Sturgeon trackers
 Student involvement at UF
 Sturgeon trackers continued
 UF/IFAS aquaculture and pond management...
 Parasites in fish - pentasomes
 Hillsborough Community College...
 Common duckweed

Group Title: Waterworks
Title: Waterworks. Volume 5, Number 3. 2001.
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00067314/00008
 Material Information
Title: Waterworks. Volume 5, Number 3. 2001.
Uniform Title: Waterworks
Physical Description: Serial
Creator: Institute of Food and Agricultural Sciences
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Publication Date: 2001
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00067314
Volume ID: VID00008
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Table of Contents
    Sturgeon trackers
        Page 1
    Student involvement at UF
        Page 2
    Sturgeon trackers continued
        Page 3
    UF/IFAS aquaculture and pond management update
        Page 4
        Page 5
    Parasites in fish - pentasomes
        Page 6
    Hillsborough Community College news splash
        Page 7
    Common duckweed
        Page 8
Full Text

University of Florida Cooperative Extension Service/ Institute of Food and Agricultural Sciences Volume 5 Number 3 2001

August 24 December 14
Fall 2001 Departmental Seminar Series
Fisheries and Aquatic Sciences/ Gainesville, FL
Friday @ 3 PM Schedule available on-line:

August 14-15
Fish Health Management Workshop
Ft. Lauderdale
Dr. Ruth Francis-Floyd 352/392-9617 ext 229

October & November
Recreational Pond Management Workshops
Call for more information or check web site:
Chuck Cichra 352/392-9617 ext 249

November 26 December 1
Marine Ornamentals Conference 2001
Walt Disney Resort/Buena Vista, FL
Beth Miller Tipton 352/392-5930

May 19-24 2002 ,y of
Aquatic Weed Control ".- e
Short Course 2002 ,
Ft Lauderdale Marriott
North/ Ft Lauderdale, FL
Beth Miller-Tipton
E-mail: bmiller-tipton@mail.ifas.ufl.edu

Graduate student Julianne Harris tracks (

Srs. Daryl Parkyn
along with biolo-
gists Doug Colle
and Jamie Holloway have
just spent a busy season
plying ancient waters for
wild sturgeon research in
the Suwannee River, with
plenty of work still ahead.
"There are three differ-
ent sturgeon projects
we're concentrating on,"
says Daryl.
"One is development
and implementation of
non-lethal methods for
examining stomach con-

sturgeon moving up the Suwannee river.

tents of these fish. It's
called a lavage method.
Basically we pump the
stomachs of live fish, and
follow that up by making
sure the fish aren't dying.
To do that, we're holding
the fish in tanks for up to
72 hours. This will give us
a better idea of the food
habits of the fish. We're
also putting telemeters in
some of these fish, to
track them in the river," he
This is also part of a
second collaborative study
which examines the sur-

vival of sturgeon that were
collected for the brood
stock program. To examine
these survival issues in
the fish, they've been in-
serting ultra-sonic tags,
pingers, which are used
to determine the location
of each fish. If the fish tag
becomes stationary for a
long period of time, Daryl
sends a diver down to

Continued on page 3.

Instte of Food and Agcultural Sciences

The following UF/IFAS
faculty and staff are
available to answer
questions or provide
technical support for
aquaculture, fisheries
and aquatic sciences,
and pond management.

Frank Chapman
Reproductive Biology
352/392-9617 ext 247
Chuck Cichra
Pond Management &
Fish Biology
352/392-9617 ext 249
Ruth Francis-Floyd
Fish Health/Aquaculture
352/392-9617 ext 229
Ruth Ellen Bowen
Fish Health
352/392-9617 ext 230
Allen Riggs
Fish Health Management
352/392-9617 ext 235

Debbie Britt Pouder
Food & Bait Aquaculture

Eric Curtis
Fish Health
813/671-5230 ext 106
Craig Watson
Research Coordinator
813/671-5230 ext 107
Roy Yanong
Fish Health/Aquaculture
813/671-5230 ext 104

Carlos Martinez
Ornamental Fish
813/671-5230 ext 109

Ken Langeland
Aquatic Plants

Chuck Adams
Marine Economics
352/392-1826 ext 223
David Zimet
Freshwater Economics

Ray Bucklin
Aquaculture Engineering
bucklin @agen.ufl.edu

John Brenneman
Polk/Hillsborough Counties
Max Griggs
Escambia County
Bill Mahan
Franklin County
Leslie Sturmer
Shellfish Aquaculture
Don Sweat
Pasco County

Undergradate and graduate students are an important part of the teaching,
research, and extension programs at the University of Florida. Student involve-
mentis highlighted in each issue of WaterWorks.

Beth Sargent, a native
of New England, has
spent the last seven
years working on un-
dergraduate and gradu-
ate degrees here at UF
She received a Bach-
elor of Science degree
in Wildlife Ecology and
Conservation in 1998,
and will earn her MS
degree later this year.
During her under-
graduate career, Beth
developed a keen inter-
est in aquatic systems.
In the fall of 1998, she
started her master's
degree under the direc-
tion of Dr. Ed Phlips and
Dr. Anson Moye, deal-
ing with the issue of
mercury contamination
and bioaccumulation in
aquatic systems, includ-
ing the Everglades.
Mercury is a major
health issue and concern
because of its negative
health effects on humans
and other organisms.
While studies in the
past have focused on
mercury in fish and
wildlife and even zoop-
lankton, few studies
had focused on algae,
specifically periphyton
or algal mats that are
characteristic of many
aquatic systems.
"The micro-ecosys-
tem of periphyton is a
major player in primary
productivity of the com-
plex Everglades system.
However, little is known
about how its structure
and function affect
mercury uptake," said
Because periphyton
is complex in composi-

Beth discusses her research with her faculty

advisor Dr. EdPhli
tion, most resear
have found it diffi
determine what f;
affect mercury u
and its bioaccumu
into the plant tissu
The goal of E
study was to ch
species from the
and grow them in t
to learn about their
ology under diff
conditions, primarily
low and relatively
phosphorus levels.
By understanding
effects of varying phc
rus levels on the dif
species of algae
physiological respond
the algae can then

chers lated to their rate of
cult to mercury uptake.
actors Understanding how
take and at what rate the
elation cells take up mercury
e. can help researchers
Beth's and managers develop
loose a better understanding
algae of how mercuryfunctions
mats in an aquatic system
he lab and how it is trans-
physi- ported through the food
erent web to such high levels.
under Data from Beth's
high work and from other
mercury projects across
ngthe the country will be
)spho- used to develop a
ferent model for predicting
, the which areas are more
sesof prone to higher levels
be re- of mercury and how
those areas can then
be managed.
"My project provides
the groundwork for
understanding what
happens to mercury at
the bottom of the food
web and how it gets
Theree" said Sargent.
"Hopefully it can be
applied to manage-
ment in the Everglades
Sand elsewhere."
Beth is currently
completing her thesis
and seeking ajob in the
aquatic sciences field.

r ^

Continued from page 1.
determine if they have a
dead fish or a shed tag.
To date there have been
no fatalities among the 18
pinger-tagged fish in the
"One interesting thing
about these tags is we
have coated them with a
substance they use on
heart pacemakers, and it
keeps the tags from be-
ing rejected by the fish,"
says Daryl. "Normally a
fish would encase a for-
eign body and expel it .'
through the body wall or Researchers used
Researchers used
the gut cavity. So far this
sturgeon to learn
technique has been
working well.
"Our third project on sturgeon examines
their environmental tolerances. We're look-
ing at the interplay between temperature tol-
erance, oxygen consumption and current
velocity. So we're trying to figure out if the
fish are getting exposed to conditions that
might put them at risk," he said.
To do that involves experiments in the lab
with young fish borrowed from the brood
stock program. They measure oxygen con-
sumption of these fish at different water tem-
peratures and water velocities. They also
monitor the oxygen and temperature in the
Suwannee River as the year goes by, so they
have a good idea of what's going on in the
river on an annual basis.
"In addition, we've released 30 large fish
that have a different kind of tag on them. The
tags will log temperatures they're exposed
to for the next five years. This will allow us to
estimate the fish's metabolic oxygen de-
mands and their metabolic rates. We also
hope to better understand what the tempera-
ture preferences are for these fish at differ-
ent times of the year.
"So if we recover these fish at any time,
we can download the data off the tag and let
the fish go. And even then that tag will con-

Temperature logging tag used for sturgeon project.

Sa tube to -stomach contents from aG G
more about the fish's diet and eating habits.
tinue recording data. With a bit of luck we'll
get some of those fish back," he said.
These three projects have been funded
by the Sturgeon Production Working Group
for the past two years. The Group is com-
prised of people from the Florida Fish and
Wildlife Conservation Commission (also
known as the FWC), Department of Envi-
ronmental Protection (DEP), the Univeristy
of Florida, and a sturgeon aquaculture indus-
try representative a wide range of people.
"Hopefully funding will continue for one
more year, but at the present time it's still up
in the air," Daryl said. "River conditions for
sturgeon were good last spring," he said.
"From February through April the river was
in good shape, with a record number of fish
in reproductive condition. At least, it was
more than we've ever seen in the years
we've been studying them. That was really
encouraging. Unfortunately, in May, we had
a decrease in river flow. So we're not sure
how that affected the survival of a subse-
quent spawn that occurred."
In June, as the river dropped, almost all
of the sturgeon being studied were concen-
trated in an area between Fanning Springs
and Manatee Springs. "Fourteen of the 18
tagged fish concentrated in this area, which
was interesting," he said. "Our hunch is that
they'll remain near the springs even as the
river rises in July from summer rainstorms.
Several studies have suggested that in sum-
mer these fish stay near the springs because
of temperature advantages. It's thought that
the adult fish don't feed during summer, and
they hang out near the springs. The lower
water temperature reduces their metabolic
4 needs. That helps them make it through the
In the fall, they start moving out initially, at
least, into the estuary region near the mouth

of the river. It is presumed
they feed there on the
sand and mud flats. This
fall Daryl, Debra, Doug and
a new graduate student,
Julianne Harris, will be
tracking these fish as they
move out of the river and
into the estuaries.
They will attempt to
identify areas of critical
use for these fish. As Daryl
explains, "This may be
4, important because
They're talking about
Dredging the Suwannee
channel there, and we
don't know yet where
of Mexico they're going to be put-
ting the tailings or where
stirred sediments will be
It could become an important issue,
especially if these fish have critical feeding
habitats. We've seen these fish jumping in
these areas in the fall, but this time we'll have
the pinger tags to keep track of them, and
help us identify if and when they're feeding.
"We do know they're not going to dredge
the East Pass where the Suwannee empties
into the Gulf, which used to be important for
boat traffic between Cedar Key and the town
of Suwannee. Now, after the net ban, it's not
as important for boat traffic. However, this has
been an important portion of the river for
sturgeon migrating upstream.
"Next spring, the pinger tags will still be
working and with some luck, we'll be able to
track these fish to their spawning grounds.
That should help us get a better handle on
where these fish are reproducing," he said.



Institute of Food and Agricultural Sciences

WaterWorks is published by the UF/
IFAS Department of Fisheries and
Aquatic Sciences. Subscriptions to
WaterWorks are free, available upon
request. See the subscription form on
page 8. Questions, comments or edi-
torial submissions may be submitted
by contacting:
Editor Joe Richard
352/392-9617 ext 225
Faculty Advisor Chuck Cichra
352/392-9617 ext 249

UFAFAS Ag -ua F ltu

and Pon Maaemn Update..


of Food and



Florida Sea Grant
continues its work on
several projects that are
related to fisheries and
* The multi-species
project is still in progress.
We've drafted a paper
that profiles businesses
targeting reef fish, lobster,
stone crab, and/or
coastal pelagics in
south Florida.
The second portion of
the project attempts to
impose access restric-
tions on various sectors
of the fishery to see
what may happen to
effort distribution, invest-
ment, and profits.
* Dr. Larkin is doing a
survey of wholesale and
retail sectors of the marine
ornamental industry via
a web site, which should
be quite interesting.
She is soliciting infor-
mation about the most
demanded attributes of
a few selected marine
ornamental species.
This would be helpful for
individuals trying to cul-
ture these species.
* The red tide project is
nearly completed. The
project had two compo-
nents: the economic im-
pact of the1999 red tide
event in Okaloosa County,
and a survey of aware-
ness of Sarasota/Manatee
County residents re-
garding red tide issues.


School children are introduced to Florida's ever popular
spiney lobster at an annual UF/IFAS Fishy"
event held at the Florida Museum of Natural History.

The data are cur-
rently being analyzed.
One interesting finding
is that restaurants and
lodging facilities located
in the coastal zip codes
of Okaloosa County
were found to be signifi-
cantly impacted by the
red tide event.
This was in contrast to
a similar study in
Sarasota and Manatee
Counties. The analysis,
which used Florida
Dept. of Revenue data,
found those industry
sectors lost about $0.5
million in sales.
* With respect to hard
clam culture, a project
nearing completion ad-
dresses the economic
impact of the hard clam
culture industry on the
Florida economy.This
project solicited market
information from 49
shellfish wholesale deal-
ers that handle cultured

hard clams. Information
about sources and des-
tination of product, sales
volumes, market prices,
and out-of-Florida sales
were gathered.
Three distinct regions
were chosen to see how
the markets for each
area differed (East
Coast, Panhandle to
Tampa Bay, and South-
west Coast). Of the firms
interviewed by tele-
phone, approximately
90 percent responded
fully to the questions
posed. Firms that
handled less than one
million clams annually
made up about ten per-
cent of the market, with
70 percent of the sales
volumes attributed to
firms handling more
than one million clams.
Clam wholesale firms
obtained the majority of
their cultured clams
from other growers (73

percent), with the re-
mainder coming from
their own personal
leases and other whole-
saler firms.
Of the total number
of cultured clams sold,
about half went to out-
of-state buyers, while
25 percent went to buyers
within the same region.
Twenty-five percent
went to buyers outside
of the sellers region but
still in Florida. Other
wholesale distributors
represented the most
important type of buyer.
Restaurants and re-
tail buyers were of al-
most equal importance,
with sales directly to
consumers represent-
ing a very small share.
The total economic im-
pact of cultured clam
sales was estimated to
be $34 million. Thus,
the added economic
activity associated with
culture clam sales is
significant, particularly
when compared to initial
grower ($16 million)
and wholesale ($22 mil-
lion) sales.
This added economic
impact is generated by
value-added activities,
out-of-state sales and
the economic activity
created as in-state
sales are re-spent with
local and regional
Chuck Adams
352/392-1826 ext 223



Tropical Fish
Farmers Recovering
from last Winter
The winter of 2000-
2001 was a killer for tropi-
cal fish farmers in Florida,
but the industry is bounc-
ing back. A series of cold
fronts that swept through
the state in late Decem-
ber and early January
were devastating to tropi-
cal fish in ponds, even
those under protective
greenhouse structures.
Estimates of how
many fish were lost were
as high as 80 percent
throughout the state.
Tropical fish are the
state's largest segment of
aquaculture, accounting
for almost 50 percent of
the total farm-gate value.
Florida is subtropical,
not tropical, and periodi-
callythe industry is dam-
aged by severe winter
weather. In response to
this threat, many farmers
cover their smaller earthen
ponds with greenhouse
plastic from October
through late March.
During normal, severe
winter weather events,
these covers provide ad-
equate protection for the
crop. While temperatures
at night may drop well be-
low freezing, they usually
will recover quickly within
the next few days, and
the pond temperatures
rebound accordingly.
Water temperatures

beneath covered pools
rarely drop below 700 F.
This past December, a
series of cold fronts brought
temperatures down, but not
to a point where the fish
were in trouble.
However, for ten con-
secutive days in late De-
cember through early
January, a continuous
series of fronts swept
through the state, all the
way to the Florida Keys.
In Hillsborough and Polk
Counties high tempera-
tures did not exceed 600
F during this time; lows at
night were in the 20's and
30's. Here at the Lab, pond
temperatures of 450 F were
measured in open ponds
and 580 F in covered ponds.
Farmers who raise fish
that are sensitive to cold
water (e.g., many of the
Cichlids, tetras, livebearers,
etc.) experienced massive
losses, with some individu-
als losing 100 percent of
their crop. Even normally
"hardy" species (e.g., some
of the barbs and danios)
perished this year.
Aquaculture farmers
should know that if they
experienced significant
losses, they are eligible
for assistance through the
USDA Farm Service
Agency (FSA). Grants and
loan programs available for
qualifying producers. For
more information, contact
your local FSA office.
The good news is that
because tropical fish
have relatively short gen-
eration times when com-
pared to many other
crops, most of the industry
has recovered enough to
resume sales.

Carlos Martinez
New Faculty
The UF/IFAS Dept. of
Fisheries and Aquatic
Sciences is proud to intro-
duce our newest faculty,
Mr. Carlos Martinez.
Carlos will serve as As-
sistant in Extension/
Ornamental Aquaculture,
and will be working out
of the Tropical Aquaculture
Lab in Ruskin, Florida.
Martinez graduated
from the Florida Institute
of Technology in 1985,
and then spent eight
years in Guayaquil, Ecua-
dor designing, building
and operating a 600-acre
commercial shrimp farm.
Upon returning to the
U.S. in 1994, he settled
in Lakeland, Florida
where he purchased a
tropical fish farm and
has dedicated the past
six years to the success-
ful production of ornamen-
tal fish. He also attended
a one-year aquaculture
extension training program
at Texas A&M University.
This position will provide
support for state-wide
extension programs
targeting ornamental
aquaculture farmers. It's
also an affiliate assign-
ment with the Florida
Sea Grant Extension
Craig Watson
813/671-5230 ext 107

Sam Mitchell


New Raceway
Construction of a race-
way system is nearing
completion. The raceway
will be stocked with the
Asian clam Corbicula to
evaluate its potential as a
filter organism for dairy
Fisheries and Aquatic
Sciences Ph.D. student
Lance Riley, under the ad-
visement of departmental
faculty members Drs. Ed
Phlips, Patrick Baker and
Shirley Baker will analyze
how and at what rate the
clams sequester phos-
phorus and utilize it for
The Florida Depart-
ment of Environmental
Protection has mandated
reduction of phosphorus
in dairy effluent. Negative
economic impact to dairy
farmers may be offset by
using the clam as secondary
crop (feed ingredient, etc.).
The project will be un-
derway in Blountstown
laterthis summer and will run
through at least next year.
Bass research
Ph.D. graduate student
Jeff Hill, under advise-
ment of Dr. Chuck Cichra,
is conducting research at
SMADF to determine
prey use patterns of large-
mouth bass and peacock
cichlids, in regard to
predator efficiency and
potential interspecific
Peacock cichlids were

introduced into south-
east Florida canals, even
where largemouth bass
were already present, to
consume over-abundant
forage fish.
Channel Blue Cats
A regional project
began in May to demon-
strate channel x blue
hybrid catfish production,
spawning technology, and
The project, funded
by the USDA Initiative for
Future Agriculture and
Food Systems, is a co-
operative effort of the
University of Florida,
Auburn University, and
the University of Georgia
and is being conducted at
facilities of all three
Though the animal is a
forced hybrid, requiring
a higher level of techni-
cal spawning knowledge,
the channel x blue hybrid
has demonstrated faster
growth rates, better feed
conversion ratios, higher
seinability, higher dress-
out percentages, and
greater disease resistance
than its parent species.
Stocking Hybrid
Striped Bass
Beginning this past
spring, SMADF began
raising hybrid striped
bass in conjunction with
the Blackwater Fisher-
ies Center of the Florida
Fish and Wildlife
Conservation Com-
mission for the
express purpose of
stocking fishing
ponds for youth
fishing events
around the state. -

After grow-out is com-
plete this first year, it's an-
ticipated that 20,000
hybrid striped bass will be
available for stocking for
Fishing for Success and
FWC events.
Andy Lazur
Moves to Maryland
After more than a de-
cade of service at the UF/
IFAS Sam Mitchell
Aquaculture Demonstra-
tion Farm (SMADF) in
Blountstown, aquaculture
specialist Dr. Andy Lazur
has taken a new position
with Sea Grant at the
University of Maryland's
Hornpoint Laboratory in
Cambridge, Maryland.
During his tenure at UF,
Andy directed operations
at SMADF and worked
on a statewide and re-
gional basis to provide
critical information to cur-
rent and potential foodfish
and baitfish farmers.
In April Andy was pre-
sented an award of ap-
preciation his hard work
and dedication to the
aquaculture industry in
Florida. The award was
presented by the Florida
Aquaculture Association
at the Taste of Florida
Aquaculture legislative re-
ception in Tallahassee.
We will miss Andy and
wish him the best of luck!
Debbie Britt Pouder

Pe i s
by RoyYanon


Q entastomes are para-
sites that have been
seen over the past few
years on several ornamental
tropical fish farms around
Tampa. They are a group of
worm-like parasites that infect
many different species of fish.
Infections have been found in
several families of fish including
Cichlidae (tilapia), Cyprinidae
(danios), Cyprinodontidae
(flagfish), and Poecilidae
mollies and platess.
How to Identify
Members of the pentastome family have
been in Florida for a long time. Not as com-
mon as some of the other parasites, they
can easily be confused with them. If you
raise fish outdoors and are visited by alli-
gators, water snakes, or aquatic turtles,
you may want to learn more about this fish
Typical pentastomid lesions seen on fish
closely resemble infections by digenean
trematodes or flukes, such as trematodes.
However, Digenean trematodes and
pentastomids have different life cycles and
different control methods. That's why
proper identification is so important.
Although pentastomes are small, they
can be seen without the use of a micro-
scope. However, a microscope can help
differentiate them from other similar para-
sites. Pentastomes in fish resemble very
small white, segmented grubs or worms.
However, they are more closely related to
fish lice such as Argulus than to true
worms. They are believed to be closely
related to members of the group of organ-
isms known as Crustacea, which include
crabs, lobsters and shrimp, as well as the
parasitic fish louse. Adult pentastomes,
which are found in reptiles, look different
from the larval or nymph stage, found in
fish. They have been described as resem-
bling prehistoric caterpillars.
Life Cycle
Pentastomes have a complex, indirect
life cycle. Infections cannot be transmitted
directly from fish to fish. Adults of the
pentastome species that infect fish are
found in reptiles, which are considered to


Top: A Lyertail swordtail in the Poeciliidae family
a livebearer. Below: Pentastomidparasites are small
but can be seen without the aid of a microscope.
be their final host. Typically, adult stages
of the parasite are found in the respiratory
system of reptiles, usually within the lungs
and/or trachea (i.e., windpipe).
Within the lungs of their reptile hosts, the
adult pentastomes deposit eggs containing
larvae with four leg-like appendages. After
deposition, these eggs are coughed up, swal-
lowed, and then passed through the reptile's
gastrointestinal tract where they are depos-
ited into the water through the feces. The
eggs develop into the infective stage and,
after being eaten by the appropriate fish host,
the larvae hatch out, develop, and undergo
several molts.
The juvenile life stage located in the fish
more closely resembles a worm and is
known as a nymph. After infected fish are
eaten by the proper final reptile host, the
parasite perforates the intestinal wall,
migrating through the body to the lungs.
When the pentastome matures, the life
cycle is completed.
A number of common reptiles are known
reservoirs of pentastomes. Florida soft-
shell turtles have been found harboring
adult stages of one group of pentastomes
in the genus Alofia. Alligators harbor adult

pentastomes of the species
Sebekia mississippiensis.
Other species of pentastomes
have been found in snapping
turtles and aquatic snakes
including the cottonmouth,
Sred-bellied water snake, dia-
Smondback water snake, and
the common water snake.
Disease in Fish Caused
Sby Pentastomes
The appearance of the
S-fish as well as the amount
of tissue damage done by
the parasite will depend on the fish species
infected, whether or not the fish has been
infected before, and the species and number
of pentastomes present. In one published
report, little damage was seen in infected
mosquitofish, whereas the same species
of parasite caused significant damage and
inflammation in infected swordtails.
Necropsy of the swordtails revealed sev-
eral clinical findings: prominent swellings
of the skin, tracks where the parasites had
migrated through the muscle, and encap-
sulated juvenile (nymph) stages present in
the body cavity as well as under the con-
nective tissue of many organs.
In some of the infected fish examined at
the University of Florida's Tropical Aquacul-
ture Laboratory, there have been obvious
swellings in the skin and muscle from which
nymph stages have been extracted.
Conversely, other fish have had relatively
few external signs of the parasite. How-
ever, in some of these fish, significant
numbers of parasites have been seen in-
ternally during necropsy. One swordtail had
over 200 pentastomes of various sizes
located throughout its body.

Diagnosis and Treatment
Affected fish may have grub-like lesions
within the skin and muscle. However, these
external signs are not always present, and
infections will occur within the fish's internal
Common characteristics of pentastomes
include a relatively short body length rela-
tive to body diameter (compared to nema-
todes); obvious segmentation annulii) of
the body (nematodes are not segmented);
small hooks on the anterior (head) end; and
a coiled nymph stage. In contrast,

digenean trematodes in fish are usually
found as immature metacercariae (a lar-
val stage in an oval, encysted form). If
these cysts are broken, the digenean
trematodes that emerge appear flatter and
have circular oral and ventral suckers.
Because pentastomes can be found en-
capsulated in many different locations
within fish, there are no treatments other
than prevention. Chemical treatments to kill
stages in the water have not been evalu-
ated. Affected fish typically must be culled.
Depending upon the severity of infection
within a population, anywhere from a few
percent to as high as 30 percent of the fish
in a pond may be affected. Consequently,
it is important that infections are recognized
early so that preventative measures can
be instituted as soon as possible.
Primary prevention of pentastomid infec-
tions in fish requires control of the final
hosts: aquatic turtles, water snakes, and
alligators. Predator control should be a
standard practice in an aquaculture facil-
ity. Fish sharing ponds with any of these
predators may be susceptible to
pentastomid infections. Prolonged expo-
sure to infected reptiles will increase
nymph loads in susceptible fish by increas-
ing the number of infective larvae in the
ponds. This number will increase with time.
Farms that have aquatic reptiles and do
not regularly clean ( muck/pump down,
rinse, and lime) and restock their ponds
will be at greater risk of infection.

Fish with whitish bumps, or raised areas
that contain parasites that resemble grubs
should be examined by a fish health spe-
cialist for proper identification of the para-
site. Some species of fish have significant
disease caused by pentastomid infections
that can contribute to morbidity or mortality.
On the other hand, infected species of
fish may suffer no ill effects, and may show
no grossly visible signs of disease at all.
Several different parasites or other dis-
eases may cause a similar appearance on
the fish, so positive identification of the
problem is an important first step.
If pentastomes are determined to be the
cause of fish disease, then turtle, alligator,
and water snake populations within the af-
fected ponds or farm should be controlled
and ponds should be cleaned and re-
stocked. Production ponds should be
cleaned at least once or twice a year. There
are no known methods for chemical re-
moval of parasites from infected fish, which
consequently must be culled.

, S~ Sew Sp l *

congratulations to Joe Nadolny,
HCC's Aquaculture student of the
year for 2001. Joe is now man-
ager of Fish World in Tampa. He
came from Southern Tropical Fish Hatchery
in Lakeland, graduated from the University
of Tampa, and was one of the first volun-
teers at The Florida Aquarium. Joe was one
of the first students in the HCC Aquaculture
program when it began four years ago.
Congratulations to Tim Thomas III, who
graduated with an AS degree in Aquacul-
ture. Tim is a third generation commercial
fisherman from Lakeland where his family
owns Thomas Seafood. He's been work-
ing since last summer for Donald Drawdy
at Imperial Tropical Fish Farm, Lakeland.
Tim did internships at Richloam State Fish
Hatchery and Imperial Tropical Fish Farm.
Joe Nadolny, Manager of Fish World in
Tampa, Jerry Kust, formerly with the US Air
Force and Segrest Farms, Chris Krannert,
and Krista Reep of Spring Hills, also gradu-
ated with HCC's first College Credit Certifi-
cate (CCC) in Aquaculture Technology.
This summer brought several new
events and programs to HCC. For the first

time, we will host a record number of nine
interns in the Aquaculture Program. They
will be assigned to VW Tropical Fish in Lake-
land, Nienow's Tropicals, Incin Gibson-ton, Sea
Critters in Dover, Lowery Park Zoo in Tampa
and the Port Manatee State Fish Hatchery.

HCC's Aquaculture Program recently
became partners with the National Science
Foundation's Marine Advanced Technology
Education (MATE) Center at Monterrey Pen-
insula College in Monterrey, California.
As a result of this partnership Dr. Bill Falls
has been selected to attend a two-week
seminar at MATE in July entitled Introduc-
tion to Marine Submersibles. Also, HCC now
has an independent contract from MATE to
survey zoos and aquariums in the American
Zoo and Aquarium Association (AZA) to
define job skills required for a Public Aquarist.
Seven students are working on this
project which will be completed in August.
It's anticipated that both HCC and MATE will
continue to benefit from their collaborative
relationship and linked websites.
Dr. Bill Falls

So What Is "Extension" Anyway ?
The Cooperative Extension Service is a partnership of county, state, and federal gov-
ernment which serves the citizens of Florida by providing information and training on a
wide variety of topics. In Florida, the Extension Service is a part of the University of
Florida's Institute of Food and Agricultural Sciences with selected programs at Florida
Agricultural and Mechanical University (FAMU). Extension touches almost everyone
in the state from the homeowner to huge agribusiness operations in such areas as
food safety, gardening, child and family development, consumer credit counseling,
youth development, energy consumption, sustainable agriculture, competitiveness in
world markets, and natural resource conservation.

Feaure Aqatic Plant I [~:4ki4I WIINIII'J

common duckweed is a s
floating plant that can t(
obscure sunlight. It most
occurs in small lakes and ponds
where the water is alkaline,
hardwater, or eutrophic.
If you see a pond covered
with this stuff it often means the
water is getting too much phos-
phorous, magnesium, nitrogen,
sodium, or potassium. These
conditions are often the result of
human influences.
Duckweed however is no in-
vader to Florida, but a wide-
spread aquatic plant found almost
world-wide. It likely earned its
name because of the fact that
visiting migratory ducks are fond
of eating it. Though native to
Florida, duckweed becomes a
problem when it colonizes an
entire pond surface and hinders
light from reaching any other aq
growth below it. A population of c
weed can double every few week
controlling it can be a real problem
Goldfish and grass carp love to
on duckweed, but they can only e

much-very often they can't catch up with a
fast-growing population of this floating weed.
It takes a lot of goldfish to control vegetation

Common duckweed (Lemna minor)
uatic like this, and predators constantly feed on
luck- the goldfish. Throwing grass carp into a pond
s, so means they will eat anything green, not just
n. the duckweed.
feed Grass carp are practically insatiable, but
at so a thick mat of duckweed requires at least

50 grass carp per acre of water to control
it. Even though carp can eat their body
weight daily in vegetation, they still can't
keep ahead of the weed's
growth curve-that is how fast
duckweed can grow! Another
problem with heavy duckweed
is that little oxygen exists in the
water column below, making it
difficult to support all but the har-
diest forms of fish life.
Two recommended herbi-
cides that can bring duckweed
under control is Sonar and Re-
ward. Neither are restricted and
do not require an applicator's li-
cense. They're sold by agricul-
ture supply stores. The pond
owner can spread an applica-
tion, and then later after the rec-
Sommended safe period, add
some goldfish or grass carp
when the duckweed count is still
fairly low-then the fish can jump ahead
of the weed's daily growth rate.
So, if your pond is coated with count-
less, tiny leaves of duckweed, treating it
in a timely and reasonable fashion will
restore it to a more normal appearance.

p----------------------------------------- *

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