Treating Fish Events Parasites

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University of Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences Volume 5 Number 1 200 1

Continued on page 3.

Calendar ofEvents

January 20Shellfish Genetics WorkshopBrevard County Agriculture Center / Cocoa, FLLeslie Sturmer 352/543-5057

Feb 8 — 19Florida State Fair Aquaculture ExhibitsFlorida State Fair / Agriculture Hall of FameTampa, FLLisa Hinton 813/621-7821

February 22 — 259th Annual Mid-year MeetingSouthern Division of American Fisheries SocietyHilton Riverfront / Jacksonville, FLLarry Connor 352/742-6438

March 16 — 184th Annual All Florida Koi & Pond ShowRamada Resort / Orlando, FLDon Hllard 352/331-1268

Nov. 27 — Dec. 1Marine OrnamentalsConference 2001Walt Disney Resort/Buena Vista, FLBeth Miller-Tipton352/392-5930

Hydrogen peroxide (HP) is wellknown as a dis-

infectant for wounds inpeople. However, formany years HP has alsobeen used for variouspurposes in aquacul-ture. For example, ifadded to water, HP willincrease the amount ofoxygen present.

One commonly useddosage for increasingoxygen content is 1 mLof 15% HP per 20 litersof water. This works be-

cause when HP breaksdown, it forms oxygengas and water.

More importantly, HPhas been used in bathtreatments againstmany different disease-causing organisms.

One of the first pub-lished reports of this useis from 1922. Over thepast several years, HPhas been given moreattention by the aquac-ulture community for thetreatment of externalparasites, bacteria, and

fungi on many differentlife stages of fish. Mostof the available informa-tion so far has beenbased on studies of foodfish.

What is hydrogenperoxide?

Hydrogen peroxide isa strong oxidizer; it issimilar in its chemical

Treating FishParasiteswithHydrogenPeroxideBy Roy Yanong and Eric Curtis

Highlighting UF/IFAS Programs in Fisheries and Aquatic Sciences, Aquaculture, and Pond Management

Joe

Ric

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Student Involvement at UF

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

The following UF/IFASfaculty and staff areavailable to answerquestions or providetechnical support foraquaculture, fisheriesand aquatic sciences,and pond manage-ment. Feel free tocontact them.

Agricultural &BiologicalEngineering

County ExtensionFaculty

Frank ChapmanReproductive Biology352/392-9617 ext [email protected]

Chuck CichraPond Management &Fish Biology352/392-9617 ext [email protected]

Ruth Francis-FloydFish Health/Aquaculture352/392-9617 ext [email protected] fas.uf l .edu

Ruth Ellen BowenFish Health352/392-9617 ext 230

Andy LazurFood & Bait Aquaculture850/[email protected]

Debbie Britt PouderFood & Bait Aquaculture850/[email protected]

Craig WatsonResearch Coordinator813/[email protected]

Roy YanongFish Health/Aquaculture813/[email protected]

Ken LangelandAquatic Plants352/[email protected]

Eric CurtisFish Health813/671-5230

John BrennemanPolk/Hillsborough Counties941/[email protected]

Chris BrooksDade County305/248-3311 ext 230

Max GriggsEscambia County850/[email protected]

Bill MahanFranklin County850/[email protected]

Leslie SturmerShellfish AquacultureMulti-County352/[email protected]

Don SweatPasco County813/[email protected]

Ray BucklinAquaculture Engineering352/[email protected]

Chuck AdamsMarine Economics352/392-1826 ext [email protected]

David ZimetFreshwater Economics850/[email protected]

Fisheries and Aquatic Sciences Gainesville

Sam Mitchell Aquaculture Demonstration Farm Blountstown

TropicalAquacultureLaboratoryRuskin

Center for Aquatic& Invasive Plants

Food & ResourceEconomics

Sky Notestein grewup in Gainesville,

Florida and thereforewas somewhat famil-iar with the Chassaho-witzka River only 80miles away, flowinginto the Gulf of Mexico.However, after spend-ing nearly 15 monthsexploring and analyz-ing water samplesfrom that river, heknows a great dealmore about it—one ofFlorida’s most scenictreasures. His workand research will leadto a master’s degreein May.

Starting out with abachelor’s degree inWildlife Ecology andConservation in 1997,Sky began researchon the river in 1998.

Since the Chassa-howitzka is a spring-fed river, there werelegitimate concernsthat harmful nitrates(nitrogen) were enter-ing the river throughthe Florida aquifer,itself a source of risingconcentrations in recentyears.

Sky collected bio-logical data during fivequarterly samplingperiods in an effort tobetter understand therelationships betweensurface water nutrients(nitrates in particular)and the vegetativecharacteristics of theriver. Physical, chemi-cal and biological datawere also collected.

One of the moreinteresting findingsfrom Sky’s thesis work

is that phosphorus mayplay a more importantrole in the river’s ecol-ogy than was previouslyrecognized. By growingperiphyton on glassslides in the field, Skysoon found that addingphosphorous greatlyincreased the growthrate of algae. The addi-tion of nitrate (nitrogen)did not.

The data that werecollected provide much-needed insight into thefactors that influencethe abundance anddistribution of macro-phytes, macroalgaeand periphyton in the

system, and shouldbe of interest to abroad group of envi-ronmental scientistsand resource manag-ers concerned withthe problems facingFlorida’s spring-fedwaterbodies.

“The work helpsprovide importantbaseline data forwater quality param-eters in this region,”Sky said. “It will helpto identify relation-ships between chemi-cal, physical and bio-logical factors in theriver. I certainly en-joyed working in thefield, often by myself,exploring and sam-pling up and downthat river.”

Sky is now assist-ing Dr. Tom Frazerwith Project COAST, anew coastal monitor-ing program coordi-nated through the De-partment of Fisheriesand Aquatic Sciences.It’s a good thing heenjoys field work, ashe will be collectingwater chemistry dataat the mouth of 13Florida rivers.

Sky Notestein in the field.

Joe R

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Joe R

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WaterWorks is published by theUF/IFAS Department of Fisheriesand Aquatic Sciences. Subscriptionsto WaterWorks are free, availableupon request. See subscription formon page 8. Questions, comments oreditorial submissions may be sub-mitted by contacting:

Editor Joe Richard 352/392-9617 ext 290

[email protected]

Faculty Advisor Chuck Cichra352/392-9617 ext 249

effects to formalin and potassium perman-ganate. To put it crudely, it “burns.” Butunlike 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 skinor eyes.)

As mentioned earlier, after a period oftime, HP breaks down into water and oxy-gen gas. This is one reason that the Foodand Drug Administration (FDA) presentlyconsiders HP an aquaculture drug of “lowregulatory priority.” In fact, more formalfield trials are currently underway exam-ining its effectiveness and safety for usein fish against fungi, bacteria, and para-sites.

Sources of HydrogenPeroxide

HP is available through most aquacul-ture supply companies. One manufactureris Elf Altochem North America, Inc.,(Woodstock, TN). Concentrated solutions,with approximately 35% active ingredient,are typically used. However, as long asyou increase the amount proportionately,you can probably also use over-the-counter HP from your local store. Theseare usually only 3% active ingredient.

It’s also available in dry form (SodiumCarbonate Peroxyhydrate) from SolvayInterox ® in Houston, Texas. The dry formbecomes HP once water is added. How-ever, this type of HP is specifically labeledfor use as an algaecide. And because thedry form is not pure HP, the reaction thatoccurs when it dissolves will also releasechemicals that tend to increase the pH ofthe water.

Therapy vs ToxicityThere are many different doses sug-

gested in the literature for use in aquariumfish. However, because there are hun-dreds of species of ornamental fishproduced in Florida, certain factors mustbe taken into account when using HP.For starters, it can be very toxic to somespecies, and certain life stages may bemore sensitive. Increasing temperatureseems to increase the potential toxicity.Dosage and duration of treatment will alsodetermine whether fish being treated willlive or die.

HP also causes mortalities if levels aretoo high, primarily by damaging the gills.

Therefore, toxic effects will often be seenrelated to gill damage, as indicated bygasping near the surface, or increasedventilation rates.

One research group (Rach, et al. 1997)recommended 50-250 ppm for up to anhour. However, this group only studiedfood and game fish, tested with a watertemperature of about 54 degrees Fahr-enheit.

The dosages reported for aquarium fishrange from 30,000 ppm for 10 minutes,5000 ppm for 5 minutes, or 300 ppm for10-15 minutes—basically all over theboard. (The 30,000 ppm dosage proveddeadly in many cases.) Such a wide rangeis probably due to different species beingtested, a variety of parasites being elimi-nated, and different water quality condi-tions, including temperature.

At the request of several producers, webegan to examine HP for use specificallyin ornamental fish at the University ofFlorida’s Tropical Aquaculture Laboratory.Although we have only examined a fewgroups of fish so far, we would like toshare our current findings with you.

Preliminary FindingsHydrogen Peroxide ResidualConcentrations

Contrary to popular belief, in water withrelatively low organic content, we found

Eric Curtis, biological scientist at UF/IFAS’Tropical Aquaculture Laboratory is involvedin the hydrogen peroxide studies.

that after nine hours, even in tanks withaeration (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. Ofcourse, any increase in organic loading willchange these numbers, but the bottom lineis that HP does not break down as quicklyas some may think. Water changes arerequired after treatment.

SummaryWe have not examined the economics

of using HP vs. traditional chemicals. Also,more effort needs to be made to examinethe effectiveness for use against fungaldisease of eggs. As mentioned earlier,results do look promising. We’ll keep youinformed.

If you do decide to use HP, be sure totry it on a small number of fish first. Pleasefeel free to share your successes and/orfailures 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 aboutany other fish health related issues, pleasefeel free to contact us at:

UF/IFAS TropicalAquaculture Laboratory813/671-5230

Note: The mention of manufacturers’ names ispurely for informational use. No endorsement oftheir product is directly or indirectly implied.

Continued from page 1.

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UF/IFAS Aquacultureand Pond Management Update

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SamMitchellAquacultureFarmBlountstown

Catfish GoalsBeginning this year,

the farm will be conduct-ing a growout demon-stration of the channel/blue catfish hybrid inponds.

This work is part of aregional project (south-east Alabama, southwestGeorgia and northFlorida) funded by USDAto demonstrate the po-tential of the hybrid toimprove farm incomeand sustainability.

The channel/blue hybridhas been shown to growfaster, is less susceptibleto certain stresses, has agreater dressout percent-age, and is easier toharvest by seining. Inaddition to pond growout,the farm will provide ahatchery demonstrationin year two of the project.

Catfish KidsDuring autumn 2000,

the SMADF and theNorthwest RegionalOffice of the Florida Fishand Wildlife Conserva-tion Commission joinedforces to put on anotherhugely successful Kids’Fishing Day. After fillingall pre-registration spotsin just two days, 211children between theages of 1 and 15 fishedduring the two Saturdaysessions.

With most children

catching their limit, a total of972 fish were taken home.

Each child received acertificate of participationwith his or her name onit, a Junior Fishing Li-cense, a poster, and agoody bag. A big thankyou goes to FWCC for allof their help!

Donations for thegoody bags were pro-vided by PureFishing, theFlorida Department ofAgriculture and Con-sumer Services Bureauof Seafood and Aquacul-ture Marketing, USDAWildlife Services, andThe Catfish Institute. Thenext Kids’ Fishing Day isscheduled at SMADF forSaturday, April 7.

Goldfish RushOn Oct. 7 the District

II 4-H “Gold Rush” pro-gram kicked off atSMADF. Participants inthe program picked upaquarium supplies andspent the day learningabout goldfish biology,aquarium setup, waterquality, and nutrition.

Over the next sixmonths, students will

SeaGrantSeminars On Nov. 28, Sea Grantagent Marella Crane andthe Miami-Dade Exten-sion office hosted a SeaScience Career Day. Over 40 high schoolkids attended the event.Marella invited speakersfrom the following pro-grams: the MiamiSeaquarium, OfficerSnook, Pelican Harbor,University of Miami,DERM and the YouthFishing Foundation. Chris gave a brief talkabout the role of exten-sion, how to prepare fora career, and what con-stitutes a typical workday. Speakers urged at-tendees to persevere

and follow their dreams.The spokeswoman forSeaquarium gave theaudience tips on internshipsand job responsibilites atthe public aquarium,ranging from public rela-tions to dolphin trainer. The creator of OfficerSnook, a water pollutionprevention program thatis for all ages, offered herstory as an inspiration toovercome adversity.Pelican Harbor’s speakerthrilled kids with her livepelican, while discussingher role as a volunteersaving pelicans that wereentangled in nets.

A dive instructor fromthe University of Miamidiscussed the valuableskills he taught research-ers so they could conductunderwater researchsafely. A Habitat RestorationSpecialist from DERMshowed the audience pho-tographs of his projects,while telling them how tonetwork and build contactsfor the future. The last speaker, fromthe Youth Fishing Foun-dation, showed a videoon free fishing clinics forinner-city youth andspoke about the benefitsof volunteering. All guests were able totour the new researchvessel Walton Smith,which features the latestin ocean research tech-nology. Her crew ledgroups of ten guests ona detailed, 15-minute tourof the ship. A post-event surveyfound that 45% of the at-tendees became seriously

Food andResourceEnconomicsDepartment(FRED)Gainesville Work continues on sev-eral projects concerningmarine aquaculture and/or marine fisheries man-agement.

♦ A USDA-funded projectfocused on developinginventory managementsoftware for hard clamgrowers is nearly com-pleted.

The draft version ofthe package will be field-tested with a smallgroup of growers in thenear future. It will allowgrowers to keep track ofhow clams planted on agiven lease site progressfrom nursery seed to har-vest-able market clams.

It also provides a run-ning total on mortality,standing inventory, ex-penses, and earnings. Acontinuously updatedmap of the lease site canalso be maintainted withthe software.

♦Another project fundedby FRED will be assess-ing the economic impactof the hard clam cultureindustry on regional and

raise their own goldfish,test water quality, andrecord their observationsand experience in prepa-ration for county and dis-trict events to be held inthe spring. For more in-formation, callDebbie Britt Pouder850-674-3184

interested in pursuing asimilar career as a resultof the presentations.

Chris Brooks305/248-3311 ext 230

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Hillsborough Community College continues to expand their aquacul-ture education program, preparing students for undergraduate or graduatelevel studies, or for apprenticeships throughout the state and even inter-nationally.

Some 21 students from Latin America and the Caribbean haveaccepted two-year scholarships to study aquaculture at Hillsborough Com-munity College, with a stated purpose of going back to their countries toproduce foodfish.

Funded by the Cooperative Association of States for Scholarship(CASS), the students receive a 24-month visa to stay in Florida. They willbe housed in Brandon. Though they can’t work in the U.S., they will havea stipend and a full-time coordinator to take care of them.

The students will take remedial English classes since most don’t speakEnglish. Aquaculture classes will be taught in English, and the program issponsored by Georgetown University and the U.S. Agency for Interna-tional Development.

Those who graduate will earn an Associate degree in Aquaculture, ora College Credit Certificate. Eighty percent of the students are from ruralareas, and half are women. All have completed high school and demon-strated leadership abilities. They represent the Dominican Republic, ElSalvador, Guatamala, Haiti, Honduras, Jamaica, Nicaragua, and Panama.

ShellfishAquacultureCedar Key

ShellfishAquacultureExtension ProgramExpands

The most significantrecent increases inFlorida aquaculture haveoccurred in clam farm-ing, with 1999 sales of$15.9 million, almost tri-pling those reported in1995.

Over the past fiveyears, increased col-laboration between theuniversity and the clamfarming community hasbeen beneficial to both,Unfortunately, extensionefforts have been limitedto a multi-county area. With this in mind, goalsfor this year’s extensionprogram include:

1) Establishing a net-work within countieswhere clam farming isongoing, by working withcounty marine agents;

2) Expanding the multi-county shellfish aquacul-ture advisory committee toa state-wide committee;

3) Conducting educa-tional workshops, dem-onstrations and provid-ing research results toother areas of the state.

Proposed workshoptopics for 2001:

♦ Introduction to remotewater quality monitoringsystems and weatherstations to be deployedat lease areas in sixc o u n t i e s ( e . g . ,CLAMMRS).

Hillsborough College Scholarships

statewide economies. Atelephone survey of allshellfish wholesalerswho handle culturedhard clams is nearingcompletion. This infor-mation will be used todetermine how the clamculture industry effectsexpenditures, incomes,jobs, and economic out-put in three regions ofthe state, and the statein total.

♦ Work also continueson a Florida Sea Grant-funded project to assessthe market acceptanceand fiancial feasibility ofcultured sturgeon. Thisproject involves a num-ber of IFAS faculty, in-cluding Andy Lazur inBlounstown and FredWirth (IRREC-Fort Pierce).

♦ An assessment of thefinancial characteristicsof mud minnow culturewill be completed earlythis year. Interest isgrowing with respect tothe small-scale culture ofmud minnows for thelive, marine baitfish mar-ket. The study will allowprospective growers todetermine whether ornot the culture process isa wise investment deci-sion. A recent FloridaSea Grant/FDACS studyhas shown that the mar-ket for mud minnows asa live bait is very strongwithin certain regionsand seasons in Florida.

Chuck Adams352/392-1826 ex. 223

New Publication A new book entitled Aquatic Resources has recently been made

available to anyone interested in aquatic education. Authored by Dr. BillFalls and three other professors at Hillsborough College, the 250-pagepublication stresses aquatic awareness, understanding, and uses for edu-cational purposes. It was funded by the National Council for AqricultureEducation, and sub-funded through USDA. There are five major sectionsincluding Aquatic Resources, Physical, Chemical, and Biological factorsaffecting aquatic systems; Aquatic Ecology; Aquatic Resource Issues;and Aquatic Careers.

Aquatic Resources covers fisheries, not just aquaculture, includingfresh and saltwater. Other items include an extensive glossary with aquaticterms, 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 Falls813/253-7881

♦Clam Crop Software —distribution and explana-tion of simplified comput-erized spreadsheets formaintaining crop invento-ries, for recording plantingand harvesting activities,for calculating yields and

crop times, and for track-ing farm income andexpenses.♦ Enhanced Seed Pro-duction— application ofgenetic breeding prac-tices and remote settingtechniques for hatchery

and nursery operators.♦ Pilot Crop InsuranceProgram - review andevaluation of policy pro-visions during the secondyear of the pilot phase.

Leslie Sturmer352/543-5057

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Submission of Fish and WaterSamples for Diagnostic EvaluationPart IIby RuthEllen Klinger-Bowen and Ruth Francis-Floyd

Submission of a water sampleFish spend their entire life in water, which means when a fish gets

sick, that environment must betested. No matter how clean youthink your water is, no matter whatyour water source is, or that yoursystem is flow-through, you musthave recent records of your waterquality parameters (e.g., tempera-ture, pH, ammonia, nitrite, dis-solved oxygen) or submit a watersample for analysis. A good diag-nostic laboratory will first test thewater for any deviation in quality.

When submitting a water sample for analysis, a few simple yetimportant procedures must be followed. First, water should besampled as soon as the fish begins to act abnormal and beforewater changes are initiated. A clean container (approximately onequart), 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 capon 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 thepond, and if the pond is large, at multiple depths and locations.) Ifthere are multiple systems involved, samples from each will beneeded. In cage culture, water should be sampled inside as wellas outside the cage.

The water sample should be separate from the fish sample. Thewater that the fish are brought in will not correctly reflect what isoccurring in your system. The chemistry of the water, whichincludes pH and ammonia, will change remarkably during trans-port. For example, while the fish is being transported to the diagnosticlaboratory, its metabolic activities (i.e., respiration, excretion) will causethe 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. Whenshipping water, place the sample on ice or ice packs. A Styrofoamcooler 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. Deadfish are rarely acceptable for diagnostic tests. However, if the fishare in good condition, that is, their eyes are clear and the gills arered, they may have some value. If they are obviously decomposed

or extremely smelly, donot submit. It is alsoimportant to submit arepresentative numberof each species in-volved. Usually threeto five fish will be suffi-cient. This ensures anaccurate diagnosis ofthe population as awhole.

If the fish are alive and appear to be able to make the trip to thelaboratory, place them into well-aerated water in a heavy ply plas-tic bag (fish shipping bag or commercial freezer bag), and aStyrofoam cooler to regulate temperature. This can then be placedin a cardboard shipping carton and shipped overnight. If the fishare dead or will not make the transport, the fish should be keptmoist with wet paper towels in a heavy ply plastic bag. Keep thesample cold, packed with ice in a Styrofoam cooler and shippingcarton. It is important not to freeze the sample, especially if tissuesare to be submitted for histopathology (examination of tissues fordisease processes at the microscopic level).

There are commercial overnight carriers that will take live anddead fish, if they are properly packed as mentioned above. Also,most diagnostic facilities require prior notification that a sample isbeing shipped to their laboratory. This ensures a contact personwill be there to receive the shipment and be able to work it up in anexpedient manner. Listed below are a number of laboratories inFlorida that are qualified to diagnose fish diseases. Contact theone closest to you for further information.

Samples that are hand delivered to a laboratory should also beproperly transported. Notify the laboratory you are coming with thesample, keep live fish in a bucket with a battery-operated aeratoror a plastic bag with well-oxygenated water, and moribund/deadfish 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 inthe correct diagnosis.

Kissimmee DiagnosticLaboratory2700 N. Bermuda Ave.Kissimmee, FL 34741(407) 846-5200

Live Oak DiagnosticLaboratoryP.O. Drawer OLive Oak, FL 32060(904) 362-1216

When fish become sick or die, diagnosis of the problem ismuch easier if clients are able to give a good historical accountof the events prior to submitting their fish or water to thelaboratory. 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 and/or fish sample to a diagnostic laboratory.

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

* Limited Service Laboratory (No veterinarian on-site)

Dept. Fisheries & AquaticSciences7922 NW 71st St.Gainesville, FL 32653-3071(352) 392-9617, ext. 229 or 230

Tropical AquacultureLaboratory1408 24th St. SERuskin, FL 33570(813) 671-5230

Sam Mitchell AquacultureDemonstration Farm*Route 2, Box 754Blountstown, FL 32424(850) 674-3184

UF/IFAS Laboratories

FL Dept. of Agriculture & Consumer Services (DACS)

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This is the first of two installmentscovering how to differentiate nativeand exotic catfish, providing informa-tion on exotic catfish in Florida .

Peninsular Florida (St. Johns andWithlacoochee Rivers and south) ishome to seven nativefreshwater and two na-tive marine catfishes. Atleast four exotic fresh-water catfish specieshave become estab-lished in this area sincethe 1960s. Exoticmeans a species thatcomes from anothercountry.

Florida’s native catfishspecies are readily rec-ognizable as catfish, hav-ing prominent barbels(whiskers) smooth,scaleless skin, and asingle hard spine in thedorsal fin and eachpectoral (side) fin.

The native freshwa-ter species belong tothe bullhead catfishfamily (Ictaluridae) andinclude the familiarchannel catfish (Ictaluruspunctatus), commonlygrown in aquaculture or farm ponds for foodor recreational fishing.

Other bullhead catfish in peninsularFlorida include Brown BullheadAmeiurus nebulosus, Snail Bullhead A.brunneus, Yellow Bullhead (A. natalis),and White Catfish (A. catus). Addition-ally, there are two small (less than sixinch) catfish species called madtoms,which inhabit peninsular Florida—Speckled Madtom (Noturus leptacanthus)and Tadpole Madtom (N. gyrinus).

Two sea catfishes (family Ariidae), hard-head catfish (Arius felis) and gafftopsailcatfish (Bagre marinus), also enter coastalrivers. Based on the exotic species cur-rently present in Florida, any catfish lack-ing armored plates or hard, rough skin andhaving a spine in the dorsal fin is likelynative 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 andsoutheast Asia, Walking Catfish is nowestablished throughout the southern half of

peninsular Florida. It was first found inBroward County in the late 1960s, havingescaped from an ornamental fish farm.Other introductions may also haveoccurred in Hillsborough County.

Walking Catfish is easily identified as acatfish by its prominent barbels andsmooth, scaleless skin. Of all the exotic cat-fishes in Florida, this species is the mostlikely to be confused with native species. Itis best distinguished by the dorsal fin. Innative catfish, the dorsal fin is short andpossesses a stout spine. The walkingcatfish’s dorsal fin lacks spines and is ex-tremely long, extending about three quartersof the fish’s length. The anal fin is also verylong. There are, however, spines in eachpectoral fin.

The walking catfish reaches lengthsof 24 inches, but is usually much smaller

in Florida, perhaps 14 inches. Originalwalking 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 extremelyslimy.

This is a voraciouspredator of smallfish, grass shrimpand crayfish. Theyare often active atnight. This speciesbuilds a nest wherethe female depositsthe eggs. The maleor both parents guardthe eggs and free-swimming fry. InAsia, walking catfishapparently breed innewly flooded areas,but little is knownabout reproductionin Florida.

In Florida they’refound in marshes,ponds, prairies, lakesand canals. Able tobreathe air, they’reconsidered to be anobligate air breather,

which means they must have air. Infact, they will drown if unable to reachthe surface.

Walking catfish are true to theirname, capable of crossing substantialoverland distances to reach new ar-eas. They walk by wiggling along theground aided by stout, pectoral spines,and as a result can easily invade newterritory. Although little research hasbeen conducted, they may have alarge, adverse impact on native species,due to their predatory habits and highpopulation densities in some habitats.They appear to be most important inephemeral pond or marshes (ones thatdry up and refill periodically). Thisspecies is an important food fish inAsia, but is not valued in Florida. WW

Native and Exotic Catfish in FloridaBy Jeff Hill

Jeff

Hill

Jeff

Hill

walking catfish Clarias batrachus

channel catfish Ictalurus punctatus

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The Institute of Food andAgricultural Sciences is an EqualEmployment Opportunity -Affirmative Action Employerauthorized to provide research,educational information and otherservices only to individuals andinstitutions that function withoutregard to race, color, sex, age,handicap or national origin.Inclusion of material in thisnewsletter does not constituteendorsement, nor does exclusionrepresent censure of any item,organization, individual, orinstitution by the University ofFlorida/Institute of Food andAgricultural Sciences.

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Editor / WaterWorksUniversity of FloridaDepartment of Fisheries and Aquatic SciencesPO Box 110600Gainesville, FL 32611-0600Phone: 352/392-9617 ext. 290 Fax: 352/846-1088E-mail: fishweb @gnv. i fas .u f l .edu

Florida LAKEWATCH has a hard-earnedand successful reputation for using vol-unteers to collect reliable water chemis-try data from Florida lakes. Because ofthis, state legislators were convincedduring this past legislative session thatthe same level of success could beachieved for Florida’s saltwater environ-ments. As a result, funding has beenmade available to expand our scope toinclude 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 besampling the same LAKEWATCHp a r a m e t e r s(i.e.,total phos-phorus, total nitro-gen, total chloro-phyll and waterclarity), plus a fewadditional itemsthat are significantto marine environ-ments—such assalinity and color.

Dr. Tom Frazer, Assistant Professorat UF’s Department of Fisheries and

Aquatic Sciences, will be co-directing thecoastal monitoring efforts along withLAKEWATCH director Dr. Daniel Canfield.

With initial funding provided by both theSuwannee and Southwest Florida WaterManagement Districts, Tom and several re-search biologists began gathering prelimi-nary water chemistry data along Florida’sGulf of Mexico coastline, from WeekiWachee to Steinhatchee in 1996.

Now that Project COAST has earnedlegislative support and funding, Frazer andhis staff will be teaming up withLAKEWATCH to train and assist volun-teers along more than 1350 miles of theFlorida coastline.

It’s an exciting time for FloridaLAKEWATCH/Project COAST. With alarge and growing database for freshwaterlakes, the expansion to coastal waters wasa natural progression.

LAKEWATCH program leader MarkHoyer says that he and his staff are look-ing forward to working with ProjectCOAST volunteers as they continue tobuild on one of the largest and most suc-cessful water monitoring programs anddatabases in the country.

A Toast to Project COAST

Anyone interested in participatingin the LAKEWATCH/Project COASTprogram is encouraged to call theUF/IFAS Department of Fisheriesand Aquatic Sciences at: 1-800-LAKEWATCH (525-3928)

Treating Fish Events Parasites

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