Treating fish parasites with hydrogen...
 Student involvement at UF
 Treating fish parasites with hydrogen...
 UF/IFAS aquaculture and pond management...
 Submission of fish and water samples...
 Native and exotic catfish...
 A toast to project COAST

Group Title: Waterworks
Title: Waterworks. Volume 5, Number 1. 2001.
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00067314/00006
 Material Information
Title: Waterworks. Volume 5, Number 1. 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: VID00006
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
    Treating fish parasites with hydrogen peroxide
        Page 1
    Student involvement at UF
        Page 2
    Treating fish parasites with hydrogen peroxide continued
        Page 3
    UF/IFAS aquaculture and pond management update
        Page 4
        Page 5
    Submission of fish and water samples for diagnostic evaluation part II
        Page 6
    Native and exotic catfish in Florida
        Page 7
    A toast to project COAST
        Page 8
Full Text

University of Florida Cooperative Extension Service IInstitute of Food and Agricultural Sciences Volume 5 Number 1 2001

January 20
Shellfish Genetics Workshop
Brevard County Agriculture Center / Cocoa, FL
Leslie Sturmer 352/543-5057

Feb 8 19
Florida State FairAquaculture Exhibits
Florida State Fair/Agriculture Hall of Fame
Tampa, FL
Lisa Hinton 813/621-7821

February 22 25
9th Annual Mid-year Meeting
Southern Division of American Fisheries Society
Hilton Riverfront / Jacksonville, FL
Larry Connor 352/742-6438

March 16 18
4thAnnualAll Florida Koi & Pond Show
Ramada Resort / Orlando, FL
Don Hllard 352/331-1268

Nov. 27 Dec. 1
Marine Ornamentals
Conference 2001
Walt Disney Resort/
Buena Vista, FL
Beth Miller-Tipton

hydrogen perox
ide (HP) is well
known as a dis-
infectant for wounds in
people. However, for
many years HP has also
been used for various
purposes in aquacul-
ture. For example, if
added to water, HP will
increase the amount of
oxygen present.
One commonly used
dosage for increasing
oxygen content is 1 mL
of 15% HP per 20 liters
of water. This works be-

cause when HP breaks
down, it forms oxygen
gas and water.
More importantly, HP
has been used in bath
treatments against
many different disease-
causing organisms.
One of the first pub-
lished reports of this use
is from 1922. Over the
past several years, HP
has been given more
attention by the aquac-
ulture community for the
treatment of external
parasites, bacteria, and

fungi on many different
life stages of fish. Most
of the available informa-
tion so far has been
based on studies of food
What is hydrogen
Hydrogen peroxide is
a strong oxidizer; it is
similar in its chemical
Continued on page 3.

Instute o Food andAgn.culural Sences


Treating Fis



. 0ydr00.0

';ty Oflo>

The following UF/IFAS
faculty and staff are
available to answer
questions or provide
technical support for
aquaculture, fisheries
and aquatic sciences,
and pond manage-
ment. Feel free to
contact them.

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

Andy Lazur
Food & Bait Aquaculture
Debbie Britt Pouder
Food & Bait Aquaculture

Craig Watson
Research Coordinator
Roy Yanong
Fish Health/Aquaculture


Eric Curtis
Fish Health

Ken Langeland
Aquatic Plants

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

Ray Bucklin
Aquaculture Engineering

John Brenneman
Polk/Hillsborough Counties
Chris Brooks
Dade County
305/248-3311 ext 230
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 atthe University of Florida. Student involve-
mentis highlighted in each issue of WaterWorks.

ky Notestein grew
up in Gainesville,
Florida and therefore
was somewhat famil-
iar with the Chassaho-
witzka River only 80
miles away, flowing
into the Gulf of Mexico.
However, after spend-
ing nearly 15 months
exploring and analyz-
ing water samples
from that river, he
knows a great deal
more about it-one of
Florida's most scenic
treasures. His work
and research will lead
to a master's degree
in May.
Starting out with a
bachelor's degree in
Wildlife Ecology and
Conservation in 1997,
Sky began research
on the river in 1998.
Since the Chassa-
howitzka is a spring-
fed river, there were
legitimate concerns
that harmful nitrates
(nitrogen) were enter-
ing the river through
the Florida aquifer,
itself a source of rising
concentrations in recent
Sky collected bio-
logical data during five
quarterly sampling
periods in an effort to
better understand the
relationships between
surface water nutrients
(nitrates in particular)
and the vegetative
characteristics of the
river. Physical, chemi-
cal and biological data
were also collected.
One of the more
interesting findings
from Sky's thesis work

Sky Notestein in thefield.
is that phosphorus may
play a more important
role in the river's ecol-
ogy than was previously
recognized. By growing
periphyton on glass
slides in the field, Sky
soon found that adding
phosphorous greatly
increased the growth
rate of algae. The addi-
tion of nitrate (nitrogen)
did not.
The data that were
collected provide much-
needed insight into the
factors that influence
the abundance and
distribution of macro-
phytes, macroalgae
and periphyton in the

system, and should
be of interest to a
broad group of envi-
ronmental scientists
and resource manag-
ers concerned with
the problems facing
Florida's spring-fed
"The work helps
provide important
baseline data for
water quality param-
eters in this region,"
Sky said. "It will help
to identify relation-
ships between chemi-
cal, physical and bio-
logical factors in the
river. I certainly en-
joyed working in the
field, often by myself,
exploring and sam-
pling up and down
that river."
Sky is now assist-
ing Dr. Tom Frazer
with Project COAST, a
new coastal monitor-
ing program coordi-
nated through the De-
partment of Fisheries
and Aquatic Sciences.
It's a good thing he
enjoys field work, as
he will be collecting
water chemistry data
at the mouth of 13
Florida rivers.

Continued from page 1.
effects to formalin and potassium perman-
ganate. To put it crudely, it "burns." But
unlike formalin, hydrogen peroxide is con-
sidered much safer. However, at high con-
centrations, as found in some of the avail-
able commercial solutions, it can be harm-
ful to people who do not use proper pre-
cautions. (It is capable of burning the skin
or eyes.)
As mentioned earlier, after a period of
time, HP breaks down into water and oxy-
gen gas. This is one reason that the Food
and Drug Administration (FDA) presently
considers HP an aquaculture drug of "low
regulatory priority." In fact, more formal
field trials are currently underway exam-
ining its effectiveness and safety for use
in fish against fungi, bacteria, and para-

Sources of Hydrogen
HP is available through most aquacul-
ture supply companies. One manufacturer
is Elf Altochem North America, Inc.,
(Woodstock, TN). Concentrated solutions,
with approximately 35% active ingredient,
are typically used. However, as long as
you increase the amount proportionately,
you can probably also use over-the-
counter HP from your local store. These
are usually only 3% active ingredient.
It's also available in dry form (Sodium
Carbonate Peroxyhydrate) from Solvay
Interox in Houston, Texas. The dry form
becomes HP once water is added. How-
ever, this type of HP is specifically labeled
for use as an algaecide. And because the
dry form is not pure HP, the reaction that
occurs when it dissolves will also release
chemicals that tend to increase the pH of
the water.

Therapy vs Toxicity
There are many different doses sug-
gested in the literature for use in aquarium
fish. However, because there are hun-
dreds of species of ornamental fish
produced in Florida, certain factors must
be taken into account when using HP.
For starters, it can be very toxic to some
species, and certain life stages may be
more sensitive. Increasing temperature
seems to increase the potential toxicity.
Dosage and duration of treatment will also
determine whether fish being treated will
live or die.
HP also causes mortalities if levels are
too high, primarily by damaging the gills.

Therefore, toxic effects will often be seen
related to gill damage, as indicated by
gasping near the surface, or increased
ventilation rates.
One research group (Rach, et al. 1997)
recommended 50-250 ppm for up to an
hour. However, this group only studied
food and game fish, tested with a water
temperature of about 54 degrees Fahr-

Eric Curtis, biological scientist at L i 1/ '
TropicalAquaculture Laboratory is involved
in the hydrogen peroxide studies.

The dosages reported for aquarium fish
range from 30,000 ppm for 10 minutes,
5000 ppm for 5 minutes, or 300 ppm for
10-15 minutes-basically all over the
board. (The 30,000 ppm dosage proved
deadly in many cases.) Such a wide range
is probably due to different species being
tested, a variety of parasites being elimi-
nated, and different water quality condi-
tions, including temperature.
At the request of several producers, we
began to examine HP for use specifically
in ornamental fish at the University of
Florida's Tropical Aquaculture Laboratory.
Although we have only examined a few
groups of fish so far, we would like to
share our current findings with you.

Preliminary Findings
Hydrogen Peroxide Residual
Contrary to popular belief, in water with
relatively low organic content, we found

that after nine hours, even in tanks with
aeration (but without fish), the concentra-
tion of HP did not decrease significantly.
After 3 days, the concentration of HP de-
creased by only about 50 percent. Of
course, any increase in organic loading will
change these numbers, but the bottom line
is that HP does not break down as quickly
as some may think. Water changes are
required after treatment.

We have not examined the economics
of using HP vs. traditional chemicals. Also,
more effort needs to be made to examine
the effectiveness for use against fungal
disease of eggs. As mentioned earlier,
results do look promising. We'll keep you
If you do decide to use HP, be sure to
try it on a small number of fish first. Please
feel free to share your successes and/or
failures with us.
For more details on the HP project,
including dosage effects for various spe-
cies such as tetras, cherry barbs, and ze-
bra danios, or if you have questions about
any other fish health related issues, please
feel free to contact us at:

UF/IFAS Tropical
Aquaculture Laboratory

Note: The mention of manufacturers'names is
purelyfor informational use. No endorsement of
their product is directly or indirectly implied.



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 subscription form
on page 8. Questions, comments or
editorial submissions may be sub-
mitted by contacting:
Editor Joe Richard
352/392-9617 ext 290
Faculty Advisor Chuck Cichra
352/392-9617 ext 249

U 1AS Aquaulur

and Pon Maaemn Update6.




Catfish Goals
Beginning this year,
the farm will be conduct-
ing a growout demon-
stration of the channel/
blue catfish hybrid in
This work is part of a
regional project (south-
eastAlabama, southwest
Georgia and north
Florida) funded by USDA
to demonstrate the po-
tential of the hybrid to
improve farm income
and sustainability.
The channel/blue hybrid
has been shown to grow
faster, is less susceptible
to certain stresses, has a
greater dressout percent-
age, and is easier to
harvest by seining. In
addition to pond growout,
the farm will provide a
hatchery demonstration
in year two of the project.
Catfish Kids
During autumn 2000,
the SMADF and the
Northwest Regional
Office of the Florida Fish
and Wildlife Conserva-
tion Commission joined
forces to put on another
hugely successful Kids'
Fishing Day. After filling
all pre-registration spots
in just two days, 211
children between the
ages of 1 and 15 fished
during the two Saturday
With most children

catching their limit, a total of
972 fish were taken home.
Each child received a
certificate of participation
with his or her name on
it, a Junior Fishing Li-
cense, a poster, and a
goody bag. A big thank
you goes to FWCC for all
of their help!
Donations for the
goody bags were pro-
vided by PureFishing, the
Florida Department of
Agriculture and Con-
sumer Services Bureau
of Seafood and Aquacul-
ture Marketing, USDA
Wildlife Services, and
The Catfish Institute. The
next Kids' Fishing Day is
scheduled at SMADF for
Saturday, April 7.
Goldfish Rush
On Oct. 7 the District
II 4-H "Gold Rush" pro-
gram kicked off at
SMADF. Participants in
the program picked up
aquarium supplies and
spent the day learning
about goldfish biology,
aquarium setup, water
quality, and nutrition.
Over the next six
months, students will

raise their own goldfish,
test water quality, and
record their observations
and experience in prepa-
ration for county and dis-
trict events to be held in
the spring. For more in-
formation, call
Debbie Britt Pouder


On Nov. 28, Sea Grant
agent Marella Crane and
the Miami-Dade Exten-
sion office hosted a Sea
Science Career Day.
Over 40 high school
kids attended the event.
Marella invited speakers
from the following pro-
grams: the Miami
Seaquarium, Officer
Snook, Pelican Harbor,
University of Miami,
DERM and the Youth
Fishing Foundation.
Chris gave a brief talk
about the role of exten-
sion, how to prepare for
a career, and what con-
stitutes a typical work
day. Speakers urged at-
tendees to persevere

and follow their dreams.
The spokeswoman for
Seaquarium gave the
audience tips on internships
and job responsibilities at
the public aquarium,
ranging from public rela-
tions to dolphin trainer.
The creator of Officer
Snook, a water pollution
prevention program that
is for all ages, offered her
story as an inspiration to
overcome adversity.
Pelican Harbor's speaker
thrilled kids with her live
pelican, while discussing
her role as a volunteer
saving pelicans that were
entangled in nets.
A dive instructor from
the University of Miami
discussed the valuable
skills hetaught research-
ers so they could conduct
underwater research
A Habitat Restoration
Specialist from DERM
showed the audience pho-
tographs of his projects,
while telling them how to
networkand build contacts
for the future.
The last speaker, from
the Youth Fishing Foun-
dation, showed a video
on free fishing clinics for
inner-city youth and
spoke about the benefits
of volunteering.
All guests were able to
tour the new research
vessel Walton Smith,
which features the latest
in ocean research tech-
nology. Her crew led
groups of ten guests on
a detailed, 15-minute tour
of the ship.
A post-event survey
found that 45% of the at-
tendees became seriously

interested in pursuing a
similar career as a result
of the presentations.

Chris Brooks
305/248-3311 ext 230

Food and




Work continues on sev-
eral projects concerning
marine aquaculture and/
or marine fisheries man-

* A USDA-funded project
focused on developing
inventory management
software for hard clam
growers is nearly com-
The draft version of
the package will be field-
tested with a small
group of growers in the
near future. It will allow
growers to keep track of
how clams planted on a
given lease site progress
from nursery seed to har-
vest-able market clams.
It also provides a run-
ning total on mortality,
standing inventory, ex-
penses, and earnings. A
continuously updated
map of the lease site can
also be maintained with
the software.

*Another project funded
by FRED will be assess-
ing the economic impact
of the hard clam culture
industry on regional and

statewide economies. A
telephone survey of all
shellfish wholesalers
who handle cultured
hard clams is nearing
completion. This infor-
mation will be used to
determine how the clam
culture industry effects
expenditures, incomes,
jobs, and economic out-
put in three regions of
the state, and the state
in total.

* Work also continues
on a Florida Sea Grant-
funded project to assess
the market acceptance
and financial feasibility of
cultured sturgeon. This
project involves a num-
ber of IFAS faculty, in-
cluding Andy Lazur in
Blounstown and Fred
Wrth (IRREC-Fort Pierce).

* An assessment of the
financial characteristics
of mud minnow culture
will be completed early
this year. Interest is
growing with respect to
the small-scale culture of
mud minnows for the
live, marine baitfish mar-
ket. The study will allow
prospective growers to
determine whether or
not the culture process is
a wise investment deci-
sion. A recent Florida
Sea Grant/FDACS study
has shown that the mar-
ket for mud minnows as
a live bait is very strong
within certain regions
and seasons in Florida.
Chuck Adams
352/392-1826 ex. 223


Cedar Key
Extension Program
The most significant
recent increases in
Florida aquaculture have
occurred in clam farm-
ing, with 1999 sales of
$15.9 million, almost tri-
pling those reported in
Over the past five
years, increased col-
laboration between the
university and the clam
farming community has
been beneficial to both,
Unfortunately, extension
efforts have been limited
to a multi-county area.
With this in mind, goals
for this year's extension
program include:
1) Establishing a net-
work within counties
where clam farming is
ongoing, by working with
county marine agents;
2) Expanding the multi-
county shellfish aquacul-
ture advisory committee to
a state-wide committee;
3) Conducting educa-
tional workshops, dem-
onstrations and provid-
ing research results to
other areas of the state.
Proposed workshop
topics for 2001:
* Introduction to remote
water quality monitoring
systems and weather
stations to be deployed
at lease areas in six

Hillsborough Community College continues to expand their aquacul-
ture education program, preparing students for undergraduate or graduate
level studies, or for apprenticeships throughout the state and even inter-
Some 21 students from Latin America and the Caribbean have
accepted two-year scholarships to study aquaculture at Hillsborough Com-
munity College, with a stated purpose of going back to their countries to
produce foodfish.
Funded by the Cooperative Association of States for Scholarship
(CASS), the students receive a 24-month visa to stay in Florida. They will
be housed in Brandon. Though they can't work in the U.S., they will have
a stipend and a full-time coordinator to take care of them.
The students will take remedial English classes since most don't speak
English. Aquaculture classes will be taught in English, and the program is
sponsored by Georgetown University and the U.S. Agency for Interna-
tional Development.
Those who graduate will earn an Associate degree in Aquaculture, or
a College Credit Certificate. Eighty percent of the students are from rural
areas, and half are women. All have completed high school and demon-
strated leadership abilities. They represent the Dominican Republic, El
Salvador, Guatamala, Haiti, Honduras, Jamaica, Nicaragua, and Panama.

New Publication
A new book entitled Aquatic Resources has recently been made
available to anyone interested in aquatic education. Authored by Dr. Bill
Falls and three other professors at Hillsborough College, the 250-page
publication stresses aquatic awareness, understanding, and uses for edu-
cational purposes. It was funded by the National Council for Aqriculture
Education, and sub-funded through USDA. There are five major sections
including Aquatic Resources, Physical, Chemical, and Biological factors
affecting aquatic systems; Aquatic Ecology; Aquatic Resource Issues;
and Aquatic Careers.
Aquatic Resources covers fisheries, not just aquaculture, including
fresh and saltwater. Other items include an extensive glossary with aquatic
terms, software videos, web sites, slides, and other useful curricula.
The book is available from the National Council for Agriculture Edu-
cation at $20, by calling 1-800-772-0935.
Bill Falls

+Clam Crop Software -
distribution and explana-
tion of simplified comput-
erized spreadsheets for
maintaining crop invento-
ries, for recording planting
and harvesting activities,
for calculating yields and

croptimes, and fortrack-
ing farm income and
* Enhanced Seed Pro-
duction- application of
genetic breeding prac-
tices and remote setting
techniques for hatchery

and nursery operators.
* Pilot Crop Insurance
Program review and
evaluation of policy pro-
visions during the second
year of the pilot phase.
Leslie Sturmer

Submission of Fish and Water

Samples for Diagnostic Evaluation

Part II

by RuthEllen Klinger-Bowen and Ruth Francis-Floyd

When fish become sick or die, diagnosis of the problem is
much easier if clients are able to give a good historical account
of the events prior to submitting their fish or water to the
laboratory. In the previous issue of WaterWorks (Vol 4 No 4),
the importance of keeping good records was discussed,
including questions commonly asked by the diagnostician.
Here, we detail the proper methods used to submit a water andl
or fish sample to a diagnostic laboratory.
Submission of a water sample
Fish spend their entire life in water, which means when a fish gets
sick, that environment must be
tested. No matter how clean you
think your water is, no matter what
your water source is, or that your
system is flow-through, you must
have recent records of your water
quality parameters (e.g., tempera-
ture, pH, ammonia, nitrite, dis-
solved oxygen) or submit a water
sample for analysis. A good diag-
nostic laboratory will first test the
water for any deviation in quality.
When submitting a water sample for analysis, a few simple yet
important procedures must be followed. First, water should be
sampled as soon as the fish begins to act abnormal and before
water changes are initiated. A clean container (approximately one
quart), thoroughly rinsed of any foreign matter or soap residue,
should be utilized. If the system in question is a pond, it is impor-
tant to submerge the container under the water and place the cap
on the container beneath the surface. This removes any air bubbles,
which could interfere with the dissolved oxygen measurement. (Ide-
ally, dissolved oxygen and temperature should be measured at the
pond, and if the pond is large, at multiple depths and locations.) If
there are multiple systems involved, samples from each will be
needed. In cage culture, water should be sampled inside as well
as outside the cage.
The water sample should be separate from the fish sample. The
water that the fish are brought in will not correctly reflect what is
occurring in your system. The chemistry of the water, which
includes pH and ammonia, will change remarkably during trans-
port. For example, while the fish is being transported to the diagnostic
laboratory, its metabolic activities (i.e., respiration, excretion) will cause
the pH to decrease and the ammonia to increase in the shipping water.
It is important to label all samples with pertinent information,
such as client's name, sample location, depth, and the time of col-
lection. Keep the water sample in cold storage once collected. When
shipping water, place the sample on ice or ice packs. A Styrofoam
cooler in a cardboard shipping carton works well for shipping over-
night to a diagnostic facility.

Submission of a fish sample
The best fish samples for diagnostic evaluation are the fish
that are near death (moribund) or showing signs of distress. Dead
fish are rarely acceptable for diagnostic tests. However, if the fish
are in good condition, that is, their eyes are clear and the gills are
red, they may have some value. If they are obviously decomposed

or extremely smelly, do
not submit. It is also
important to submit a
representative number
of each species in-
volved. Usually three
to five fish will be suffi-
cient. This ensures an 1
accurate diagnosis of
the population as a
If the fish are alive and appear to be able to make the trip to the
laboratory, place them into well-aerated water in a heavy ply plas-
tic bag (fish shipping bag or commercial freezer bag), and a
Styrofoam cooler to regulate temperature. This can then be placed
in a cardboard shipping carton and shipped overnight. If the fish
are dead or will not make the transport, the fish should be kept
moist with wet paper towels in a heavy ply plastic bag. Keep the
sample cold, packed with ice in a Styrofoam cooler and shipping
carton. It is important not to freeze the sample, especially if tissues
are to be submitted for histopathology (examination of tissues for
disease processes at the microscopic level).
There are commercial overnight carriers that will take live and
dead fish, if they are properly packed as mentioned above. Also,
most diagnostic facilities require prior notification that a sample is
being shipped to their laboratory. This ensures a contact person
will be there to receive the shipment and be able to work it up in an
expedient manner. Listed below are a number of laboratories in
Florida that are qualified to diagnose fish diseases. Contact the
one closest to you for further information.
Samples that are hand delivered to a laboratory should also be
properly transported. Notify the laboratory you are coming with the
sample, keep live fish in a bucket with a battery-operated aerator
or a plastic bag with well-oxygenated water, and moribund/dead
fish wrapped in wet paper towels in a plastic bag on ice in a cooler.
Parasites could fall off and changes in bacteria load (i.e., decom-
position) set in quickly, so following the above protocol will aid in
the correct diagnosis.

Dept. Fisheries & Aquatic
7922 NW 71st St.
Gainesville, FL 32653-3071
(352) 392-9617, ext. 229 or 230
Tropical Aquaculture
1408 24th St. SE
Ruskin, FL 33570
(813) 671-5230
Sam Mitchell Aquaculture
Demonstration Farm*
Route 2, Box 754
Blountstown, FL 32424
(850) 674-3184

Miami-Dade County
Extension Office*
18710 SW 288 St.
Homestead, FL 33030-2309
(305) 248-3311 ext. 230

Kissimmee Diagnostic
2700 N. Bermuda Ave.
Kissimmee, FL 34741
(407) 846-5200
Live Oak Diagnostic
P.O. Drawer O
Live Oak, FL 32060
(904) 362-1216

* Limited Service Laboratory (No veterinarian on-site)

FFAFAS Laboratories

Natv an ExtcCtihi lrd
By Jef Hill

This is the first of two installments
covering how to differentiate native
and exotic catfish, providing informa-
tion on exotic caffish in Florida.
Peninsular Florida (St. Johns and
Withlacoochee Rivers and south) is
home to seven native
freshwater and two na-
tive marine catfishes. At
least four exotic fresh-
water catfish species
have become estab-
lished in this area since
the 1960s. Exotic
means a species that
comes from another
Florida's native catfish
species are readily rec- ... ,
ognizable as catfish, hav-
ing prominent barbels
(whiskers) smooth,
scaleless skin, and a
single hard spine in the
dorsal fin and each
pectoral (side) fin.
The native freshwa-
ter species belong to
the bullhead catfish
family (Ictaluridae) and
include the familiar
channel catfish (Ictalurus
punctatus), commonly
grown in aquaculture orfarm ponds forfood
or recreational fishing.
Other bullhead catfish in peninsular
Florida include Brown Bullhead
Ameiurus nebulosus, Snail Bullhead A.
brunneus, Yellow Bullhead (A. natalis),
and White Catfish (A. catus). Addition-
ally, there are two small (less than six
inch) catfish species called madtoms,
which inhabit peninsular Florida-
Speckled Madtom (Noturus leptacanthus)
and Tadpole Madtom (N. gyrinus).
Two sea catfishes (familyAriidae), hard-
head catfish (Ariusfelis) and gafftopsail
catfish (Bagre marinus), also enter coastal
rivers. Based on the exotic species cur-
rently present in Florida, any catfish lack-
ing armored plates or hard, rough skin and
having a spine in the dorsal fin is likely
native to peninsular Florida.

Labyrinth Catfish (Family Clariidae)
Florida is home to a single species of
labyrinth catfish, the famous Walking Cat-
fish Clarias batrachus. Native to south and
southeast Asia, Walking Catfish is now
established throughout the southern half of

peninsular Florida. It was first found in
Broward County in the late 1960s, having
escaped from an ornamental fish farm.
Other introductions may also have
occurred in Hillsborough County.
Walking Catfish is easily identified as a
catfish by its prominent barbels and
smooth, scaleless skin. Of all the exotic cat-
fishes in Florida, this species is the most
likely to be confused with native species. It
is best distinguished by the dorsal fin. In
native catfish, the dorsal fin is short and
possesses a stout spine. The walking
catfish's dorsal fin lacks spines and is ex-
tremely long, extending about three quarters
of the fish's length. The anal fin is also very
long. There are, however, spines in each
pectoral fin.
The walking catfish reaches lengths
of 24 inches, but is usually much smaller

in Florida, perhaps 14 inches. Original
walking catfish in Florida were albinos,
but they quickly reverted to a more nor-
mal solid gray or grayish-brown color.
There are four pairs of barbels (whiskers)
around the mouth. The eyes are small,
the skin extremely
This is a voracious
predator of small
fish, grass shrimp
and crayfish. They
are often active at
night. This species
builds a nest where
the female deposits
Sthe eggs. The male
or both parents guard
the eggs and free-
swimming fry. In
Asia, walking catfish
apparently breed in
newly flooded areas,
but little is known
about reproduction
in Florida.
In Florida they're
found in marshes,
S ponds, prairies, lakes
and canals. Able to
breathe air, they're
considered to be an
obligate air breather,
which means they must have air. In
fact, they will drown if unable to reach
the surface.
Walking catfish are true to their
name, capable of crossing substantial
overland distances to reach new ar-
eas. They walk by wiggling along the
ground aided by stout, pectoral spines,
and as a result can easily invade new
territory. Although little research has
been conducted, they may have a
large, adverse impact on native species,
due to their predatory habits and high
population densities in some habitats.
They appear to be most important in
ephemeral pond or marshes (ones that
dry up and refill periodically). This
species is an important food fish in
Asia, but is not valued in Florida. ww

A t P CA

Florida LAKEWATCH has a hard-earned
and successful reputation for using vol-
unteers to collect reliable water chemis-
try data from Florida lakes. Because of
this, state legislators were convinced
during this past legislative session that
the same level of success could be
achieved for Florida's saltwater environ-
ments. As a result, funding has been
made available to expand our scope to
include monitoring of estuaries, bays,
and offshore waters around the state.
The new saltwater component is be-
ing called Project COAST (Coastal As-
sessment Team) and volunteers will be
sampling the same LAKEWATCH
(i.e.,total phos-
phorus, total nitro-
gen, total chloro-
phyll and water
clarity), plus a few
additional items
that are significant
to marine environ-
ments-such as
salinity and color.
Dr. Tom Frazer, Assistant Professor
at UF's Department of Fisheries and

Aquatic Sciences, will be co-directing the
coastal monitoring efforts along with
LAKEWATCH director Dr. Daniel Canfield.
With initial funding provided by both the
Suwannee and Southwest Florida Water
Management Districts, Tom and several re-
search biologists began gathering prelimi-
nary water chemistry data along Florida's
Gulf of Mexico coastline, from Weeki
Wachee to Steinhatchee in 1996.
Now that Project COAST has earned
legislative support and funding, Frazer and
his staff will be teaming up with
LAKEWATCH to train and assist volun-
teers along more than 1350 miles of the
Florida coastline.
It's an exciting time for Florida
large and growing database for freshwater
lakes, the expansion to coastal waters was
a natural progression.
LAKEWATCH program leader Mark
Hoyer says that he and his staff are look-
ing forward to working with Project
COAST volunteers as they continue to
build on one of the largest and most suc-
cessful water monitoring programs and
databases in the country.


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Phone: 352/392-9617 ext. 290 Fax: 352/846-1088
E-mail: fishweb@gnv.ifas.ufl.edu

Anyone interested in participating
in the LAKEWATCH/Project COAST
program is encouraged to call the
UF/IFAS Department of Fisheries
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1-800-LAKEWATCH (525-3928)

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