm average shell-length)
which represent the two size classes that
are typically in the field during summer
months. Groups of clams were exposed
to 14 different treatments, representing the
range of salinity, temperature and dissolved
oxygen conditions to which clams might
be exposed during summer in Florida.

I found that there was only one treatment in
which triploids survived in greater numbers
than diploids. Pasta-size triploid hard
clams performed well at high temperatures
and low dissolved oxygen, while diploid
hard clams had lower survival. Growout-
size diploid clams performed better or the
same as triploids in all of the experimental
conditions, suggesting there may be a
disadvantage to triploidy at a smaller size.

Is triploidy a potential solution for Florida's
hard clam industry?

Based on the results of these laboratory
challenges, probably not. However,
additional on-going research relating to this
project, including scope for growth studies
and larger-scale field experiments, will
provide additional information and perhaps
a modified answer to that question.

A large number of tanks were used in a controlled
laboratory setting to allow exposure of clams to a
wide range of water temperatures.

Despite the apparent lack of higher survival
rates under adverse conditions, triploidy
does have other benefits. Sterility, or lack
of reproductive activity, would be beneficial
in areas interested in containment of
non-native species for aquaculture use.
In addition, sterility has been found to
correlate with higher glycogen content in
triploid oysters, giving them a sweeter taste.
This may also be the case for clams.

Elise is a Master's student and her advisor
is Dr. Shirley Baker.

Design and Management of Artificial Reefs for
Fisheries was the title of a European Union-
funded short course held in May 2007, as the
first of its kind in the world.

Attendees from various natural resource-related
ministries, academia and businesses came to
Zaragoza, Spain from several countries of the
Mediterranean Sea basin, but also from as far
away as Malaysia, Mexico and Norway.

One of the invited organizers and lecturers was
Bill Seaman of the FAS faculty, who delivered
presentations on matching reef ecology to
ecosystem management and on reef planning
concepts and practices. Major topics of the
course included the ecology of artificial reefs,
their design and evaluation, and role in fishery
management, with theory balanced by a week-
long case study and independent reef system
planning exercises.

While artificial reef-related research and
development may have peaked in some
nations, in others areas there is growing

An enrollmentof28professionals from 13 countries
joined 8 organizers and lecturers including FAS'
own Bill Seaman (far left, third row up) for the
week-long short course in Zaragoza Spain.

interest in fisher
conservation and ec
tourism applications. The
were about 100 application
for 28 openings. The court
was held under the auspic
of the International Cen
for Advanced Mediterrane
Agronomic Studies, throu
its Mediterranean Agronomic Institute
Zaragoza. The Institute offers both sh
courses and graduate residential programs
subjects including aquaculture.

Dr. William Seaman is Professor Emerit
in FAS. For much of his career, he has be
involved with developing and extending t
scientific basis for artificial reef technolo
and continues this effort as part of broad
more recent activities related to stewards
and sustainability of earth and sea resource
globally. He is an invited speaker for the 20
World Fisheries Congress.

Contact the author:
Email: seaman@ufl.edu

WaterWorks is a publication of the
UF/IFAS Department of Fisheries and
Aquatic Sciences, aimed at providing
up-to-date information on activities
of the Department to prospective
students, alumni, stakeholders, and
agency & academic partners.

If you would like to contribute an
article or informational bullet for a
future issue of WaterWorks, please
contact the Editor, Dr. Karl Havens,
by email at khavens@ufl.edu or by
telephone at 352-392-9617 x 232.

Thank you.


o- Sttutdl~ent
re & iFacildty
rse (e / v vs
:es \ \\\
tre Dr. Tom Frazer
an was selected
gh to receive a
of University
ort of Florida
Research Foundation
in Professorship Award. The
three-year professorship
.... -. ,.. ,faculty who have
:us established a distinguished
en record of research and
he scholarship at UF
gy' Nikki Dix and
er, Zy Biesinger,
iP N both PhD
:es students in FAS,
08 were i.. .. .i i.,/ for their
research in marine science
at the UF capital campaign
Gala Kickoff Event at the
O'Connell Center.

SCarl Walters
joins us again
this fall, teaching
an advanced
fisheries management
course to FAS students and
fisheries experts at state
and federal agencies. Carl
is a Professor at U. British
Columbia and an Eminent
Scholar in the UF/IFAS
Department of Fisheries
and Aquatic Sciences.

New Students!
Welcome to
(PhD student),
Jessica Beasley (PhD),
Felipe Carvalho (MS), Eric
Casiano (MS), Amanda
Foss (MS), John Hargrove
(MS), Nathan Johnson
(PhD) Darren Pecora
(MS), Eric Thomas (MS),
and Erika Thompson (MS).


The Kissimmee Chain of Lakes

The Kissimmee Chain is a group of natural lakes located just to the south of
Orlando, forming the headwaters of the Kissimmee River and the northernmost
part of the greater Everglades ecosystem. The numerous lakes of the Kissimmee
Chain were historically connected by streams and sloughs and it was typical
for the lakes to experience large seasonal and year-to-year variations in water
level. This unpredictable hydrology resulted in diverse communities of
submerged and emergent aquatic plants and adjacent wetlands around the
lakes, which provided a large regional habitat for fish, wading birds and migratory waterfowl. Today the lakes continue to support
important ecological values and several of them are prized for their recreational fisheries -- in particular largemouth bass. However,
the natural hydrologic variability has largely been lost in most of the lakes, as a result of man-made canals that now connect many
of the lakes and regulate water levels -- necessary because development has occurred in many places right down to the region of
historic high water. In recent decades, stabilized water levels in the Kissimmee Chain, coupled with explosive growth of the invasive
plant Hydrilla, have led to reduced diversity of shoreline plant communities and build up of 'tussocks' of dead plant material and
detrital muck along the lake shore. This material degrades the shoreline habitat and reduces the lake's ecological and societal values.
To address the problem, state and federal agencies have traditionally carried out short-term rehabilitation projects in which water
levels are lowered, muck is scraped from the shoreline and deposited in spoil islands within the lake, and herbicides are used to
control regrowth of undesirable plants. The South Florida Water Management District and its state and federal partners now are
looking at ways to reintroduce more of the natural hydrologic variation to these lakes, as a longer-term solution to the problems noted
above. UF Faculty, including Dr. Mike Allen, serve on advisory panels for this work. [Photo Credit: www.sfwmd.gov]

Rock Lobster!
Don Behringer is our newest FAS faculty member. His
research focuses on near-shore marine environments
where he studies the impact of human-related changes
in habitat and water quality on organisms at population
and community levels. His current research deals
with the dynamics of a lethal pathogen that infects the
Carribean spiny lobster.
This research is centered on PaV1, an irido-like virus
that he and colleagues at Old Dominion University and
the Virginia Institute of Marine Sciences discovered in
1999. It is the first naturally-occurring virus found in
any lobster.
The goal of this
research program
is to determine how
stressful environmental
conditions, coupled
with life history changes
in host behavior and
disease susceptibility,
generate the pattern of
infection prevalence
and distribution
observed in the Florida
Keys. One important
early result is a finding

that healthy lobsters are able to detect and avoid
diseased lobsters, potentially limiting disease
transmission in the wild. This is the first discovery of
such a behavior and it stands to change our perceptions
regarding the role of behavior in the transmission of
disease in social animals.

In addition to this work with spiny lobsters, Dr.
Behringer has worked on the inter-habitat con nectance
of food webs using stable isotope tracer techniques.
In the Carribean, seagrasses produce much of the
organic carbon in shallow waters, and it has long
been assumed that much of this carbon is exported to
nearby habitats, supporting their foodwebs. However
recent results with hard bottom habitats suggest they
are largely supported by autochothonous production
of algae rather than seagrass.

Dr. Behringer also is interested in the influence of
enhancement, restoration, and conservation efforts
on populations and communities. The use of artificial
enhancement mechanisms to maximize animal
abundances is widespread and while most investigators
have studied the efficacy of the mechanism, the effect
of habitat enhancement on the processes creating
such patterns remains largely unknown.

Contact the author:

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