Ricg K. G. 1996.D''namics ofexploitation on the Amedcanalligator: envionmental contarninantsand harvest. PhD Diss. Univ. ofE. 165pp.

Rice, K. G. andH. F. Percival,eds. 1996.Etrects ofenvironmental contaminants on the demographicsand reproduction oflake Apopka's alligatorsand other taxa.Fla. Coop.Fish and Wildl. Res. Unit, U.S. Biol. Serv.Tech. Rep. 53. 85 pp.

SAS Institute Inc. 1988.SAS/STAT user's guidg release6.03 edition. SAS Institute Inc.,Cary, NC. 1028pp.

U.S.E.P.A.1994. Biological assessment: Tower Chemical Superfund Site. United States EPA Region4, Atlanta, GA. 21 pp.

Webb,G. J. W., S. C. Manolis,and P. J. Whitehead.1987. Crocodile manag€mert in the Northem Terdtory ofAustalia. Pages107-124. tz G.J.W.Webb, S.C.Ir{anolis, and P.J.Whitehead, eds. Wildlife manag€ment- crocodilesand alligators.Chipping Nortor\ New SouthWales. Australia. woodward, A. R., M. L. Jennings,and H. F. Percival. 1989.Egg collectingand hatch ratesofAmerican alligator eggsin Flodda.Wildl. Soc.Bull. l'l . 124-130.

Woodward,A. R. andw. R. Marion. 1978.An evaluationofnight-light aountsof alligators. Proc. Annu. Conf Southeast.Assoc. Fish andWildl. Agencies 32. 291-302. woodward, A. R., and C. T. Moore. 1990.Statewide alligator surveys.Bureau Wildl. Res.,Fla. Gameand FreshWater Fish Comm.,Tallahassee. Final Rep. 24 pp.

Woodward,A. R., H. F. Percival,M. L. Jenningsand C. T. Moore.1993. Low clutch viability ofAmerican alligatorson Lake Apopka. Fl. Scient.56:52-64.

201 --1 E 099 EI s<-

-oolcr.o* ': \o 6 : S !- le.rY -i;:

"sl lI1qi .- .i

ol Orct6 $5ee 9=3 ? {l ;l -o -ot @ .\ co qn 91 -.r 6i

*l ohi{' ,i:I o c.r ri *r oiri^ *vi,{ F6TY/

.Et :- >l 00 o -,i .o-P \oo.= 9vt: oo:/

SE ooo9! -34 Z6A e

9? -ii

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202 Table2. Mean densities,trcnds, and regressionresults for lakesApopka andWoodrufffrom

1980-1995.All trendsadjusted for waterlevel effects.

Year Studyarca Density Est.pop. Sizeclass (cm) (#/km) Change(%) Trendlyr Ridj

Woodruff (n=26) 30-121 6.19 +183 0.108 0.001 0.717 122-182 1.59 +140 0.086 0.001 0.677 9.88 +l2l 0.081 0.001 0.609 183b 2.10 +44 0.033 0.003 0.347 Apopka (n=26) 30-121" 4.30 +480 0.291 0.010 0.780 122-182 1.00 +4 -0.007 0.780 0.004 7.18 +160 0.159 0.010 0.868 183 1.89 +20 0.006 0."134 0.005

'Representsthe total population. h.epresentstotal adults. cResultsreoresent most recent trend. 1989-1995-

203 : 0.0l6dbe\ - 0 644{rid.r' 69.309ifFr \ 1939

P<0.01 : 7&,t19 + 0.r1(tiac+&9!rr) ifFr > 1939

<5

1980 1982 1984 1986 1988 t9m 1992 r994 1996 Year

Figure l. Population trends for 0.3-1.2malligalors basedon night-light srrn eys conducted on Lake Apopka fiom 1980-1995. Counts adjustedfor water level.

h(Mr)= -3.20+ 0.r1(Fe)

13

<5

1980 1982 1984 1986 1988 1990 1992 r994 1996 Year

Figure2. Populationtrends for 0.3-1.2malligaon basedon nightJightsurveys conducted on I-akeWoodrufffrom 1981-1995.Cornts adiustgd for q,aterlevel. 0.8 T 0.018(t'oe)- 0.Itqrirc) + 0.753ifFr < 1933 0.7 P= 0.05 1,..203+ O,074rirrc+4,98nif}€r > r9d8

0.6

0.5

0.4

0.3

(J 0.2

0.1

0 1982

Figure 3. Trendsfor clutch viabilit basedo! alligator egg collectionsfrom L€ke Apopka from 1983-1995.IIr fomul4 clutch viability ratesare arcsine squareroottrarsfomed.

0-9

0.8 I

0.7 I 06 t- 0.5

0.4

0_3 02 t- 0.t 0 t9a2

Figure 4. Trendsfur proportionofclutches which produc€no ha&hlingsbased on alligator egg colleclionsfiom l-ake Apopkafiom 1983-1995.In formul4 proportion is arcsinesouareroot transfomgd. 205 A Population Study of Morelet,s crocodite (qlglgdylg! moreletii) in the New Riyer Watershed ofNorthern Belize

ThomasR. Rainwaterl,Steven G. platt2,and Scoft T. McMurryl tThe Institute of Environmentaland HumanHealth, Deparhnent of Biological Scrences, TexasTech University, 1207 cilbert 'Wildlife. Dr., Lubbock,TX, 79416,USA. ConservationSociety, Lamanai Field ResearchCenter, hdian ChurchVillage, OrangeWalk Disrdc! Belize

ABSTRACT

Recentstudi€s suggest that in the absenceof commercialover-exploitation and habitatloss, Morelet's crocodileG. moFletiil populationsin northemBelize faceno imnediate threats.However, Q. morelaii eggscollected ftom a lagoonin northem Belize werefound to contain the insecticideDDT, suggestinga potentialhealth threat to crocodilesinhabiting the lagoon. A study was initiated in 1996to examinethe populationstatus ofg. moreletii in northemBelize andto assessexpostue and effectsof environmentalconlaminants, particularly pesticides,on crocodileswithin the study area. The New River watershedwas selectedas a referencesite and variousecological and toxicological endpointsare cunently being examined.The purpose ofthis paperis to presentpopulation data generatgd on e. moreletii in the New River watershedand to discussfutule researchdilections corceming exposureand response of crocodilesto environmentalcontaminants in northem Belize. Sizeclass distribution for C. moreletii variedamong years and no hatchlingswere observed in 1997and fe9e. Unusualyhllfr water levels in 1997may haveprcvented females ftom oestingor flooded existing nesls. A]l overall populationsex ratio of 1:3 (femalesto males)was observed,but the reason for this male-biasedratio is urlclear. A rotal of 199crocodiles was observedalong 395.25km (0.50 crocodileslkm)of shorelineduring spotlight surveysin 1997and 1998. Highestdensities were observedduiing drier months,suggesting that qocodiles disperseinlo floodedwoodlands and savannasduring wetterpedods. Efforts are currentlyrmderway to examineexposure ofe. moreletii to environmentalcont2minants in northernBelize and assessrcsulting effectsat both the individual andpopulation levels.

INTRODUCTION

Morelet's crocodile(Crocodvlus moreletii) is a medium-sized,freshwater crocodilefound in the Atlantic lowlandsof Belize. Guatemala-and Mexico (Croombridge,1 987)- I! Belize, it is commonlyconfused with the American crocodile G, @U$ wherethe two occur slmpatrically in coastalhabitats (Platt and Thorbjamarson,1997). Both C. moreletii atd C. acutusare curcndy listed as endangeredunder the United StatesEndangered Species Act and includedon Appendix

206 I ofthe CITES (Conventionon IntematiotralTrade in EndangeredSpecies ofFlora and Fauna)treaty (Thorbjama$on, 1992). Commercialcrocodile hunting began in Belize in the late 1930'sand 1940'sas the importanceof forcst prcductsin the local economydeclined (Hope and Abercrombie,1986). Subsequentover-harvesting led to the depletionofboth Q. moreletii and C. acutuspopulations (Chamock-Wilson, 1970). Crocodileskins werc sold to buyersin villages and larger towns, and after progressingthrough a chain of middlemeq exportedto Europefor processing(Abercrombie et al., 1982;Hope and Abercrombie,1986). Unfoftunately,quantitative survey data ftom this period are lacking andthe practiceof categorizingboth spottedcat and clocodile skins as simply "hides and skins" in governrnenttrade statisticsmakes it difficult to determinepast levels ofexploitation (Frost, 1974;Abercrombie et a1.,1982; Hope and Abercrombie, 1986). Furthermore,a cbnsidenblenumber of crocodileswere shotby sport hunters and memben of the British milit ry garrison,and an unknownnunber of skins were expodedillegally ( Chamock-Wilson,1970). By the 1960's,both Q. moreletii and C. acutuswere neady extirpatedftom Belize (Chamock-Wilson,1970; Neill, 1971).However, e. moreletii was affordedlegal protectionunder the Wildlife Protectior Act of 1981(Marin, 1981)and subsequendy, substantialpopulation increases have occurred in nor0rcmBelize suggestingrecovery &om pastover-exploitation (Platt, 1996). Curently, in the absenceof organized commercialhunting and habitatdestuction (MyeN, 1993),there appearsto be no immediatethreat to the continuedsurvival Q. Se!919!i in noithem Belize @latt I 996). Although C. morcletii populationsin northemBelize seeminglyface no iimediate tbreats,exposure to environmentalcontaminants, padicularly pesticides, may presetrta subdeyet significantlong-term threat to populationsin celtain ateas. Although most industrializedcounuies impose restrictions on the useand disposalof pesticidesand other toxic substances,regulations goveming the production"distributioq and useof chemicalsin many developingcotmtries are scant or inadequatelyenforced (Munay, 1994).Laxge quadities ofchemicals areroutinely usedin the tropics for agriculture,mining, crop storage,alld vector control (Incher and Goldstein,1997) at comparableor higherrutes thatr those in developedcountries (Castillo et al., 1997). In addition,many compoundsbamed in most industrializedcountries are cod[nonly used in topical areas. DDT is readily availablein many SouthAsian countries(Mengech et a1.,1995) aud is reportedlyused for pestcotrtrol in sollle coudries in CentxalAmenca. ln CentralAmeric4 no training or certifiaationis requiredfor a personto buy or apply pesticidcs(Castillo et al., 1997).Over 300 pesticidesare curently rcgisteredwith the PesticideConhol Board for usein Belize (Hagert, 1997). Although aot officially regisler€d,DDT is still usedin homesand businessesfor malariacontrol (Hagert,pers comm) andillegal useofDDT and other chemicalsfor agriculturalpurposes may also occur. we found contaminants,including DDT and/orits breakdow! products,DDE and DDD, in C. moreletii eggsfrom threelagoons in northemBelize (Rainwateret al , unpubl data). ExposureofAmerican alligators(Allieator mississiopiensis)to theseand other organochlorine(OC) chemicalsin Lake Apopk4 Flodda (Heinz et al.' 1991)is thoughtto be at leastpartly responsiblefor numeiousrcproductive effects including low egg viability (Guillette et al., 1994;Woodward e1al., 1993),reduced n€onatal survival (Guillette et al., 1994),altercd steroid hormone levels (Guillette, et al., 1994, 1996)and gonadalabnornalities (Guillette, et al., 1994,1996). In tum, theseeffects mav be responsiblefor decreasedjuvenilerecruitmenr and populationdeclines in the iake (Jemingset al., 1988;Woodwad et a1.,1993). In 1996,we begana studyto ftrrdrerexamine the statusand ecologyofe. moreletii in northemBelize andto assessexposure and effectsof eqvironrnental contaminantson crocodileswithin the study area. Cunently, we are aoncentatingon characterizingthe contaminantprofile ofone ofthe lagoonspositive for DDT. Tie New River watershedwas selectedas a potentialrefercnce site and we are in the processof collecting sedimentsamples to characterizecootaminant levels in the New River, New River Lagoon,and associatedwetlands. Given the lack ofany substantial dataon past or curent chemicaluse in theseareas, characteiziag chemicalprcfiles in thesesystems is a slow process. Our long-termplan to assessthe level and extentof contamtrantexposure is to usea combinationof techniques,including residueanalysis of sedimentand selected rissue samples. In this paperwe report primarily on the resultsof field eflorts in the New River watershedftom Oatober1996 to April 1998. Numerousbiological samples(e.g., blood, fal eggs)have been collected from crocodilesfor chemicalresidue and biochemical analyses.The puq,oseofthis paperis to presentpopulation data generatedon e. moreletii in the New River wate$hedand to discussfuture researchdirectio$ concemingexposure and responseof crocodilesto envirorunentalcontaminalts in northemBelize.

STUDY AREA

The New River watershed,consisting ofthe New River, New River Lagoon,and associatedtributaries, is encompassedwithin the boundariesofthe OrangeWalk and Corczal Distxictsin northem Belize (Figure 1). This drainagesystern extends approximately80 km from the headwateNto CorozalBay, and flous northeast following faults in the wderlying bedrcck (Ilartshorn * al., 1984). The river flows througha regiou of litue topographicalrelief, and nowhereis the elevationgrcater than 15 rn abovemean sea level (Hartshomet a1.,1984). The meanamual rainfall for this areais approximately150 cm, andmost occursduring a pronouncedwet season extendingftom Junethrcugh November(Johnson, 1983; Hanshom et al., 1984). Surfacedrainage within the New River wate$hed is poorly developed,aqd most water level fluctuationsresult ftom subsurfacerecharge (June to November)and depletion (Decemberto Ma, (Hartshomet al., 1984). Armual water level fluctuation is approximately1.0 m (Johnson,1983), although during someyears it may be much geater (pe$. obs.). The New fuver study site includesNew River Lagoon(17"42N, 88'38'W; ca. 23 km long) and an approximatelyl8 krn segnent ofthe N€w River extendingnorth from the New River Lagooumouth (17'47N, 88"38'W)to the Shipyardboat landing (17'52N, 88"36'W) (Figure 2). The westemshoreline of New River Lagoonrises 2 to l0 m abovethe floodplain alrd containslittle wedandhabitat. However,extensive Cladiummarshes and seasonallyflooded savannaoccur along the eastemshoreline.

208 Within our study site, a floodplain up to 5 km wide occursalong the New River. In additionto the main charurel,numerous parallel charnels,creeks, ald oxbows arefound within the floodplain. The vegetationalong the New River is chaxacterizedby alluvial swampforest and Cladium and Phrasnitesmarshes. Most of the land within the floodplain is inundatedduring exceptionallywet years. Densebeds of aquatic vegetation(Ceratophvllurn, Nymphaea, Utricularia, and Eleocharis)are found in shallowwater in both the lagoonand dvet. The New River andNew fuver Lagoonare presendynot includedwithin the lational systemofprotected areas.However, Zisman (1996)considers them to be essentialelemelts in a proposednetwork of corridors linking vadousprotected ateas within Belize. The northwestemshore ofNew fuver Lagoonborders the ancientMaya center oflamanai, known to havebeen occupied contiituously for more than 2000 years,the longestknown occupationspan ir the Cental Maya Lowlands(Pendergast, 1981). Although the subjectofsome debate,the nameLamanai is believedto be derivedfrom the Maya place-lameLama' anq)in,mea ag "submergedcrocodile" (Pendergast, l98l). I! the mid to late 1970's,recovery ofvessels bearingreptilelike adommentsand more significandy, pottery masksdepicting an individual wearinga reptilian headwith an uptumedsnout, protmding eyes,and tab-like maxillary teeth stronglyreinforced the eqmology oftle site rLameas Lama' anayin (Pendergast,1981). Appearanceofthe crocodilein this cercmoniallyimportant mamer suggeststhat the animal €njoyedan exaltedrcligious statuswithin th€ cosurunity @endergast,1981). Becauseno crocodile remainswere includedin ofGrings and intemrentsrecovered during excavations, Pendergast(1981) speculatedthat this religious statusrtray havedictated protection of the animalrather than sacrificeor other ritual uses.However, ongoing analysis ofthe faunalmaterial recoveredftom the site hasresulted in the identification ofan increasing numberof crocodilianremains. Although the majority ofthese havebeen rccovered from generalfood refuseaccumulations, or middens,sorne may also be fiom rihral contextsand may representtie leftoversofdtually preparedmeals or feasts(Norbefi Starchly, pe$onal communication).

METHODS

Crocodileswere capturedat night fiom a motorboatfor generalsampling and marking purposes. Captues were madein July (onenight), August (oneweek), and October(one week) 1996;March throughApril and Juneth,rough Octobef, 1997; and January(one night), March (onenight), andApril 1998. Animals werelocated using a haodheldQ-beam spotlight (250,000aandlepower) and auxiliary l2-volt headlightsto detecteyeshine rcflections. Smallerqocodiles (total length [TL] < 90 cm) were captued by hand or dip net, while larger crocodiles(TL > 90 cm) were captued using selfJocking breakawaysnares. All crocodilescaptued wele measuredand classified by TL as hatchlings(TL<30.0 cm), yeadings(TL=30.1 to 40.0 cm), juveniles (TL:40.1 to 75.0cm), subadults (TL=75.1 to 140.0cm), or adults(TL>140.1 cm) (Platt,1996). Sexofeach crocodilewas determinedby cloacalexanination ofthe genitalia.Observed ntios weretested against a null hypothesisof a 1:I sexrctio using Chi-squlre test (caughley, 1977). Animals for which sex could not be confidently determinedwerc not includedin amlysis of sex ratios. All animalswete examinedfor extemalparasites, injuries, and abnoqnalities. Eachoocodile was markedby clipping cuudai o, with a uniquely numbercdcattle tag attachedto the fust singlJcaudal scute""ure,and then rcleasedat the odginal capturesite. Spotlight surveyswere usedto estimatecrocodile densities (Bayliss, 19g7)and from mid Juneto mid October 1997,shorelines and islandswithin the study site werc searchedfor crocodilenests to exa$ine crocodilereproductive ecology. Spotlight surveyswerc conductedfrom a motorboatpropelled along the shoreline,using a handheldQ-beam spodight (250,000 candlepower) and auxiliary I 2-volt headlights. Crocodileswere locatedby noting eyeshinereflections in light beamsand classifiedas hatcblings,yearlings, juveniles, subadults,or adultsas descibed above. Crocodilesthat could not be approachedclose enoughto estimateTL were classifiedas ,.eyeshiqe only". Distancetraveled'in eachsurvey was calculatedwith a Magellan Giobal PositioningSystem (GPS) 2000 satellitenavigator or a cartometer-usingropogaphical mapsobtained ftom the Depaxhtrenlof Landsand Surveys,Belmopa4 Belize. Crocodiledensities were calculatedas the numberof crocodilesobserved per kilometer of surveyroute. allowing quantitative comparison with othersurvey data-

RESULTSand DISCUSSION

Size distribution

A totalof144Q. morelaii as capturedfrom July 1996though Apdl 1998.tn 1996,yearlings constituted the most ftequenfly capturedsize class (41.1 %) (Figure 3). Conversely,in 1997and 1998morc juveniles, subadults,and adultswere capturedand few young animals(4 yearlings,no hatchlings)were found. Sevemllarge animalswere captured,including a 303.0 cm (TL) male caughtin August 1997. This size class distribution may not be representativeofthe true distribution due to differenaesiII captue effort amongyears and habitats. However,no nestswere found in the New River wate$hed in 1997after approximately110 hours ofsearch effort over a 14-day period fton July tbrough August. We speculatethat heavyrains and unusuallyhigh water levels may haveresulted in inundationof all potentialnesting sites or a complete loss of nestsftom flooding. Someoests may havebeen overlooked during surveysas locatingnests in New River and New River Lagoonis inherentlydifficult due to the expanseofthe are4 the abundanceofpotential nestingsites, and limited manpower (oneresearcher in 1997). Although no flooded nestswere found in the study arcE 10002ofmarked nests(6) at Gold Button Lagoon(appoximately 15 km northwestof New River Lagoon) were formd submelged.Platt (1996) observeda similar phenomena in Gold Button Lagoonin I 993 when healy rainsresulted in higher than nonnal water levels and most nestswere lost to flooding. Total nestloss from flooding has also been obsened in {. mississiopiensis(Platt et al., 1995).

2t0 Sexratios

Sexwas determinedfo! I 18 e. morcletii captued in the New fuver watershed ftom July 1996through Apnl 1998. The overall po-pulationsex ralio \4as l:3 femalesto malesand significandy difered ftom a I :1 ratio(,f:34.71; p<0.005).The reason for themale-biased sex ratio is unclear.Platt (1996) observed a similarsex ratio (l:2.2;l = 9.28, p<0.01) for e. moreletii throughoutnorthem Belize and speculatedthat because sexntios ale highly dependanton inaubationtempemture (Lang andAn&ews, 1994),it is likely that they differ anauallyas a result ofvariable nestingconditions. Atthough samplingbias may accountfor the observeddeviations ftom a I : I sex ratio (N,ftosovsky and Prcvalch4 1992),live capturescan yield a relatively preciseestimate ofpopulation sex rutios in oocodilians (Rootesand Chabreck,1992).

Population€stimates

A total of 199Q. moreletii was obsewedalong 395.25kn of surveyrcute in the New River wate$hed (0.50 crocodiles.&m)(Table l) during spotlight surveys. The majodty of animalsseen could not be approachedclose enough to estimateTL, so we werc unableto usethese data to estimatesize class distibution. The highestdensities rccoded werc in the New River Lagoonduring March 1997(1.02 crocodiles,4

Reproduction

No nestswerc found in the New River watershedin 1997. Due to inhercnt difficulties in locating nestswithin the study site, it is possibletiat sometrests were overlooked. However,the lack of hatchlingsard yearlingsin fall 1997and early 1998 suggcststhat althoughnests are difficult to find, few or nonewere constucted ol sucaessfirlin 1997. As statedabove, rve speculatethat unusuallyhigh water levels during the nestingseaso4 particularly at the time ofoviposition (1 July 1 I I days;Platt, 1996),likely inudated most or all nestingsites witiin the study area. High water levels probablyprecluded females ftom constructingnests or laying eggs,or flooded nestsconstucted prior to healT rainfall. Femalecrocodilians may not rcproduceevery year and althoughthe reasonsfor this are unclear,possible mechanisms include exposureto a sfessor, insufficie[t energyreserves, metabolic stimulation or inhibition ').tl ofthe endocrinesystem, behavioral responses, or genetically-determinedolulahon pedods(Ferguson, I 985).

Occurrence of C. 4ggqggin the New River: watershed

Perkins(1983) repodedC. acutusfrom the New fuver Lagoon. However,this was likely due to conirsion with Q. moreletii as only the latter havebeen found rn extensivesurveys conducted from 1993to 1998@latt, 1996;Rainnater et a1.,unpubl data). In Belize, e. acutusappeam restricted to offshorecays (islaods) and atols;.\Mitha few individuals occurring on the coastalmainland (platt and Thodamarson, 1997). Thereis no evidencethat e. 4qqlfugoccurs in any inland, freshwatetwetlands.

Toxicological investigations of g. moreletii itr the New River water.shed

A major issuein the field ofwildlife and environmentaltoxicology involvesthe potentialfor envitonmentalcontaminants to disrupt nomal firnction ofthe endocnne system,thereby impairing regoduction in exposedspecies. Numerous endocrine- disruptingchemicals (EDCs), including pesticidesand industrial chemicals.have been releasedinm rheenvironment during the last 50 years(Colbom er al.- 1993).A primary concemis the profound andpemanent effect that exposureto thesecompounds, particularly during critical periods of development,can haveon the future well-being of wildlife (Colbom et al., 1993). Numerousstudies have rcported wildlife exposweand rcsponseto envirorunentalcontaminants, many of which arenow recognizedas eadocrinedisruptors. Reptiles have largely beenignored in ecotoxicologicalresearch, unlike birds, mamrnals,and fish, which haveattracted much attentionleadins to legislationand regulationsofvarious chemicals. However,due to recentstu-dies demonstratingtheir sensitivityto EDCS,reptiles arequickly emergingas importad focal speciesin wildlife toxicology @ergeronet a1.,1994; Matter et al., 1998). Much ofthe concemregarding EDCS stems fiom datashowing reproductive impahmeotand population declines ofA. mississippiepsisin Lake Apopk4 Florida. Thegincipal objective ofthe prcsentstudy in the New River watershedis to examlne exposureand responseofg morcletii to EDCs in Belize and assessthe effect ofthese chemicalson crocodilepopulations. In 1995,we found EDCs, includingp,p,-DDE, in q moreletii eggsfrom threelagoons in Belize (Rainwateret a1.,unpubl data). We are going to test the h]?othesisthat qocodiles inhabiting contaminatedlagoons contain higher EDC concentrationsin their tissuesthan individualsin non-contaminatedareas andthat differencesin crocodilemorphology, blood homone levels, serumchemistry, reproductivesuccess, population density, and juvenile survival exist betweel contaminatedand rcferencesites. To assessEDC exposure,blood, fat, and non-viableeggs will be collected(non- lethally) ftom crocodilesat contaminatedand refereocesites for analysisofplasma vitellogenin levels (blood) and OC conraminants(fat, eggs). To assesscrocodile responseto EDC exposue at the individual level, differencesin biochemical (plasma testosterone,l7B-estradiol, serumchemistry) and moryhological(penis size) endpoints betweencontaminated and reference sites will be examined. Crocodilercsponse to EDC exposureat the populationlevel will be assessedby examiningdifferences rn 2t2 endpointsof rcproductivesuccess (nesting success, clutch viability) andpopulation demographics(density, size stuctue, sexrutios, juvenile suwivability) between contaminatedand refercncesites. The primary goal ofthese toxicological assessmentsis to provide infomation on the linkage betweenEDC exposureat the individual level and resultingeffects at the populationlevel. Comparisonof thesedata with dataon 4. mississippiensisfiom Lake Apopka will provide a uniqueopportunity to examinewhether Lake Apopka is a worst- casescenario or if similar reproductiveproblems and populationdeclioes occur in other crocodilianspecies exposed to EDCS.This studywill alsoprovide additionalinsight into the efficacy ofrcptiles, particularly crocodilians,as sensitiveindicators of erlvironmentalcontaminalioo and ecosystemspotentially at risk. This information will be especiallyusefirl fo! ecologicalrisk assessmentitr trcpical counaieswhere reptiles arc abundantand regulationsgoveming the useof chemicals,some of them EDCs,are underdevelopedor inadequatelyenforced.

ACKNOWLEDGMENTS

The authorswish to thank Malk andMonique Howells of LamanaiOutpost Lodge for generouslyproviding accommodationsand logistical supportthroughout this project. Field assistancewas Fovided by RubenArevalo, SandraBlack, Amanda Colombo,Travis Crabtree,Beqjamin Cruz, Luis Gonzales,Debbie Green, Aathony and Julie Hawkes,Denver Holt, Laua Howard,Leslie Leone,Blanca Manzadlla, Mick Mulligan, Rusty Nale, Araba Oglesby,Tommy Rhott, Patti Schick,Cynthia Sills- McMurry, Mia Tomol4 and JoseTones. The necessaryresearch and collectionpermits wereissued by RafaelManzanero, Forest Deparknenl ConservationDivision, Ministt-y ofNatural Resources,Belrnopan, Belize. Supportfor this project was providedby LamanaiField ResearchCenter, Indian Chuch, Belize and U.S. EPA Grant ProjeatNo. R826310. S. Platt was supportedby Wildlife ConservationSociety.

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Guillette,L.J., ft., T.S.Gross, G.R. Masson, .M. Matier,H.F. Peraival, and A.R. Woodward. 1994. Developmentalabnormalities ofthe gonadand abnormalsex hormongconcentations in juvenile alligators from contaminatedand control lakesitr Florida. Environ. Health Perspect. 102:680-688.

GuiUett€,L.J., Jr., D.B. Pickford,D.A. Cnin, A.A. Rooney,and H.F. percival. 1996. R€ductionin penis size and plasmatestosterone concentrations in juvenile alligato$ living in a contaminatedenvironrnent. Gen.Comp. Endocrinol. 101l'3242. '97. Hagert,T. 1997. The Belize pesticidesmanual PesticidesCotrtrol Board, Central Farm,Cayo, Belize. lst ed. BRC Printing Ltd., BenqueViejo, Cayo,Belize.

Hartshom,G., L. Nicolait, L. Hartshom,G. Bevier, R. Bdghtman,J. Cal, A. Cawich, W. Davidson,R. Dubois, C. Dyer, J. Gibson,W. Hawley, J. Leonard,R. Nicolait, D. Weyer,H. White, and C. Wright. 1984. Belize countryprofile: a field study. USAID, and RobertNicolait and Assoc.,Ltd., Belize City, Belize.

Heinz, c.H., H.F. Percival,and M.L. Jennings. 1991. Contaminantsin American alligator eggsfiom LakesApopka, Grifhn, and Okeechobee,Florida. Environ. Monit. Assess.16:277-285.

2t4 Hope,C.A. and C.L. Abercrombie. 1986. Hunters,hides, dollars, anddependency: Economicsofwildlife exploitationin Belize.Pp. 143-152.In: Crocodiles.Proc. of7' Working Meeting of Crcc. Spec.Group, IUCN, Gland, Switzerland.

Jeruings,M.L., H.F. Percival,a:rd A.R. Woodward.1988. Evaluation ofalligator hatcblingand egg removal from tbreeFlorida lakes. Proc.An:nu. Conf. Soutieast. Assoc.Fish and Wildl. Agercies.42:283-294.

Johnson,W.C. 1983. The physical setting:Northem Belize and Pulltowser Swamp. In: Pulltowser Swamp: Arcient Maya habitat,agricultue, and setd€mentin northem Belize. Tumer, B.L. and P.D. Hanison, editors. Univelsify ofTexas Prcss,Austin.

Lacher,T.E. aod M.I. Goldstein. 1997. Tropical ecotoxicology:status and needs. Environ.Toxicol. Chem. 16:100-111.

Lang, J.W. and H.V. Adrews. 1994. Temperature-dependantsex determinationin oocodilians.J. Exp.Zool. 270.2844.

Madn,F. 1981.Wildlife PrctectionAct 1981.No.4. Ministryof Natual Resouces, GovemmentPrinting Oftce, BelmoparqBelize.

Matter, J.M., D.A. CrairL C. Sills-McMurry, D.B. Picldord, T.R. Rainwater,K.D. Reyoolds,A.A. Rooney,R.L. Dickelsoo and L.J. Guillette, Jr.. 1998. Effects of etrdocrinedisrupting contaminantsin rcptiles: alligators. In: Piinciples and processes for evaluatingendocrine disruption in wildlife. Kendall, R.J., R.L. Dickersotl J.P.Ciesy and W.P. Suk, editols. SETAC Press,Pensacol4 Florida.

Meogech,A.N., K.N. Saxen4 and H.N.B. Gopalan. 1995. Integratedpest management in the topics: Curent statusand futule prcspects. JohnWiley & Sons,New York

Mrosovsky,N. and J. Provancha.1992. Sexratio ofhatchling loggerheadsea turues: Dataand estimates from a 5-yearstudy. Canadian J. Zool. 70: 530-538.

Munay, D.L. 1994. Cultivating crisis: The huma! cost ofpesticidesin Latin America. University ofTexas Press,Austin.

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215 coT_T1aqol statustand managemenLUnpubl. Reportto New york Zoological Society and Yale Schoolof Forestryand Environrnenta.lStudies.

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Zisman,S. 1996. The directory ofBelizean protectedareas and sitesofnatue conservationintercst. Govenment Pdnting Office, Belmopan,Belize.

216 Figure 1- Map of Belizeshowing the locationofthe New Riverwate$hed (in box)'

211 ffim Figure 2. Map ofthe New River watershedstudy site. 218 1998 n=40 40 30

20 s 10 E 50 q, 1997 n=75 5 CL 30 IE o 20 o o 10 E o o 50 o 1996 n=29 (J 30

20

10

YR SA AD

SizeGlass

3. Sizeclass disribution of Morelet'scrocodiles captured 1th" I::-lju"t Fisure length(TL) as *lsr?, iq97, and l998 Sizeclasses are based on total *i"t.rt"a - (JV): ( 30'0cm; Yearlings(YR): l0 l 40 0 cm; JLrveniles fofio*.. ffut"f,fing. 1HA): > 1400 cm' +i,li-'isl (se): ls t - 1400 cm;and Adults IAD): "-,-i-itja"tts 219 Table l. Resul6 ofspotlighrsurveys conducred for lvioreler'scrocodiles in the New fuver walershedfrom July 1996to Aprii 1998. Dala6om theNew tuvermoulh (at CorozalBav) ano Four-niie(San Roque) Lagoon* are from plan andThorbJamarson (1997) ard areinctud;d tor comparison.

45.26 r.02 l8 J@eI997 5 45.26 0.1|

?0 Auglst 199? 6 45.26 0.ti

ll S""ptemberI 997 5 43.26 0.1I

l0 Ocrob€rr997 4526 0.07

14April 1998 t.63

24 Aprj] 1991 ?0 t7.61 l l3

30June 1997 9 t7.67 0.

12.l!ly 1997 17.67 0.23 '11.67 16Augu$ 1997 0.?3 '7 l2 Seprenbcr1997 t7.67 0.30

II Ocbb.r 1997 6 17_67 0.i4

8 April l99E l0 t7_67

2 July1996 t5 6.0 2.5

6 Dcccmb€r1995 I9 7.2 2.6

i Julv1995 5 7.5 0.66

li9 ?71.56 0.il

60 l?3.69 0..19

r99 19525 0.i0

*Linkedlo New fuver b).,a chainel (Databom Planand Thorbjamalson,1997). **Toralsdo not includedaia from Ne$ fuver moulhand Four-mileLasoon.

220 NILE CROCODILE (Crocodytusniloticns) RESEARCE PROJECT in the KRUGER NATIONAL PARK SOUTE AFRICA D.G.J. Swanepoel,P/ B.rg X102, Shth@a,Sottth Africa' 1350' sw4'vtie@f8'lia''Et

1. INTRODUCTION sanctuariesfor tlrc Nile ; SouthAfiica, the K$ger Natioml Park (KNP) is one of the largest in Natal this is tie onlv J."""O", i"ttiiJ ;ttdiuiaudt io ls94' Besidesst Lucia o/oofthe curent ou*rj oopulation"l"tt?soo ofC rt,Joticurin SouthAfica About 95 rivers' cr-ossingthe Park ;;;;;"i*in"* Kd;'t acan be found in anv one of the swen major river is the largestone m io'* l,l"t, to ottty tlree rivers are perennial,atrd the olifants "*I termsofcrocodilenumbers.seeFig'2'Besidestbearrnualaoial}uppopobmusc€nEus'no Nle crocodile During o,t er iuru *u, *", *lected in Kruger National on any aspectof the proj€ct ofits kind ,h" hiooo -i;; coult is dorc as well. Besidesbeing the first in a number ;;";i s-;*h""o,u"' " ",ocodileNational Parks (SANPARKS) this project is quite unique ot aspeqs. is in a perennialriver with It breaksnew groundin our local researchprograr4 the study area someunique aspecls no largeware;body or maomade structues in the rivet andit includes from indusrial ilH;ii;;;tf ;"r qualities,quantities and the efects of heavvmetals looationof nestsand the nm*m irrto ttt" ;""r. it pto;""t ut* io"tudesdata ort nesting; " to and abovewatet JrriUi" i"nu"."" of""rtairenvironmental pararnetersi.e. slopg distance iwel and clutch sizeand egg dimensions' somepathologioal and Anodrerunique feature ofthe project is that a stad was madeto collect samplesfrom the size toJ"iJa"t"L frtg" uadt indivi;uals An efort was madeto collect fitittrg t.J;,n" project Besidesthis data-the largestradio traosmitter ""f"sfnlJ""operationon crocodilesin SouthAfrica waslaunched *h"n t2 ttu*tittot oere fined to large(>3,0m) individuals. This will supplem@ttlle existingdata otr their movemedsand the time and extentofthe movelnent.

STUDYAREA The studv areacovers about 2l km oflhe OLilants riverprior to it enteringMoz.obique Thisrepresenr a the npes ofrerrain varyingfiom a sbgle cbaoneled shallowstrearn to a multi-channeledfast or siogledeep slow movitrgstream. Se€Fig. 1. Beforethe flood in FebruarvI996 the river bedwas predominantlyan oDerbasalt rock bed with weu establishedislands in someparts oftie river. This all changeddurbg the flood, and currentlythe river is aoveredifl sandbanks ard areasoflsrge silt deposits. The str€m changedto this might havea possible a wide shallo* charmeland Tt . sruov ano t, 0,. x"ucER NATIoNALPAF affect on the moverneltsofcrooodiles The whole 221 The total length oftle breedingfemales was determineusing Hutton (1987) andmeasudng the print ofthe hhd foot. None ofthe previousyeaxs (1996) nestswere usedby the females and or y on rare oc,casioBswas it foutrd that tie previousyears site was used. It seeqsas if the ferlalesrcst at differert sitesevery year. Thereis only one femaleotr recordtlEt nestedin two consecutiveyears, and on both occasionsshe used the samesitg but not the sane negt. The averagebreeding size (3,02m)for fenales seemsa bit larger than Zimbabwe(Hutton, 1987).

6, POLLUTION The Olifantsliver is one ofthe worst polluted dve.s in the coutry (Theroq Grifisebl & Pulen ConsultingEngineers. 1991), ard cardesa large amountofiadustrial aflueat (Se1more,1994), (Selurore et a1.1994).This pollution carriesa large numberofmetals and this is depositedin the silt layer after everyflood (Seymoree/ 4/.1994). In an attemptto shed light on the decreas€irr numbers,a seriesofanalysis were doneon culled crocodiles. Four individualsfrom the Olifaits andtwo iom the Sabiriver were arBlisedfor a wide spectrumof metals.

Thewater level in the Olifantsriver is controlledby a banagejust outsidethe KNP, and this vaxiationin water levelscan be seenas a form ofpollution. At agreemetrtassur€d a constarfi minimalflow of0,6 cusecduring the dry winter peiod, but wate! canbe releasedon special request. This resultsin abnormalhigh or low water levelsdurilg tron conespondilgperiods.

The project proofedthat the low water level is a rcstrictiotron movemerlt,but this might influencebreeding sites as vr'ell. Dudng the dry poiod, the large pools are sharedby a large oumberofhippos atrdthis naturallyresults in a deteriorationofwater quality. Studiesshowed clearindicatioas that somemetals are depositedwith silt only to be releasedduring high flow or floods.

The analysisshowed a numberofparasites present in the tlache4 hart, and lungs. The numbersand degreeof infestationwas about rcImal but it could contdbuteto infectionsand poor conditioo. Someoftle pentastomesfoutrd was:

Leiperia citcrmolis Sebekiawedli Sebehaolavargomsis Sebekacesarisi AWa simpsoni

During May andJune 1997 someseve! laxg€adult individualswere $c€trto be itr poor health andcordition. All ofthem died within tiree weeksofbeing sighted,but oo caroassescould be recoveredfor analysis.This leadto a more detailedstudy but the data catrnotbe comparedto anythingavailable. Somemore work is neededon this aspect. Swen individualswere collected,five from the Olifantsard two from the Sabidve! for detailedanalysis.

223 Table 3. Liver and Kidne! anallsis of mdals in C' niknicut in the Olifan's rieer' Note that ctocodilc 6 and 7 were colleded in lhe Sabi fiver' The nunber, sa and total LIVER 1(F)- 2(M)- 3(M)- 4(F)- 5(M)- 6(M)- 7(M)- 2,l?trl 2,36m 3,50rn 1,48h 4,15rn 2,L4trl 3,gorn 329 42,3 53.4 44,2 66,4 2972,6 3136J 3465,6 22734 2750,4 ?aoa,5 3041,6 l,tg tt?,5 119,8 t373 86,3 97,O co (ppn) 2.4 2;7 cu (pp'n) 18p L9,5 8.0 AP L?,3 3?t4t 4501,8 LZZA5,6 5031.8 1247,6 2474,\ 3016,2 2.6 si (pF) z9 t,6 2,4 & oFn) 3J 2,6 3A zn (rpn) 7t,a 69.6 649 569 5249 x (ppi) 603,2 1353,3 296t 430,5 544,6 579,3 252,6 No (pp'n) 963 199,8 ?r9,a 165,3 tal

3 (r'4)- 4(F)- 5(M)- 6(M)- 7(M)- 3,50m l,48|rr 4,15m 2}4m 3,90h Ca 73,8 494 90,4 65,5 $57,2 2118.9 1961,8 na59 ?0E13 38,1 103,4 69,3 co (pFn) 6, (pp,n) t.7 4p F" (PF) 764 101,1 94,6 57,Z Itn (pptn) 1,8 3,2 sG (pFn) 2,7 2F z. (ppn) 407 5A,2 7l,l 45,6 x (PF) 98F 81,1 zoaS 190p tlo (ppn) 144.5 1t4,5 248.4 275,l

and Sabi rieers. Table 4. Data on lhe blood of rte LUe clocodile in the ALOODCEEM]'TRY Table 5. Analysis and Sabi crocodiles

(M)- 2,36.r 3 (M)- 3.50h

6 (M)- 2.14h

2 (i4) - 2,36h 3(A)-3,50h 172.55

) - 4,15n

! (n - 2,L2tn

5 (M)- 4,15rn 6 (M, - 2,r4rn

6 (M)- 2,14n

BD= Below O.001ug,/g 225 Table 6. Blood C. nilaticlls in the ad Sabi tivers. BLOOD CHEMISfRY

226 APPM{DX1. cBo@DLEONT WA

CROCd)I.Eq.JNIS t5 SecbrB

Groupsin Sln"l;,P'o"o "nd

CR@DII!o.NT fuC

-r S(tlirgs-Total

Fig 2. Totalsand Groups in Sector B.

t- sirrEs -r.td FIG3, Groupsand nrrnbers iySedorC. crcDnEo.l fuD

29 &

7@

Ftet Groups& Tohls in Secdor n

221 TOTALCROCODILE studv Area ftom 1994 - 1997 950 850 750 650 Hso 450

250 150

FlGs. Totalsin studyarea, countswere done in May,Aug & Dec.

OlifantsRiver Aedal CensusCounts

1lxtl

lttat4

idg a\o p\ tsz ts: ng Yar

FIG6. Totalsfor fp entireOlilanb river. Bibliography

HUTTON, J.M. 1987.Mo.ph@dics andField Estirratioosofthe Sizeof tle Nile Crocodile.lficaz Joumal of Ecolog, 25: 225-230.

TIUTTON, J.M. 198?.hcubatiol t€ryerahres, sex ratiosadd sex determinati@in a populdion of Nil€ croc.diles Crocodylusnilonas . Journal of Zoolog/ 217 143-155.

KOFRO\ C.P. 1989,Nesting ecologyoftie Nile CrocodileCrcoodylus niloncus. AAican Journat of Ecologl 27| 335-341.

LOVERIDGq t.P. 1992.Tr€nds in Nest NumbeF aDdCldch Sizesof Crocodllus nilonaa at fo]Jr localitiescn Lake IGriba, Zidnbabwe.PrcceeAhgs ofthe I lth WorkingMeetingof the Crocodile SpecidlistGroup of the Species&.rvirsl Cotirnission oftle IUCN. yictoia Falls, Ziribabwe..

POOLEY, A.C. 1969.PrelirniDary Studies m the Breedingofthe Nile Crca./.ile Crocodylusniloticlrs i Zu\rl:rnd. Iammeryele r 10:.2244.

SEYMORE, T,1994. Bioaccumulati@ofM*als i^ Barbvs ,narepentis frour the Otbrts river, IGuger Natiooal Park and l*thal leveJsof Mangaese tojtwr,ile Oreochromit tuossambtcls.MSc. R d Afikaaos Uai'ersity.

SEYMORE, T., DU PREEZ, H.H., VAN I'IJUREN, J.H.i., DEACON, A. ; STRYDOM, G. 1994. Variatims in selectedwater quatig vaiables aad net"l c@c€ffiic'Ds i! the sedimedofthe loser Oli&rts a[d Selatiriwrs. SornhAfrica. Koedoe37: l-18.

TIIERON, P., GRMSEHL & PULLEN CONSIJLTING ENGINEERS. 1991.V/atlr R€sourc€s Plaming ofthe Olifars River Basi!. Studyofthe Developm€dPot€osial and MaDagem€dofthe Wder kEsotnc's. DWA ReportNo.P.B000/00/0191 1: ExecutiveSudnar'.

229 wo.kshop Report. World Tradein Crocodilianskins. current events and trends.

J. P. Ross Executiveofiioer CSG

A workshop was convenedat the 14'Working Meeting ofthe CrocodileSpecialist croup in Singaporcon 15 July 19988. The workshopwas moderatedby Mr. Kevin wq Jaarsveldt(Zimbabwe) CSG Vice Chairmanfor Trade,and rec.eivedreports and discussionfrom a panel,followed by genelaldiscussion oftrade issues. The panel consistedofMr. C.H. Koh (Singapore),Mr. Y. Takchara(Japan), Mr. D. Ashley (USA), Dr. J. P. Ross(CSG), Mr. L. Roiter (Colombia),Mr. Paul Stobbs(Papua New Guinea) and Mr. C. H. Giam ( Singapore).Additional substantialcomment and informationwas receivedfrom IUr. H. Kelly (South A&ica), Mr. Alvaro Velasco(Venezuela), Mr. Hank Jenkins(Australia), Ms. Vickii Simelesa(Australia), I\4r. GeofMcclure (Australia) as lrvellas the generalaudience.

Individual w'ittell reportsand commentsfrom tr4r.Koh, Mr. Takehara,Dr. Rossand Ms. Simelesaare publishedfollowing in this volume. A generalsummary of importantpoints and is$resnised in the disossion are summarizedhere.

Kevin van Jasrsveldtopened the discussionby noting the increasingtransparenay oftrade and suggestedthat the fee flow of information abouttlade andthe organizationoftrade was an important c.mponentfor continuedstability ofthe intemationaltrade in crocodilian skins. Maintainingthis trade on a legal, sustainablebasis and linking it to conservationof wild crocodilianswas the major emphasisofthe CSG.

Following the presentationofpanelists, gercral discussionidentified the following points:

N{arketlrends. Therehas been a shift in demandfiom primary emphasison high value classicskin productsto a mix of classicsand lower value caimanskin products. Thereis an increasingemphasis on quality ofconsumerproducls and this is reflectedback down the chainoftrade to theproducers. Quality ofskin at productioohas become ofprimary importanceand hasdrastic effects on pdce and demandfor raw skins.

The current economicdow[tum in Asia is causingAsian productsto seeknew marketsin Europe andUSA (rwersirg the traditional flow oflinished produas). Asian manufacturersare also reducinguse ofalligator but this is beiDgbalanced to some€xtent by the use of alligato. skin in the US andMexican cowboy boot market. The boot market is estimatedto be ableto absorbapproximately 40,000 classic skins and 60,000 caiman skins annually.

Market prospecls. Consumerdemand is expectedto retum with the swing ofthe business cycle in a coupleofyears, but in the meantime,less efficient opefaton in both production and manufacturingrnay leavethe industry. If caimanskin demandrcmains high with the relatively fixed legal productior\ pdce shouldinqease which may swing interestback to classicskins. The weaknessof Asian currenciesis giving a competativeedge to Euope and USA. The potentialofa hugedomestic market in Chin4 particularly for lower cost caimariproductq was rcted with interest. The degrceto which China satisfiesits demand fiom domesticallyproduced captive bred productswill be an important facto!.

Tlade data. Presentationsfiom Don Ashley and PerranRoss highlightedthe deficiencies ofavailable trade information. It is now well recognizedthat information derived fiom CITES couitry annualrelrorts is usually late and inacorate. Severalareas ofdiscrepancv betweenpublished reports and actualproduclion figures were explaineddudng the discussion.In Australiathe very large discrepancybetween reported produclion and CITES export figuresmay be dueto the widespreaduse ofpersonal effects exemption certificatesfor exportedtourist items. Leon Roiter pointedout that Colombiaactually expons around300,000 - 400,000caiman skins annuallybut that reponsto CITES include aumbersof skins on permitsapplied for but trot used. He f.rrther reportedthat new Colombianregulations require 60% ofexported skinsto be processedto crust and that tiis percentagewill rise to 8flo by the year 2000. M$eporting ofexport datain CITES reportsremains a problemfor exampleboth USA andZimbabwe report the great 'Captive majority ofth€ir exportsas bred' when in fact most ofthese are .ranched'. Someconcem was expressedthat the currentdemand for caimal skins of a larger size suitablefor bag manufacturewould createincreased pressure for the illegal harvestingof larger wild animals. Alvaro Velascopointed out that most of Verczuela's legaL produclionwas suchlarge sizewild skins, althoughrecent production was reducedto around 15,000skins annually due to low marketdemand.

Impedimentsto trade. In discussionseveral facto$ which exacerbatethe curent low demandfor arocodileproducls were mentioned. The stricter domesticmeasurcs adopted by many CITES padiesinhibit the free transportofperso@l effects and toudst items. This is mademore acuteby inaccuratepublicity promotedby somemisguided conservationgroups, particularly in the form ofairpolt displaysdiscounging purchaseof ardmalproduc,ts. Don Ashley reportedon the succ€ssfulnegotiations with WWI-UK, HM Customs{lK andthe Heathow Airport Autiority for the removalof inaccurate matedalsthere. However,similar displaysremain in placein many other places. A generalsediment againstaoimal use, and widespread promotional campaigns against wildlife purchaseare perceivedto effect demandfor crocodiliaaproducts, although objective confirmationis lacking.

A widespreaddiscussion ensued on what role the CSG shouldtake in rwersins these trends. Ideasput fo.ward includedendorsement of productsor programs,pubiic relations development,independent funding for crocodilianconservation, influencing development ofCITES policy andresolutions, active advocacyofsustainable use, preparation of educationalmaterials and documentariesand the developmentof partnerships with both private sectorand intemationaldonor groups. From the ideasand empbasesexpressed in the meetinga generalconsensus ofthe meetingwas reachedthat CSG shouldinvestigate in depthhow it might interveneto ensurethat the conservationpositive effectsof sustainableproduction and legal bade are cornmunicatedto the itdustry the public and

231 consumers.Following this discussiona task force underthe guidanceof CSGDeputy ChairmanDietrich Jeldenwas establishedto examinethis issueand rctum to the CSG SteeringCommittee with recommendationsfor aclion.

In summarizingthe workshopKevin van Jaarsveldtnoted that to meethis appealfor a transparentmarket, there was a needfor accuate andtimely tade informatio4 particularly on productionlevels. He suggestedthat CSGwas uniquely positionedwith its extensivecontacts ad high gedibility to obtainsuch info.mation directly from national managementagencies and producer groups and distdbuteit fairly and freely. The continuingneed for CSGto carefullybalanc€ its interestin conservatiol andtrade to erNurethat botl constituenaiescontinue to be served. Addressingthe needsfor a CSG role in trade promotior! disrributionofaccurate trade dataand finding a solutionwithin CITES for the personalexemption problem provided guidancefor CSG aclivities in the trade spherefor the immediatefuture.

232 r4TE CSGWORKING MEETING JIILY 98 - SINGAPORE PR.ESENTATIONON TRADE - ASIA RDPORT C. H. Koh, Henglong LeatlerCo. 50Detu Lane 7, Singapore. I[troductioD

1I:**1J t"T ? **ks onJuly 2 1997that the Asian Financial Crisis besan when ,! cufr_eocy,the baht to floatfreely in thefinanciat markJ prungeo.r,1u""T9 19)p esatnst anclit oy I )7.o thegreeDback v/ithin a few hours.This led to a lossirl coD.lldeDcerD tte economiesofAsian countriesand speculators began to tum their attetrlioqto Asia. On I4_Augusr97. thehdonesian rupiah was alfJ*"aio n"ut _A srnce.Ben|l nas.cnshedthough maly floorsbriDgiDg with it onepresidenl eshared over 1,000people dead and 5,000 buitdbgs bu-, tLrgl ,n" turmoil- *fiiJ Malaysiaabandoned the defence of its .or.-"i, ,f," ,inggla,-ii"*,i"*'i"Jrral.rir]o" ;o;t l*yre 9.e" sog*.On Ocrober l, rhe phitippine peso rai t ucroDerll. ItoDg lfuog had to raise ovemight intercstrates to leady 300 percenrro oereDorts cturency--- peg s againstthe US dollar. On NovemberlZ, the l(oreao won oroppeq Delow l,U0t to the US dollar. On November22, yamaichi Securities- Japar' s_fourthlargesr securities compa.qy, collapsed Little S-ga;;;;;il., not.spared.-its clrreocy pluDging fiom t.4 ro i .8 igainst tfre USfri.itt tufrnost:o"zl " penodof6 motrtbs.

This is the grim economicsituation itr Asia and it hassubstattial qocodilian dircct iDQDacl- on the industy_One year after, *rc are still suife.ing nom Ois Gan fiu The topic on Asian trade is very extensiyeand this paperwill coverthe followiag areasof iaterests: i FactorsAffecting Demand& Supplyin Asia i Market TreDdsin Asia t FutureProspects in Asia

FACTORS AIFECTING ST,?PLY & DEMAI\,D IN ASIA The foliowing factorshave significant effectson the supplyatrd demand of crocoslan skursand Foducts in Asia over tbe past I to 2 years. l. Japatresef,conomic Slowdonr

Japan remaiDsthe most iEporta[t consuing county of crocodile aad allimror leatn€rproducts ln Asia_The continuiageconomic slowdonm even before ihe Asian financial crisis hasadversely atrected rhe purchasrngpo*er of tfr" Jup.""r" cons]lmels. We haveseen prices of crocodileskins and prod-uct declinine sincs 1996.In Asian cities suchas Singaporeaod itoog Xong, retaiters;i**?lltn* producls calenngto Japanesetourists have experienced a substantialdrop in sales as a rcsult ofthis coutinuingeconomic slowdown-

213 2. Forest Fires iD lrdotresia

Forestfiles itr Sumatraand Kalimartan, stan€dby hurnanbeings clearing land for agricultue but blamedon El Nino, causedthe much publicisedhaze in the skies acrossSoutheast Asia for the most part of last year al polldion levelssornetimes dangerousto health-This resultedin substantialloss in tourism in this part ofthe world. The finarcial damageto lie rcgioDwas estimatedto b€ aroundUS$7 bitlioD, a largepart ofwhich was attributedto the loss ftom tourists revenue.In Singapore,some retailers of exotic leatler productsexpedenced sudden drop in salesof50 to 60% irDmediatelyfollowing the haze.This year, thanksto the good rainfall, a similar disasterhas been avoided.

3. Arian Financial Crisis

Following the start ofthe haze,Southeast Asia initially and the rcst ofAsia subsequendy,werc hit by anoth€rdisaster, the financial crisis. The adv€rseefects are far-reachingfor our iadusFy and it will take the rcgion rnanyye3rs before it startsto rocover.Refer to App€trdix I which showsthe efect ofthe crisis on the Asian stock marketas an indication ofthe severitvofthe cdsis oBthe Docketsof the corsumers.

Prior to this crisis happening,the qoc-odileindustry hasdeveloped s€veral niche marketswith pot€ntialfor firture growth:

One marketis Kor€a.The Koraaoshave been inseasing drc coNumption of producs suchas handbags,and other small leathergoods made Aom caimaa fiscus. The numberof tamed caimanfuscus skils exportedto SouthKorea $ €stimatedto be apprcximately60,000 to 80,000per annumfor 1995/1996. Most ofthese were manufacturedinto products in Korea and consumed domestically.Additionally, Koreantourists were also big consumersof crocodilian productsin other Asian countriessuch as Thailand and Singapore. The financial squeozeon the Koreansfollowing the crisis hasrcsulted in a substantialdrop ofKoreans tourists tavelling abroadand a reductionin tie shoppingbudgets ofthose who travels. The exotic leatherproducts industry in Korea is now refocusedto produc€handbags, shoes and other small leather goodsfor export to other courties like Japanand USA

A.notherniche marketis w€althy non-JapaneseAsians like Taivanesq Hong Kongersand Iodonesiansspending money on fashiotrproducts including qocodile handbagsand leathergoods especially when they go on shopping holidays overse3s.For example,many wealthy hdonesiaDscome to Sitrgapore for larious puposes- visit their chil&en wlro ar€being educatedhere, medical checkupsor simply shopping. It was very commonthat whilst here, they would spendmoney buying brandedfashion goods and crocodileskins productsar€ one oftheir favourites.Their favourite qocodile handbagmust be big, glossyand with expensivemetal fittings- Not otrly did they buy for themselves,they would buy gifts for relativesand Aiendsback home.The fioancial and political problemshave to a largeextent killed this emerging niche market

234 4. W€akening Exchange Rrtes

Oneresult ofthe Asian economicctisis is the depreciationofall Asian currencies (eglinst the US$ and Europeanscurrencies in general)other ll|qn the Hong Kong dollar and the Chinesereminbi or yuan which are peggedto 6e US$. Refq to Appendix 2 for an analysisofthe comparativeexchange rates ofAsian currencies over a period ofone year.

Almost all dealiagsin raw crocodileand alligator skills are canied out in US dollars. The depreciationofthe Asian curencies has2 major impacts:

n It mates qocodilian productsmore €xpensiveand thereforeless afordable;

i It makesgoods produced in Asia more price competitivein other pertsofthe wodd. Today oue would find Koreanmade qocodile or ostrich leafter shoes exportedto USA and more American and Europ€antoudsts buying crocodit€ leatherproducts in Hong Kong/Singapore.

Hoog Kong, which hasmaintained the value ofits currency'g'i'rst the US dollars hassuffered an oconomicslowdown and substadial loss in toudstsrevetue as it becomesa comparativelymuch more expensiveplaca to visit Jt $/asrcported that the Japenesetourisb arrival in Hong Kong during the worseperiod ofthe crisis &opped by as much as 70%. One of the priacipal reasonsfor this drop is th€ strengthofthe HK dollar. Hong Kong also had beenvery usfortunateto be s&uck by the bird flu and the red tide recendy.Prior to the Asian financial crisiq there was a growing retailing ftdustry for exotic leatherUoduc{s careringto the rich Hong Kongersand foreigtr tourists.Most ofthe retailershave cut back their operationor refocusedthei businesstowards maoufacludng for te-€xpo.t.

Volafilityofexchangerates ofproducingatrdconsumingcounties' curoqcies againstthe US dollars hasbecome an importantAcbr in pricing ofmaterials.

5. Declinitrg Ostrich Istber Prices

Up to 1993,the ostich firming and leather "nning industy in the world eisted maiDlyin SouthA.frica in tle Kloin Karoo rcgio! as a monopolycontrolled by the Klein Karoo Coop *{rose membersare the sweral thousandfrrmen- All activities reLatedto the osbich industsyin SouthA.frica wereregulated by laws designedto preservethis monopoly.The Coop maintainsa network ofappointed agents worldwide tbrough r&om os&ichleather are marketedto the world. The monopolyresulted iD high prices ofleafher and much inefrciencies in the industry. The ostrich indusay in SouthA.frica *as deregulatedin 1993.This resultedin an immediateproliferation ofostich productionin SouthAfrica and other neighbouringcounties (Zimbabwe,Namibia) Live birds were exported from Aftica to non-indigeDouscountries * USA Austr-ali4China,Israel and wen Indonesia.The new playeE to the hdusty sincr deregulationwere attractedby the high retums enjoyedby the industy wlren pricesof leatherwere set at artificially high levels by the monopoly.Like all &eemarkets, the resulting ovenupply eventuallyhits the market r€sultingin declining prices of l€atherin the last 2 to 3 years. 235 Ostrichand crocodile leather exists in the samematket in Asiaas substitutes or compliments- thsy arcboth used primarily for bandbagsand-other fashion products.The industrypeopla in Asia involvedin the crocodilianleather and productsThJ ;roductsare also the samepeople handling ostrich learher and 4ss1;ii'g ostrichleather pdces over the last2 to 3 yearshas rcsulted in hi-..gher levelofactivities for ostrichleather industy at the expenseofthe qocodile leatherirdusay. Pric€s for ostrichleather bas &opp€d by approximately50% ftom US$40to Us$20per sq. ft. duringtlis periodand is sill dropping' Consumptionof ostrichleather bas incrEased substantially. This is oneofthe contributinghctors causingthe drop in demandarld tlErefoE pricefor crocodile skinsdudng this period.

6. AbtrormalIlcrease in Nurnberof CrocodileSkfus Catering to Asia

PNG - El Nino

PapuaNew Guinea' s prcductionof PorosusandNovaeguinea€ i5 normally about 25,000to 30,000skiDs pet annum.Last year the couotry experienceda.severe. drought causedby El Nino. This madeit much easierto harvestcrocodrle as nvels and iaterways dried up, Export of crocodileskim inqeasedsubstantially as a result - estimatodto b€ between40,000 to 50,000skins. This incr€asebas a noticeableadverse efect on prices itr the Asian markets.

Liftirg of Morstorium on Export by Indonesia

Indonesiaimpos€d a moratoriumon export ofcrocodile skins in 1994prior to tI€ 9s CnES co'Dferenc€in Fort Laudeidale.The moratoriumvras ofEcially lifted in the middle of 1997.The liftiDg ofthe moratoriun has inqeasodimmediate supply to the Asian Darkot. Indonesi; hasa potentialto supplyabout 15,000to 20,000 skins DaraDnum. These are mainly Noraeguineaeand somePorosus'

MARKE'T TRENDS IN ASIA

1. Shift towards Lower Yalue Erotic Leather Products

Over the last 2 years,wc baveseen a shift in demandby corsumersAom high value to lower value productsbecause ofaffordability. Demandfor Porosus, Novaeguioeae,Nile crocodileatrd alligator skitrsin Asia hasbecome very sluggish.Demand for caimanfuscus skins of haDdbagsizes has urcreas€c noticeablyespecially in the last 12 montbs.

2. Gr€ater EBphasis on QualitY

Becauseofthc difficult matlct colditions, coisrmers havebegome very discemingon quality andthis filters downwardsto rctailels, distribdors' maoufactite.s, ta""in and finally farmen. Gradingsof raw skiDs'finished leather conditions, and final Foducts havebecome very tough. In the curent markot 236 thosefarmels, tar]rletsand product manufacturerswho are ulable to make improvementsand adjustnentsto meettlrc stringed requireflents are likoly to be pushedout ofbusiness.

3. Asia Manufacturirg for Other lvlarlets

Up to reaendy,most of Asia' s productionof finisbed leatherandproducts were consumedio Asia- The ercsionofthe oa*et in Asia for crocodilian skitrsaud productsdue to the economicsituatio[ has qeated a situationin &&ich ta@ers and maDufacturerchave to find new marketsto survive.Increasingly, crocodiliao lcathertanned in Asia aDdproducts made in Asia are finding their marketin America and Europe.For example,one can find aligator skins Aom US farns exportedto andtatltred in Asi4 then re-e4orted to Europefoi manufictue of productssuch as watch sFaps,shoes, b€lts etc in Europeand fiully exportgdto the USA for consurirption.

I)ecline itr Consumption of Alligator Skins

The last 3 yea$ hasseen a drunatic increasein consumptionofalligator aod qocodile leatherand prcductsin USA Ofparticular importac€ is the vr'estertr wear or co*toy fashioL I would estimatetbat tog€therUSA aDdMexico colsume about30,000 to 40,000alligator skins and abod 60,000caiman skins a year for the westemfsshion industry. One positive sidc effect ofthe grorad ofthe US narket on Asia is that it reduc€sthe supply ofmany alligtor skins to Asia at a time when there is an ovenupply ofoocodile skiru coming herefiom othor parts ofthe world. Without the American marketas it is today,the oversupptyof crocodilian skins ofbandbag sizesin Asia would bavebeen worse.

PROSPECTSIN ASIA

Despitethe curent problemsfaced by the crocoditiatrindustry itr Asi4 I believethe Asianconsumers'demandforcrocodilianleatherproductswillrcmaininthelong term. Howeverin my vieq it will take at least 2 yearsfor the ma*et to recover.In the prccess,the situatioais likely to get wone before it getsbetter- The low pdcesand poor marketconditioDs will forced someofthe lessefficignt farmels, taDners,product nanufactuers and retailersgut ofbusitress.Unfortunatelv tbis is the crueltv ofthe free market.

The increasein demandfor caimal firscusskiu both in thg Asian mark€t as it shiffs to lower value productsand in USA,Moxico for the westemfrshion industry is likely to graduallypush the price for caimanskins up. The combinationofthis price increasefor caimanfuscus and the price reductionfor classiccrocodiles in Asia witl eventuallysee more demandretuming to classiccrocodilian goducts.

The weak culrenciesin Asia hasmade the region muchmore competitivein the world market.We are likely to seean inc.easein supply offinished leatheror productsAom Asia being exportedto USA and Euope.

231 The single most im!,ortantfictor which will bring the indusay back to life will be the recoveryofthe Japaneseeconomy. To this extent,we all hopetbat the rcw Japanese economicstimulus package and chaagein governmentwill bdng coDfidenceback to its financial msrket andeconomy.

In the longer tem, therelies a potentially hugedomestic market in China-Atready we are experiencingtourists from maidand Chinabuying small leatllel productsmade ftom caimanfiEcus in variousAsian cities. This will no doubt leadto the developmentofthe domesticmarket in ChiDaeventually_ Until suchtin9' we all still haveto preserverand work our way out ofthe current di.fficulties.

238 IMilT [$ia[ stoclmaflrGt irdicGs

Beginning End of Endof o/otage Of JuIy 97 Dec97 June98 cha hilcnGsio n2 N2 440 -8916

talaysir r0l9 5tf 450 -Et% Ilall0nd 5t9 0t3 26r -S3% ?[ilitlirGs 28rtC ilt9 ftt0 -88% lrDaI 20fr6 fi259 f5880 -ZHr scrnllrca t!8 3r0 298 -Et% iloitlbnn 15058 10123 8!f8 -ffir Sinm!!rc rgSc r500 1t3C -'4!, Taisr[ 8S0t nE l54t -t0% s[arilal n8 29n 3220 +lnh

239 |Iletrdix z Ixchangelates ollsia currencies (againstUS$l)

o/otage Jun 97 Dec97 Jun 98 change

IndonesiatBuilahl 2,600 5,450 t5J00-480% Malaysiaminggiu 2.50 3.86 3.90 - 56% TnailandtBanu 25 4l 40 - 00%

Pnifl[dncslPesol 264 40.8 38.4 - 4W/o

laDantYGnl 114 t30 t46 - 28Vt SouUKorGa twonl 88r r,695 t 383 '1f/o longltung l$l t8 Ll5 L8

Singanoret$l lI2 1.60 1.68 - l8o/o

Taiwantsl 2r.8 32.6 34.8 - 25o/o GninatYuanl 8.28 8.28 8.29

240 The CrocodilianSkin Ma*et h Japan Summaryofcomments madeat the Trade$r'orkshop, 14'Working Meeting ofthe CSG, Singapore,15 July 1998,Singapore.

Yoichi Takehara HoriuchiTradins Co. IA Building,3'd Floor Misuji 1-2-5,Taito-ku Tokyo, Japan

The exotic lesthersand leathergoods market in Japanhas been primarily dependentupon the demandfor ladieshandbags, which haveconstituted about 80oZofdemand during the last 25 years. The sizeofthis marketin Japancarlbe estimatedfrom tie impons ofskins into Japanwhich are estimatedin TablesI and 2.

Table l. Estimatesof skins andIeathe6 importedinto Japan. Estimatesare approximate to the nearestthousand. Skinsarc also expressedas the equivaled handbagsthey represent.

ClassicCroc Ostrich Caiman Skins (=bags) skins (=baes) skins (=bass) 1980:s 75.000 (45.000)40.000 (50.000) 200.000 91-95 60,000 (30,000) 45-80,000 (60- 100,000 (50,000) 150.000) 96-97 60.000 (30.000) 115.000 (200.000) 80.000 (40.000)

Table 2. Impods of finished handbagsinto Japar. Eslimatesare approximateto the nearestthousand. I{andbagsare also expressedas the equivalentskins they reprcsent.

ClassicCroc Ostdch Caiman pcs (=skins) pcs (=skins) pcs (=skins) 1980:s 40.000 (60.000) 30.000 (25.000) 30.000 60.000 91-95 25-000 (40.000) 40.000 (25.000) 5.000 fl0.000) 96-97 10.000 (r5.000)50,000 (30.000) 20.000 (40.000)

Note that in November 1993,Ostrich industries in SouthAfica were de-regulatedand the previousSouth African monopolyon production ended,increasing supply and reducingprice.

Fromthis we concludethat demand in te.msoffinished handbags (all skins)sold is curently over300,000/year and has almost doubled since the 1980's.The distibution of this demandamong the availableskins variesand dependspartly on supply and price as well as on changingfashion dictates. While the total numberofbags sold and skills used

241 hasincreased, the numberofclassic crocodile bags sold has decreased, both in absolute numbersand in termsof marketshare.

In 1981Japan Reptile Skins Associationadopted I producttag programwith goal of promotingpositive public relationsfor naturalleather products, including crocodilians. The tag, attachedto finishedproduc.ts, informs the consumerofthese major points: l) The productis genuineleather. 2) The product is a legal commodity 3) The producl is madein Japan(important for Japaneseconsumers).

Startingin 1993,with th€ assistanceof CSGand the CITES Secretariat,an additional messagewas addedto the tags:

4) The productis producedsustainably and contributesto conseNation.

Tags areaccompanied by a leaflet and attachedto larger products,primadly (98-99%)to hadbags. Distribution oftags is shownin table 3.

Table 3. NumbersofJRA producltags distributedon ffdishedproducts.

Piecestaesed Total bass made Yoc}verAge 1982 120,000 240.000 50% 1989 160.000 240.000 6so/o 1993-94 200.000 250.000 80% 1997 300.000 310.000 9jyo

Table4. Distribution oftags amongdifferent skins. Estimatesapproximate nearest thousand.

Total Classiccroc Ostrich Caimanand other 1980's 240.000 20% 20yo 6OYo 1993-94 250.000 15yo 40vo 45Yo r997 300.000+ t0% 65% 25%

Coverageofproducl lags on finishedproducts curently is around900lo. The changing market shaxeofclassic crocodilehandbaes is also indicatedin table 4.

Conclusions.The crocodileleather market is greatlyinfluenced by the competingostdch leather. When ostrichproducers increase supplies to the marketby offedng aheaper prices,crocodile has to eitherfollow or stopbusiness. RE?oRToN cRocoDtr-IANTRADE FRoM LATn.{ AI&RICA

JamesPeran Ross Florida Museumof Natural History Box I17800University ofFlodda GainesvilleFL 32601USA

Paperpresented at the l4s Working Meeting ofthe Crocodile SpecialistGroup, Singaporc14-17 July 1998

l. CaimanTrade.

Available statisticson exportsofcaiman skins fiom Latin America we.e aollectedfiom recentIntematioml Alligator andCrocodile Trade Study(ACTS) reports(ColliN and Luxmoorc 1996) and informationprese ed in the CSGNewsletter (Collins 1998,Collins 1996,Collins 1995). Data are available from 1983to 1996.These data are all provided by World ConservationMonitoring Center(WCMC) under contractto the CITES Secretariat.The information is extractedfrom annualreports submittedby Parties (-countries) to CITES, compiledinto a database and annualand county estimatesof world trade generated.The datacombine infotmaijon on Cqimoncrocodilus crocodilus, C.cfusats. C.c, chiqasius ard C.c.yacarc (= Caimonyscqre) without differentiatingthe subspecies,although some inference about probable taxon can be derivedfrom the ^^,,-+^, ^f^;-i-

The caimanexport figures are given by year and country in table 1. At the height of caimanpioduction fiom Latin America in the 1960'sand 1970'strade was saidto have reached7-8 million skins a year althoughfirm data arelacking. In the earlier yea$ of CITESrecord keeping 1983- 1988 produdion approached 1.5 million reportedskinVyr and the majority ofthese were fiom Paraguat aod Bolivia. Repoltedcaiman exports declinedto a low levelofaround 300,000 skinV].r in 1989-91reflecting vigorous efforts to bring the major exporten into compliancewith CITES. Productionhas steadily recoveredsince 1990 to cunent1995-1996 reported exports of700,000 - 900,000 annuallywith the great majority ofthese skinsexported from Colombia. Other major producersare Venezuelawith minor but sigoificantproduclion continuingftom Hondu.as andNcalagua. Therehas therefore been a shift in productionfiom the southerncone countriesoflargely C c/dcare to nofihern SouthAmerica and CentralAmerica C.c croc odi lu s/fu s cu s S igure 7a.).

Allegationsare sometimesmade (usually by classicskin producers)that the caimantrade cannotbe profitable andthat it hasalready overfilled its market capacityand cannot sustainits growth. Continuingexpansion ofproduaion and the apparentlyeffortless absorbtionby the marketofthe increasedproductior suggeststhat suchallegations are ill founded. In fact the caimantade providesa very valuable 'middle-lower value' product that may be complementaryto the classiatrade, andto a degreeactually promote and supportit. Frcm a conservationperspective, conservation of caimansis equallyas valuableas conservationofcrocodiles and the applicationof zustainableuse mechanisms Production/expoftCaiman skins CITESReDort data WCMC

z5 6Z

+ Allsourcas ^ Colombia o Pa.aguay

Production/exporlCentral America clTEsRilport data wcMc

-€- --r_ Elsalvador a HonduGs o Nicatagua Guat€mala

Figue 1. Produclionof Caimanskins estimated from expodsreported to CITES; a. Total.b. CertralAmelica. to do so is an integal part ofthe CSGst ategy(Ross & Godshalk1997). It seemslikely the tlade in caimanskins will continueto grow- perhapsback toward its historic level of 7-8 million skinsa year.

Colombia oontinuesto dominateproductioq achievinga reportedexports ofover 800,000skins in 1995. Corcem contiruesto be expressedabout the real production capacityofcaptive breedingin Colombiadespite the careful examinationby a CITES team in 1993which concludedthat the observedproduction was well within the theoreticalcapacity ofthe facilities examined(Jenkins et al. 1994). A factor which may explainthe high leve1ofexports in 1995is the failue anddissolution ofa numberof Colombianfarms which may haveliquidated their breedingstock asthey closed. The observationof numbersoflarge skins in shipmentsto Europeat that time (J. Lefkowictz, J. P. Ie Duc pers comms.)supports this explaration. The estimatesmay also include signilicant exportsoflive juvenile caimansfor the pet tnde.

Examinationofthe export statisticsindicates some anomalies that are at \.ariancewith geogaphy and the distribution ofcrocodilian habitatand populations. Knowlegeable sourcesin Colombiaindicate that actualprcduction is closerto 400,000-500,000skinvyr. The higher ffguresreflected in CITES teportsrnay be due to the fact that Colombian repofs to CITES arebased on the numbersofexport perrnitsapplied for. It is suggested that a propofiion oftlEse are not usedand the actualnumbers produced and exportedare tierefore consistentlyoverestimated. Why Colombiareports permit applicationsruther than actual expofis remainsunexplained. The well documented(Mourao et al. 1996) wild harvestofCarrnan crocodilusyacare from the Brazilian Pantanalis nowhere reflected in thg export dataand two CentralAmerican countries with relatively little caimanhabitat showedsignificant exportsbetween 1984 and 1986(Guatemala and El Salvador,Figure 1b) which presumablyreflects skinstlansferred fiom other countries. The recentexport of 6,000 skinsfiom Hondurasis also at variancewith the published information on caimanpopulations and the statedgovemment policy on exportsftom that country. Exchangeof skins betweencountdgs, sometimes without adequate documentatio4remains a confusingfactor in analyzingproduction levels and trendsftom tade data.

2. Accuracv ofTrade data.

Theseanomalies led me to investigatethe accuracyofthe information availablefrom the CITES party annualreports through WCMC. The problemswith the CITES database arewell known ard straightforwardlyexplained by WCMC reports. CITES annual reportsarc often late or not submittedat all and the, urits usedare variable (e.g. expods arevariably reportedas 'skins'. 'flanks', 'kilograms' and 'squaremeterc'). The labeling ofoocodilian skins by source(wild, captivebred or ranched)is very inconsistent,and oftell inaccurate,evelr in countrieswith sophisticatedreporting methods such as USA and Zimbabwe. In caseswhere export rcportsare not availablg the report compilerscalculate exportsby summingknown importsthat indicatea given country asthe country of origin of skins. In somecases information hasto be adjustedfor krcwn or suspectedenors and distortions 2+j Harvestv Export VenezuelaCaim;n

*&s*es,-'s-;EG';;

z Hd.sr E €rrdrs N^.r.hn,

C.porosusAustraiia

zz P@d!. oi - Erpoic N Djn rcn@

USAlligator

@Ptodudr$ l=E4a.B N DitL'd@

Figure 2. Net ditrelencebetween repoded Produaion (Harvest)and RepodedExpofis showingthe cumulativedifference and apparent o{cess ofskins reportedexported (CITES data)see text for datasources.

246 To test tlle acoracy ofthe reportedinformation I compiledstatistics on actualraw produclionofcrocodilian skins from a few countlieswhere it is available-Venezuela (Velascoand Thorbjarnarson 1998), USA (Joanenet al. 1997,David et al. 1996,Elsey pers.comm., David pers.comm. ) andAustlalia (Webb et al. 1994)and comparedthese to report€dexport figures. I would not gxpectexport figuresto matchprodudion figures for a given year, exceptpeftaps ir the most approximatefashion. Skinsproduced in one year may be sold in following years,stocleiled or usedintemally. However,over time, produclion and exportsshould be approximatelyin balance. To test this I summed produclion artdexports for eachyear and all previousyears and calculatedthe difference betweer thesenet productionand net export estimates.I would predictthat the diference betweenproduction and expott would fluctuat€up and down, or possiblyshow a small deffcit of exportsover time, reflecting i'rtemal use of skins that are not exported. Much to my surprise,the datafo. eachcountry showeda steadyaccumulation ofan excessof exportsover skinsproduced. The acc'umulatedexcess amounted to between 8% (USA alligator) and34yo Nenez'rela caiman)to 4l% (AushalianC polonls) oftotal production(Figure 2.). The CITESAffCMCtrade statisticsthereforc appear to overestimateproduction within a country althoughthey may possiblyreflect total trade.

How car a country's repoted expofs exceedtotal productionofcrocodile skins? Therc arefour possibilities.

1. Errors, mis-reportingand poor recordsin both produclionestimates and CITES export repofis. It is unclearwhy sucherrors would be so consistentlyin the directionofan ocess ofexports.

2. Introdudion of illegal skins into trade within the country of export. E.g. illegal wild skins claimedas farmed and issuedfalse documentsand tags.

3. Introduclion ofillegal skins into trade Aom other sourcaswhich deceptivelyclaim to be from the country. E. g. illegal skirls from country X presentedwith false documentsand tags indicating ftom country Y

4. Double (Multiple?) reporting ofre-exported legal skins. E.g. Skinsfrom Venezuelaexported to USA re-exportedto ltaly reportedon Italian reportsas "origifl Venezuela.." with legal documentsand VZ tagsand thereforecounted fwice in CITES reports as exportedAom Venezuela.

To further investigatethis anomalyI comparedestimates of skins expodedgenerated by one country (Venezuela)with thosegenerated by WCMC from CITES reports. This indicatesthe scarcelysurprising result that the export figurespublished by Venezuela matchtheir productionfigues quite well with a net differenceafter 14 yearsofonly 3,350 skins or lessthan 0.4olooftotal production. Figure 3 showsthe relationshipof CITES and Venezuelanexpod dataindicating that the discrepancyis not due to a single orjust a few yearsbut dueto a consistentover eslimateofexports in most years. Ifthis were dueto illegal trade (2 and 3 above)then we would expectthat there would be some

24',1 Comparisonof exportdata Venezuelav CITES/IVCMC

>E OE =i

LIJ F

Venezueladata Ghousands)

Figure 3. Comparisonof twvest datafor Caimancrocodilus, Venea)elanational statistics and the exportsderived Aom CITES reponsindicating con"i.t*t o"e"" of estimatedexports above the known harvest.

244 recognitionsomewhere in the world ofin excessof I million alligator, porosusand caimanskins circulating wilh false tagsand permits. we needto recall that theseskins arenot in the 'hidden' illegal trade occurringwithout inspectior! permits or tags,but is tradewhich is conductedquite openly andwith apparentlycorrecl documentsand tags, ard coming to the altentionofCITES authoritieswho report it to the CITES Secretariat.

In tlle caseofthe Australiandiscrepancy, one postulatedcausg is that Australia usesa systemof specialCITES permitsfor personaleffects lvhich are issueddirectly by retail vendorsto touristswho puchase ard export smallproducts such as belts ard wallets. As in the Colombiancase, a failure ofthe ManagementAuthority to correctlyreconcile permits issuedwith whole skins producedand exportedmay be a pimary causeof overestimatesin the CITES data"

It seemsprobable that a large part ofthe discrepancyis due to factor 4. Multiple reportingthe sameskins due to poor lecording ofactual routesand origins, althoughthe possibility that error and illegal trade contdbutesto the problemmust be recognized. Someimportant conclusions emerge:

. The WCMC data derivedftom CITES aruual rcports may indicatetrends and directions,but camot be usedto acauratelyestimate quantities or real production figures. It is unlikely that thesedata can be improvedwithout a substantial investmentin new data collectionand analysis. It is thereforeimportant to recognize the valuesand limitations ofthis data set aswe cortinue to useit.

. It is exkemely advantageousfor CITES partiesto maintaintheir own accuraterecords of produclionand exportsto counterallegations that lalge quantitiesof skins are edering trade illegally. Ind€€dthe crocodiliantagging resolution 9.22 and some proposedamendments to that resolutionrcquire that suchrecords be maintained. Becauseof concemsabout competitivenessbetween producers, buyers and countries, it seemsnaive to o

3. Trendsin Latin America.

Pricesand demandhave been depressed for Latin Americanskins as for much ofthe world crocodiliantrade in the last year. This appearsto be a continuatiol ofthe q?ical cyclic oscillation in price and demandwhich is known for at leastthe last centuryand is well describedin Woodwardet al. 1994. Beyondthe continuinglarge scaleproduction of caimanskins, a seriesof new initiatives areunderway in Latin America to bring additional specieson line for commercialtrade. Theseare parlicularly focussedon productioaof speciessluch as Melano&tchxs niger zndCrocodylus .rp.which havehigher unit valuethan caiman skins. 249 In Mexico, one farm is CITES registeredto export captivebred C,,ocodylusmoteletii and a proposalis in an advancedstage ofpreparation to dornlist someMexican populations to CITES AppendixII for the pur?oseof ranching. Currentcapacity for captivebred skinsis around2,000/y. and the potential for 5,000- 10,000ranched skins within 5-8 yearsis possible.The technical development of crocodilianhusbandry is well advanced and ifthe regulatory,conservation and managementissues can be developed,Mexico has the potertial to becomea sigdficant producer. Mexico is alreadya significant processor ofskins in theregio4 importingmore than 40,000 skins in 1995for domestic manufacturing,paniculaf,ly of cowboy boots.

In Cub4 one farm is CITES rcgisteredfor captivebredC. rhombifer with a production capaaityof 1,500- 2,000 skinVyr. To dateexports have been minimal and the bulk of producliol is consumedintemally. Cubahas recently exported several hundred caiman skins generatedin control programsfor the introducedcaiman population on the Isla de Juventud.A prcposalis irl theearly stages ofpreparation for dol'ntistingC aczrzsin Cuba for larching.

In Honduras,one farm is CITES registeredfor ex!,on ofcaptive bred C. acatuswith a produclion capacityof3,000 - 5,000skins /year althoughexports to date havebeen minimal. Hondurasalso hasa tannerywhich processescaiman skins fiom Honduras, Nicalaguaand possiblyother coultries in the region.

Colombiacontinues the large scaleproduction ofcaiman skins in farms. Thereis also aggressivedevelopment ofcaptive breedingfor C. acltus , C, intermedixsu\d, Melanos'uchusniger althoughcommercial production is not aoticipatedfor someyears.

Ecuadorcontinues slow developmentofranchitg of M. niger in a singlefacility. Commercialproduction remains a distantgoal as a combinationoftechnical dilficulties and regulatoryinadequacy prevent economic levels ofproduction or export. The one Ianch hasa cunent stock 150 animalsof40 cm - 1.5 lengthand hasrecently appliedfor CITES approvalofexports oflive animalsfor zoo exhibit purposesto generatemuch neededrevenue for the ranch. Both Ecuadorand Peru haveshoun interestin caDtive breedingand./or ranching of C, ac1!tusin coastalpacific arcas. Howeverthe very depletedand fragmentednature ofthe wild populationsis an impedimentto development of commercialproduction.

Blazil probably hasthe geatest potentialfor productionofcaiman skins. However, developmentofcaptive breedingprograms has been recently set back by the persistent failure to openUS marketsand the irdustry is qtrrently in a stateofdecline with a majorityoffarms becoming inactiver. Aprogamto developranching of Caimon crocalilus )mcare from the Pantanalis similarly under economicpressure.

The ranchingprogam for Cdimanldtirostris in Argentinacontinues its steadyprogress with the lirst dist.ibutior ofhatchlings to commercialproducers underway and first skin

I Footnoteadded in proof At thelime ofwriting, Septernber1998 the US hasFoposed a specialrule to allowimportation ofyacare 250 exportsanticipated by 2OOOl200l.Potential produclion remains in the order of only severalthousand skins annually.

The generalprognosis is for continuedincrease in variety and numbersofskins produced in the region. Potentialadditional contdbutionto the wo d crocodilianskin supply at presentis ofthe orderofonly around10,000 non-caiman skins. Because ofdifficulties breakinginto intemationaltrade with soall quantitiesofskins, manyproducers in the region are looking into incleasedvertical iltegratioq local processingand manufacture and internal use. Sucha strategyis consistentwith the increasedeaonomic importance andgreater manufacturing capacity in severalcountdes in the t€gion suchas Mexico, Venezuelaand Brazil. There is also an increasinglywell developedinfrastructure of biologists and resourcemanagers who are eagerto apply sustainableuse to local resources@oss & Godshalk1997, Ross 1997)and an absence(so fad ofoverly restrictiveconservation legislation to inhibit retail use. The developmentofregional fade agreementssuch as NAFTA will encourageregional trade linkagesin qocodilian skins as ir other naturaland agriculturalproducts A signifiaantfactor driving this rend is the continuedclosure of lucrativeUS marketsdue to slrict domesticlegislation (US EndangeredSpecies Act) preventingthe import of most Latin Americancrocodilian speciesinto the US.

Th€ developmentofcaiman productionir Colombiaand Brazil hasled to some interestingtechnical developments in processingand somesmaller caiman skins ofclose 'psuedo to classicquality and appearancewere produced. It is unlikley that these classics'or skins ofMe larc&lchus andC, lqtircstris erill displaceclassic skins for the top-of-the-marketfashion products. But theseaheaper products allow the developmentof arl intermediatepricg midlevel marketthat might ieadto expaNion ofthe consumer retail acceptanceofcrocodilian produclsand be a significantboost to the tegional and world market.

Latin Amedca seemslikely to continueprogress in crocodilianconservation based on sustainableuse, and to becomca largely self supplyingmarket for ploduc'tsas well. While Colombia and Venezualawill continueto supplythe majority of the raw caiman skins for world wide tradg the new modelofregional economicself sufticiency and integrationwill provide opportunitiesfor crocodiliantrade.

References.

Collins,L. 1995. CrocodilianSkin Production 1992-1993. CSG Newsletter l4(l):18-19. Collios.L. 1996. CrocodilianSkin Productior 1993-1994. CSG Newsletter l5(3):15-16. Collins, L and R. Luxmoore. 1996. World Tradein Crocodilian Skins, 1992-1993. (Publishedas IntemationalAlligator and CrocodileTrade Study,D. Ashley ed.). World ConservationMonitoring Center,Cambddge UK:40 Pp. Collins.L. 1998.Crocodilian Skin Production Estimates 1995-1996. CSG Newsletter l7(l): l4-15. David, D., A. M. Brunell, D. A Ca6onneau,H. J, Dutto& L. J. Hord, N. Wiley and A. R. Woodward.1996. Florida'salligator management progmm, an update- 1987 to 1995. 251 Pp. 410- 428In Crocodiles,Proceedings ofthe 13- WorkingMeeting ofthe Crocodile SpecialistGroup, SantaFe, Argentina. ruCN-The world Conservation Unioq Gland. JenkinsR. W. G., F. W. King andJ. Ayarzaguena.1994. Managementof Captive Breedingof Wildlife in Colombia"with a panicular emphasison Car'rzazcrocodilus fuscus.Report to the 3ls Meetingofthe CITESStandi4 Committee,Doc. sc 31 9.2 :44PD+ annexesCITES Secretarial,Geneva. JoanerL-T.,L. McNease,R. Elsey & M. Staton. 1997. The commercialconsumplive use of tile American alllgator (Alligqtor mississiryie sis) in Louisiana, its. ellects on conservation.12. Free-sgC. 1E9'7- (Ed.) llarvesting wild species:Implications for biodiversitv.The Johns Hopkins Universitv Press, Baltimore, USA. Mourao. G.. Z. CamDos.M. Couthino& C. Abercrombie 1996 Size structureof illeg;ffy harvested and surviving caimur Caiman crocodilrs yacare itl Pantanal, Brazil. BioloeicalCooservation. 75 1 261-265. Ross.J. P. & R 6dttt"tt. tgsl". El uso zustentable,un incentivo parala conservacion de qocodilos. Pp. l4'l-154InFarLg,T.,R. Bodmer,R. Aquino& M. Valqui(Eds ) Manejo de FaunaSilvestre en la Amazonia.Universidad Nacional de la Amazo{ia Peruam.y Tropical Conservationand DevelopmetrtPrcgram, University ofFlodda. Ross J. P. 199','b. Biological basis and applicationof SustainableUse for the conservationof crocodilia;s.Pg. 182-187In. Memoriasde la 4ta ReunionRegional del Grupo de Especialisasde Cocodrilosde AmericaLatina y el Caribe. Centro Regionalde lnnovacionAgroindustrial S.C. Villehermosa" Tabasco VelascoA. andJ. Thorbjamarson.1998. Venezuela'sCaiman Harvest Program. An historical perspectiveand analysisof its conservationbenefits. Working PaperNo. 11. wildlife conservation SocietyNY:66Pp. Webb, G. J. W., S. C. Manolis andB. Ottley. 1994. Clocodile managementand research ir th€ Northern Tenit ory: 1992-1994.Pp. 167-180 In Ctocodiles,Proceedings ofthe 12frWorkilg Meeting ofthe Crocodile SpecialistGroup, pattays, Thailand rucN- The World ConservationUnior; Gland. Woodward,A. R., D. David andR. Degner.1994. The rise and fall ofclassic crocodilianskin prices:where do we go fiom here? Pp. 596 -621 In Crocodilg Proceedingsofthe 2'd Regionalmeetiog ofthe CrocodileSpecialist Group, Darwi4 Australia. ruCN and Conse.vationCommission ofthe Northem Territory, Darwin. Table.l. _Repoltedexport figu.es for Caimanskins by year and country. SourceWCMC andCITES repons as reponed in Collinsand Lunnore 1996.

BOL PRY BRA GUY vEz 1983 43500 909303 0 1130 0 188094 1.984 700024 835 72950 108334 1985 L200 17 4457 2L2273 0 108408 54644 1986 6000 27352 143635 0 41350 128095 54226 24L42 45357 o 47905 73990 40704 1988 5654 166164 53707 0 76A24 224550 e2233 1989 1110 139l-5 147 25 7 49249 !70347 1L039 265 10503 204206 91386 1991 105 Ia76a? L2952L 4992 o 0 233 6496 L23594 204669 L993 0 3000 5806 7523 28A6 8731"4 477606 499 4 0 0 5466 54038 53650L 0 L9793 1995 0 1040 00 29996 665522

PAN AI, SAL GUAT HON NIC unknortn 1983 279a2 0 0 0 45000 4349426 19a4 L?49 47 LL6234 47705 1 79349 1333281 1985 23445 207644 349685 59466 1r3711 L42aL45 1986 1186 o2 26244 0 2r0 58134 58504O 19a7 20066 L285L 7907 463 2449! 353 012 1988 76 7375 33341 100 46944 752933 1989 2lO a26a 8587 40 296947 1990 353 2513 200)- 4L 3427 68 1991 o 2LO6 a2 0 24720 244333 !992 o 0 2LOL4 47549 4L0296 1-993 7 469 106 0 799 750O0 677472 L994 2A40 0 o 0 4919 o 609320 1995 2005 o 0 2000 4234 0 9L4743 L996 o 0 0 6000 L07 95 o

253 IBt€ltlatiollal ALligator/crocodl,le rlaale atualy (IAcIa) ,tune, 1998

Forrrard and Overvi.elr by ,t. Don Ashl"ey

World trade in classic hides reached a total of 447,010 skins

in 1994 and lrhen increased doDestic trade in the ADerican Alligator is considered in 1995, total trade aqain exceeded 4oo,o00 cl.assics. This record voluDe of classj.cs approaches the historic high of about a half ttrillion hides a year estiDated to have occulred j.n the late 195O's and earl.y

196ors. And as has been predicted in IACTS and other reports, the rapid increase in supply without adequate attention to expanding denand is resulting in sj.gnificant econoDic pressure lrithin the industry.

MilLionE of dollars have been spent to devel.op the research, nanaqeEent and enforcement gnridelines necessary to establish sustainable use prograrls for crocodilians. But relatively Iittle has been spent to narket, pronote and educate censumers worldwide. Even !0ore classic crocodilians can be produced, and not just the Arerican Alligator and NiIe

254 CrocodiLe &'hich conbined nade up 87 percent of the totat trade of classics in 1994-95. l.tany other species could increase production and particj.pate in the sustainable use cantribution to connerce and conservation.

But prelit0inaly 1996 trade data begins to docuDent the supply and denand predictions that nust al.so be a part of real-istic sustainable uge prograns. We have proven through research, Danagelettt and enforceDe.t the sustainability of crocodilian lesources and proven the econonic incentive can benefit both people and wildlife. We have not provell the sustainabiLity of a lror]d narket capabLe of absorbing at ]east 5oO,OOO cl.assic hides a year and nore than one nill.j.on caiEan skins at a reasonably profitable Level- to producers. Admittedly, current economic dj.fflculties in the pacific Rjr and Japan have ruagnified this problen. And there is no doubt soue larket expansion in lratchstraps, nestern boots, snall leathergoods and the U.S. product denand in general is occurring. But it does not replace a historic market like cermany that at one tj-ne used about IOO,OOO classics a year and had more thah 20 handbag nanufacturing conpanies. Today cernany j.s reduced to three handbag nakers, using Less than 5

253 percent of that volurne and a consuner base that is reluctant to carry any lrildlife produet j.n public. when that reality is conbined tr'ith the negative iroages of wildlife products discussed in the last IAcTs Repott at Heathrow, Gatlrj-ck, Hong Rong anil other internatj.onal airports as well as the procrastination of industry and governnent to recognize the need for better pronotion or education, the result is a great conservation program based on ecoltoDic incentives that nay not be eo@ercially viabfe for many producers. Thi.s is a tragedy and is avoj.dable. But not without a concerted effort to better explain the concepts of sustainable use (not endangered or il'legal), reDove the politically incorrect stigrla of carryinq a lrj'ld]ife product, encourage more manufacturing, retailing and purchasj'ng of finished products (proDotion and price) and focus industry and governnents on the reafity of sarket sustainability as wel-f as that of renelrable natural resources.

The idea this can be done in a short ti'oe or vith a silver bullet pronotion is off base. More shoul'd have been done incremental for the last ten years when all Eigns pointed to the rapidly increasing supply but a sluggishly expanding

256 denand curve vrith a narrolr consuDer base tLed to only a few countries. It is not diffj.cuLt now to see for exa$ple how draDati.c the ilpact on wi.ld alJ-igator hide prj-ces are

when the Japanese do not purchase as malry handbags and the Italians do not Dake enough shoes o! other products that can use large sqafe patterns. The inpact on programs for other crocodile species can be nore devastating lrith lj.ttte rnvestrlent potential if rnarkets rehain tight or decLine further.

The point is that nore Dalket stabil.ity is difficutt vithout

a nore diversified narketplace. And that requires loore lanufacturers producing a product at a price that r[ore retailers and consumers !'iJ-l buy. InpediDents to those sales (toisinfornation, Disleading custoes displays, incorrect buyer beware ads. etc.) nust be renoved and &ore independent conservation experts nust step forward and publicly explain the benefits of sustainabl.e use, Fl:ankly, they should start lrearingi or carrying the products thenselves and dispense lrith the h]'pocrisy of undelstanding tbe sustainable use concepE. but not accepting responsibitity for providing any econonlc i,ncentive to nake it wo!k.

251 not much tine A9 preatlcted in the previous -IAcTs Report ' pronotion and education' reuains to nake a better effort at culrent probfens' General ecanooic crisis has dagnified the year 2ooo if hide supply but they lrere cornLng anlrnay by the to product conti.nued itE rapid pace ltithout nore attentj'an deband and tlte inpeditlents to it'

above all' others ln It is inportant these points be raised grown frou 55'245 thi.s IACTS Report. The classic tlade ttas But the strarn skins in 1984 to uore than 4OO,OOOin 1995' !'i11 be even oore is apparent in the initial 1996 data and evident tthen ttle 1997 reports are filed'

trade for L994-95' the f ollowing table su@arj-zes the cl-assic

538 22O,535 558 Alligator 283 ,454 244 123,7O9 31t Nile Crocodile 106, 560 2L,476 5t Nelr GuiDea crocodil-e 32,640 7Z 53 2!,476 6* Saltr.rater crocodile 20,O2r 9 24 ALl others 4,29! rz ,42O

39a,377 TOTAI, 447 ,OLO 254 Ahe al.ligator decLined belolr 60g for the first tine since 1990 wj.th a significant increase for the Nile crocodile.

There stiLl nay be sone double counting of Nile hides due to backstrap trade and reporting differences, but the overall increase is apparent. tikewise the Sianese Crocodile trade also increased significantly in 1995 to 5470 hides but that nay not be sustained if the current pacj.fic Rin econonic crisis continues. In generaL the coDing data for 1996-9g nay need to be averaged for a conpLete pieture because the narket slolrdown during that period shifted sone exports bet!,een years. But the point is the value of the classic trade declined lrhen the threshoLd of 4OO,OOOskins t'as reached. And as predicted, the classic trade coutd not reach the historic high of 500,000 skins profitably erithout significant narket expansion.

The inpact on the eaj-[an trade lrj-th a less valuable hide !.'il]. be even nore dramatic and already the data is cotfusiDg. while our previous estinate of about 1 Dill-ion caj.nan rn trade was verified vith 1,055,197 reported in 1995, the al,nost doubl,ing of exports fron Colollbia since i993 to

946,9f4 oi 90t of the total cainan trade is extraordinarv.

259 Particularfy since the reliance on captive production waE certain to j.ncrease costs and potentially undernine other ranching prograns with more conservatiolt value in tbe region' j'n of the This needs to be carefully revielted' not onty light potential econooic vi.abili.ty of prograns in colot0bia, but the level- iDpact on other caiman manaqeDent prograns ' can this did of captive production and export be naintained? Iihy j'n 37o Brazi.l drabatically dectine fron 43,574 1994 to only in 1995 and rrhat has happened to the ?5 registered ranches

there? Are there options to nitigate the financial i'npacts can on colombian farners and are there ranching optj-ons that

be considered?

It is also significant that this IACTS Report does not docu[ent recent infractions of crTEs iDport/export of requirements. But persistent questions about the origin some caiman shipments and the relationship of exportlnq countries needs to be reviewed and clarified'

use overal-l though the progress of implenenting sustainable stlategies for caiEan after the el'inination of cITEs tras been reservations and j-nplenentation of universal tagging

0 good considering the conplexity of the trade. The najor producing countrj-es of Brazil. Colonbia and Venezuel.a though

could help sort out the reEaining questions. Sone nay sinply be double counting from sone countries nrho report exports as franes or skj-ns and others lrho report inports as sides or fl-anks.

But the significant decrease in exports fron Bolivia and

Paraguay fron 1986-88 leveLs and the inptenentation of a ranching: prograr! in Brazil shouLd have resuLted in nore substantial- exports by now for Brazil. With the exception of 43.574 skins in 1994, this has not occurred and the dramatic decline to 370 skins in 1995 is inexpl.icable unless the

Darket decline or export data shift between years is responsible. A revie!, though {outd clalify ttruch of thi-s cqnfusion and better support sustainabl.e use prograns for cainan in the region.

It is also clear that more j.n-depth analysis of both classi.q and caj-man trade data rould help nonitor the iuplenentation of sustaj.nable use prograds. Unfortunatel-y, the request the last two years to increase research funding to VtCltCresulted in a decrease when Florida again chose not to natch the

26r Louisiana contrj.bution to the Project. Florida has decl-ined rrnarket agaj.n this year, with a request for a tuore sinplj'fied report'r approach to trade data. Unfortunately this again t0isses the point of a trade study that has fo! 15 years provided an independent review of trade data as well as inplementation of sustainable use prograhs for crocodilians' Louisiana vil.f consider an increase to wcuc for further analysis' particularly for inpteDentation of CITES uniwersal tagging, inport/export reporting guidelines' the cairnan tlade and infraction reports of all crocodilians in trade.

ThiE is a critical tine for crocodilian sustalnabl-e use progralF and each one j.s ultinately dependent on all of theD producing econornic and conservation benefj'ts to people and wildlife. IACTS has r0onitored the ups and dolrrls since 1984 and recohmends that the issues discussed here be i.Dnediately adabessed. The difference will be I'hether ttle century turns in favor of sustainable use or documents its economic decline. q0""N\

262 Table 29. Minimum net trsde iD classiccrocodiliaB skiDsreDorted in

* Datadeficient # Grossexpons from the USA Net rradeshould be a! leas!52,000 (see note on Zirnbabwe'slrade in Crocodylusniloticus) Net tradeshould be a! leas! | 6,000(see nole on Auslralia\ tradein Cracod)Ius porosus\

2f3 Mcki Simlesa: Dept Primary Industry Fisheties GPO Box 99o, Darwin, NT 0801, Australia. The NorthemTeritory in Australia,has eight commercial crocodile farms. Farming C,porosuq and to a lesser ertenl Ciohn*oni.The NT crocodileindustry is involvedin commercialproduction, tourismand education. NT production data from 1994 to 1997is displayed:

CrocodileProduct Sales.

B.lly skin!.nd 8..t.1,.p. s.1...

C.porosusProcessed.

c. poro3us BslaingAnlm.ls Process6d.

I

261 C.johnstoni Processed.

c. JohnstoniFat6tns antmate a!oco3s€d.

Crocodile Flesh Production-

Crocodlle Flesh Produced in Years.

40000

35000

30000

25000

E 20000

15000

10000

5000

0 1992 1993 1994 1995 1996 1997

255 Total Numbers in years.

Total Numbers: End ot Ysar.

. 25000 : 20000 = tsooo

10000

Total Numbersin Classes.

Total t{umbors In Ctarsss: End of Yoa..

.: E

26 Hatchling Gain.

Hrtchling Galns per Ye.r.

261 General Introduction to Re-introductions

by 'StanleY 'Soorae,P. S. & Price, M. R.

'Pritpal S. Soorae,Technical Project officer, rucN/Ssc Re-introduction SpecialistGroup, Aftican Wildlife Foundation,P.O. Box 48177, Nairobi, KENYA. E-md.|.Psoorae@a',$ke orI & 'Dr. Mark R. StanteyPice, Chaiman, ruCN/SSC Re-intoduction SpecialistGroup, African Wildlife FolndatioD, P.O. Box 48177' Nairobi, KENYA. E-maili Mstanlewice @a' tke.org

ABSTRACT The thrce important aspectsof a re-introductionarc biological, socio-economic and political and post-releasemonitoring. Lnportaotbiological aspectsarc taxonomy,choice of relgasesite and habitatrestoratiotr, availability of stock aIId vgterinaryscrcening. Iroportant socio-economic and political aspectsare socro- economicstudies, political supportand doitrg a re-iltroductiotr as a carefully desigDedexpedment. Important post-release aspects are monitoring of leleased iodividuals and having specific objectivesfor measudngsuccess. The majority of crocodilere-introduction projects ale re-enforcament/supplementatiolexercises' Ilnportallt issueto coDsiderfor crocodilereleases are acclimatizationto the reliase site, food locatiDgskills, avoidanceofpredators Ooth inta- and inter specific),release of single size classes,fitness of individuals destinedfor release and the potential of diseasespread.

INTRODUCTION The ruCN/SSC Re-intoduction SpecialistGroup (RSG) was formed io 1988by ruCN in @sponseto the large numberof releasesthat were taking place wortdwide.The RSG currently hasover 300 membersworldwide replesetrhng re-introductionpractitioners in govemmentaland non-govemmenul organizations,researchers, lega.l practitione6 and other intercstedindividuals'

The RSG also publishesa bi-annualnewsletter, Re-introduction NewJ, which is distributedto ove! 500 subscdbe$worldwide. This is the only newsletter worldwide which is dedicatedsolely to re-intoductions.

The higblight of RSG hasbeen the developmentof the Re-itrfoduction Guidelines,because a neodwas felt for specific guidelines'to help insue that re- intoductions achievedthei itrtendedconservation beneflt. Theseguidelines have now beenalso pdnted into bookletscomprising five major iltematioDal languagesnamely Spanish, French, Chircse, Arabic and Russianbesides El8lish. The Re-i[troduction Guidelitreswere madeofficial ruCN policy in May 1995when they were official apprcvedby the 4lst. Meering of ruCN Council

Aims and objectives of a re-introduction Accoding to the ruCN Guidelinesfor Re-introductions,1999, the pdncipal arrn of a rc-intoduction shouldbe to establisha free-rangingviable populationin the wild of a species,subspecies or mce, which has becomeglobaly or locally exttnct, or extirpatedin the wild iD that particular area.The objectivesof a rc- introductionmay include:-

. To enhancethe long-term suryival of a species. . To establisha keystonespecies (itr the ecological or cultuml sense). . To maintain and/orrcstore natural biodive$ity. . To provide long-terqt economicbenefits to the local and/ornational economy. . To promoteconservation awareness.

Underthe re-introductionguidelines there are four main terms:-

1. Re-introduction: An attemptto establisha speciesh an areawhich was oncepart of its historic range,but from which it hasbeen extirpated or becomeextinct.

2- Re-enforcemenVSupplemeDtation:The addition of individuals to an existi[g populationof conspecifics.

3. Translocation: The deliberateand mediated movement of wild individuals to an existing populationof conspecifics.

4. ConservationlBenign ltrtroduclions: An attemptto establisha species,for the purposeof conservation,outside its recordeddistribution but within an appropriatehabitat andeco-geogmphical area. This is a feasible conservation tool when there is no reinaining area left within the sp€cies, historic range or for somespecilic reasons e.g. marooning on isla.nds.

Main aspectsofa re-iDlroduction Thereare threemain aspectsof a successfulrc-introduction project-

. Biological Aspects- pre-projectactivity o Socio-economicand Political Aspects- pre-projectactivity . Post-releaseAspects - post-projectactivity

259 BIOLOGICAL ASPECTS Taxonomy Taxonomicalissues are very important.when individuals are destinedfol a rc- introductiotrthey shor.tldbe of the samesubspecies or raca asthose that were extirpated,unless adequate numbers are not available.An investigationof historical information aboutthe loss andfate of ildividuals from the re- introductio! areashould alsobe conducted.If there is a doubt of the individuals' taxotromicstatus then a study of geneticvadation within andbetween populationsof this and rclatedtaxa canbe useful (IUCN, 1998).

The African violet (SantipauliLtongwensis) is an endemicplant, that is only fou[d at 3 sites,in the Tangaregion or the nothem coastofTanzania. At the site whereit is found in large numbersthe populationexists alonga waterfall' The river was divertedby a water supplyproject, which lead to a general desiccationof the area,and this was threateningthe African violet population.It was then decidedto move a part ofthis populationto anothersuitable site to cleate a secondpopulation.

After a part of the original populationwas traNlocated it was found out that the traNlocated populationand rcsidentpopulation were both at risk from hybridizatiol. This could result in a loss of their geneticintegrity. In African violets eachseparate population rcprcsetrts a uniquetaxol eventhough the microhabitatrequirements may be similar for all the all species.

It was thereforedecided to rcmove the tanslocated populationback to their original site and try to createa suitablehydrological regime to maintain the populationat its original site- It was also decidedto useother methodsof ex-Jitu ionservation measutessuch as seedbanks atrd maiotenance of living germplasm to protectthis species(Simiyu, 1995).

Choice of releasesite and habitat restoration The site chosenfor a speciesre-intoduction shouldbe within the historic latrge ofthe species.The site also hasto be evaluatedfor its suitability and changeof the natual habitat sinceextirpatioD must be considerd. Wherc therehas been subshnrialdegmdation caused by humanactivity a habilalrestorarion program shouldbe initiated before the re-intoductioD is carried out. Also the identificatioDand elimination of the prcviouscauses of declineshould be undertaken(IUCN, 1998).

The RoundIsland skittk (I'eiolopsimatelfairi) is endernicto RoundIsland near Mauritius. This specieshas been Part of an extensivecaptive-brceding program' A re-introductionplan was idtiated but it was found that populationsof this skirk werc alreadyat carrying capacityon Round Island The specieswas 210 previouslyknown to occur on Mauritius, Flat Islatd and Gunneis' euoin. At the latter site ir occuned rill the late 1800'sbut was extirpatedby the in&oductionof blacktuts (Rat us rattas). It seemedthat Gutrle$, euoin seemedthe best location, but a full ecologicalinvestigation was recessary,before a re- introductioncould prcceed.It was also impodant to samplethe ilvertebmte faunawhich would form the diet of the skink and the D@senceof rats on the island.

Resultsof the surveyindicated that introducedIndian black-naped harcs(lzpus nigricollis) have cha\ged the vegetationftom a Mascareneflora to a morc pantropicaltype. The invertebmtepopulation was also found to be inapprcpdate. A rc-introductionin this casewould be feasibleonly if the lats aod harescould be elimi[ated and a comprchensivehabitat restoration prcgrallt undertakel to restorethe original flora (Bloxam, 1982).

Availability of stock It is desirablethat sourceanimals come from wild populations.If thereis a choiceof the stock origimting from a wild populationit shouldbe closely related geneticallyto the original native stock and show similar ecological chamcteristicsto the original sub-population.If itdividuals comeftom captiveor artificially propagatedstock then they must havebeen madaged both demographicallyand genetically(ruCN, 1998).

The Arabian ostrich (Struthio camelussyriac6) becameextinct in the late 1950'swhen the last individual is thoughrto havebeen shot in northem Saudi Arabia. It was thereforedecided to rc-introducercd-decked ostriches (St/ut io canelus camelus)from Sudanas this is the nearestliving rclative of the extinct Arabian sub-species(Seddon & Haque,1996). This decision was basedon phenotype,distlibutiotr and conservationvalue (Seddon& Soolae,In-press).

By the 1970's,red wolf (Canis rufiis) pop\tlationsin south-eastUSA, werc dwindlirg rapidly due to loss of habitat,loss of young to paBsites,persecution by man and geneticpollution from invaditg coyotes. Thercfore a decisionwas takento find and createa captive colony aod re-establishthe speciesback into the wild in its natural range.In the late 1970'san operationrcsulted in 4OO capturedwolves. Out of theseonly 14 individuals were genetically-pue red wolves.By 1988,the captivepopulatio[ had risen to 80 red wolves and these wereheld at 8 breedingsites (Parker, 1986).

Yeterinary screening It is importantto undertakethe appropriatehealth and genetic scrceningof releasestock. If releasestock is wild-caught,cale must be takento ensurethat the stock is ftee fiom infectious or contagiouspathogens and parasitesbefore

211 shipment.Also to ensurethat the stock will not be exposedto vectorsof disease agentswhich Inay be prcsentat the releasesite (and absentat the sourcesite) and to which they havero acquircdimmunity (IUCN, 1998).

The relocationof wild animalsis never the movementof a single speciesbut the relocationof a "biological package"comprising of the animal itself (host) and passelgerorganisms such as viruses,bacteria, fungi, protozoans,helmiDths, arthropodsarld other pathogens(Davidson & Netdes, 1992).The deserttoftolse (Gopherusagassiaii) in the westemMojave desertin the US hasbeen affected by an upper respiratorytract drseaseknowD as the UpPerRespiatory Disease Syndrome(URDS). This diseasecoupled with nutdtional prcblemsand long- term environmentalstless is alwaysnearly fatal. The agentresponsible is an exoic Mycoplasmawhich hasbeen thought to be introduced by the rcleaseof caplive-individualsinto the wild population.Captive itrdividuals catrreadily pick up exoticpathogens whilst in captivity(Dodd, Jr' & Siegel'1991).

Tbe following rccomendationsmay prove useful in re-introductionprgects (Woodford,1997):-

. Diseasepotentials must alwaysbe consideredby a wildlife veterinarian during a re-introductionprcject. . A literatue review may help in identiffitrg potential diseaserisks. . The animalsto be movedmust be qualantinedfor a period of time dunng which screeningshould be undertakento identify pathogensThis sort of cotrtainmentcan also have anotherproblern that it can lead to social suess (Dodd,r. & Sieget,1991). Vaccination should also be comidered. . Aoimals both wild and domesticmust be examinedat the releasesite as they rnay threatenthe healthof incoming, narvetanslocates.

SOCIO-ECONOMIC AND POLITICAL ASPECTS Socio-economicstudies ard political support Human interestsare of paramountimportance when conductingre_introductions' The prognm shouldbe fully undeNtood,accepted alrd supportedby local communities.It is thereforeimportant to conductsocio-economic studies to assessimpacts, costs and benefitsof rc-introductionprograms. These ProJects are generallylong-term andrequirc long-termfinancial and political support(IUCN. 1998).

Large camivorere-intoduction posethet own specialset of problems.Latge camivorescan be dangerousand even fatal to humansand their livestock. It is very impofiant to win the supportoflocal codununitieswhen re-intloducilg lamecamivorcs orthe successofthe prcjectcan be compromised. In Florida, mountainliots (Felis concolor stankyana) were rcleased.into nofihem Flodda to test rhe feasibility of rc-introducingFlodda panthe$ (Felir cotrcolor coryr. D]uitrg a! initial surveybeforc the expedmontalrelease over 7070of respondentsfavored the rc-introductioneffort in their own or surouDdingcounties. There was howevera negativebacklash, after the expedmentalrclease, when rcsidentsin the countieswhere the releasetook place formed an organization"Not In My Backyard" to opposethe re-intoductiotr efforts@elden & Mccown, 1996).

The Pilanesbug National Pa* in SouthAftica was fencedand re-stockedwitL native wildLife in 1979.In the early 1980'scheetah were rc-intl.odtrced(Aciconyx jubatus) and despitecompetition from leopard(Panthera pardus) and brown hyaena(Hyaena brunne4) the populationincreased fiom 7 to 17 aoimalswithin a year (Anderson,1983). Pilanesburg made its itrcome ftom crcpping, hunting and tourism activities. To completethe gameviewing experienceit was coNidered logica.lto re-inftoducelions. A detailedcosGbenefit analysis was conductedon evaluatingthe re-iDtroductionof lions to Pi.lanesburgNationa.l Park. This study showedthe North-WestemParks Board who managedPilanesburg National Pa* stoodto lose roughly US$ 280,000/yearfrom the capital and openting costs.A loss of rcvenuewas also expectedthrcugh stoppingplains garnehunting because of its incompatibility with lions. Therewould also b€ a loss of revenueftom live animal saleswhich would now form a prey basefor the rc-intoduced lions (Stuart-Hill& Grossman,1993).

The region as a whole would benefit with an income of US$ 7,225,000/yeardue to the incrcasednumber oftourists visiting to seethe lions and stayingin the nearbyresorts of Sur City and Lost City (Vorhies & Vorhies, 1993).This offset in revenueswas balanced by the resortsdonating US$ 280,000to the North- WestemParks Board to obtain morc hippopotanw (Hippopotamusanphibious) and elephant(Iaxodonta africana) besldesmeetitg other miscellaneous expenses(Stuart-Hill & GrossmaD,1993).

Re-introduction as a carefully designed€xperiment It is importatrtto design the pre- aod post-rcleasemonitoring programsso that eachre-introduction is a carefully designedexperimelt, with the capability to test methodologyand scientifically collecteddata (ruCN, 1998).

Thereare manycases where wild animalsare simply releasedinto the wild. It is very impodant to plan wildlife leleasesas well desigted experimentswhich can genemteuseful scientific data.Re-intoductiotrs should not just be a tool to prcvent extinction of vulnerablepopulations but also a way of unde$tandiogthe speciesand its predicament.Re-inftoduction biologists should aim to rclease animalsunder gorously controlledexperimental conditions which test specific hypotheses.In a long-term situationthis information will be importa[t for the suicessof re-introductionprojects (Armstrong et al ' 1994)'

ExDerimentshave been conducted with taNlocated hihi birds (-ly'otoi'1)tt's cinera),which is an endangeredNew alandhoneyeater, to test whetherthe high mortality expedencedis due to a limited food supply at their re-intr-oduced that food sif, lArmstrong 6! Perrott, 1995).Recently available datasuggests - . limitation ma/not be the limiting factor but other factols suchas diseasecould accountfor the high mortality rate (Armstrong, 1998)

POST.RELEASEASPECTS Post-releasemonitodlg of individuals may be one of the most imPoftantactlvlly of re-inroduction projects.This monitodng can either be donefor all the releasedindividuJs or a sampleof individuals. Direct monitoring usually itrvolvestagging and telemetry studies.Indirect monitoring can compdseof usitrgspoor or informanb (ruCN, 1998).

In rc-introductionprojects long-term commitmentis essential Monitoring a toad re-infoductiotr can c;ntinue for l0 - 15 yearsbut extendfor over 20 yearsfor slow-b&edingand long-lived speciessuch as tortoises This is importantto ensue thc pr;sence of releasedindividuals and the successor failurc of rcproduction(Dodd, Jr. & siegel,l99l).

Indicators of success The prircipal aim of any re-intoduction shouldbe to establisha viable' ftee- rangingpopulation in the wild (rucN' 1998). h-S19t- Captive-breedingattempts with the Arabian oryx (Oryx kucoryx) . aratiu ueganin-ietO with a captive herd of 57 animals' SinceMarch 199?'thele a arenow aiproximately 380 individuals in two protectedareas in the wild,with captiveheri cornprisirg of 245 oryx. In the Mahazat as-SaydProtected Area the - populationgrowti ofthe F-infoduced herdhas increasedat 15 204aperyear (Ostrowski& Bedin,1997)

Captive-raisedwolve s (Canis lupus)were re-iltoduced in Georgia' C'I S in the Trialete Mountain areawherc they had beenearlier wiped out This project was deemedsuccessful after the third generationof wild-bom pupswas obseryeorn thewild @adridze,1994).

A re-inuoductionneeds to havespecific objectives to prcvidea measureof success.Therefore when theseobjectives are met the project canbe declared successful.

2',74 CROCODILE RE.INTRODUCTION PROJECTS TheRevised Action Plan for Crocodiles1996 (CSG, 1996) and Kitrg (1990)was rcviewed to obtain infoqnation on re-infoduction projectsinvolving crocodiles. Table I (Appendix 1) showsthe 16 speciesout of a total of 23 for which there is somesort of conservationaction involving a re-introductioncomponent. The table showsthe species,principal tbreatsand the t]?e ofre-htroduction ploject.

Crocodile releaseprograms Figuie 1 below shows that cunetrdy therc are 3570o[-going releaseprograms (8 species),a further 267oarc in the proposedplanned release stage (6 species)and 9Eoarc in captive-breedingpro$ams (2 sp€cies)which have a proposedrclease component.3070 of the species(7 species)have Do curent plannedprojects

Figurel. TJpe of re-introduction activity

Threats facing crocodiles Accordingto ligure 2, habitat destructionaccoutrts for 4770of the thrcat facedby the 16 speciesfor which there is a re-itrtoduction component.This is followed by a limited distribudon 177r,illegal hunting 3070and both conJlictwith people and competitionfrom inhoducedexotics at 37oeach. Figure 2. Categoriesand severity of threat faced by the 16 speciesof crocodile

T]?e of re-introduction Projects The majodty of crccodile re-intoduction projectsare mainly rc- enforcernent/supplemeBtationtype projects.This is the addition of individuals to an edsting populationof conspecifics.Re-enforcement's should only be done when there are a few remnantwild individuals remaioilg in the wild population and the Therc is always a high possibility of diseasesprcad, social disruption . intoduction of alien genestheleby ha$teningthe deathof the remnantpopulatron (rucN,1998).

Releaseto the wild The majority of crocodilerelease are "head starting" plojects' In this method ari hurch"dio in"ubatols aod the hatchlingsraised until theyare larye. ei6ugh"ggr to resist predators.They ale then releaseditrto the wild (King, 1990)' Commercialcroiodile famers, in somecases' are expectedto provide their rcspectivewildlife authodtieswith juvedle crocodilesfor re-stockingPurposes' In Zmbabwe the wildlife depaftmentis entitled to 57oof the numberof eggs collected.This hasnot been srotrgly enforcedbecause currendy adequate populationsexist in habitatssuitable for Nile crocodtLes(Crocodllus niloticus) (child, 1987).

Concerns Thereare various concemswhen releasingcrocodiles back to the wild These concemscan be listedas:- n6 . Acclimatization to the rcleasesite . Locating food . Avoidanceof predarors(both inta- ard inter specific) . Releaseof single size class . Fitnessof irdividuals destinedfor .elease . Diseasespread

Acclimatization During rc-intoductions of animalsit is very importantfor the aDimalsto be familiar with their releasesite. IIl manycases anioals arekept in penswith wirc fencesto enablethem to developan affmity to the releasesite. When releasing birds ofprey a techdque known as hackingis used.When the Mauritius kesael (Falco pmctatus) wa.sbeing re-introduced, they would be kept in an aviaiy at the releasesite, to encoumgesite faiDiliarity before release(Jones ar., 1991). ", In Ghaial (Gavialis gangericur)reteases in Iodia many individuals havebeen swepthundreds ofkilometers downsteam (Whitaker, 1987).In Ugandajuvenile Nile qocodiles (Crocodylus nilotbus) bei'rigreleased into the Muchiso; Fans National Park have disappearedfrom the releasesite (pels. collun., Richard Baguma).Ir 1960,8 adult Americur alligatorc(Attigator mississi?iensis) werc releasedinto the EvergladesNational Park. Affer two weeksof being released6 individuals disappearedand the remainingrwo a.lsodisappeared aftei a funher period (King, 1990).

Crocodilesdestined for leleasecan be maintainedin pensat the releasesite which shouldincorpomte a palt of the water body and shore.The iodividuals can be kept in this pen for a pedod of time after which they can leave ar will. This solt of a systemwould be easierfor a take. In fast-flowilg rivers it may be possibleto constructa small pond which is linked to the main river. Natural food can be provided but upon releasethe qua.ltitiescan be reducedto encouage movemeBtaway liom the holding pen.

Locating food In captivity most individuals being rcarcd arc fed on a prcparcddiet of fish and,/ormeat. It is very impoftant for individuals destinedfor rcleaseto be fed a natulal live diet as possible.Juvenile gharial (Gavialis gangeticns)are fed small live fish. Juvenilemugger (Crocodylus palusrnt) arc fed live frogs and tadpoles. Juvenile sa.ltwatercrccodrle (Crocodytus poroszs) are fed crabsand prawns. Largerindividuals are fed wirh choppedfisb. buffalomeat and rars 6Wt ituker, 1987).Nile crocodiles (Crocodylusniloticur) which were mised at the Kyarimi Park Zoo in Nigeria during I 977 were fed on a diet of live Titapia andCiarias fish duringtheir lasr four monthsin captivitybefore release (Morgan-Davies, 1980). 217 Crocodilesthat arebeing raisedfor rcleaseshould be fed on a natual diet as possibleto developand maintainfood gathedngskills necessaryfor survival in the wild. Provision of naturalfood availableat the releasesite shouldbe an importalt poitrt to consider.

AvoidaDceof predators Crocodilesbrought up in penswith the absenceof predato$ canbe at dsk wher releasedinto the wild. Captive-rearcdthick-billed pa$ots (Rhynchopsitta pachyrhyrha) rcleasedin Arizona, USA, after a six-monthperiod in an aviary with wild-caughtbirds, showedno sign of vigilance againstavian predatorsupon lelease.These parrots had beenco-existing with wild birds in an aviary for six- monthsand showedno aptitudefor leaming (Srryderet al., 19??).If individuals cannotavoid prcdato$ it is basically a meansofprcviding an exPensivemeal to potentialprcdators.

Training can be one methodwith which to teachindividuals to avoid prcdato$ Houban bustards(crlamydotis undulatamac4t"ezii) destinedfor rcleasein SaudiAmbia were frightenedwith a live, ruuzzledfox in the presenceof wild- caughthoubara to provide the appropriatefear response.Houbara alam calls were also playedduring the exelcise.A post-releasemonitoring study showed that proportionally more predatortrained birds were alive after undergoingthis fright tnining (Heezik & Maloney, 1997).

Releaseof single size class Many tanslocations fail to establishnew populationsbecause of stresson the admals. This can be due to disruptionofprcvious social bondswhich can lead to lowered survivability, scatteringin the new habitat and increasedvulnerability to predatoN(Stanley Price, 1989).Crccodile rclease programs usually take a specific age$oup for release.Programs usually target individuals betweenl-3 yeals old. It may be importantto rcleaseindividuals rcprcsentinga varied age structue. In captivity hatchlingsofdiffercnt sizesundergo stess due to dominancehierarchies being established (Hutton & Jaarsveldt,1987). This may be undesirableurder commercialctcumstances but imponant for individuals destinedfor rclease.

In Cubaduring 1994a re-introductionprogram involving CubaDcrocodiles (Crocodylusrhombifer) released200 animalsthat were gradedaccording to ther size.This was dolle to representa natulal size distributioo fron juveniles (90 cm tail-length)to sub-adults(120-180 cm. taillength) (Soberon 1996). "tar., Wheojuveniles arereleased they will face attacksfrom larger territodal malesas they begin to mature(King, 1990).When individuals are destinedfor release there shouldbe few la.rgerindividuals to avoid ot reducecases of cannibalisnr and aggressionfrom larger wild idividuats. Individuals destinedfor rclease shouldcomprise of a differcntia.lage stucture to try and reproducea natum.l social structureas that found in the wild.

Fitness of individuals destined for release ,fit' Lldividuals destinedfor releaseshould be in terms of their ability to survive in the wild, Runrsor otheN with physical defectsshould not be pan ofrelease programs. This may be more ofa concemwhere a certainpercentage of individuals are given to wildlife authodtiesfor releaseto tie wild. ihis may be more of a problem with 3" or 4' generationirdividuals bom in captiviw ani targetedfor a re-in[oductionprogram.

Large scalecaptive-bleediDg and releaseprograms have their own genetic implications.When individuals aremaintainJd in captivity there is-thepossibfuty of artificial selectionin captivity. The characteristicithat make the individual successfulin captivity may not be the samefactoN that will ensue survival in the wild. If a large numberof individuals with suchprobtems are released into an existitg natuml populationthis could have a rcgative impact on the existing gene poolin thewild G.einerr,1991).

Disease Crocodilesare known to suffer from various diseasesadd ailments.Corffnon crocodilediseases are viral hepatitisand eateritis,pox virus itfection, bacteriar infections,fungal infections,coccidiosis, helminthiasis, kidnev disease- deficiencydiseases and runt syndrome (Foggin. l9g7). Cubancrocodiles (Crocodylus rhombifer) releasedat the Isle of pines in Cubawere in qualantine during captivity and underthe ca.ieof a veterinarian.Thesg individual: had a very lare occurrenceof diseaseand there was no reports of parasites(Soberon ?/ al.,1996).

In 1995 a total of 15 American crocodiles(Croco dylus acutus)were rcIeasedin Venezuela.the teleasedcrocodiles were given veterinaryexaminations two monthsprior to their release.This was to prcvent immunological deficiencies andthe dsk of introducingpathogens to the wild (Boedee, al, 1995).

It is very importantto_ ensure that adequatedisease screening protocols are put into placefor crocodilerelease progEms.

Conclusion Re-introductioDsare being usedas a managementtool in crocodilian coNervation worldwide. This is mainly in the folm of re-enforcementsto boost low numbersin the wild. Though it is encouragingto note that depleted

219 populationsare being rc-stocked,it is also importantto follow established guidelinesand protocols,to ensurethat theseconservatiol actionsare being done accordingto soundcoNervation biology Pdtrciples.

Acknowledgements We would like to thank EMIRATES ai ires for prcviding a discountedticket to enabletravel for the Tecbnica.lProject Officer to attendaod presenta speechat the 146Wo*ing Meeting of the CrocodileSp€cialist GrouP in Singaporc.We would like to thaak Dr. JarnesPen"an Ross for providing necessaryinformation pertainingto crocodiles.

280 References

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124 Relative Costs of Re introducing Crocodiles to the Wild Dy rsoorae, P. S.. T. Elliott & ?. Muruthi tPritpal S. Soorae,Technical Project Oflicer, IUCN/SSC Re-introduction Specialist Group, African Wildlife Foundation, P.O. Bor 48177, Nairobi, KENY.{ E-mail. Psootd@x'Jkaory

zJoantraElliott, Coordinator, Conservation, Economics & Commerce Program, African Wildlife Fouudation, P.O. Box 48177, Nairobi, KEi.[YA- E -ma,i|:J E I I iot@twJke. ory 3Philip Muruthi, Coordirator, Species& EcosystemProgram, African Wildlife Foundation, P.O. Box 48177, Nairobi, KENYA. E -mail: PM u r uth i@4n1lke. o r g

1.0 IntroductioD This posteraims to look at the most cost-eflectivemeans ofconseryation and re- introductionof crocodiles.This posterlooks at four scenariosi

. 1n-sirr.conservation in the wild o Corservationcaptive-breeding for rc-introduction (can be both in-situ or ex- sit in-country) . Faming for profit aod conservation(ca:r be both iz-slrz or ex-sr'tain- country) . Speciespreservalion in zoos (er-xr'tuin-country or overseas)

Our dm is to indicatethe relative net benefit oi cost ofthese four scenarios.The outcomeof eachscenario is re-intoduction to the wild or naturalsurvival as indicatedin scenario1. The costs,benefits and risks for eachsituation arc oudined.Economic costs include diect costs,indirect costsatrd oppoftinity costs.The economicbenefits include dircct benefits.indirect benefitsand non- use values(existence and option values).

2.0 In-ritz conservation in the Wild This is the maintenanceofa wild populationin the wild and allowing natural recruitmentto maintainthe population.Crocodile nestsaverage a clutch of35 - 40 eggs.These are under constantthreat from predatorssuch as Varanid lizards. Oncethe hatchlingshatch they are fed on by a variety ofpredators suchas fish and birds. Nestscao also be destoyed by flooding or excessivedesiccation of

285 the nestingsite. In the wild usually about 1 to 3 crocodilesftom a clutch makeit to adulthood.

2,1 Main Benefits The benefitsof ir-.rilll conservationin the wild are wide-rangingincluding speciespreservation, habitavecosystem prcservation, park income,low disease risks (ftom releasedcrocodiles from an er-sl, source),preservation of other speciesand employmetrtof local co[ununities.

2.2 Main Costs & Risks The costsand dsks of suchan approachare park costs(OPERATIONAL: fuel, boats,vehicles, salaries, maintenance costs & FDGD COSTS:initial cost of setting up the park and in somecases rclocation ofpeople), compensationfor damageto humansand/or livestock, opporhnity costsof land and resources,in- country risks (war, poaching& habitat encroachment)and stochasticrisks such as droughts,floods and earthquakes.

Examplesofthis ir-Jita conservationactioo is that ofNile crocodiles (Croco$ius niloticus) in Murchison Falls National Pa q Uganda(Cott & Pooley,1972).

3.0 Conservationcaptive.bieedingforre-intioductiou This is the captive-breedingof crocodilespurely for re-stockingand is done for conservationpurposes only. In this sceoario,crocodile eggs are collectedfrom the wild, incubatedin incubators,raised in pensuntil they are ofa suitablesize and then releasedinto the wild. ln this exampleit is assumedthat a clutch of eggscollected ftom the wild averages35 - 40 eggs.At post-incubationa hatchingrate of 80% can be assumed which resultsin 28 - 32 hatcl ings. Taking mo ality duing this stagewe assumethat approximably 23 -26 cxocodtles arereleased into the wild. In this caseifthe rcleaseis doneearly (at about one year) then it is assumedthat fewer releasedindividuals will survive so more haveto be released.Ifindividuals are releasedlater (threeyears of age)then a higher survival rate is expectedand fewer individuals needto be rcleased.

3.1 Main Benefits The benefitsof sucha conservationaction ale restoringspecies diveNity, involvementof local peopleliving in surroundingcommrmities, species preservatio&habitat/ecosystem preservation, park income,medium diseaserisk, preservationof other speciesand toudsm income. 3.2 Costs & Risks The costsand risks of sucha conservationcaptive-breeding operation are egg collection & tiansport, coNtruction andmaintenance of incubator& pens, electricity or solarheate$ for energy,palk costs,medium disease risks, compensationfor danage to humansand./or livestock, opporhmity costsof land andresources, feeding, mortality, vgterinaryscreening and labour.

Exampleofthis sort ofan opemtionare the rc-stockingofthe mugger (Crocodyluspalusttis), saltwatercrocodile (Crccodylus porosus) ul.d.gJrwial (Govi.tlis gqngeticus)in India (Whitaker, I 987).

4.0 Farmilg for profit and conservation This is the farming of clocodiles for profit through the saleof skins, meat and gatercvenues. In many suchopemtions there is a hiddencost for the farmerwho hasto rctum an).whercfrom 5Vo- l89o of crocodilesin the I - 3 yearsage group to the wildlife authoritiesfor re-stockingpurposes.

In this example,it is assumedthat from a clutch of35 - 40 eggs,with a 80% hatchingiate yields 28 - 32. In this scenarioabout 5oZ - 180/oofhatchlings are given to the appropriaGwildlife authoritiesfor ie-stockingpurposes. If younger individuals areused then more hatclLlingsa.re retumed to the wild. If larger individuals areused then fewer individuals are retumedto the wild. This is on the assumptionthat larger individuals will have a higher suwival rate when comparedto smallerindividuals.

The other farm stock ir culled for meatand skins. Therc is also an opportunityto collect gaterevenues from viewing. Thesefarrns can also provide an educational experiencethrcugh lectues and live demonstrations.Sustainable utilization can be well illustrated in this way.

4.1 Main Benefits The benefitsfrom such a qocodile farm are its toudsm potential,profits fiom skins & meat,ecooomic & biodiversity benefits,demand for socodile products, key speciespreservation, sustainable utilisatioq educatiolrpotential and gate revenues.

4.2 Main Costs & Risks The costsand dsks of sucha clocodile falm are the opentional costsof farning e.g. feeding,veterinary, labour & enelgy, cost ofthreat to species present,high diseaserisk letum of5 - 18%ofstock for re-stockingpulposes, tiarcport costs,technical expertise, dsk of inbrceding,release of runts and

281 diseasedindividuals, hicl diseaserisks, potential for coruptio!, ultimatere- introductionand its opporhrnitycost.

In Zimbabwe,the wildlife departnentwas ertitled to 5oloofjuveniles, from the total the numberof NiLe uocodile (Crocodylusniloticus) eggscollected (Child, 1987).In Ugand4 the nationalparks authority havea five year agreementwith a commercialNile qocodrle (Crocodylusniloticus) famer for 5oAof I year old juveniles ftom the 4000 eggsit collectsftom the MurchisonFalls National Park (Soorae,t 995). In otherprograms this figure is ashigh as 18olo (Perran Ross, PeIs.Comm.)

5.0 Speciespreservation in zoos This is the preservationof speciesin zoosand canbe viewed as a modemday Noah's Ark whele individuals can be maintainedagainst the rising tide of extinctions.When conditions are more favorablethese individuals can be re- introducedinto protectedor restoredhabitats (Hutchins e/ al, 1996).In this scenarioeggs are either obtainedftom the wild or ftorn breedingwithiD the zoo After hatchingthe young are either maintainedas exlibits or sold/givento other zoos.In very few casesare these captive-bred stock used for re-stockingin the wild.

5.1 Main Benefits The benefitsofmainatining crocodilesin a zoo arethe maintenanceof speciesin an er-situ location.This acts as an insulancefor the wild populationas well as generatingdonations, research gnnts, educationalopportunities and zoo profits,

5.2 Mai! Costs & Risks The main costsand risks of maintaining crocodilesin a zoo are egg collection either tom wild or tom breedingstock maintainedat zoo, velerina.ryscreening, labour fansport, high potential of diseasespread to wild populationifre- introduced,constuction ofincubator & pens,genetic disorders including inbreeding,tameness, mortality, domestication,invasive potential, high mortality, electicity or solar heaters,hybridisation risks, opporhrnitycosts of land and resoucesand feeding costs.

Thereis ao examplewhere offspdng of the Philippine oocodile (Crocodylus mindorensis)isbeing bred at the GladysPofer Zoo in Texas,USA aud will be retumedto the Philippinesfor re-intloduction (Iting, 1990).

288 6.0 Discussion 6.1 lz-rrh conserration ilr the Wild In the fiIst scenadonormal recruitnent of crocodilesinto the populationwill avemge1 - 3 crocodilesper clutch. The main risk for sucha caseis that in- country dsks i.e. war, poachingand habitatencrcachment can lhreaten a population.The benefitsare that there is biodiversity preservationand other speciesalso benefit.

6,2 Cotrservatiolcaptiye-breedilgforre-introduction This is doneto either supplementexisting populationsor for re-introducingirto areasfrom wherethey havebeen extirpated. In this casean averageclutch of eggscan yield 23 - 26 crocodilesfor re-stockingif good husbandrypractices ate 'fitness' followed. The main risk ftom this caseis the ofindividuals destitredfor release.When crocodiles are reared in captivity therc are many facto$ that catr makethem unsuitablefor releaseinto the wild. Theseconcems are acclimatizationat the releasesite, food locating skills, avoidanceofpredators, releaseofsingle size classescan lead to social di*uption alrd the possibilitiesof diseasespread (Soorae & StanleyPrice, In Prcss).

6.3 Farming for proFrtand coDservation In somecountries there is a tequirementfor commercialfarmers who collect eggsto rgtum a percentageofoffspring for retum to the wild. This numbercan vary between50lo - l8%, Ifthe individuals destinedfor releaseare ftom an older agegroup then fewer individuals needto be rctumedas their survival rate improveswith ageand size.

Thereis a hiddencost of raising individuals which arethen provided for release to wildlife authorities.This is a cost the cofiunercialfarmer hasto absorb.A concemis that the individuals prcvided for releasecan be runts or thosewith other prcblerns.The survival of such individuals in the wild can be very low and there is a high chanceof diseasetransfer to the wild population.

6,4 Speciespreservalion in zoos Crocodilesmaintained in zoos in a-srh locationsacts as an insurancefor wild populations.Ifthe speciesgoes extinct in its naturalrange there will still be individuals in captivity for a future re-introductionprograrn. The educational value is also very important for a zoo situation.The risks ate geneticdisorders 'filrless' and inbreedingwithin zoo stock and ofindividuats destinedfor release as discussedin the previoussection 6.2.

Thereis also the risk of individuals being releasedaccidentally or intentionally and forning a feral population. This is the casewith the introduction ofthe

289 commoncdmur (Cqituan crocodilus) il C:uba.Tt,€rc is also a dsk of hybridizationin captivity aswas the casewith Cubat crocodiles(Crocodylus rhombifer) urd Si,amesecrocodrle (Crocodylus stazrezsir) in Vieham (CSG, 1996).

7.0 Conclusion 1r?-Jituconseryation in the wild will havea relatively higher cost per adult crocodilebut this also hashigh potentialbenefits. Conseryation captive-breeding for re-intoduction has a lower cost per adult but also lower benefits.Farming for profit and conservationstill has a low€r cost per adult but belefits accrue p ncipally to fanll ouners. In an et-'t;t4 zoo there is a relatively high costpe! adult. This is mainly dueto very high opportunitycosts of land and rcsourcesir- an oveGeaser-.rita loaation.

Overall the different scenariosmay be usefirl to difelent sPeciesdepending on site and other circumstances.This papertries to outline someofthe costs,risks and benefitsthat may be involved underdiffer€nt scenaxios.

Acknowledgements We would like to thank EMIRATES airlinesfor providilg a discountedticket to enabletravel for the TechnicalProject Oflicer to aftendand present this posterat the 146Working Meeting of the CrocodileSpecialist Grcup in Singaporc.we would like to thank Dr. JamesPeran Ross,IUCN/SSC CrocodileSpecialist Groupfor providilg necessaryinformation pefiaining to qocodiles.

290 References

Chitd, C. 1987. The managemenrofcrocodiles in Zimbabwe14 Wildlife Management:Crocodiles and A.lligators.Ed. By GrahameJ. W. peter Webb, S. ChartieManolis and J. Whiiehead.Surrey Beatry and So[s. Pfy. Ltd. In associationwith the ConservationCommission ofthe Northem Territory. pp. 49-62.

Cott, pooley. H, B, & A,. C. 1972.Crocodiles: The status ofcrocodiles in Aftica. A papercontributed to the First Meeting of Crocodile Specialists. Sponsotedby the New york Zoological Societyand organizedby 'l the SSCComnission at the Brcnx Zoo. New york 15s _l 7s March 97I . YoI.(2\:73.

Crocodile SpecialistGroup (CSG). 1996.Status survey and conservationacrion plan: fevised action plan for crocodites1996. J. p. Ross(ed.) IUCN _ The World ConservarionUnion, Gland, Switzerland.Wortd iVlde Wel Edirion.

Hutchins, M., R. Wiese& K. Willis. 1996.Vy'hy we needcaptive breeding. AZA RegionalConference proceedings.

King, F. W. 1990.The conservationofcrocodilians: the releaseofcaptive-rcared specimens.Erdangered Species IIpDATE. Vol. g (1):48_51.

Whitaker,R. I 987. The Eranagementof crocodiliansin India !a Wildlife Management:Crocodiles and Alligators. Ed. By Gaharne J. W. peter Webb, S. Charlie Maaolis and J. V/hitehead.Surrey Beatty and Sons.Pty. Ltd. In associationwith the ConservationCommission ofthe Northem Telritory. pp. 63-72.

Soorae,P. S. & StanleyPrice, M. R. ln press.General Iat oductionto Re_ intoductions. Keynote speechpresented at the 146Working Meeting o the^CrocodileSpecialist Group Meeting held in Singapored-uring Jul-y 1998_

Soorae, P. S. 1995.Uganda. Crocodile Specialist Group Newsletter. Vol. 14(3):

291 Reintroductionof Aliieators and Other Crocodilians

as a ConservationTool

Ruth M. Elsey Larry McNease LouisianaDspartment of Wildlife and Fisheries GrandChenier. Louisiana 70643 USA

E, BarryMoser RebeccaG. Frederick LouisianaState UniveNity Deparhnertof ExpedmentalStatistics BatonRouse. Louisiana 70803 USA

Egg ranchingis a consewationtool allowing utilization ofa resourcewhich would otherwisebe lost to high natual mortality, ard hasproven very successfulin many crocodilian species.The LouisianaDeparhnent ofWildlife and Fishsriesregulates an experimentalalligator egg collection prcgram,which requiresthe rehrm ofa portion ofjuvenile alligato6 to ensue recruitinentand replacewhat would havebeen expected to sureivehad the eggsnot been harvested.An extensivetag aod releaseFograrn of fam-relgasedjuvenile alligatorswas evaluatedby analysisoflater harvestofrecaptued sub-adultand adult alligatorc. Results suggesthigh survival ratesoffam-released alligators. Factorsaffecting tag rccoveryrates aod obstaclesencountered itr the analysisof this preliminary dataare discussed.Areas for futule researchin this long-term study areoutlined. Ma[agementimplicatiols for alligator egg ranchingprograms are discussedas are considerationsapPlicable to other crocodilian species.

Prcceedingsof the 14uWorking Meeting ofthe Crocodile SpecialistGroup Singapore Iuly 14-17, 1998 SURVIVALINDICES FOR FARM-RELEASEDAMERICAN ALLIGATORSIN A FRESHWATERMARSH

Robert H. Chabreck,VemoD L. Wright, and Bray c. Addison, Jr.. School of Foresay, Wildlife, and Fishedes LouisiaDaState UDiversity Agricultural Center BatonRouge, LouisiaDa U.S.A. 70803

Abshact: Statisticalprocedures were usedto comparcsurvival indices ofjuvenite fann-raisedAmerican alligators (Alligator misJiJsDpr'ez.rDreleased into a fteshlvarer narsh in southeastemlruisiana to the survival indices ofjuvedle wild alligators in the samearea. Indices comparedwere live capurrerates, malk-recapfirre,recovery of tags ftom stonachs of pledator alligators, and lecovery of taggedalligators on baited hooks. Live captureof farm aqd wild alligators on 111 dghtty captureeffolts indicatedDo difference in the captureper effort of wild alligators from 1991to 1992but the caDrure per effort declined 65% amongfarm alligators dudng that time. Mark-recapturedata itrdicatedthat the recapturerate of taggedwild alligators (O.48%l wasjg% greatertharL the recapnrrerate of falm ^lligatarc (0,27%). We examined612 stomachsof wild adult alligators harvestedftom 1992 tbrough 1995 ad tecoveredtags ftom 42 of 1352 marked farm alligators (3.40%) and ftom 7 of 1106 wild alligarors (0.63%) taggedand releasedin 1992. The recovery rate of taggedwild alligators releasedin Lggl afi.lgg2 and capturedwith baitedhooks during Septemberharvest programs from 1991 to 1996 was 28 times greater than the recovery late of farm alligators.

INTRODUCTION Alligato! egg collectionsfrom the wild on pdvate lands was permitted by a plogam initiated in Iruisiana dudng 1986. The Dumberof eggscollected eachyear has remainedfairly stablesince 1989, nd m 1996,2j9,237 eggswere collected and 233,0'16yovng,r,f'e hatched(Elsey 1997). In oder to maintain witd populationsin areaswith egg collection programs, stateregulations initially required that a portion of all alligators hatchedin captivity ftom wild producedeggs (ranched) be returnedto the wild when they reached1.2 m total leugrh (IL), which was at approximately20 months of age. This percentagewas derived from the proportion of wild hatchlings surviviug to 1.2 m TL (Taylor and Neal 1984). In 1992, a sliding scalewas deveioped that allowed for retum of alligatoN from 0.9-1.5 m TL with the returDrate basedon the proportion surviying at those sizesas reportedby Taylor alld Neal O9g4) and extrapolatedfor sizesbetween 0.9 m and 1,5 m. h 1996,40,919farm-nised (ranched) alligato$ producedftom wildrollected eggswere leleasedin Iruisiana (Elsey 1997). The releaseptoglam was basedon the assumptionthat survival of farm-raised (farm) alligators doesnot differ from the survival of wild alligatorsof similar size. This assumptionmust be testedto evaluatethe long-teml impact of lruisiaDa's egg collectiotr progmm on wild populations. Under the curent managementprogram, farm alligaton are releasedin many wetlandhabitats of Louisiana, and farm-released alligators may eventuallyconstitute a substantialportion of the wild a igator population in Dany areas. The objective of this study was to comparcindices of survival of farm alligators releasedin a fteshwatermarsh to thoseof wild alligators occupyingthe rcleasesi!e. The study was funded by the LouisianaAgricultwal Expeliment Statior, Louisiana SeaGrant College hogram, The GheensFouDdation Inc., Louisiana DeparhEnt of Wildlife and Fisheries,The Louisiara I-and and Exploration Company, Williaos Inc., McllheDtry Company,Avery Island Inc., E. A. McllhenDy Enterprises Inc., aDdSweet hke Land and Oil CompanyInc. We are grateful fo! their conaibution to the study. The assistanceof B. Crain, C. Chanc€,H. Robichauxof Golden RanchPlantation, R. Mo€rde of Golden RanchHunting Farm, and studentsat Iruisiana StateUniversity and Nichols SrateUniversity is gleatly appreciated.

METHODS

The study was conductedin LaFourcheParish, Louisiana, on the 20,235-ha Golden RanchPlantation (GRP) located approximately33 l(ln southwestof Nelv Orleans. A 4,203-ha iqtensivesirdy arca was locatedon the northwestemportion of GRP. The study areawas locatedin freshwatermarsh and consistedof approximately 50% openponds and 50% marsh. Pond depthsranged from 30-90 cm. The intensive study areacontained 23 hl of canalsthat were approximately3 m deepand 15 m wide, and approxtnately 25 lm of ditchesabout I m deepand 2 m wide. We compaledcapture rates of farm and wild alligators, recapturerates of taggedfarm and wild alligators, recovery mtes of tagsof caDnibalizedfarm and wild alligators ftom stomacbsof predato! alligators takeoduring harvests,aDd recovery mtes of taggedfarm and wild alligators capturedwith baited hooks during harvests. From May 1991 - August 1992,2,166 'ttild aLligatolsranging in length from 0.92-1.52 m TL were captured,measured, tagged, and releasedin the inteosive study area with 111 nightly captule efforts. Each alligator was markedwith two like- numberedmonel web tags that were approximately10 mm long and 2 mm wide. One tag was attachedto the webbing of a hind foot, and one was attrachedto the webbing of a fiont foot. Alligators werc locatedfor captue by slowly tmveliog through the area at night in an air boat and shining with a Q-beamlight. Alligators wele captued by the hand-grabmethod (Chabreck1963), and total leDgthwas measuredalong the animal's dorsal surface. Farm alligators releasedinto the wild as part of the egg collection prog&lm were sexed, taggedand measuledby personuelof the I-ouisianaDepartDrent of Wildlife and Fisheriesprior to release. Farm alligators were taggedsimilar to the wild alllgarors exceptthat in 1991 farm alligators had ody I monel tag, and it was attachedto the webbing of a hind foot. From 1991to 1994, 6,065 farm a igators were rcleasedon GRP. Tag nurnberswere lecorded from all alligators recapturedduing night capure sessions,alld the alligators were sexed,weighed, measured,and released. During nightly captureefforts in 1991 and 1992, innature farm and wild alligators were capturedat randomthroughout the intensive study area. The goups were recognizedby the presenceof web tags, and the number capturedper nightly effort in 1991 and 1992 was assumedto be Foportional to the numberpresent in each goup (Davis and Winstead 1980). We testedthe nult hypothesisthat the amual capture rale of farm alligators from 1991 to 1992 did not differ from the amual capturerate of wild alligator ftom 1991 to 1992. The recapturerate of taggedfarm and wild alligators dudng nightly capture efforts in 1991 and 1992provided data on survival of eachgroup. Data were not included for farm or wild alligators until 100 or more taggedanimals were availablefor recaptureq.ithin each group. Available recaptues wete defined as alligators that were released3 or more weels prior to recapture.The yarianceused was that found amoDg the proportions from different recaptue dates.The model usedfor this analysiswas similar to the Brownie-Robsonestirutor (Btownie et al. 1985) and assumesthat the survival rates and probability of being recapturedaDy given night was the samefor farm and wild alligators. If the recaptue rates were different, then we assumedthat everything but the survival rates were the sameand concludedthat the difference was attributed to differential zurvival betweengroups. AII index to survival of farm alligators was developedftom data on recovery of falln alligator web tags ftom stomachsof wild adult alligatols capturedduring au aruual Septemberharvest program. Adult alligators were harvestedthroughout GRp where farm alligators were releasedaDd were captuledby trappe$ usiDgbaited hooks. All harvestedalligators were markedwith a numberedtag; and after eachanillnl was skfuned,stomachs were removedfrom alligatoN >2.2 m TL, atrd the contenB were visually inspectedfot web tags. Stomachcontents wete then radiographedwith standardx-ray equipmeDtto locatetags not found dudng visual inspections. We assumedthat the numberof trumtur€ farm and wild alligatols cannibalized by larger alligators was proportioDalto the numberof farm alligators presed and that the number of web tags presentin stomachswas proportioDalto the number of farm alligators camibalized during the year. Most web tags are eventua[y expe[ed from the stomachof an alligator by regugitation (Chabreck1996); however, we assumedthat tags from farfi and wild alligators \rere expelledat equal lates. We comparedthe plopodion of taggedfarm and wild alligators cannibalizedby compa ng the number of tags recoveredfrom juvenile farm and wild alligatols ragged and rcleasedin 1992 and re4overedfrom predatoralligato! stomachfrom 1992-1995. Data from farm alligators releasedin 1991 were not usedin this analysisbecause only one web tag was attachedto eachanimal. We useda 2 x 2 contingencytable to test the null hypothesistbat the proportion of farm alligator tags recovereddid not differ from the proportion of wild alligator tags recovered. The capturerate of taggedfarm and wild alligators with baited hooks during the Septemberalligator harvestprogram was comparedas an index of survival, The number of taggedwild and falm alligators capturedin eachyear classwas assumedto be proportioral to the rumber of alligatorspresent in the year class.Because wild alligators were only taggedand releasedin l99l ar:d 1992, only farm alligators released h 1991 and 1992 were includedil the test. The captureof alligato$ with baited hooks is usually selectiveto larger alligatols becauseof the height that baits are suspended abovethe water aDdhook size (Nichols et al. 1976). Therefore, most taggedfarm- releasedand wild alligatorsused in this study requAedsevenl yearsof gro$'th before reaching a halvestablesize. Alligatols capturedwith baited hooks werc evaluatedfrom 199l-1996, and oDly capturedalligators that coDtainedweb tags for positive identification were included in the analysis.A 2 x 2 contingencyrable was usedto test the mrll h'?othesis that the propotion of taggedfarm alligatofi capturedwith baited hooks dudng the Septemberharvest program did not differ from the proportion of taggedwild alligators captuled.

RESULTS

Tag -Recaptu re Du ng 62 nighdy captureefforts in 1991, we captu{ed138 farm alligatorc and 1104 wild alligaton (Table 1). During 49 captue efforts in 1992, we captured35 farm alligato$ and 1094 wild alligators. The numberof wild alligato$ capturedper nighdy effort in 1992 (x : 22.7) did not differ (r = 0.503,6 df, P = 0.3164)from rhe number of wild alligatols capMed in L991(x = 2n.), However, the number of farm alligators captuled per nighdy effort in 199 (x =0.8) was 65% lessthan (t : -3.566, 6 df, P = 0.0O59)the numberof farm alligato$ capf,red in 1991 (x = 2.3). A 2 x 2 contingencytable usedto comparethe number of farm aod wild alligatorscaptued in I99l ^nd 1992indicated differeDces between Sroups (t'z = 56.11. 1 df, P< 0.00O1;Table 2). The trull hypothesisthat farm alligators were capturedin the sameproportions in 1991and 1992 as were wild alligators was rejected. The recapnuelare was greater(t = 6.84, 161 df, P < 0.01) for wild alligators (0.0048) than for farm alligators (0.0027; Table 3). Sufficient numbersof wild alligators were marked so as to have 100 availablefor recaptureon 97 Dights, and 100 or more farm alligators were availablefor recaptue on 66 nights. A total of 397 wild and 46 farm alligators were recaptued and the nunb€r of recapturesper tagged alligator was'18% $eater for wild alligators than for farm alligators. We assumedthat the capalle of both $oups was proportional to their abundanceand that dispe$al rates were not differeDt. :296 Table 1. Number ofjuvenile farm and wild alligatorscaptured per 4ightly captue eflof during montlrly and bimonthly periodsin 1991and 1992, GoldeoR ll"h pl-tut,or, . Louisiana.

Dale No- of No. ofalligato$ captured efforts Farm" Total

1991 M;iine 27 1.7 36r 13.4 407 July 19 58 3.1 357 18.8 41s August 9 t6 1.8 r99 22.1 215 Sep-Oct 7 18 1.87 29.3 20s Total 138 1104 1)4)

1992 March-Apdl 5 4 0.8 109 21.8 I 13 May 9 u t.2 212 23.6 223 June I4 9 0.6 360 25.'7 369 July-Aug 2l 11 0.5 413 19.7 424 Total 49 35 1094 ll29

" lncludes only farE alligatorsreleased in April 1991 .

Table 2. A 2, contingencytable comparingthe proportions"ofjuvenile farmb and wild alligatorsiive-capturcd in 1991and 1992on the intersive shrdy area, Golden RanchPlantation , Louisiana.

Year No. of alligatorscaptured captued Farm Wild Total

1991 138 1104 1242 t992 35 1094 1129

Total t73 2r98 237|

f :56.11,l df,P<0.001. Includesonly alligators€le3sed in Apil i 99I 291 Stomach Analysis Ige examined612 stomacbsof alligato$ >2.2 m TL that were capturedduring the Seplemberbarvest from 1992-1995(Table 4). Tags from 46 ot 1352 (3.40%) tar,r. alligators releasedin 1992 and 7 of 1106 (0.63%) wild alligators taggedand releasedin 1992 were recoveredftom the stonachs. The proportion of farrl alligator tags in the stomachswas 5.4 time greater tllan the proportion of wild alligator tags; thetefore, we rejectedthe rull hlpothesis. The proportion of tags of falm alligatorc basedon tags recoveredfrom stomachs ftom the 1991and 1992harvess in the htensive study areawas comparedto that on the remainderof GRP. We found no differenc€beiween the two areas(t' = 0.486 and 0.231,df = 1, P = 0.486and 0.631) duling 1991^rf, 1992,respectively, which indicatesthat the predationrates of farm alligators on GRP did not differ betweenthe iDt€nsivestudy areaand the remainderof GRP. This allowed direct comparisons betwe€npredation mtes of farm alligators ard wild alligato$, even though wild alligators were taggedonly on a portion of GRP and fann alligators were released acrossthe entire area. Baited Hooks The harvest rates of taggedfarm and wild alligato$ captued with bairedhooks indicatedthat the proportion of farm alligators capturedwas considerablyless than the propofiion of taggedwild alligators captured(Table 5). Thereforc, we rejectedthe null hlpothesis and concludedthat a differenceexisted b€tween farfr aDdwild alligators. The proportion of taggedwild alligators captued with baited hooks (0.0212) was 28 times greaterthan the proportion of farm alligators captued (0.0008). DrscussloN Tag recovery atrdrecapi[e rates are an indication of survival rates (Brownie et al. 1985). The methodsused to compareindices of survival ratesbetween farm and wild alligators were methodsthat provided estimateswith a minimum amount of bias. The methodsindicated that recapffe rates of farm alligators ruged from 65-78% less than the recapfirrerates of wild alligators. The recovery of tags from stomachs irdicated that the Foportion of wild alligators cannibalizedwas 81% less than rhe proportion of farm alligators camibalized. The recovery rate of farm alligators capturedwith baited hooks was 96% less than the recovery late of taggedwild alligaton captuled with baited hool6. Cannibalismwas a greate! causeof moriality amoogjuvenile farm-leleased alligators than juvenile wild alligato$, as indicatedby the rc€overy rates of tags from stomachof adult alligato$. Farm alligators apparentlylacked the experiencenecessary to avoid predatorsaod, thus, had a lower survival rate than wild alligatoG. Simila! results havebeen reportedwith othel specieswhen captive-laisedanimals were released into the wild. Bmkhage(1953) found that four speciesof captive-raisedwaterfowl had higher mortality rates when releasedinto the wild than wild birds. Soutiere(1989) Table 3. Recapturerates oftaggedjuvenile farm-releasedand wild alligatoN in 1991and 1992, GoldenRanch plantation . Louisiana.

Farm w d

Nights" 66 9'7 Number of recaptues 46 39'7 Recaptues/tagged 0.002'l 0.0048 alligator SE 0.00047 0.00039 Mean difference 0.0020 SE diference 0_0038 Mlue 6.48(161d0 Probability <0.0001

' Includesonly capturenights with > 100tagged alligators at risk and alligato$ captued with > 21 dayssince thelast capt[e .

Table 4. Number oftags ofjuvenile farm andwild alligatorsthat were taggedand reieasedin 1992and recoveredftom 612 stomachsofha.rvested adult alligatois tom 1992to 1995,Golden Ranch Plantation- Louisiana-

FARM w.TTD No. taqsedard released: 1352 1106 Year recovered No. Stomachsexamined Number recovered 1992 105 17 1 1993 t51 18 2 1994 184 63 1995 t66 5l TOTAI 6t2 467 Recoveryrate 3.40% 0.63yo x 22.09 P

299 fouudthat whenhand-reared mallards (,4tas p latyrlrynhcos)vterc rcleased, survival rateswere lower aDdDon-hutrting mortality rates were higher tban for wild mallards. Theyalso stated that game-farmmallards apparently have little poientialfor restoring breedingpopulatioDs because they survivepoorly in the wild. Kruegeret al. (1986) reportedthat the rate of returnto spawningreefs by hatchery-raisedlake ftout (SalvehnusnansJcush) was significandy lower thanthat for nativetout. Theyalso notedthat predationby otherfrshes can limit the successof aDadromousfish stocking progruns.

Table5. Numberofjuvenile farm and\trild alligatorstagged and rele3sed in 1991and 1992and captured with bailedhooks ftom 1991-1996,Golden Ranch Plantation, Iruisiana.

1991Releases 1992Releases Farm Wild Farm Wild No- tassedand rcleased 1243 1111 1352 1106 YearcaDnrred -----Number caDtured------1991 0 1 aa t992 0 2 03 1993 1 6 03 t994 o o 19950803 1996 0 5 TOTAL 1, 28 119 Capturerate 0.O8% 2.52Va O.O7Vo 1.71% r( 29.61 20.63 P <0.001 < 0.001

Other studieshave indicatedwide variation in survival ratesof wild alligators. Nichols et at. (1976) estimatedthat the averageanDual survival rate rvas78.8% for wild alligators in ihe 1.2-1.5-m TL size classin southwestemLouisiana based oD size class distribution. Taylor and Neal (1984)used a size classftequency distributiotr and found t]Flt 59,2% of the wild alligators of the 1.2-m TL size class survive to the 1.5-m TL size class. Dietz (1979) fouDdthat 14% ofa sampleof lake alligato$ survived thrcugh two years in Florida. woodward et al. (1987) estimated2-year survival ofjuvenile wild alligato$ in OraDgel,ake, Flodda to be 8%. The wide range of estimatesof survival rates is attdbutablein part to the diffelencesbetweeD years and areasand also reflect biasesdue to different techniques.The purposeof our study was not to determinethe survival ntes of farm-releasedor wild alligato$ but to comparesurvival indices of farm and wild alligators occupyiDgtle samerelease site. Becauseof the wide vaiation in survival ratesamong areas, data on recovery Iates of farm-released alligators are meaninglesswithout simila! data on their wild counterparts. Addison (1993) usedradio klemetry to comparesurvival rates of furm aud wild alligators on GRP and found no differencebetween the two gtoups. Survival rates of alligaton with radio collars were in contrastwith data from the recaptureof tagged alligators and the recovery of tags ftom stomachstaken in the harvest. Addison stated that his samplesize was not sufncieDtto detectdifferences that rnay have occurred b€tweenfarm and wild alligatols with radio-colla$. Although, wild alligatols normally were mole expe encedthan farrtr alligators in avoidiug predators,the external radio- collars apparendyreduced the ability of wild alligators to avoid predation, as suggested by Rossand McCormick (1981) for fish. Bossert(1993) statedthat extemal radio_ collars may adve$ely affect the behavior of alligators and make the animalsless hydrodynamic, thereby reducingtheir speedof swinming and movementthough vegetationand floarirg rna$h. We believe the difference in rccaptue and recovery lates betweenfarm aud wild alligators reflects differential survival betweenthe two groups. Other possiblecauses of differential recaptureand recovery ntes are differential dispersalatrd differential catchabilify. Telemetry data indicatedno differcoce in movementrate or dispersal betwe€nfarm and wild alligators (Addison 1993); therefore, differential disDersalwas not lesponsiblefor differential recapturemtes. We found that farm alljqators were easierto captue than wild alligators and would often remain motionlesJwhen approachedand makeno effort to resist capture. This increas€dthe proportion of farm alligators captureda'ld suggeststhat olu recapturcrate for farm alligators may be slighdy inflated, which would indicatean even lower relative survival rate than calculatedfor farm alligators. The releaseof farm-raisedor hand-rearedanimals to supplementlvild populationshas beenattempted with many speciesof frsh, birds, and maDrnalsand to a lesserextent with reptiles (Dodd and Seigel 191). Survival of the farm-released animals was generally less than survival of trativewild animalsin the releasearea. Little infornution is availableon survival of farm-raisedqocodilians releasedinto the rvild. Someearly observations(Chabreck 1971, Smilh and Webb lggt indicated survival rates similar to thoseof wild crocodiliansoccupying the site while Blake aDd I-oveddge (1975) reportedvery low survival amongfarm-released hatchlings of Nile cr@,odtles(Crocodylus niloticus\. Pooley (1973) statedthat crocodile hatcl ings should be releasedin permarcntly flooded wetlandswith denseemerge vegetation. He recommelldedthat areaswith a high populationof adult crocodilesbe avoided for releaseof hatcblings. Jenningset al. (1988) evaluatedchanges in alligator population stucture associatedwith remoyal of 50% of the annualproduction of alligator hatclfings and eggs ftom lakes Jessupand Griffin in Florida ftom 1981-1986. No harvestsof la.rger alligators were conductedon the lakes nor faro alligators releaseddudng tbat tkne. On kke Jessup,increases were foutrd in the >0.6 m size class; but on Irke Grifdn ancla 301 conffol lake with no collections, alligator populationsrernained fafuly stabledu ng the study. Rice (1996) continuedthe study reportedby Jenningset al. (1988) and removed 50 % of the eggsproduced on lakesJessup and Gritrin ftom 1987-1991. Also, no large alligato$ were harvestedand no farm alligatorswere released. fuce notedthat the 0.3-1.2m sizeclass increased on Iake Jessupby 24%, orLlake G'jffrn by 31%, but on the control lake by 190% during his study. Rice also did a 2o-year simulation model of the alligato! population on kke Orangeand test€dthe population responseto armual eggharvests of0,25,and50%; adultalligator harvest (> 1.2 m TL) of 0, 5, 10, and 15%; and eachcombination of both egg and adult alligator harvest with no releaseof farm alligators. The model indicatedthat the alligator populationcould be best mainlainedwith not mole than a combined5 % ^dllt ufr 25% egg harvest. The 50 % egg-oDlyand 10% adult-only harvestsalso maintainedstable populations. The maximum harvestntes of eggsand adult alligators that will allow an alligator populatiotrto remain stablewill dependlargely on the degreeto which compensatory mechanismsfunctioD in the population (Jenningset al. 1988). Smith and Webb (1985) developeda simulationmodel of a Crocodylw johnstoni populatioDand concludd, that 30% of tfu C. johnttoni eg$scould be removedeach year atrdthe populationwould Dotbe gready affectedevetr if farm-laised crocodiles were not returnd to the wild. Smith and Webb (1985) also calculatedthat if 90% of the eggswerc removedeach year fo! 10 years, the c. Jbrtutoni population would only decline 50%, However, the egg collection program evaluatedwas without an added hawest of subadultand adult qocodile$. Elsey (1998) reportedthat less tban 207. of the availablealligator eggs statewideio lruisiaDa are collectedby ranchelseach year. Also, the harvestof subadultand adult alligators is regulatedto remo\e orly 4% of the population amually (N.KiDler, 1998; pers. comm.) The l-ouisiana alligator and egg harvestprograms have b€eDin effect fo! 10 years and the alligator populatioohas remainedrelatively stable. However, the releaseof farm-raisedalligators hasbeen a part of the egg collection program since its onsetbut ofunknown yalue to the program. The harvestrates of alligators and eggsin IruisiarD are within the llln,its (5% zfr 25%, respectively) recommendedby the Rice (1996) model for maintaininga stablealligator poputation. However, the leleaseof farm-laised alligalols is not hcluded as a part of the Rice (1996)model. Becauseof low survival rales, the releaseof farm-raisedalligato$ contdbute very little to th€ maintenanceof the GRP alligator population. The collectioDrate of alligator eggson GRP is well abovethe statewideaverage and eggsare collectedfiom all neststhat can be locatedwith a searchby helicopte! and airboars.Many alligator rcsts on GRP obviously go undetectedor are blTassedand thus provided hatchlingsto maintain the population. Also, in someadjacent areas eggs are not collected, and alligator movementftom theseareas may supplemeotthe alligator population on GRP. Because of the low survival rale of farm-releasedalligato$ as indicatedby thts study, adjustments to the egg collection late or adult harvestrate should be comidered, if declinesare noted in the Louisianaalligator populationi4 the futue.

LITERATURECITED Addisor, B. G., Jr. 1993. Surviyal and movementof farm_raisedalligators releasedin a freshwatermarsh itr southeastenLouisiana. M.S. Thesis, t:ulria* st"t" Uuiv., Baton Rouge. 79pp.

Bossert, D.C. 1993. Comparisonof growth .ates of inmature farm_raisedallisators releasedinto the witd and irlmature witd alligaton. M.S. Thesis, Louiiiana StateUniv., Baton Rouge.61pp. Brakhage, G. K. 1953. Migration and mofialify of duckshand_reared and wild-rmppedat Delta,Manitoba. J. Wildl. Malage. 17.46547:-. p. Brownie,C., D. R. Anderson,K. Bumham,and D. S. Robson. 19g5. Statistical inferencefrom band recovery data - a handbook. U. S. Fish and Wilcll. Serv. ResourcePubl. 156. Washington,D.C. 217pp. Chabreak,R. H. 1963. Methodsof captuting, markhg, and sexing alligators. proc. Annu. Conf. Southeast.Assoc. Gameand Fish Conun. 1i.47_5O. Chabreck, R. H. 1971. Mamgementof the American alligator. Crocodiles, IUCN SupplementaryPaper No. 32. Morges.I:I37-144. Chabreck, R. H. 1996. Regugitation of rhe Ame can alligator. Herpetological Review27:185-186. Chabreck,R. H., V. L. Wright, B. G. Addison,Jr., andD. C. Bossert. 1996. Retentiotrrates of metal tags in sromachsof American alligato$. pD- 437440. I4: Crocodiles. Proceedingsof the l3s working meetingof the Crocodile SpecialistGroup, ruCN, The Wotld ConservationUnion, Gland, Swi rland. Davis, D.E. and R.L. Wi$tead. 1980. Estimatingthe numbersof wildlife populatioDs.pp.221-U5.l^ S. D. Schemnitz(ed). Wildtife Manasemenr TecbniquesManual 46 edition.Tbe Wildtife Sociery,WashingtonlD.C. Dietz, D. C. 1979. Behavioralecology of young American alligators. Ph.D.Dissertation, University of Florida, Gainesville,Fla. l52pp. Dodd, C. K., and R. A. Seigel. 1991. Relocation,repatriation, and traDslocationof amphibiansard reptiles: are they conservationstrategies tlat work? Herpetologica47:336-350. Elsey, R. M. 1997. Iruisiam Departmenrof Wildlife and FisheriesReDorr. I-ouisianaAlligator Farmersand RanchersAssociation. Baton Rouge. 6 pp. Elsey, R.M- 1998. Deputy Vice Chairman, North America, Crocodile Speciatist 303 Group. g-etter to Bob Chabreck,Louisiana State Univenity, Baton Rouge). March 24. Jennings,M. L., H. F. Percival,and A. R. Woodward. 1988. Evaluationof alligato! hatchling and egg removal Ilom three Rolida lakes. hoc. Aruu. Corf. SoutheastAssoc. Fish and Wildl. Agerc\es 421283-294. Krueger,C. C., B. L. SwaDson,and J. H. Selgeby.1986. Evaluationof hatchery-rearedlake trout for leestablishmentof populationsin the Apostle Islandsregion of I-ake Superior, 1960-84. Pages93-i07 !4 R. H. stroud, ed. Fish culture in fisheriesmanagemed. Ame can Fishe es Society. Bethesda, Maryland. Nichols,J. D., D. L. vieman, R. H. Chableck,and B. Fendenon. 1976. Simulatiotr ofa commercially harvestedalligator populationin lruisiana. Iruisiana State university Agric. Exp. Station Bull. 691. BatonRouge, I2. 59pp. Pollock.K. H.. S. R. Winterstein,C. M. Bunck,and P. D. Cutis. 1989. Survival amtysis in telemerry studies: the staggeredentry design. J. Wildl. Manage. 53:7-14. Rice, K. G. 1996. Dynamics of exploitation on the American alligator: environrnental contaminantsand harvest. Ph.D. Dissertation,University of Florida, Gainesville,Fla. 163pp. Ross, M.J. aod J.H. Mccormick. 1981. Effects of externalladio traosmitterson fish. Prog. Fish Cult. 43:67-72. Smith, A. M., aod G. J. Webb. 1985. Crocodylusiohnsroni in the MckiDlay River area, N. T. VII*. A populationsimulation model. Aust. wildl. Res. 12|54r-554. Soutiere,E. C. 1989. Survival rates of hand-rearedmallards released on 2 private farmsin Maryland. J. Wildl. Maruge.53;114-118. Taytor, G., and W. Neal. 1984. Managementimplications of size-classirequency distributioDsin l,ouisiana alligator populatioDs. Wild. Soc. Bull. l2:3L2-315. Woodward,A. R., T. C. Hines,C. L. Abercrombie,add J. D. Nichols. 1987. Survival of young American alligators on a Flodda lake. J. Wildl. Manage. 51:931-947.

3{X MOVEMENT OF JWENILE FARM-RELEASED AND WILD AMERICAN ALLIGATORS IN A TRESHWATER MARSH IN LOUISIANA

BrayG. Addison,Jr. RobertH. Chabreck VemonL. Wright

Schoolof Forestry,Wildlife, and Fishe es LouisianaState University Agricultual Center BatonRouge, Louisiana 70g03 USA

ABSTRACT

Movementsofjuveniie farm-mised alligators (Allisator mississippiensis) released into a freshwatermarsh in southeastemLouisiana in t991 and t giweiimpared to movementsofjuvenile wild alligatorsin the area.Radio telemetry data indicated no differencebetween the juvenile groupsin movementrates, dispeNal rates. or home ranges.Pooled data indicated that movement rates in thesum;er l99l season(661 m) weregreater thar duringthe winter 1991-92 (364 m) andsummer 1992 (3g9 m). Radio telemetrydata also indicatedthat 75 of78 farm-raisedand 43 and 44 wild alliearors monitoredfor dispersalmovements, dispersed <5 km duringrhe study. Mean iome rangesfor both groupswete

INTRODUCTION An alligatoregg collection prcgram was initiated in Louisianain lggg thal allowed commericalegg collectionform the wild by p.ivate landowlers. The eggswere artifically incubatedto pioduce alligator hatchlingsfor rearing on farms.The piogram wasgradually expanded and as many as 293,000 eggs were collected in oneyiar (J. Tarver, LDWI, pers. commun.).In orderto maintainwild populationsin areis where eggswer^e collected, farmers were required to releaseinto thewild 17%ofall alligators halchedfrom collectedeggs when the alligatorsreached 1.22 m total length (TL) (approximately20 monthsold). The l7oloreleased rate was an estimateofthe number of hatchlingsthat normally survive in thewild to reachl.22m TL Q.,licholset al. 1976, Taylorand Neal 1984).Regulations were later revised to allow therelease of fam_raised alligatorsbetween 0.91 and 1.52 m TL andthe release rate to fluctuatebased on thesize of fie releasedalligators. The teleaseprogram was basedon the assumptionthat the movementand survival offarm-releasedalligators did not differ fiom rhatof wild alligatorsof similarsize. This assumptionwas not tested,and no studieswere conductedto evaluatethe movementof farm-raisedalligators after their rgleaseinto the wild. A betterunderstandine of movementoffarn-released alligators is neededto evaluarethe effectof Louisiana'segg collectionprogram on wild populations.Regulations on alligatoregg collections also requirethat fam-raised alligators be releasein thevicinity ofthe oiginal eggcollection site. Wild alligatorsrcleased into unfamiliar teritory show a tendencyto move 305 considembledistances from therelease site (Chabreck 1965); therefore, it is importantto know iffarm alligatorsreleased near an eggcollection site will remainin the vicinity of the site. Theobjective ofthis studywas to determineand compare the movement rates, dispersaldistances, aad home ranges ofjuveniie farm-raised alligators relgased in a freshwaterma$h to thoseofjuvenile wild alligatorsoccupying the release site. The study was fundedby the Louisiam Agricultural ExpedmentStation, LouisianaSea Grant College Program, The Gheens Foundation Inc., Louisiana Deparhrenl of Wildlife and Fisheries,The LouisianaLand and ExplorationCompany, WilliamsInc., Mcllherny Company,Avery lslandInc., E.A. McllhennyEnterpdses Inc., and SweetLake Land and Oil CompanyInc. We are graleful for their contribution to the study.The assistance ofB. Crain,C. Chance,H. RobichauxofGolden Ranch Plantation, R. Moertle of GoldenRanch Hunting Farm,and studentsat Louisiara StateUniversity alld Nichols StateUniversity is greatlyapprcciated.

METIIODS Desciiptionof StudYArea Thestudy was conducted in LaFoucheParish, Louisiana, on the20,235-ha Goldeo RanchPlantation (GRP) localedapproximately 33 km southwestof New Orleans.A 4,203-haintensive study arca was locatedon the northwestemportion of GRP. The study areawas locatedin Aeshwatermarsh and consisted of approximately 50oZopen ponds and 50% marsh. Pond depths ranged ftom 30-90cm Theintensive study areacontained 23 km of canalsthat were approximately3 m deepand 15 m wide, and approxirnately25 km ofditches about 1 m deepand 2 m wide

Radio Telemetrv Onehundred radio collars were purchasedfrom Lotek Engineering,Auron, Ontario, Canada.Transmitters were hermetically sealed and weight was approximately 225 gmmsor about5olo ofthe weightofan alligator1.22 m TL. Eachttansmitter operated oo a fixed ftequencybetween 150.00 and 151.99Mhz (frequencieswere separaled b) approximately10 Khz). Mortality sensonwere activaled ifthe tansmitter was not moved during a continuous24-hour period, and causedthe signal pulseto increaseAom 55-60beats per minute to 100-I 10beats per minute. Each &ansmitter and antenna was attachedto an adjustableleather collar placedaround the alligator's neck. The radio hung beneaththe alligator's neck, andthe arterulawas lacedthrough the collar and emerged abovethe dorsal suface ofthe neck. Thereceiving systems consisted ofthree Telonics model TR-2 receivers; three nlrll-peak arraysconsisting of two 7-€lementyagi antemas(Wildlife Matedals, Carbondale,Illinois), and one 3-element collapsible, hand held yagi aotenna(Wildlife Materials). The three null-peak anayswere locatedat 4 sites(one tower was switchedlo an altematelocation fiom NovemberI 99I -FebruaryI 992) along canalsand ditchesin the study area.The tbreepdmary siteswere locatedusing the meanLORAN-C location obtainedfrom individual LORAN-C readingsthroughout the study Standarddeviation of LORAN readingsfor towerlocations was estimated by comparingthe individual readings obrainedrhroughout lhe study ro lhemean ofthose readings 306 E3charr.af was ^ .. mounredatop a 6-mtelescoping mast. Each antenia was orienled ror orrcctlonuslng a decltnatedstaff compass, aod a 360_degreecompass rose. The array was usedin thepeak mode to find thegeoeral direction ofG signalana ttre iennea oearngwas detefiIllned usrng rhe nu]l oprion.The hand_held arrenna was used predominately from ao airboatfor homing to rccover collars and to obtain bearingsused in triangulatiol. Direction to peaksignals was measuredusinga hanafraa ^"m"ti" compass. A testtalsmitter wasplaced at a locatjonnear rhe center of the studya!ea. l.hree lndependentmeasureme s ofthe bearingftom eachanrema siLe to theiesr nansminer wele obtainedwith a staffcompass.We trcatedthe meansofthese bearingsas the true bearingsto the transmitterand estiEBtedthe bias associatedwith eachto;r bv subtractingthe meanofthe obsewalionsfrom the tue beari]lg. Standarddeviaiion of telemetrybeadtgs was estimatedby comparingthe individual beadngsto the meal! of thosebearings using the genenl formula:

Bias rangedfrom 0.6-2.60 for the four tower-locationcombinations, and standard deviationranged from l.0l-2.78'. Thesefactors may have affectedthe accuacy of locationsof farm-nised and wild alligatols, but did not a.ffectour ability to detecta differencein movernentsbetween groups. Frcquency ofdistance movedwas plotted in 10-mincrements. The most ftequently observed distance represenred locations obtained in the winter on animalsthat had movedvery liule or not at all, and was a good indicator of theprecision of the system.The rrost ftequentlyobse ed movementw; g0 m, and this was usedas an estimateof systeo erlor. Farm-raisedalligators (1.19-1.48 m TL) ftom a groupscheduied for releaseon GRP were fitted with radio collars ard released26 Juiy 199i. Wild ailisalols of approximatelythe samesize (1.07-1.37 m TL) werecaprured in the viciiity ofthe release site between26 July and 5 August 1991,fitted with radio collars, and released.Alligators weretaced weekly and locatioDsdeternined usingtriaDgu.lation. Whelt or y two bearingswere measuredon the sametralsDittei, iltersection was usedto deterornethe location (White and Garot 1986).When a signal could only be detectedfrom a strgie fxed array, we usedhoming to get within 25 Itr ofthe tlansmitter alld recorded1he aaimal's location as the latitude and loDgitudevalues provided by a hand-heldLORAN C receiver(PL-99 Ray Jefferson,Phiiadelphia).

Data Atralvsis Only datafrom alligatorswith sufficient locationsin a season(:5 for summer 1991,July-Septembe4 and slrmner 1992, Aprii-Augusq ard:15 for winter 1991_92, October-March)were usedto comparemovements for farm-releasedand wild alligafors. Differencesbetween farm-released ald wild ailigators(g!oups) werc comparedusitg the variability betweenalligatols as the elror term. Diflerencesbetween seasons and the seasonby groupsintenction werc testedwith ANOVA usidg the variation among aljmais within seasonsand groups(General Linear Model procedure,SAS Institute, Inc. 1989).

301 RESULTS Standarddeviation ofLoran readingsfor towerlocations was 31.5 m East-West by 35.9m North-South.We assumedthat elrorc associated with locationsobtained ftom mapswere even smaller than this. The standard deviation ofbearings obtained from null- peakarrays was 1.23"and for hand-heldantenna readings was 5.31o.

MovementRate A leastsquare analysis was used to comparedistance moved between consecutive locations.Mean movement rates did not differbetween farm-released alligators (46i m) andwild alligators(487 m), andno interactionbetween seasons and goups wasfound- Themean distance moved differed among seasons (F = 33.00,df-2,72,P <0.01).A Duncan'stest (SAS Inst. Inc. 1989)showed that the grcatestmovement rate was during summer1991 (575 m) andmovement did not differ betweenwinter 1991-92(355 m) and summer1992 (365 m).

Disoersal Disperalwas defined asthe straight line distancebetlveen initial location and the lastlocation. Mean dispersal distance was 1,228m (SD- 926m) for 43 wild alligatorc and 1,260m (SD= 968m) for 75 farm-raisedalligators and did not differ behveen goups (t = -0.3615,116 df, P = 0.36).Three farm-released and one wild alligaior dispersedmore than 5 krn ftom theirrelease locatioDs. Most dispersal occurred in the summer1992 season.

Home Range Homeranges were estimated using 100o/o minimum convex polygons for all alligatorslocated at leastfive timesin a season.Mean home ranges for farm-releasedand wild alligatorsdid not differberween groups (F = 1.45;1, 105df; P = 0 231)or seasons (F = 0.05;2, 72 df; P = 0.954);and no groupby seasoninte^raction (F =-0.32;2,'72df]' P = 0.729)was detected. Home ranges varied ftom 0.012km" to 8.06km' for wild alligato$and 0.008 km'to 3.5 km'for fam-Eised alligators.

DISCUSSION Duringthe early 1960's, alligators were translocated fiom refugesin Louisiana wherethey were abundantto other areasin the stale.Chabreck (1965) found that translocatedwild alligatorsdispersed at a rate 3 to 4 times greaterthan alligatorsthat were captued, tagged,and released in the sameaxea ithere captured.He recaptured19 alligators6-12 months after release that were relgased in thesame location where they werecaptured; they had moved an averageof 1.02km (range0-0 to 5 65 km.) Alligalorc rcleasedinto newareas were recaptured after 6-12 months and had moved an averageof 3.03km (mnge0.81 to 9.68km.). McNeaseand Joanen (1974) followed (with radiotelemetry*) 30 ilr)matlllewild alligatorsfrom 27 March1973 to 5 March1974. They found no significantdifference in daily movementsbetween immafure males arrd females and amongseasons. Meal daily movementsfor femalesranged fton1 138 m in thewinter to 294m in the spring.Mean movementsofmales langed from 185m in the fall to 278m in the spring.They had insufficignt dataon malemovement in the winter to makea comparisonfor thal season. Maleshome ranges varied from 24.7ha - 610.5ha., and averaged 230.g ha. Females rangedfrom l2.l ha- 622.6ha., and averaged 179.2 ha, but did not differ statistically from males.Deitz (1979)found no differencein movementofjuvenile male and female alligato$at locationsstudied in Floridh. We useddistance moved between consecutive locations as an index ofmovemenr. Seasonalmovement averages for wild radio-coliarcdalligators ranged from 39gm in the winter 1991-1992season to 684m in the summerl99l season.Foifarm_raised radio_ collaredalligators seasonal averages ranged from 360m in thewinter season to 6l l m in the summer1991 season. Mean seasola]home nnges for the alligatorswe studiedwere consistenflv smallerthan those repoted by McNeaseand Joanen (1974). Individual home ranles for farm-releasedaliigaton ranged from 1.2ha to 806ha. Mean seasonal home rangel for farm-releasedalligators varied aom 43.9ha (SD=55.4ha) in thesummer 1992 to 96.2ha (SD=76.5ha) in the sununer1991. For wild radio-collaredalligators, individual home rangesvaded from 0.8ha to 350ha. Mean seasonal home ranges forjuvenile wild alligatorsmnged from 85.4ha (SD=56.7ha) in thesummer 1t9l to i17.2 ha (SD=137.3 ha)irl thewinter 199 I - 1992. Tayloret al. (1976)tracked 23 immaturewild alligators(11 nativeand 12 translocatedfrom coastalmarshes) on two iakesin northeastemLouisiana from 10April to 4 December1975. They detected Do overall difference in dailymovement or home rangesize oflocal andtranslocated alligaton. The alligators Enged in sizefiom 1.05- l 82 m TL. Averagedaily movementsftom springto fall for local alligatorsranged fiom 5.05to 633.9n/day andaveraged 115 rnlday. Introduced marsh alligaiors movemems mngedfrom 38.2to 332.2nlday anda\eruged 118 rrlday. Homeranges for local alligatorsranged from 0.8-321.8ha., and averaged 97.8 ha. Introduced allieators home rangesranged from 2.4-228.8ha., and averaged 90.4 ha. Our hndingsare similar to the resultsof their study. In our sludy, the movementlate for summer1991 was greaterthan the other seasons.This wasin agreementwith thefinding by Chabreck11965) rhat hanslocated alligatorshad greatermovement the first seasonaftet they werereleased. During the summer1992 we were unableto obtainlocation estimationsacross the entirc seasonon many ofthe alligato$ becauseofradio failure andpredation on many farm_released alligators. Dispersaldistances werc measured at the endofthe studyregardless ofwhen the animalwas instumented. Twenty-eight ofthe 75 fam-raisedallieato$ used in the analysiswerc not instrumenteduntil the beginningofrhe surnmer-j9a2. but theywere originallyrcleased on the areain thesummer 1991. All wild alligatorswere initially radio-collaredin summer1991. Therewas an extremelywide nnge ofsizesofhome ranges.Home range size is corelatedwith themrmber oflocations used to estimateit andthe time pe od involved. Chabrcck( I 965) reportedthat movementwas progressiveand proportionalto time. Thefirst season(surnmer l99l) was 10weeks long. Mean distance moved was greateiid the fiIst seasonthan in the oth€rs,but meanhome range sizes lvere nor siglificantly different from the othe. seasons.The facl that rhis;as dre shortesrseason with the fewest locationslikely biasedthe homerange estimates downward. The radio failureproblems ofthe summer1992 caused similar problems in thatwe did not gera 309 sufficientnumber oflocations on enoughalligatols for anadequate measue ofhome langesize. We foundthat juvenile alligators moved about dudng the winter which colfirmedthe results of McNeaseand Joanen (1974). The lvinter season was the longest seasonwith the greatestmean number locations and was probably the only seasonfor whichwe hada viablemeasure ofhome range.

LITERATURE CITED

Chabreck,R.H. 1965.The movement ofalligators in Louisiana.Proc. Arm. Conf. Southeast.Assoc. Game and Fish Comm. 19:102- 110.

Dietz,D.C. 1979.Behavioral ecology ofyoung Americanalligators. Ph.D. Dissertation, UniversityofFlorida, Gainesville, Fla. 152pp.

McNease,L., andT. Joanen.1974. A studyof immaturealligators on Rockefeller Refuge,Louisiana. Proc. Ann. Conf.Southeast. Assoc. Game and Fish comm. 28:482-500.

Nichols,J.D., L. Viehrnan,R.H. Chabreck,and B. Fenderson.1976. Simulation ofa commerciallyharvested alligator population in Louisiana.Louisiana State UniversityAg c. Exp.Station 8u11. 691. Baton Rouge, LA. 59 pp.

SASInstitute Inc. 1989.SAS language and procedues: usage, Version 6, FirstEdition. Cary,NC. 638pp.

Taylor,D., L. McNease,and T. Joanen.1976. A comparisonof intoducedimmature alligalorsio northeastLouisiana. Proc. Ann. Conf.Soulheast. Assoc. Game and FishComm. 30:362-370.

Taylor,D., andW. Neal.1984. Management implications ofsize-class fiequency distibutionsin Louisianaalligator populations. Wildl. Soc.Bull. 121312-315.

Whit€,G.C., and R.A. Ganott.1986. Effects of biotelemetryt angulationenor on detectinghabitat selection. J. Wildl. Manage.50:509-513.

310 REINTRODUCTION OF NILE CROCODILES TO I.AKE KARIBA, ZIMBA,BWE

RichardFerguson

CrocodileFarmers Association ofZimbabwe, p.O. Bor EG 11,Eighlands, Harare Zimbabwe

ABSTRACT

The go&'th ofthe crocodileranching industry in Zimbabwehas led to inqeasinglevels of utilisation. A conservativedecision \vas made to ensurethe sustainabilityofutilisation was implementedin the form ofa programmein which crocodilesare releasedto the wild. A numberofcrocodiles, equalto 2 % ofthe numberofwild eggsincubated, were releasedamually betweent 990 and I 994.

A two year field studyof releasedcrocodiles was cardedout in Lake Karib4 Zimbabwe. The aim ofthe studywas to evaluatehow suchreinlorcement affects the wild crocodile population.Three aspects were investigated; - the survivalofthe releasedanimals; their groMh and conditionchanges after releaseand their dispersalbehaviour after release. Data were collectedby frequentlocation ofmdio-telemetered crocodiles and by spotlight surveysofthe study areaduring which taggedcrocodiles were identifiedvisualiv andbv physicalrecaptures. These data led to the fomulation ofindividual historiesfrom whiih survivalcan be estimatedby severalmethods. The recapturesallowed collection of measurcmentdata a'ld dispe$alwas analysedfrom geog.aphiclocations ofall contacts. In all tkee aspectsattempts were madeto comparedata for the releasedand wild crocodiles.

Therewas a declinein the numberof survivorswith time after releasqaccompanied by a concurrentdrop in the probabilityofsurvival. Lessthan halfthe numberofreleased animalssurvived for a year afler release.Survival ofwild crocodilesis generallygreater than for releasedanimals.

The body massofreleased crocodiles, initially extremelyhigh relativeto wild crocodilesof the samelengtb fell over severalmonths to a minimumdudng or shortly after the non_ growing seasonbefore positive $owth occurs. Body length,ly contrast,shows seasonallyd€te.minedinqemental steps ofgrowth. Wild crocodilest'?ica.lly havehigher body condition sco.esthan releasedanimals after thesehave expedenced their first non- growing season.

Movementimmediately after releasewas random. pattems or .,strategies,'appear later - someanimals establish a singlearea ofusage while othersmove betweena numberofsuch arezlsarld someappelr to dispeneio a consistenldirection out ofthe study area. No significantditrerence in survivalcould be shownbetween these groups. Unlike studieson

3ll wild crocodiles,a distinct homerange could not be shownfor most ofthe released animals.Long distancehoming was shownto occur,proving that sub-adultcrocodiles possessthe motivationand mechanismsto hometo whete theywere hatched

This study also higl ights severalother potentialeffects which were not consideredwhen the ieinforcementprogramme was started. It was concludedthat the reinforcernent progmmmewas not essentialto sustainthe wild crocodilepopulation- The short-term successofthe releasedanimals is apparentlyrelated to the densityofthe wild population at the releasesite. Greateremphasis should be placedon monitoringofwild populations witi releaseto the wild retainedas an option for specificsituations where the wider reouirementsare fulfilled.

3t2 Radio-trackingcaptive-reared Orinoco crocodiles(Crocodvlas intermediuslreleased into the CapanaparoRiver, Venezuila.

Maria del. C. Muioz! and JohnB. Thorbjamarsonz ' UniversidadSimon Bolivar, Departamentode EstudiosAmbientales, Aptdo. 89000, Caracas,Venezuela. <[email protected]> ' Wildlife ConservationSociety, 2300 Southem Blvd, Broo<,Ny 10460USA

Abstract To test the f€asibility ofrestocking depletedwild populationsof Orinoco crocodiles (Crocodylusintemedias) by releasingjuvenile, captive-reaxedcrocodiles, we conducted a adio-telemetrystudy. Eight socodiles(l15.2-139.3 cm totallength) were equipped with radio-tansmittersand releasedin the CapanaparoRiver in southwestemVgrlezuela. Crocodileswere followed from Apdl l99l to March 1992in orde, to determine survivorship,pattems ofhabitat useand movementpattems, and grcwth rates. Croaodile movedconsiderably during the fust monthfollowing release,with four crocodiles reachingtheir maximumdistaace from thepoint ofrelease (1.0 to g.0km) withrnone month.The maximum distance moved was l l.6 km by onecrocodiie four monthsafter release. Six ofthe eight crocodilesmoved upstrearL while only two movedrelatively short distancesdownstream. Crccodiles tended to remainin areasoffavonble habitif, principally along the main courseofthe river. prefefied habitat durins the drv season werein sectionsofthe river with abundantlow-gradient sandy beachei devoid of vegetationthat were favored for basking. As the river rose during the wet season, crocodilesremained in the sameareas, but movedback into shallow-waterareas amoDg flooded riparian vegaation. Our observationssuggested that thesewere the same patternsofhabitat useamong wild-bom juvenile crocodilesas well. Growth ofreleased crocodiles(mean 0.079 cm,/day)was similar to that ofwild-bom iuvenile crocodiles_ Basedon the resultsofthis study we feei that a carefullydesignei programof releasesof captive-rearedcrocodiles carl be an effective conservationtool to speedthe recoveryof depletedpopulations of Orinoco crocodiles. However,care must bi takento insurethat tie releaseFogramis designedas one componentofan ovemll docodile strategl.and not an excuseto avoidthe onerousissues ofthe protectionofrvild crocodilepopulations and theirhabitat.

Introduclion The Orinoco crocodile(Crocodylus intermedil.r) is one ofthe most world's most endangeredcrocodilians (Thordamarson 1992)_At onetime commonlvfound throughoutthe Orinoco and irs major fluvial bibutaries,Ori'loco crocod'ileswere brought 313 to nea.r-extinctionlevels by commercialskin hunting between1930 and the 1960s.Since that time little evidenceofnatural populationrecovery has been noted (Thoftjamarson andHernendez 1992). The captive-rearingand rel€aseofcrocodiles is being usedas a conseftationstrategr in certainprotected areas in the Venezuelanllanos ln Venezuel4 theie are curently four captive-breedingand rearing stationsfor Orinoco crocodiles. Most operationsare small and are fundedby private individuals or institutionsinterested ifl assistingthe recoveryofthis threatenedspecies (Aneaga et al. 1994).Releases of Orinococrocodiles have been underway since 1990, with in excessof 1,500animals having beenreleased back into three prctectedareas (Capanaparo-Cinaruco National Parlq Aguaro-GuariquitoNational Park, andthe caio GuariticoNational Wildlife Retuge)(Aneagaand Hemandez I 996). Two t]?es ofreleaseprognms havebeen conducted. Most qocodiles that have beenreleased including rhe vast majority ofthose usedin the Aguaro-Guariquito National Park andthe Ca.io GuariticoNational Wildlife Refuge,have been a.nimals offspring ofcaptive breedingstock maintained at the breedingcenters Thesearimals havebeen used to reiffioduce docodiles into areaswhere they havebeen extirpated, or wherethey exist at critically low levels. However,the CapanaparoRiver, with > 100 adults,contains one ofthe largestknown remainingpopulations ofOrinoco crocodiles (Thorbjarnarsonand Hem andez1992). Pincipal thrcatsto this populationhave been the collection of eggsfor food by Indians,as well as the aaptureof neonatesby Indians and Venezuelancampesinos, for saleas pets. As a result,recruitment was extremelylow and it was felt that a restockingprogram based on headstartinganimals from nestscollected alongtie Capanaparocould be an efective conservationstlategl ln an effort to evaluate the conservationvalue ofthe headstartingprograil! we conduoteda tadio-telemetrystudy of captivereared crocodiles releas€d into the CapanaparoRiver-

Materials and Methods Stud!'Area. The study was conductedin the Rio Capanaparo'a tributary ofthe C)rinoco River in Apure state. The rcleasesite was within the Cinaruco-CapanaparoNational Parlqbetween San Jose and Caio Amarillo (Lat. 6' 54'41" b 7" 03'23",I,ong. 6a" 36'06' to 68" 23'M'). The region is characterizedby a treelessaeolian savanna with thin sfiips ofgallery forestsalong dver and streamcourses Armualprecipitation averages 19i5 mm Gante 1400-2600mm (MARNR- Direccion de Hidrologia y Metereologia)and the climate is highly seasonalwith a well definedwet (July-November)and dry (D@ember-June)seasons. Dudng the dry seasontlrc water level in the CapanaparoRiver is quite low, with extensivesindy beachesand shallow sre&hes (meandepth I 3 m; Ndl) that altemate with deeperpools (>2.5 m deep).The dver meandersand hasnumerous oxbows or isolatedfloodplain lakes. During the rainy seasonthe river dses approximately4 m over its lowest level, coveringmost beachesand in someareas flooding sectionsofgallery forest. Rive$ide vegetition is dominatedby riparian tees ard shrubs(Cdmpsidndra comosa,Psidium maribense,Coccoloba obtxsifolia), or savannaspecies (Brysozima crassifolid, Couepidovatifolia. Erismd nciwaum)'nherc'iver meandeNenter the surounding savannas.Hurnan population pressure ia the region is low, with scattered communitiis of Yaruro Indiansand small cattle mnches. The dver also supportsgood 314 populationsof spectacledcaiman (Caiman crocodih.ts), nver dolphjns(hia geoffrensis), nver fifiIes (Podocnemisunirths) a d.giant iver otters(ptenuewq brdsitiehsis). Radio-telemetrvStudv. Eight juvenile crocodileswere releasedwith radio tansmitters in late March and April 1991. The crocodileshad beenhatched fiom eggs collectedalong the Capanaparofuver on 25 February1987, and subsequentlyreared at the crocodilefacility at FundoPecuario MasaguaEl, apprcximately 200 km nonheastof the site ofcollectioa. All eight crocodileswere males,and radio transmitterswerc aftachedto the dolsal caudalscutes immediately antedor ofthejunction ofthe single and doublecaudal crests using nylon monofilamentfishing line. Radio-transmitterswere 3.0 v Lonner modules(A\M InstumentCo., Ltd) that producedsignals in the 164-165lfIlz frequencyrange. Radiosmeasu.ed 8.7 cm by 2.3 cm and weighed62 g. We located crocodilesusing a TelonicsTR-2 receiverand an RA-2A antennafrom an aluminumboat with an outboardmotor. Thelocalions were plotted on a 1:100,000topographic maps. Dispersaldistance was consideredto be the distance(following rhe main river course) betweenthe crocodile'slocation an it's initial point ofrelease. Macrohabitatuse was classifiedas l) pdncipal courseofthe river, 2) a secondary channelor 3) oxbow lake. Microhabitatwere describedbased on the natureofthe shoreline-waterinterface, the presenceand tyfre ofvegetation present,the gadient ofthe shoreline,the type ofsoil and the degreeofwave exposure.

R€sult! Eight male qocodiles with radio transmitterswere releasedon 2g March and 4 April 1991dudng the heightofthe dry season.Crocodiles mnged from 115.2 to 139.3 cm total length (Table 1). Between5 April 1991and 22 March 1992we radiolocated the crocodilesa total of 1,278times. The meaninterval betweenndioJocations was l.7g days(Table l), and sevenarccodiles were followed for iiterwals of235-352 davs. Two weeksafter beingreleased, one crocodilewas killed by a yaruro Indian who rnistookit for a spectacledcaim an. Caimdn are rcg)lLrly huntedfor food by the yaruros using a bow and anow; crocodilesare not hurfed or eatenas the yarurc claim they tastebad_ The crocodilefollowed for 235 dayswas lost when its radio-transmitterfailed_ Crocodilesbegan moving immediatelyfollowing release. Many ofth€ crocodiles reachedtheir maximumdispersal distance within one morth ofrelease (Table 2). Maximum dispersaldistance was I 1.6 km by a crocodilefour monthsfollowing release_ In general,arocodiles followed one ofthree patteriLlong distanceupstreztm movemenas (6-8 km upstream),moderate distance upstream dispersers (3-5 km upstream),or short downstleammovements (l-2 km)_ During the low-water, dry-seasonperiod, dispe.saldistance reflected movemenrsro areasofpreferred habitat, opensections ofthe dver with extensiveand beachesand a mitlture of shallowwater and deeperpools (to 5 m deep). As the rains beganand the river level beganto rise in June-July,crocodiles remained in the sameareas, and moved back into shallowwater areasaround flooded riparian vegetation. Maximurr river levels occurredin August-Septemberand qoaodiles were mostly sedentaryduring this period. Crocodilepreferred the main river course(82olo ofradio-localions). but occasional enteredoxbovr' lakes ( l2yo) or secondaryriver courses(6Zo)_ The use of oxbows- abandoneddve. meandersthat are still connectedto the main river course-was 315 principally dudng the early part ofthe study and crocodilestended to moveout ofthgse lakes. Releasedcrocodiles were observedmostly in shallow-waternear the shoreline ln the dry seasoncrocodiles principally usedlow-gadieft, openbeaches without any vegetation. Dudng the wet seasolthere was a grcatertendency to encourterthe crocodilesamong partially submergedlive or deadvegetation- At the end ofthe studywe werc only ableto recapturefour ofthe six crocodilethat sti11had functioning rudios. Mear gowth for theseindividuals was 0.079 cm tota.l length/day,equivalent to an annualgowth rate ofapproximately 29 cm. Thesegowth figures are similar to onesfiom wild juvenile crocodilescaptured in the samearea (0.089 cm Tlldar.

Discussion Basedon the ability ofcaptive-rearedcrocodiles to adaptto naturalconditions, the use of captive-rearedcrocodiles for restockingpurposes appears to be a viable stategy for speedingpopulation recovery in depletedpopulations. Although crocodilestended to dispers€from the releasesite, dispersalwas not eLtreme(maximum ofless than 12 km) Aside fiom the one crocodilemistakenly killed by a local resident,all crocodilessurvived and grew at ratesequivalent to thoseof wild crocodiles.Based on our studiesprior to the restockingeffort, both capive-rearedcrocodiles ard wild crocodilesshowed similar habitatpreferenc.es and were frequently seentogethet in the sameareas along the river' When first .eleased,the crocodileswere, unlike wild crocodiles,easy to app.oaohat night from a boat. This behavioris more like that ofthe sympatricspectacled caima4 and is probablywhy the one crocodilewas mistakenfor a caimanand killed early in the study. However, by the end of one year the captive-rearedclocldiles had becomequite wary and were difticult to approach.Some ofthis is due to orr plesenceover the course ofthe study,but in other areaswhere intensivefollow-up studieshave been not been conductedwe hav€similarly observedthat captive-tearedarocodiles are easily observed shortly following releasebut becomevery wary with time. While our studygoup ofcrocodiles adaptedwell following release,caie mustbe takenwhen extrapolatingthe resultsofthis studyto other arcas. The CapamparoRiver representsoptimal habitatfor the species.If releaseswere conductedin other areas, iniluding smallerrivers with lessabundant open beaches (prefered dry-seasonhabitar), which charaotedzessome ofthe other releasesites, crocodiles may be lesssedentary and may disperselong distances-Evidence from the Ca.froGuadtico suggeststhat at least someofthe releasedcrocodiles have moved 70-80 km downstreamwithin 6 monthsof release. Also, the crocodilereleased in this studywere rcarly four yean old and measuredover l-2 m long. In subsequentyears, most releas€d crocodiles were one yeaJ old andmeasured 70-100 cm total length. The size ofanimals when released most likely will havean influenceon movementpattems, habitat use, survivo$hip andgowth. Nevertheless,we feel that if designedprcperly (including the following of ruCN guidelinesfor reintroductions),a head$aningprogram such as this one canhave positive conservationbenefits in Venezuela.In areaswitl remnantcrocodile populations, programscan be readily designedto protectnesting beaches and monitor armuallesting levels as pan of efforts to collect eggsfor head-starting.Follow-up studies,based on

316 noctumal spotlight countsand lhe recaptue ofanimals can Drovidemuch needed informationfor programevaluaLion. Also, reintroductionprograms involving the releaseofanimals producedfrom captivebreeding stock, which hasbeen the casesin the other areasin Venezuelawhere crocodileshave been released, can also havepositive conservationconsequences. Extirpatedpopulations can be re€stablished.and this maybe particularlyimportant in areaswhere protected habitat and existing crocodilepopulations do not coincide. Howgver,in thesecases there is no "built-in', monitoring componentand specialeffort must be inadeto conductfollow-up surveysto monitor the progressofthe program. perhaps _ However, the greatestdrawback to captive-rearingard releaseprograms rs that theseeforts caneasily becomethe sole focus of conservationeforts, at the expense ofadequateprotection ofwild crocodilepopulations and their habitat.By breedingand releasingcroaodiles, one feels that active measuresare beingtaken to addressthe conservationdilemma ofthe species.However, these measires rnust onlv be takenas part ofan ovelall conservationprcgran that addressesthe root causesofthe specres decline.In the particular caseofthe Orinoco crocodile,this is mostly the killiry of adult crocodilesafld the captureand saleofjuveniles as pets. Crocodileconservatio; nust be madeone ofthe statedobjectives ofmanagement plans that are preparedand implementedin protectedareas where crocodiles are released, and iollow-up monitoring both shon-term(as h this study)and long-terrL must be incorporatedinto tlle prograrn designAom the beginning. Unfortunately,the situationin the two main protected-a.ea releasesites in Venezuelahas been less lhan ideal as civii unreslhas prevented crocodile conservatio!work in the Capanaparcregion since 1993,and becauseregulations have allowed commercialfishermen continued access to the Caio Guadtico refuge.Captive breedingand releasingofanimals back ifto the wild must not be usedas an excusefor not addressingthe onerousissues ofhabitat prctectionand enforcemeff ofnational wildlife legislarion. In summary,we recommendthat the captive-rearingand releasesbe continugd,but within the context ofa national crocodilgconservation stmtegy that placesmore emphasis on in-situ protection. In particular,field programsshould be design€dto monitor nesting levels ofrcmnant crocodilespopulations, work with local communitiesto protectbeaches andredlce qocodile mortality, and incorporate.as pan ofthe overall stratiry, the collection of someeggs and juveniles for headstanin*.

Literature Cited

Arteag4 A. y G. Hemandez.1996. Evaluation ofthe reintroductionof Crocodvtus intemedius in tlrc Cailo GuariticoWildlife RefugelApure Srate,Venezuela). pp. 207-222.In: Procer,dingsof the l3th Working Meeting ofthe Crocodile Specialist Group.ruCN - The World ConservationUnion, Gland. SwitzerlandISBN 2- 8J l7_ 0327-1.516p. Thorbjarna6oi, J. B. 1992.Crocodiles: An Action plar for their Cons€rvation.Fl. Messel,F. W. Kiog, J. P. Ross(eds),IUCN/SSC Crocodile Speciali$ croup. 136 DD.

3t7 Thorbjamarso4J. B. y G. Hemandez.1992. Recent investigations ofthe statusard distribution ofthe Orinoco crocodrleCrocodllus intermediusin V enez:uela. BiologicalConservatior\ 1992. 62:179-788.

Table 1- Lenstll mass.and study interval ofcrocodiles usedin the radio-telemetrystudy- Crocodile Date Snout-vent Total Mass Last radio # Days Mean Released length (crn) length (kg) location. radio radio- interval (cm) locations tracked (days 28/03/91 1t.o 130.8 9.0 11/04/91 5 t4 2.80 '74.9 c44 28/03/91 138.8 11.5 6/02/92 187 313 1.6',7 c37 04/04/l9t 62.5 115.2 5.5 1'1/03/92 195 34'l 1.78 c33 04/04//91 65.4 120.8 6.5 22/03/92 185 352 1.90 c26 04lo4ll91 68.9 127.0 8,5 17t03t92 l9l 347 t.az c38 04lo4l/91 70.5 103.3 8.5 2541/92 134 235 t.'75 c34 04tMt/91. 71.5 l3l.9 9.0 22103192 191 352 1.84 c40 04/04//91 75.3 139.3 11.5 t7/02192 t90 319 1.68 Mean 70.0 125.9 8.7 2a4.9 1.74

Table 2: Maximum dispersaldistance (in krn) ofcrocodiles from the releasesitg by mo h. Crocodile Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar 1991 1992 c32 3.3 c44 1.0 0.7 0.7 0.5 0.4 0.4 0.4 0.3 0.4 0.3 0.3 c26 5.8 5.'7 5.7 5.7 5_'1 5.7 5.'7 5.7 5.7 )J 5.5 5.5 c34 2_7 )l )l 5.1 4.8 4.8 4.8 5.6 5.6 2.1 5.4 5.4 c38 )6 6.0 5.2 ) I JJ s.8 5.8 4.8 c33 1..'7 t.7 1.1 1.3 0.6 0.5 0.6 1.0 18 l. I 1.8 1.8 ',7.7 8.0 8.0 8.0 8.0 7.4 7.4 7.7 77 7.4 9.9 l0.l 11.6 7.s 7.3 7.3 7.9 7.6

Mean 4.5 5.3 4.5 4.6 4.7 4.4 4.1 4.6 5.1

318 Figure 1 Mean monthly dispersaldistance of sevencrocodiles. Each point is the mean ofthe absolutedistance from the releasesite for that month_ tr) 't0

.,

!! o

Aug Sep Oct Nov Dec Jan Mar Month

319 Evaluationof the ReintroductionProgram for ArErican crocodiles lcrocodylus acutusl in the CuareWildlife Refuge,Falcon state, Venezuela. Alvaro Velasco& Alfredo Lander ServicioAut6nomo de FaunaProfauna EsquinaCameio, Edii Camejo,Mezzanina Oeste, CSB, Caracas 1010, Venezuela. e-mail [email protected]

The CuareNational Wildlife Refuge locatedir the Silvamunicipality in Falconstate ir Venezueb was createdby Decree#991 on 31 May 1972,publish€d in tbe Venezuelan Official Gazefre# 29,820of2 June1992. The reservecontains a surfac€ar€a of11,853 ha"and is dividedinto two main areas,a rnaidandsection and offshore islands (Galvez 1992).

The geation ofthe CuareReserve was tie rcsult ofthe n€edto plotect habitat critical for a mmber of speciesofresident and migatory birds (MARI\R-PROFAUNA- RJDENA 1992). Anotber ofthe principalobjectives ofthe reservewas tie recoveryof wild populationsof the Americfii crocodile(Cr@dylus aalas), which is consideredan endangeredspecies in Veoeanela.

Within the reserve,crocodiles are found priacipallyin the Gufof Cuare,its Estem ofhtarconnect€d streams,and the Ostionallagoon (60 ha). The Gulfhas a surfacearea of approximately1,964 ha, andis 12 Ian long rangingfrom 0.5 to 3 km wid€ (Galvez 1992). Within the reservethere are a total of 18 sf€ms anging Aom 100m to 1,500m long (CanoH Buco), which in somecases are opencanals within the margrovesthat encircle thegun

Brckgroond

Previoussfudies ofcrocodiles in the Cuarerefuge have reported population densities of0-38 crocodileVkn (I-opez 1986),0.92lkn (Art€ga 199a)aad 0.72lkm(kteaga 1997). Thes€density figures are lower than thosereported for the samespecies io other neartryareas such as tl€ YaracuyRiver (4.82lktg Arteagaand Sr4nchez1996), the Tocuyo River (5.10/lim), the Tacariguareservoir (2.75-3.25llsn), the Jatirareservor (3.22llot) andthe TacariguaNatiooal Park (2.28/lsn)(/lrtezga 1997\.

Previousreleas€ plograms with Americancrocodiles in Venezuela(Tacarigua reservoir;Afieaga and Henera 1997),in the Cafroadel SumideroNational Park, Mexico (Sigler 1996)and in Lake Enriqui.llq DominicanRepublic (Schuben et al. 1996)irdicate thal captive-rearedcrocodiles adapt well to naturalconditions.

Begiming in 1995,the Venea.relanwildliG depannent (PROFAUNA) begrll rel€sing captivcrearedcrocodiles in the CuareWildlife Refuge,siarting with a group of 320 48 crocodil€swith a rnear sizeof77.6 cm total lengthard 1.676kg (Boedeet al. 1995). The-followingyesr anothergoup of22 crocodiles(mean 76.1 tL, Z.Ot5 k9, aod io 1997^.,addiriond U crocodiles(mea! 74.67 crq 1.764kq;\ wae "- releasedin tire refuge. Crocodilesused in the releaseprognm came&om two sources. Crocodilescollected ftom wild neslsin the Turuano (Aragua Bay state),were rearedat a hcilitv oDelatedbv - PROFAUNA in the city ofMaracay. Other crocodilescame from a caDti!€ breedine ceoteron the Masaguaralranch in Guirico state.

The- _ objectiveofthis studywas to determinerhe statusand populationdla|amics of tie_Americancrocodile population in the CuareWildlife Refugg focusingon the maingutt and the systemofinterconnected streams vr'ithin tlre mangroves.SpecifiJ objectrves were: 1-Dstemine populationdelsity and size-classstruature 2. Recaptulereleased crocodile to determinehow they adaptto living in the refuge.

Study Area

Th€ study{'as conducted .^ throughoutthe entire Cuarerefugg includingthe main gulf@d the rnangove canals,but focusedprincipally on the southemeage oithe gufana the OstionalLake andthe Caio el Buco.

Methods

Ove-ra period of9 rnonths(April andDecernber 1997) we conductedmo*bly surveysof dayslength to: l Carry out nocturnalspotlight counts (Chabreck 1966, Woodwsrd and Madon 1977)to estirn4tethe detsity ofarocodiles. Deisities w€re calcuatedbased ooly on the numberofindividuals greaterdun 60 cm TL 2j - .. ?et:r4ry the populatior size-classstructure using size-categoriesdefined by Seijas(198E. Class <60 I cm TL; Class 60-120cm TL Classm izo-ttO cm tt ; ClassM 8G240 cm TL; and ClassV >24Ocm TL. qocodiles 3. Capure usingwire noosesto measrreTL, massand determinescl<- Results

D€nsity Crocodileswere ody observedalory the northem shoreofthe reserve dudng two ofthe 9 surveys,with densitiesof0.0g llorn$d 0.24/km. Hicher delsities were_observedalong the norfhem shorewhere crocodiles were seeoduing all 9 zuveys ard dersitiesrangei fiom 0.61-l.97kEL

Sizc.classstrusture. The size.class$huctue ofthe populationshowed a clear q-4 in sizeclass tr (79.37%),with only srnall 991turyT"l mrnbersof targeranirnals (ClassIV-l.59olo: ClassV-0%). Nwertheless,it is inrerestinSto note that durirg our srrveyswe observeda total of I I hatcbliDgcrocodiles, whieh indicatedthat ther; are adult crocodilesin tle regionand that they are rqrroducing sucessfully. 321 Grol*lh" DuriDgthe studywe w€re ableto recapfirrel5 qocodiles: 4 fromthe MaracayMing center, 10 Aom the Masaguaralcenter, and one tbat halcbednaturally in the refige. Sorlleindividusls w€rc capturedas maayas tbree times. Mean growth oftb€ rnirrnls tom Maracaywas 8.41 Mr/day TL, ftom Masaguaralwas 425 m/day TL, and the one crocodiletom the refuge gew 55.06m/day. In terms ofweight gaip,tha Maracayuocodiles grew at a Dean .ate of I .55 g/day,and the Masaguralcrocodiles 0.259/day,

Figure 1. Size-classstructue ofcrocodiles observedin tbe CuareRefuge dudng this study coqarcd to tbe resuhsofArteaga (1997) for the sane arca"

Frgr.3E d&c|mFbna.

Discussioa

Densitv. The differencein crocodiledeosity between the northernand southem sboresofthe Gufofcuare is a resuftofthe greaterdegree ofhuoan disturbanceof babitatsaloDg the northem shore,whbh is wherethe town ofChichirivicbe ald tbe village ofFlanengo arelocated. Tbe southemshore ofthe guEis almog corrylet€ly uryopulated and containstbe bestcrocodile habitat h the refuge.

O|tI r€porteddersities are slightly gleaterfh,n the rahresfourd in previoussurvels ofCuarc (Lopez 1982, Aneaga1994,1997), Nevertheless,we feel tbat the popuhtion bend is sable rathertbm hdeasiDg.

Size-classstructure, The populatioosize-class distdtution we found is very similar to tbst reportedby Arteaga(1997XFi9. 1). Howwer, we found smallernuurbers oflarge erocodiles(Class IV aod 9. However,our obs€r%tionsofDeoDates in th€ Cuarerefuge indicatesthht a br€€diugaduh populationis presen. The releaseof I 16jwenile crocodileswith a rean lengthof95-07 cm TL is !!ost likley one oftbe reasoDsfor the observedincrease ia ClassII crocodiles(Fig. 1). Growtb" Large diferencesiD gloivth r-at€swcie found for crocodilesthat came froltr tbe two rearirg c€nters. The 'nimls collectedtom wild nestsatrd rearcd at tbe PROIAITNA c€lter in Ivfaracaysbowed much high€r gro],th rat€srhatr thos€ bom in captivity at Masaguaral

Tberear€ two potedial erylaioationsfor ltreseditrerences. First$, the wilid bom crocodilesmay havebad tbe opportuDityto learnhuDdng of wild pt€y beforebeDg brought into captn/ftywhereas crocodiles bom in oaptivetyhave not iraa tn" oppom-ity. Anotq eoptial ftctor is tbat they bare beenr€captured only a sbrt tinosaft; beirg rekase4 and Day still be in tb Foca$s ofadaptilg to their rcw environmeft.

The gowth rate,sreported h€re are slighfly g.este! ihrn thosefouDd by Ateega aDd Henera {1997) for the Tacrigua reservoir,which is tocst€dDea( to tbe CuarcRefi€e.

It shouldbe loted that or two occasiooswc aaph.[edajuvenile that batcheelin tbe CuareRefuge, and rtdch demlstlaied ao elrhenply high growth rate (55.06 nu/day), geatty eNrc€edbgtbat ofthe captivereared individuals.

CoDchsioDs

Within the restrictionsoftlE sbort perkld oftime over which this foltow-up shrdy was coDducte4our iryression is that the crocodileswere ableto adaDtto their uew enviromnt following release.Nwerthelesq it is reclmended tlat iollow-uo studies cominuein otder to deterEinesurviviorshiD levels. Basedoo our ffnrthg andthose ofprwbus studies,tlE resid€ntcrocodile popu.l,ationin the CuareReftge appearsto be stable.

Acbmwledgnents.Ne would hiketo tbrok PROFAUNA 6r assisingwith the udertaking ofthis study. We also tbankto Roldid and the CuareRefuge guards Amaldo,Walto and Joseito, and the pROFAUNA Maracay statio statri"foo uoafr,f"ri" Josefilr!without whose assistance it would not bave been possible to condictthis stu

Literat[re Ciied

Afteag4 Alftedo. 1994.Situaci6n actual del Caimdnde la Costaen sietebcalidades del EstadoFalc6a, Venezuela Mioeogmfiado, 2 pp. .m Arteag4 A. & C, SrDcbcz I 996. Conserrationand r.glnege'r'l,entof Croco$rlus aahts o_fthe $:t*:y 91sE Yagny river, Venezuela.153-161.-Ia: Crocodiles. froceeaiugs oe 13* Wolkilg Meeting oftbe CrocodileSpecialist Group, IUCN-Tbe Vy'orldCoos€f,Etior Unioq Gla!{ Switzedad. ISBN 2-831?-0327-1.516p:

Arteaga,A. 197. Actualizaci6l de la situaci6Dpoblariooal de Crocodylusae*us y qocodihrs Cqiman ss!. En las costasde Venezuelafr{enorhs de h 4ta Ifeuoi6n Reciolal 323 del Grupo de Especialistasen Cocodilos de Am6ricaLatina y el C&ribe.Centro R€ional de Innovaci6nAgroisdustrial S.C. Vrllahermos4Tabasco. 6-16 pp.

Arteaga A. & E. H€Irela. 1977.Resultados preliminares del estudiosobre crecimiento, sobrevivenciay uso de hetitat de Crocodylusacutus irtroducidos en el Embalsede Tacarigu4 edo. Falao4 Vonearela.Memoiias de la 4ta Reuiti6nRegional del Grupo de Elpecialistasen Cocodrilosde Amirica Latina y el Caribe.Centro Regional de Innovacion Agoisdustdal, S.C.\rl ahermoss"Tabasco.lT-20.

Boede.E: A Laoder-M. J. Gonzalez-Femandez& A. Velasco. 1995. Reintroductionof Crocdylus edus in Verczuela.NEWSLETTER, Crupo de Especialistasen Cocodrilos. l4(4):16.

Chabreck,RH. 1966. Methods of determinetlle size and composilion of A.lligator populatiols in Louisiana.Proc. Annual Conf Southeast.Assoc. Game & Fish. Cornm. 20: lQ5-112.

Galvez"Sara. 1992. Refugio de Faunay Sitio RAMSAR 'Cuarc". RevistaPROFALTNA. aio 2, N" 3: 3-6.

L6pea Esteban.1996. Refugio de FaunaSilvestre de Cuare.Basos pala un Plao de Marcjo. TrabajoEsp€cial de Grado.Esc. Biologia. Fac. Ciencias-Universidad Central de Venezuela.Calacas. 145 pp.

MARNR-PROFAIJNA-FUDENA.1992. Plan de OrderErierto y Manejo Refugiod€ Fauru Silv€sfie'Cuar€". mimografado.88 pp.

Seijas,Andr€s Eloy. 1988.Habitat us€ by Amedcancrocodile qnd the SpectacledCaioan coexistiogalong the VeNrezuelancoastal region. Tesis de Maestria.Universidad de Florida. Gainesville.

Sigler,Luis. 1996.Conservation ofthe AmericanCrocod;7e, Cr.Eofulrs aclrtus,i^ Cairprl. Suoidero National Parlg Chiapas,Mexico. 162-165.In: Crocodiles.Proc€edings of 13"' Working Meetirg of the Ciocodile SpecialistGroup, ruCN-The World Conservation Unio4 Gland, Switzerland.ISBN 2-8317-0321-1.516p.

Schub€rt,A, W. James,H. Mendez& C. Sartana.1996. Headstanting and tra.slocatioo of jwuoile Crocdylus aczrusip Lago Euiquillo, DominicanRepublic. 16G175 In: Crocodiles.Proceedings of 13"' Working M€etiog ofthe CrocodileSpecialist Group, IUCN-The World CooservationUdon, Gland S*itzerland. ISBN 2-8317-0327-l- 516p.

Woodwar4 AR & RW. Marion. 1977.A! evaluationof facto$ affectingnight lglft countsofalligato$. Proc. Ann. Conf S.E. Assoc.Fish & Wildl. Agercies32:.291-302.

321 PhysiologyofReproduction and Captive Breeding in theAmerican Alligator ,- oY$TiT:,l;:f::",",,, Sar Diego, Califomia 92112USA

and

Ruth M. Elsey LouisianaDepaltment of Wildlife alld Fishedes RockefellerWildlife Retuge Graqd Cheder, Louisiana 70643USA

Captivebleedirg hasbeen successfirl in many crocodiliao species.IrI somespecies, captivebreeding has had poor resultsand raochingof wild eggsis a more economicalsource of stockfor commercialproducen. Captivebreeding can be an important conservationtool in propagationofseveral endangeredcrocodiliaos (\. sinensis,C. rhombifer. etc.) aad understarldingthe poor reproductiveperfonnance of somecrocodilians in captivity presents someintriguing questionsin physiology,endocrinology, nutition, and behavior.

This prescntationwill initially outline the reproductivebiology ofthe American alligator, and hormonaland physiological factorsinvolved. A rgcentreview ofresults ofcaptive breede$ on commercialfarms in Louisianawill be discussed.For example,in 1997a total ofonly 10,508 hatchlingswere obtainedtrom 3,407 adult breedersmaintained (3.1 hatchliogs/adultmaintained; or 5.6 per mature femalemaintained). Only 33.1% ofthe matue femalesmaintained nested; and 53.2%ofthe eggshatched. Severalfarmers had no nestscoflstructed, although the alligators werc 8-12 yeaxsof age,aDd should be Eature. Many captive alligatorswill mate, co[struct nests, anddeposit eggs; but poor fertilify andlow hatchability remaiDproblsErs causilg captive breedingattempts to be essentiallycost prohibitive in mady cases.Io our prcvious studiestherc werc no significaot diffelencesin homones aod trace elementsbetween wild and captivenesting alligators. Captive alligatorsare usually significantly heavierthan wild specimensofthe same lengthand most ofthis additionalmass appears to be the rcsult ofexcessive fat. Amlysis of plasmalipids show that captive animalshave significandy higher cholestqrol,triglyce.ides, and phospholipidsthan wild alligators. Researcheffolts to improve egg quality and hatchrates will be discussed.

Proceedingsof the 14s Wo*ing Meeting of the CrocodileSpecialist Group Singapore July14-17, 1998

325 Environmental Conditionsfor Rearing Crocodylusporosus on Farms

R Mayer, S Peucker,B Davis and H Stephenson Departmentof P.irEry Iddu$tries,PO Box 1085Towrsvile, Queensland4810, Australia

AES'IBS

Hatchliagatrd juvenile Crocodrlusporosus (C. poros6) requirecontrolled environrnentreariug facitties and a high quality diet for rapid growth andreduced irciderce of morbidity andmortality. Curlent researchbuilds on previous environrnentalaod nutritional work cooductedat the crocodileresearch conplex at Torusville, Queenslau4Australia (i9' 15' S, Ae 45' E).

An experirnerto! hatcblitrgsinvestigated the effectsof providingO, 1 or 2 hide-boards in the reariqg tanksin faqtorialcombination with two water terrperatures.Ilatchlings grew more rapidly in wate! at 34t tha.!itr water &t3Xc (W 3O-5Vo). For rie latget groups ofhatchlitrgs,those reared itr tanl6 with two hide-boards(coYering 8O7o of tln latrd 8lrd wator areas)grew 557ofaster than thoseitr tankswithout hide-boards.

Separateexperiments otr the sameadmals at five and ten monthsof ageshowed that inc,reasi4gtbe volumeof water i! ths tatks to coverthe floot areafrom3oVo to 5O7o achievedconsist€nt grovth late ircreasos(13Vo atfive mofi)ts, 5Mo at tetrtnolths). Th€rewere generallysrnaller advadages in raisingthe water level to 80 or 10O74, exc€ptfor two tankscortaidhg larger ten month old anirnalswhich exhibitedstrong agodstic teodencies.

INTRODUCTION

Crocodilefarmers ia Austalia haveloog recogtrisedthe needto provide-specialrearing facitties for C. poro.rrr hatcblings.Rearilg deDsitiesof l1 hatchlingvnf bavebe€n reconnnended@lake 1974)and successfuIyused in the industry. Researchon nine month old juvenile aqimalsin thesercsearch tadis showedno differeDcein growth (the ratesfor large! sizedadmais -reared at deDsiti€€ranging betwe€n 1.3 and7.7 upper limit tested)animals,/nf nor for srnallersized animals resred betwe€n 3.8 and 10.2 (upperlimit) auimals/m'(Mayer et al 1997). It is well recognisedthat caregive! in the early stagesof a hatchli[g's develoPrnentprovides lolger term beoefils. Hutton et 4I (1993) statedth4t the sizeof atraaimal at two j€ars of agecan oftetr b€ accuately predictedby its developmeatin the frst few motths of life.

326 In spite of the exka careprovided by farmersin rearingtheir haichlings(in ierrrisof good qua.lityheated Aesh water, vitaminsupplemented diets, darkercdenvironme[ts) there is still a relatively high loss ofproduction though runtism and actualmortalibr to one year of age (over 3070on somefams). Of coursethis is muchlower tha! estimatedmortslity amonganimals bom in the wild (98-997o)but still represertsa substantialtross alrd presentsa cballengeto researchersto test eveqbetter rearing practices.

This repod preseotsresearch on two specificasperts of rearingC. porojils to one yeat ofage:- . provision ofbide-boa.rdsand water at differentteoperatues . provision of a rangeof differentvolumes of water in lhe tanks and follows on from earlierstudies on the efferts of air andwater fempelature,light, grading on size andrearing .The 1995report gave detaiieddescriptions of the resedch facility specificallydesigned and set up for studies relatedto farming sahwatercrocodiles. Resesrchon light showedthat ono and sevetr month oli aaimalsgrew fasterunder d.rker conditiors. The exp€rirnenton hide- boardswas set up to seewhether this effect may ha!€ be€nassociated with stess levelsand whetherhide-boards in associstiorwith dim lighting (on a diuroalclcle) might achievesimilax resdts for hatchlttg anirnals.

METHODS

The aninuls useditr the current studiescornprised 275 snimalsfiom 8 clutches(4 Aom a farm otr WestornCape York Peninsular,3 from a farm in Cairns,1 Aom a s.ildlife park in TowNvile). Animalswere fed daily from Mo[day to Friday aod tankswerc ernptiedand refiled with clean,warm water after eachfeedidg. Dirnrnedartifcial light was provided for 12 hours eachday. In eachexpedrnent animals were first divided into bro sizeclasses termed snall/medium (S/IVI) and rnediur!/laxge (1,4/-) aod then allocatedto groups basodon clutch representationand weight to achieve'equivalent' d^nnc ^f "ninal.

For the hide-board,/watertelDperature trial the aninralswere sevenwe€ks old and weighedan averageof 74g each. Rearbg delsities were 4.4 animarym2for the lvI,/L groups a.!d 5.9 anim.alvm'for the S71vIgroups. Tbir trial wasrun for a period of 10 wecks. TreatrnentscorNisted of :- . 0, 1 or 2 hide-boadsper tank (covering0, 40, 8070of l€rd ard water area! rosPeltivel9 o waterat 32'or 34'C . S/lvI or 1vt4-sizB groups in all factorial combilatioas (giving 12 individualkeatrnents). Analysis ofvariance 'tank was conductedon average'resporues and usedhigher-order interactiotr terms as 'erlor'.

321 Two wate! volurnetrials werc carried out or! the sameanirllals (rea ocatbg at the start ofeach into lrew 'equivalent'groups) andra! Aom 20 weeksofage (averageweight 2659) to 29 we€ksofage (4889) andAom 42 we€l$ (7289) to 55 weeks(10199). Treatrnentsfor the frst trial were :- . 30, 50 or 807otank floor areaurder water (volumes66, 133,314litres respective9 . S/M or lvllI- siz€gloups with two tank replicatesof eachof the six treatmentcombhations. Rearingdensities were 4.1 animals/m2for the I\4& groupsand 5.6 animals/m2for the SA4 groups. Obviouslythe volurne of rvaterautoinatically affe.ted water quality (dilutiotr of aninlal wasteand food scatteredia the water). Anarysisof variarcewas carriedout or! 'tark average'responses.

Treatrnentsfor the secondwater volune trial were :- . 30, 50 or 10070tank floor areaunder water (volurnes66, 133,350 litres respectively) ' S/M or lvtll siz€grouPs in fsctorial combinstion. As this trial exteodedpast the nornal 12 monthlimit two researchtanks had to be resorvedto acconrnodatethe aFivsl of tle 300 hatchlingsfor the 1998/99re.search gograrn Consequendytho trial wasrosbicted to 10 tanks,so that the 507oS/r4 and lvtll teahnent! were eachevaluated ia one talk oDIy(the other combhatioDsitr two !ad

RESIJLTS

1. Hide-board / Water Temperature Trial

The followhg tablopresedts the animalrefponse to eachof the Inain fieatrnentfactors, togetherwith st tistical cornpaiisons.

Food consumed Food conversion Liveweight gain (s DIWarimaVdaY) ratio (e/animavdav) sa.{ WL s/M M/L SA4 MJL Numberof 0 1.5o* 1.6bc 0.83c 1.11a 1.2d 1.8c hide-boards 1 2.Ob 2.7a 0.81c 0.86bc L.6c 2.3b 2 2.0b 2.9 a 0.82c 0.94b 1.6c 2.8a Water 32"C 1.7b 2.4a 0.70c 0.87b 1.2d 2.0b temperature 1.9b 2.5a 0.94b 1.U a 1.8c 2.6a,

* Within eachtreatment group (hide-board,tenperuture) rolues followed bJ a similar lefter do no, differ signlfican lf @>0.05).

328 Food i akesfor eachsize ciass of animaldecreased in talks without hkle-boardsbut thore was little differencebetwe€n 1 or 2 hide-boards.For both sizegroups the water at 34t induc€da slight increa$cin food corsurnptioo. Ilide-boads had !o appreciableeffect on food conversionefEciency by the S/r,I aaimalswhile amongthe lvt/L anirn ls there were higheryet more variableresu.lts. The higherwate. temperatureresulted in significatrdybetter food conslrnptiotrfor both sizeclasses. The cornbinedeffects of food eatetrand conveNionefEciedcy led to the patiern observedir liveweight change. The hicle-boardeffect paralleled the responseoffood consurned.By increa-singfood eatenand also eficiency of conversio&34oC water producedsignificandy heavier animais in both sizeclasses (507o for S INL 3OVofor I\4&).

2. Water VolumeTrials

Resultsof thesetrials are presentedin the folowing table. Whenthe anirnalswere tumed onto their backsfor snout-ventlengtl$ to be neasuredid Trial B, a visual irspection was lnade of the bely skin! and ally skins with evideoce of rnarks or sqatches were noted.

Tnal * l5l9 - l7/lll97 TrtalBt 1612- l9l5/98 AverageWeight Average Weight 70of Animals Water Gain (g/animaVday) Water Gain (g/animaVday) wift Blemisheson Level LeYel Bellv Skin s/14 MIL sa{ MIL s/M MN 3OVo 1.9a* 4.3b 30E 2.9 a, 6.2 a r7b 52a 5O7o 2.3E 4.5 b 5OVo 3.9a 10.3a 0c 0c 807o 2.4 E 4.8b 1@9o 4.9a 2.9I 0c 23b

* Valuesfollowed by a similar lexer do not differ signifca tly (p>0.05).

In Trirl A there was a consistenttrend amoogboth sizecjasses for anirials to grow fasler when more water q.asavailable in the tad

329 DEEISN

1. Ilideboard / TemperatureTrial

Video surveillanceof the hatchlhg auimalsduriry the study observedthat during the 12 hous wher dim light wasprovided ir the roomshatchlings in ts*s with hide- boardspreferred to stayunder the boardsand ody comeout to feed. In talks without hide-boardsthe anirna.lswere observedto clulnp togetherin eachof the two water 6lled corne$. Lang (1987) noted that io thet wild habitathatal ings of different crocodiliansperies tend to form socialgroups and remain in the vicinity of their nest site aod that this group living pre$rDablydecreases an individual'srisk ofpredation.

Researchcarried out otr hatchlitrgC. porosirson a conrnercialfa.rm @iese 1995) recordedweight gais of0.30, 0.45 and0.46 g/animaldaywhen animalswere reared in tanks with 0, 15 and 307ocover respectively,and 1.85,2.0I afr,2.12 d.Bjrnavdsy under 0, 3Oand 607ocove! ia a secondstudy. lllese growth ratesare lower tha! thoseof the prese study b€causethey were achievedunder arnbient te{tperatues on the farm but show the salltepattems ofres?orise to inqeasing amouotsof cover.

Increaseirl glowth of hatchlingcrocodiles at the higherwater ternpetatue of 34" has bee! leported in a group of aaimalsin Townsvillei! a Fevious year (Mayer et 4l 1995), H\rtlon et al (1993)recolr,rrEnd that hatcblingswith largeresidual yolks shouldbe kept at fairly high water ternperature(34'C) to facilitate absorption. Lang (1981) showedthat hatcbli4gCrocodtlus noraeguineae(b€tween the age! of &2 weeks)setrected an envio6rent of 33.4-33.9'Cwhen plac€d in a thennalgadient situation.

2. Water Volume Trials

In previousstudies carried out usiDgthese rerearch tanks aninuls of all agesup to ono lear of ageare observed(by video cafieras) to staymore in the heatedwater than on the land areao! oo top ofhicle-boards.Thus by providhg a geatet amountofwater (aj1dconsequendy less land area)the rearingdersity is reduced. The diet fed during eachtrial consistedof minc€dchicken heads atrd kalgaroo neat, supptrernentedwith a speciatvitamin/nineral prernix. Animalsoften draggedpieces ofmince offthe feed tral6 and into the water, so that the water was sootrpolluted. Thjs is the reasonthat the tankswere ernptie4 hosedout andrefilled with warm water soonafter each feedilg. Over the weekendswhen no feedingor cleaningwas cafied out, animal wasie built up (esperi8ly for the tel1motrth old ]v!ll animalgroups) ard tlle water 1n the 3070tanks belame very poluled. Thg confoundingefrects of water volurneand water quality v/ereiDseparable in thosestudios atrd there js no way of krcwing how mucheach one influencedthe lower growth ratesrecolded in the 3070tatks.

330 The fust trial on five molth old aoi[uls produc€dconsi$tent re$ ts for the r€plicates of eachtreahnent alld similar trerds for eachsize class of increasedgrowth with hcreasedwater. Patternsin the seco[d trial with ten month old arrit'als werc more erratic and not helpedby ihe fact that the trial was lestrictedto just ten tanks. In particularfor thc lvvl- anirluls tie two tankswith 10070w.ter producedtho lowest gowth coupledwith the greatestlevel ofskin damage.Expedence in catchinganirnals for measuringhas shown that aaimalsare lessagglossive to handleNwhea the animals are submersed.Hence it was articipatedthat anirrulswould havebeen less aggressive towardseach other in the 1007owater tanks. Further researchis neededto cot6.rm this hypothesis.Ifit is true in generalthea the aberrantrcsponse recorded in the two 10070lvtr/L tanks in Trial B must be attributedto specificagonistic interactions betwe€llthe particuLr groupiogsof researchadnlals.

CONCLUSIONS

I. Hat&ling C. porosus shouldbe provided with amplehide-board areas and water hated to 34"C for increasedgrowth rals.

2. Juvenilecrocodiles (o 10 monthsof age)grow fasterwhen provided with a greaterbody ofwater.

3. At the sameage, larger animaisgrow lnore rapidly thar do smallerone5, 80 it is preferableto keep them seglegatedin differetrtgroups.

ACKNOWLEDGEMENTS

Thesestudies were Eupportedfinancially by the AustralianRual IndustriesResearch and DeveliopmentCorporation. The authorswoulC like to acloowtredgethe support providedby the corporation'sresealch manager Dr P Mcl@es. The irnportantdaily dutiesof measurhgout food, weighingresidues and cleaning the talks were carried out enthusiasticallyby Mr R Jack. Mrs L Morissy assistedin prepadngthe rranuscriDtand the associatedDoste!. BIBLIOGRAPIIY

Blake, D.K. 1974. The rearingof crocodilesfor conrnercialand conservation purposesh Rhodesia.Rhod. Sci News 8, pp 31+3U.

Hutton, J.M. andG.J.W. Webb. 1993. The principlesof crocodilefarming. hoceedings of the 2- RegionalMe€ting of the ruCN CrocodileSpecialist Group. Darwin N.T..

Lang, J.W. 1981. Thermalprefere[ces of hatchli€ New Guineacrocodiles : efferts of fa€dingard oatogeny. J. therm. BioL Vol.6,pp73-78. 'Wildlife lang, J.W. 1987. Itr Managemenr: Crocodile.satrd Alli.gators, by Webb, G.J.W.,S.C. Manolis atrd P.J.Whitehead. Pp 301-317.

Mayor R., S. Peucker,B, Davis, A Thornas,R. Bloomfiet4 H. Stephensotraod B_ Warfielt. i995. CrocodileResearch Bulletfu VoL l. eu€elslaad Dopt. of Pdnury Itdusbies Report.

lvlayerR., S. Peuckera.rld A. Thomas.1997. CrocodileResearch Bulletin VoL2. Queenslad Dept. of Prir!|aryhdustries Report.

RieseG. 1995. Facto$ afeciitrg food htake andgowth irl captivesaltwator crocodiles. MastersThesis, University of Queenslard. Researchingthe Requirements of Captiye Estuarine Crocodiles in Australia.

BM Davis, RI Mayer, SK Peucker, Depafimentof Primary Industries,PO Box 1085,Townsville, Queensland4810 Australia

MA Read,Deparhnent ofEnvironment, PO Box 5391,Townsville, Queensland 4810 Australia

Abstract

Preliminarywork leadingto imprcved commercialproduction of captiveestuarine qocodiles in Austalia is complete. Depalhnentof Primary lndusties' (DPI) rcsearch and development(R&D) Fogram hasgood resourcesboth in scientific sta.ffand equipmenl Work in progressin two key areas,namely geneticsand nutrition is advancedbut not complete. OtherR&D activities are dircctedat environment (temperature,light, water,volume, hide boards)and management(feed spaceanimal rearingdenities, grading on size)for hatcblingand post-hatcblingCrocodylus poroszs. This work is directedat identirying ideal conditionsin which to rear commercia.lqocodiles. Fulther still, work is in progess identifying major causesof skio damaga(disease, fighting) and minimising these. It is anticipateddlat this multi- discipline R&D approachwill yield resultsby the end of 1998that will promotethe Foduction, growth and welfare of captiveestuadne qocodiles.

Itrlroduction

The commercialfarming ofestuarine crocodiles(C pozasas)is relatively new in Australia and as with other intensivelivestock industries,R&D is necessaryfor the effeclive and efficient husbandryand nutition ofthe species.

Over the pastfive yea$ in particular,research agencies such as goverffnent departrents, univeNities,private companiesand researchfiDding bodieshave been promoting andpursuing a vigorouscooperative research approach. This is a departure from the pastwhen eachagency pursued its researchgoals mainly in isolation.

Agenciesin Australia which fund researchon crocodiles,such asthe Rural Industries Researchand DevelopmentCoryomtion (RIRDC) have adoptedan unofficial policy which haspromoted, if not insisledupon, cooperativeresearch programs. The pdmary goals of cooperativeresearch are impmved rcsearchoutoomes, avoidance of duplicatedresearch programs and research cost efficiency.

In this papera researchprogam dedicatedto crocodilesinvolving severalagencies is discussed.The researchagencies include the:

. DeparttnentofPrimary Industries- Queensland . Departnent ofEnviiorunent - Queensland . University of Queenslaod- Zoology Depaftnent . JamesCook University - Zoology Depadlent - farmersand scientists . QueenslandCrocodile Advisory Group a combinationof r Rural lndustriesResearch and DevelopmentCorporation'

Coopention betweenthese agencies is stong and there is a geluine interestin the collective researchprograms designed to advancethe causeof Australia's commercial estuadnecrocodile indusry

Identiryirg ResearchPriorities

Australia is developingits crocodilefamring industry on the sustainableuse ofits crocodileresource. Crccodiledistlibution in Australia is shownin Figure l ' In the Northem Territory wild crocodilesare mole numelousand eggsand hatct ings are harvestedfiom the wild underan approvedranching program. WestemAustalia also practiceswild harvestingbut many animalsare also farm bred. Queensland'sindustry is totally dependenlupon falm bred animals.

I I Figure Crocodile Distributionin Austnlia

Source:Webb (1989)

Differing productionprograms due to differcnt regions having diferent needshave promotedinterest in both effectivenutritional and husbandrypractices in Australia' iwo key researchissues have been identified, one is ofnational significanceand the other of particular significanceto Queensland They are:

. Developingpelleted feed for crocodiles r The declining performanceofcaptive breederanimals.

334 Olher :esearchissues of sigaificanceare: o Defining/determiningimproved conditionsil which to rear hatchlingand growor crocodilesin captivif . Producilg supsior qlalify skins . Estabtishingfte feed/floor spacerequtemeDts ofhatclLling/growet ciocodiles'

Facilifies

Researcbis conductedeither on commelgialfarms or al the Departneft of Primary lndustriespurpose-built qocodile leseach Aci[ty in Tou*ville.

On-farmbreeder research uses treatnelts and contols which can ielate 10one-on-one, one-on-teroand oae-on-threematiags Resealchis also donewith colony populahons bu: thesepresenl greater difficul:ies in applyirg rigorousresearch design' The productionperformance ofaial animalsis mo]}itoledthrough a computerploductlon recordingscheme called CROCTEL.

The D€panmert of Primary Industdeshas two purposebuilt arocodileresearch Acilities at Townsville (t9p 15'S,146" 45'E). Thesewelc desigredto house hatchiings0-12 oonths ofage (Figure 2a) and growersfrom 12 monthsofage to ha;vest(Figure 2b).

Thesesheds inco?orate lhe followilg features:

. Total envirotrmentalcontrol . Capacilyfo! 300 animalseach . Identical,replicated tanks atrdrcoms fot experimentaldesign.

Figure 2a. Ilatchling Facility Figure 2b, Grower Facility

Staff

In Queenslanda scientific research team approach is used.A biometricianis responsiblefor trial design,dafa analyses aod the interpetation of rcsearch,esults. In addition&e researchtearn has tbe servicesof biologists,nuaitionists, veteriuarians' Th: i"ql::l bacteiologists.virologists- extension and computer specialists and productive out- iil"tn t:i" t"""irch group and other agenciesis extensive . group as ls worrung&'rrD sourcingspecialist "-" tasks is employedby lhe core research works closetywith the ori""t" i"-p"tl"t. For exarnile, the researchteam manufactuersof vitamin/mineralpremixes'

CrocodileBehaviour and Physiolory

Thebehaviourofcaptiveestuarinecrocodileswilldictatetoalalgedegreewhatcan variable' t" aon" io tfr" animal researchsphere Estuarinecrocodiles.exhibit \J,'1* u *l-1: clfich-dependent"uptiu"gro\t'th ratesand complexsocial interaclions theE lequremen6 rn dominancehierarchy. It is recognisedthat little is known about view point' ri,*""* they are dIfiicLrltro work with fiom an experimental ""p*" ";,1 predators Thel hayea Crocodilesare poikilothermic, opportunistic,camivorous chemical -*.J*,'Jigestion'ana -ooog^lic gut which beginsthe digestivegocess using the gross mJchanicil digestionto reduceparticle size Figue 2 shows anatomyofa crocodile.

a - Post-pLlnotury n nbr@ b - Luhss b- Risht lobe aftieer

- storage orgu .l - Lieer, aall bladder d Meserteic lat e - P8t-hzpdtic menbrahe

a -Mese ericfat storaqeoean

L - Kidnets Ketze' 1993) Figure 3. The Gross Anatomy of a Crocodile (Van Der Merwe and 336 Previousrcsearch showed that crocodiles:

. Grow beston high protein (to 50yocrude Fotein dry matter)diets . Preferentiallyusa protein over fat as an energysourae r Comparedwith other species,crocodiles have good food conve$ion ratios . They are efficient at digestingnulients: . Enercy (ApparentDigestibility coefficieot (ADc) 65 to 90%) o Protein( ADC range7O to 90Yo) . Fat (ADC lange 60 to 90%).

RESEARCH PROGRAM

The Queenslandcrocodile rcsearch progam is fimdedby the:

- QueenslandGoverment thfough the Deparhlent ofPdmary Industdas - AustralianGovemment tbrough the RIRDC programand the - University ofQueenslandtbrough the StrategicPartnership with Indusfy - Researchand Training (SPIRT)program.

Objectives

The objectivesof the crocodileresearch progmm areto producecost-effective outcomeswhich prcmotethe efficient growth, productionand welfare of farmed grower and breederestuarine qocodiles. In padicular theseobjectives rclate to nutritional and husbandryrequirements of animalsas theseare perceived to be top researchpriorities.

Discussion

BreederPerformance. Breederperformance declines have been noted on several commercialfarms in Queensland(see Figure 4) forcing the ownersofthese properties to seekassistance in determiningwhy thesedeclines have occurred. 100

s .g t60 I

40

91192 94/95 97/98 Season

Figure 4. Breeder PerforEance Over Time

Two avenuesare curently being investigatedrelative to breederperformance and irclude the:

r effectsofage and geneticdiversity (or the lack thereof)on breederperformance . effectsof vitamins and mircrals on breederperformance

SPIRTprogram

FollowiDgthe identification that one ofthe main factors limiting the ecoDomicviability ofseveral for conmercial crocodile farms in Queenslandwas a decline in hatchingrates, tfuee possiblecauses with this problemwere identified: I ) failue of specificadul$ to Produceviable gamet€s;2) lroblems haniling and managementof newly laid eggs(including effectsofpathogens); 3) Possibledeficiencies in vitamin and mineral nutrition ofbreeder animals. Theseproblems are non_exclusive but are amenableto experimentalanalysis With the goal of conductingresearch to investiSatethe problem of declininghatchabitity on Queensland'scommercial crocodile farms' a collaborativegloup of researcheNand indust-y rcpresentativesheld a meetingto formulate a rcseatchplan This goup includedpeople aom: . DePt.ofPrimary lndustries . Dept. of Environment . Dept. ofzoolog/, The University ofQueensland . Dept. ofzoolog/, JamesCook Uriversity ofNortb Queensland . QueenslandCrocodile IndusEy Group

338 Following the meeting,a grult applicationwas submittedto th€ Australian 'Stategic Parolershipwith Induslry - Researchard Training (SPIRT)' finding body with supportftom the Crocodile Specialist Group.

The main aimsof the res€archproiect are: To improve th€ economicviability of crocodilefarming by determiningcauses ofpoor harching successand identirying practicesthat overcomethese. This will be achievedby: .Idefiirytheparentsandextentofmultiplepatemityofspecificclutcheswithvaryinghalch ratesand thus detemining the optimal mtio ofbreeding malesand femalesin communal ponds, . In clutchesofknow parcntage,determining the stage(s)ofembryonic monality and idendq/ingthe effecrsof specific parents,egg handling procedures,nulritional statusof adultsand infection of eggsby pathogens,and . experimentallymanipulating parcntage and managementprotocols, as appropriate. To improve the ecologically sustainabilityofthe crocodiie industry and provide information necessary to ranchingand conservationmanagenent by: . determiningthe stock structure,extent and patteh ofgenetic differcntiation and distribution of conservatiot\lunilA for Crocodylllsporosur in Queenslandand northem Australia. To detemfne the t&xonomicand consenation statusofcrocodile speciesin south-easrAsia by: . measuringthe geneticdifferentiation and relationshipsamong isolated populations of fteshwalercrocodile species throughout the region and rclaling the resultsback to regional a5sessmen6ofpopulation numbersand viability, and . doing the samefor geographicpopulations ofthe widely distsibutedestuarine crocodile, C. porosl.ts.

The k€y outcomesof th€ rqsearch rvill be: . inaeased hatchinglates and thus economicviabilitt for lhe crocodile indusr-y, . enhancedunderstanding ofc.ocodile mating systemsunder captiveconditions and ways of manipulatingihis to improveproduction, . developmentof single locus fingerprinting methods, . information on the distribution ofgenetically distinct stocksin both estuarineand freshwater speciesrelevant to immediatemanagement issues ard to the sEategicdevelopment ofan ecologically sustainableindusEy in Austsalia, . rcsolution ofsome long-standingproblems in taxonomyand evolution of sp€ciesof Crocodyhlsm the region that will contributeto more infomed managementofthese speciesin captivity and tle wild.

Fundingfor the Fojecr wasgranted in late 1997and work hasstarred on the geneticsand vitamin/mineralresearch. Aspects ofthe researchwill be repoted as compl€ted.

339 TheRole ofvitamins: Relatively little is known aboutthe mineral or vitamin rcquirementsofreptiles accordingto Allen and Oftedal (1994). In a generalsense what is known abouttheir usein animal productionaccording to Puaca(1986) is that vitamins are specific organiccompounds required in diets in critical amountsto maintainthe productivepowers of animals. Further,it is known that eachsingle vitamin is ireplaceable in its speaificfirnction and a deficiencyofany vitamin has seriousconsequences for animals,particularly thosehoused under intensive conditions. Statonand Vemon (1991)take the view that "consideringthe effectsthat a deficiencyof oIIe or more vitamins or mineralsmay haveon animals,the cost is minimal and they should be includedin diets as insurance". Identirying ideal cotrditiotrsunder which to slorevitamins over time hasbeen researched by Davis et a/. (1982). It was demonstratedthat in the absenceofideal stonge conditions (reftigeEtion was found to be ided) vitamio premixesdecline rapidly in topical conditions.

Laboratorytesting has shownthat prcsentfeed sourcesused by the Austalian estuarinecrocodile industry, for brcederanimals, namely spent (old cage)hens and feral pigs, contaitrnegligible amountsof vitamins. lt is assumedthat breederanimals take food for body maintenancepiimarily and reproductionsecondly. Because presentfeed sourcesare so poor in vitamin reservesand the diet is not fortified with a vitamidmineral pemix, it is assumedthat captivebreeder animals are likely to be deficientin both vitamins and/orminerals. This could have seriousconsequences fo! the animals' reproductiveability, leadingto both poor hatahabilityand poor viability of hatchlings.

Vitamin/mineralpremix tiials arecunently underwayon fle commercialfamrs in Queensland.Should the progam be successfulin raising the level ofproductivity the perceivedbenefits are reflected in Table 1 wheremonetary values are reflectedin Australiandolla$.

340 Table 1. PerceivedBenelit of Vitamin Supplementation- BreederOperation

7o Ilatchability No. Ilatchlings Estimated Annual produced/40 eggs Value of Hatchlings per incubated Breeder 47 l9 665* 57 23 805 67 27 945 77 31 1085 87', J5 r225 97 39 1365 100 40 1400 Poultrytindustry cuten f achieees90% hatchabw * Cutent Situation

Pelleted Feed

Austalian captiveanimals are usually fed monotypic diets consistingof fish, poultry and mammal. Feedingmonotypic diets is often undesirablebecause it leaveslittle scopefor dietarymanipulation ald effective animal nutitional management.Fresh diets areoften expersiveto buy, difficult and costly to storeand ftequently only availableseasonly. Suchis the casewith feral pig, which is precludedftom diets during the monsoonseason because harvesting is impossibledue to flood conditions.

The nutient compositionof cunently researchedgrower crocodilepelleted feed is shownin Table 3. Findings to dateare that crocodileswill take pellets on land as well as in the water. Both hatchling andpost hatchlingcroaodiles accepted pellets witlout a "weaning" period. However,the level ofacceptancehas been vadable between pens. Breakdownofpellets irl water is minfuIlal. The textue is goodbut slightly oily. Ultimately pellets for breederqocodiles will be trialed also.

341 Table 3. Nutrient Compositionof the CrocodilePellet

Composition (g/kg) Ingredieut Dry Matter Crude Fat Crude Protein Additives Choline cbloride 1.8 0 0 Lecithin 0.1 0 0 Vitami!,/mineralFemix 4.5 0 0 Dil entsand fillels Water 0 0 0 Enern) TallodveeetableoiVfish oil 124 t24 0 Protein and amino acids Wheatgluten 135 5 111 Meat meal (50% CP) 83 8 50 Chileanfish meal (67% CP) 79 l0 43 Blood Meal t02 10 95 FrcshKangaroo Mince 59 2 52 TOTAL 588 160 351

What remainsto be doneis to:

. Removethe mince component . Fine tune the diet specifications o Detemine which diet ofers the bestcost/benefit llltio to producers . Test equipmentand improve upon teabniquesfor the on-Arm manufactureof pellets.

Enyironmental Conditions for Rearing Crocodiles

Severaltrials havebeen conducted on watertempemtues in which to gow hatchlirog crocodiles. The influenceofhideboalds on gowth rateshas also beenresearched as hasthe effect ofwaler volume. The fiDction ofthese tdals is to Fovide benchmark standardsfor industry. Researchcovedng these topics is repoltedin the Crocodile SpecialistGroup (CSG) 1998proceedings. For detailssee Mayer et al. (1998) "EnviroDmentalCorditions for RearingCro codylus porosus onFatms".

Summary

1. Technicalteams have been formed in Queenslandto pursueresearch progmms \rhich will promotethe production,gronth and welfarc of corEnercialestuarine crocodilesand thesetearns are well equippedto pursueresearch prograrns. 2. Breederperformance has diminished over time. The SPIRTFogram hasbeen implementedto ad&essthis decline. The researchprograrn has geneticsand nutrition as its main focus.

3. Techniquesto manufactue pelletedfeed which crocodileswill acceptare well undentoodand can be appliedto the corDmercialmanufactue of feed.

Crocodile diets needto be testedto determinewhich diet will uovide the best cost/benefitratio.

Bibliography

Allen, Mary E. & O.T. Oftedal. 1994. The nutrition ofcamivorous reptiles. In J.B. Murphy, K. Ader and J.T. Collins (eds.) CaptiveManagement and Conservationof Amphibiansand ReptilesSocioty for the Study of and Reptiles, Ithaca(New York). Contributionsto Herpetology,Volume I 1

Davis,B.M., K. Mccuigan,& P.K. O'Rourke. 1982.Vitamin stability in hot climates. In Pig and Poultry Nutdtion in Tropical Climates,Departnent of Primary Industries,Tounsville, Australia.

Puac4 V. (1966). Premixesin CompoundFeed Industry. Institute ofFood Industry. Livestock FeedsDepaftrent. Novi,/Sad,Yugoslavia.

Stanto& Ma* P. & Bdan P. Vemon. 1991. FormulatedCrocodil€d Feeds in IntensiveTropical Animal ProductionSeminar Ploceedings, Departnent of Primarylndustries,To\rnsville. Austalia

Van Der Merwe, N.J. & S.H. Ketze. (1993). The topogaphy ofthe thoracic and abdominalolgans ofthe Nile crocodile (Crocoalus niloticus), Onde$tepoort Joumal of Vetetinary Resetch, 60:219-222.

WeebGrahan, Charlie Manolis. (1989). CrocodilesofAustralia. ReedBooks, FrenchsForest NSW 2086.

Acknowledgments

The efforts and suppoft of the following arc acknowledgedin pursuit of the estuarine crocodileR&D prcgram.

Mr R Jack,M$ L Modssy, Mrs HP StephensorLDr S Johnsoq Dr A Thomas,DPI, Townsville Dr P Mclrmes,Rural lldustries Research& DevelopmentCooperation Mr A Pamell and Ms M Betts, RhonePoulenc Animal Nutition Dr R van Bameveld,Bameveld Nutrition Dr K Williams-CSIRO I\4rA Stallmanfudley Agriproducts Dr B Duffreldand Mr P Kul:ulies.DPI. Brisbane Thelate Dr P Mullaney,Primary Tasks Membersofthe QueeoslandCrocodile Advisory Group.

344 APPARENTIMPRINTING OF CROCODILEI{ATCHLINGS AND POSSIBLE IMPLICATIONS

F W Hucbzermeyer,P O Box 12499,Onderctepoor! 0110, South Aiica

Imprilting ofhatchlingscorlrnonly oc.urs iD birds andaletemines paredal andlater sexual matererogmtiorl llimaD impddilg ofhtersively rearedostlich chickscauses desertiotr stressproblems wh€n the chick areleft alonefor periodsduring the day,interferes with sexual materecognition causing infeftility problemsa.trd leads to maleaggessivity -- to$ards humansperceived as competiton (Huchzermeyef 1997).

knprintilg itr crocodileshas rcver beendescdbed but basrec€ntly beeq poshrlated .I]his to explaiil ParentlatchJing rDteraction (HuchTrrmeyet 19961. paperreports a caseofapparent humarlilprinting ofinteDsivelyrea.Ed crodile (Croc.dylus niloticus) hatcblings ;d drscussespossible implication oII jwenile andadult behaviour.

CaseHistory On a newlyestablished focodile farmill SouthAftica 4OOnerr,ly hatched crocodiles vrere boughtin andplaced in a smallenvironruerfally codtrolled house ea.ly in 1997.The hatchlhgswere kept in neadarhess, orceptwhen an obs€rvetwas pres€nt. The laaly bec€meso intriguedby the crocodiles,thai shedaily spentseveral hturs with the hatcblings while cleadtrgand feeding orj6t siEply obsewltrg.The bakhjingsbecame very rame, ruluungup to ber aodallowing her lo touch$em.

Subsequetrdya larger rearing house was build andeady iu 1998the crocodiles,aow yearlilgs weremoved to this newhouse. In additionyeadings were bought from €llothe. frrm andpfacedin otherpens iq thesdme house- The newty-purctrasea feartings setUea in veryquickly andcaDle b fte food arfeediDg tirne, wbile tle ownharctriings ajpeared to remarnvery shy.runnhg awayido a far comerof their pe!, wien a personapproached, Discussion Io F yl4 Nit""r"aoaile batcblingsstay wilh tbeir morherfor rbe6rn year,but teaveher beforerhe new cluEh harchesout. lf Lhismother-hatcblng interacton was governed by ihprintidg, onewould expecta switchin the behaviouroft" Ut"ttiog" uf-npp-*iait"ly oney€r ofage fromdependebceto avoidarce,and this is whatappears-fo havi tappenjt lhe d€scribedcase. Providcd the iderpretatiodofthis caseis correc! it couldhav;;evqal rmpllcaoons:

Orlewould assumelbat aorDrallyfrfir€-raised qocodile b-tchling(would not impriDt.It c-ouldbe that sucha failwe to imprintwould prevelt the halchlingsfo find the comfortof parentalprotectiotr that \rasfollnd to beofvital importancero ostich chicks(Huchzemcyer, 1997) atrdtherefo.e be exposedcodinuously to a highlevel ofsaess.

Failureto implirf would abo preventy€arlings and olderjweniles to re€ognizelarg€r crocodilesaspoteotial drnger. This in tum c.uld explainthe high lossesin rcbaJafin_ r€aledcrocodiles from canrdbalismdescribed by Bossertet al (itr this book)for Americatr alligatoG,butalsoho\}nfiomtheNilecrocodile(...,....).it*ouldmeanthattherele3se offamFrearedcrocodiles \rould bepossible oDly into a habiratcurreffly A€eoforccodilos. Crocodil€farmeN in SouthAliica haveobsefled that frrm-reared crocodiles are l€ss agessivein breedingcolonies than wild-oaugbt ones. Breeding colonios of500 andmore breedingcrocodiles are common on th€s€farms. It maybe that aon-imprintedmale crocoahl€sto someexlend fail to rccogDiseother males as competitors and the.€fore give the impressionof docility.

Sexualmate recogDitiod is gov€medby otherEecbaoisDrs (e.g- pheromones) as weu, atrd thereforenon-imprinted crocodiles would b€ €xpectedto mateand reproduce quasi-rlormall). It wouldbe interestinglater to obsere the agressionalrd sexual behaviour ofthe supposedly himar imprinteddocodiles ofthis case,ifthey wereallowed to reachthat stage.

Furtherobsewations and experiments will be rcc€ssaryto confirmthe prcsenceand exact consequenc€sof irEprintingin qocodiles.The possible implications for lhe managementof crocodileson farmsand ofrestocking programm€s oeed also b€ investigatedfurther-

REFERENCES

346 Artificial Incubationof eggsof Crocodylusuorcletii ttader eaptiyeconditions.

FranciscoJ. Leon Ojeda,Patricia L. ArredondoRamos and Manha C. RoblesMontijo

CocodrilosMexicanos S.A. de C.V. PaseoNnos Heroes#276 Pte. Culiacan,Sinaloa Mexico

Anyone wishing to undertakeprojects involving the conse.vation,the augmentationof wild populationsor captivecultivation ofqocodilians must considerthat incubationis one ofthe most importantelements of suchprojects. The successor failure ofthe plojectmay be dependenton successfulincubation.

It hasbeen abundantly demonstrated (Chabreck 1971, Ferguson and toanen 1992(cited in Mosesand Chabreck1 990)) that a$ificial incubationof crocodilianeggs zubstartially improvesthe productionofhatchlings by eliminatingthe natural losses causedby climatic effectsand predation. For this reasona wide variety of incubation techniquesare usedaround the world which havein commonthe objectivesof maintainingthe temperatue constantat around32' C, an elevatedhumidity (higher than 90% RID and an acaeptablelevel ofgas exchange.To achievethese goals the various equipmentand matedalsready to handare used, and incubationvaries fiom rudimentaryrelocatiol ofeggs into atificial nestsdug by peoplein strategiclocations to the industrialhigh technologyapplication using electroniccontrols. As a cons€quencerthe rcsults arevery variablebut clearly observedin diffe.enaesin the percenthatching and the subsequentglo]'th ofhatchlings.

Disinfection of eggsis an importantpaxt ofadificial incubationas this processhelps to eliminatea large quantity ofbacteria and fungus. Theseusually havea small effect during the courseof incubation. However,dudng hatahing,particularly the fungi which persistin a latent stateas resistantspores, contaminate the hatchlingsand aancause a varietyofsystemic illness and a highlevel ofmo6idity andmotality (Hibberd1994). In the sameway, the applicationofantibiotics andvitamins onto the egg and through the shell and rnembrarcs,which havethe capacityto absorbthese substances, may help to avoid infection and improve the nutdtional statusofthe embryo@. Ruvell pers. comm.).

At the CooodrilosMexicanos S.A. crocodilefarm we havebeen successfully rcprcdudJ\gCrocodylus moreletii since1990, and with the passingof time we have improvedthe techniquesofincubatior and allowed the farm to dra.rnaticallyincrease its stock. The farm operatesexclusively through fie produclionfrom a group of reproductiveadults whose fertility hasoscillated annually between 80% and 85% ofthe total eggsproduced. The objectivesofthis study was to eslablisha standardmethod of inatbatiot for Crocodylusmoreletii using exising levels of technology.

341 Methods. We useda total of224 fertile eggsfrom different nestsproduced by crocodilesof different sizeand age,these eggs being producedduring the later portion ofthe reproductiveperiod of 1997. The fetility ofthe total annualproduction was lower becauseour finest reproductivefemales are the last to nest. The processof collectionof eggsand movementofthe eggsand managemeotto the incubatorwas donewith great careusing techniques described by Ferguson1981. Thisprocess consists firstly of an inspectionearly in the moming to identify newly laid nests. Wheo detected,nests were recordedin a registernoting the ambienttemperatue andhumidity, nesttemperature, diameterand height ofthe nestand the numberofeggs. Follorting this tlle eggswere collectedone by one,using great careand markingthe uppermostsurface in orderto conservethe oientatioo ifl the sameposition as it was found. The eggsfrom eachnest v/ereplaced into a separatepolystyrene box with materialfrom the nest. The boxes were movedinto a 'walk-in t'?e' incubator8m x 4m insulatedwith 2 inchesof polyurethane.Temperatur€ cortrcl was achievedwith a model SS-120Hired Hand 'Y' airconditionerwith a 120,000BTU capacitywith a duct andthemistor. Humidity was maintainedabove 90% RH with a BAHSON qpe EEIA humidifier with a capacity of 3 gallonVhr. and integated humidistat. Gaseousinterchange was maintained throughthe incubatordoor during entry to the incubato!. Oncethe eggswere placedin the incubatorthey were left there urdisturbedfor 24 hrs. then on the following daythey were examinedand thoseappearing discolored were ideotified as infertile. The eggs were then incubatedin new polystlrene containersin a substratedeveloped on the farm consistingof sandand vermiculite. The containerswele perforatedin thet lower parts to allow drainageand avoid excesshumidity, exceptthe four receivingthe plastic aover treatment(see below). The useofthese boxesgave some security that the temperature ofthe eggsdid not fluctuatg althoughthe temperatureof air entedngthe incubatorwas 40"- 45"C but the ioterior was maintainedat 31.5"Cas the boxesameliorated any changes.Eggs Aom different nestswere distributedbetween different boxes (treatments)so that approximatelyequal nuober ofeggs were in eachbox, with a diferenca ofno more thar 2 eggs. The boxeswere then assignedto 12 different treatmentsvarying the coveringofthe box, the disinfectionofthe eggs,application of vitamins and antibioticsand administrationofextra oxygenduring the last two daysof incubationas follows:

Treatment Lid Disinfection Vitamins and Oxygen antibiotics I Dolysttrene Yes Yes 2 none Yes Yes 3 Plasticfilm Yes Yes 4 none Yes Yes 5 Plasticfilm Yes Yes Yes 6 Doiystrene Yes Yes Yes 7 Control DOlystlrene 8 none 9 Plasticfilm l0 none 348 11 Plasticfilm Yes 12 polystyrene Yes

Treatment7 Contol followed our normalincubation procedure in which the box hasa Ironnal polystyrenecover but no interventionofdisinfectad. vitamins. aotibioticsor oxygenbut with a topicalapplication ofiodine to theurnbilicus at hatchinsand as necessaryafte.ward. Treatments l-6 followeda processofdisinfection with Nolvosan at 2yo(Diacetate chlorohexide) in a proportionof l: lO0. The solutionwas maintained at a temperatureof32oC andthe eggswere placedin net aontailer and suspendedin the solutionfor 1 minute. Theantibiotic and vhamin treatment consisted ofapplication of first oxyerracyclineand then a completevitamin supplement MTAFORT itaning on day three ofincubation and repeatedevery tkee weeksduring incubation. The materialswere appliedwith a sprayerspreading a smoothlayer directly onto the surface of eachegg and finally a generalfine sprayover all the eggs. Oxygenwas administered to teatments 5, 6, I I & 12 dudng the last 24 hoursofincubation throuqh a seriesof tubesconnected to an oKygentaok which administereda constantflow for 24 hr to eactr box. Tempenture of eachbox was modtored daily throughoutincubatioo.

Results. The averageperiod ofincubation was 69 dayswith a differenceofthree daysbetween the first and last hatching. Averagetemperature during incubationwas 31.8oCand relative humidity was above90%. Ofthe 244 eggsincubated, 194 hatchedgiving a hatchsuccess of79.5%. Ifhatchlirgsfailing to reabsorbtheir yolk (,tubbies')and some lacking a tail (all from the sameclutch) are excluded,the overall hatchsuccess was 68.9% (Table 1) . Compadngthe hatchntes ofthe differcnt trcatments,the bestwere treatments5 and 7 with 85.770and treatment1l with 9O%.

Hatch rate ofthe bandedeggs was 69.6010and a higher numbereggs hatched in the boxeswith somekind ofcover, either a polystrenetop or a plastic cover. A pairwise comparisonoftreatments I vs 7, 3 vs 9, 5 vs l l i.e thosereceivins some kind of intervention(disinfectior! antibiotics, vitamins or orygen)indicaGs rhat there is a better hatchIate in the coveredboxes which also receivedchemical interventior.

We not only measuredtemperature in the expe mentalboxes but in the other boxesm the incubatorand detecleda gadient oftemperaturewithin our incubatorboth from back to front and from one sideto the other. We also observedin Table I that tne majodty ofthe eggswhich did not hatchsuffered from early embryonicmo.tality with infectiorl giving a clear signalthat mismanagementofthe eggsduring the ffrst 35 days ofincubationor possiblypoor quality eggs are responsible.

Conclusions.

From the observationmade dudng this gxperimentwe are ableto makesome clear suggestionsfor a practicalmethod which will result in the maximumhatch Deraenrase - andproduce healthy and vigorous hatchling. We stronglyrecommend the use of 349 disinfectionofthe eggsprior to incubationusing whateverdisinfectant is availablewith bacteriacidaland fugicidal action in doseswhich do not affectthe d€velopment ofthe embryo.

It is also imponant to coverthe bandedeggs as otheri{isethe egg shell and membraneis exposedand though this meanscan loosea large amountofwater. As incubation advancesthis .esultsin a gradualdehydration ofthe eggwhich can result in embryonic mortalityor in developmentalabnormalities such as deviations ofthe spinalcolumn. Our methodofincubatio4 using polystlrene boxes, sand and damp ve.miculite as a substratefor the eggs,and plastic coversas used in this experiment,has allowed a high perc.entageofbanded eggswhich in other conditionseasily become desiccated, as this experimenthas shown. It is also useful to administeroxygen dudng that pedod of incubationduring the last stagesofdevelopment when the oxygenrequirement ofthe embryois incleased. Another impotant factor is ensurethat a systemofventilation within the incubatorpemits adequatecirculation to avoid the formation ofthermal gndients.

Finally, it is importantto cladfy that the conditionsofincubation for crocodileand alligator eggshave been shown to be slightly diffelent, asthe fomer requirehigher temperaturesand slightly lower humidity to achiev€adequate hatching. We have found that following the letter ofrecommendationsfor temperatureand humidity describedfor alligatorswhen incubatingcrocodile eggs results in notably different results. For this reasonit is impoiant to unde$tandthe particular incubationconditions that argbest for eachdifferent species.

350 l,

x

x .i .9 5

R

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5

,t R .l a ? 3 ?,a t9 z< fx F z 3 z 3Z () p 55 a z 5> g> AA ,d tz i.l a9 z II :< o I z o >- F a t o () E f l )F BIBIIOGRAFIA.

F€rgr$otl Mw.J., 1981.Thc aplicatioDof enbryologicalsMics to aligator farming, efigator Prod-Coof (Gainesvilb,nc,rida) LtL29-L45.

Itrbber4 E.L4.d, 194. Fuogal diseasein eggs ed hatchings of farmed poraszs.In: Crocodiles.Procedbgs ofthe 12 th Wo*ing Mesting ofihe crocodile Specialisl Group, IUCN-Th9 World CooservarionUtrioq Glaod, Switrerlatrd Volume 2. ISBN 2- 8317{23Y9. 34Op.

Mos€s,RichardD., dd Robert CbakEck f990. Tznsporrarionand alificial ltcubalioo of AmericanAtlig'lor egss.pp.81-90.

Ruw4 1 . Conper. GenevaFarms, INC. Florid4 U.S.A. USEoF ANABoLICSTERoDS IN T}IEcoMMERcIAL RAISING oF cRocoDILES.

FranciscoJ. Leon Ojed4 Paficia L. ArredondoRamos and Martha C. RoblesMootiio

CocoddlosMexicanos S.A de C.V. paseoNinos Heroes #276 fte. Culiaca&Sinaloa Mexico

Many ofthe shiningexamples ofcommercial anirnal production, such as beei prgs, poultryetc.,.have included the use ofgrolv,th promotiog substarces in theirmanagement pmchceto obtarnanimals which were heavier, more vigorous and resistant to disiase. The use ofgrowth promotors(Antibiotics, anabolicsetc.) is authorizedbv the health authoritiesof eachcountry and is routine in the larger te;hniaally advancedcommercial farms in Mexico, asin the rest ofthe world. the oblectiveofcommercial growth ofa speciesis to maximizeits geneticpotential or to exploit to tie maximumthi animals metabolismto obtainthe greatestpossible development in the shortestpossible time. It is obviously only possibleto obtail suohgroxth under optimal environmintal conditions, nutrition and iD the absenceofdisease.

In the caseofcrocodiles, this is a specieswhich hasnot undergorcgenetic improvement in domestication.At presentthere is no Iine or raceofcrocodiles dJvelooedbv hybridization and selectionfor commercialuse. Hybridization is reportedfrom many zoos and someaommercial farms but becausemany speciesofcrocodiles remain endangered,this practiceis not encouragedfor fear of causingthe loss or modification of genot ?ic and phenot?ic characterswhich arevaluable to wild populations.

Becausethere hasnot beenextensive selection for geneticimprovement, crocodile farmersknow the greatvariation of gowth ratefiom a clutch of hatchlinesfrom the same parentscan be as great asthat variation observedin a whole cohort. On iire other handit importantto mentionthat the conditionsof incubation(Temperature, humidity, gas exchange)exerts an importantinfluence on developmentaftir hatching(Whiteiead et al. 1994). Becauseofthis, an egg fiom parentsdemonstrating high growth rate,ifincubated under suboptimumconditions, will show a growth late much lower than its parents. Even underthe bestincubation conditions about loelo ofa clutchwill produceslow growrng hatchlings('runts'), which can be ashigh as 60010 ifconditions are suboptimalland tratch rutesare also compromised. These runts also have a highmonality (Joanen et al. 1987).

Anabolic steroidsincrease the s].nrhesisofprotei4 particularly in skeletalmusale, lnducrnga garnin weight. Thepharmacological effect ofdifferent anabolic bormones is different. Andogenichormones are generated, and thought to act, on the skeletalmuscle potentratingthe deposit ofnew proteinwhile the siteofaction oiestrogenic hormones ls thoughtto be the hwothalamusor the anteriorhlpophysis wherethey iause the secretron ofgrowth hormonewhich acts at the level ofthe striatedmuscles incieasing the secretion ofsomatomedina(Pelosii et al. 1994). In this sludy we investigatedthe effects oflauate ofnandrolona(Laurabolin MR) in increasingthe length ard weight in the fehabilitationofslow growing hatchlingsof morelet'scrocodile.

Methods We used40 crocodilehatchling ofaround four month agewhich demonstratedslow gowth which had led to a periodofinanation, but which were physicallyreoperating at the time oftle experiment. Thesewere distributedinto thre€ expedmentalgtoups (labelledenclosure 36, 37 andl8) anda controlgroup (enclosure 39) held at densitiesof i0 hut"hline/rn'.The animals were seleated to be representativeofdifferent nests. Each erouo was ield in an enclosue of I if (3oyowarer, 7oo/o land) in which a heate!was i-nstailedto maintainthe water at 32 Coand coveredwith an opaqueplastic coverwhich servedboth to maintainthe temperatureand to isolatethe animalsftom a large amountof stress. The hatchlingswere weighed,measured and disttibutedas evenlyas possiblein the etrclosures.The biomassof eachgroup was usedto delerminethe steroiddose and a proportionatequantity of food.

We appliedLaurabolin MR (Laurateofnandronola) at a doseof 1omgfor each10 Kg of lve w;ighi. The steroidwas injectedintramuscularly illto the baseofthe tailevery 2l daysfoia poiod of 60 days. The steroidwas diluted in an oil base(proplenglicol) to obiain the concentruionswhich were injectedinto eachhatchling. Mean initial hatchling weightwas 64.5 g.

During the tleatmentpedod w€ took five samplesto obtainweight and lengthgains and to adjustthe steroiddoses ard food tation accordingto the new weight.

The result wete a&lyzed using an analysisofthe variance.

Results.

The resultsofthe expetimentare shownin table l. Intables 2 and 3 it canbe seenthat the averageweight and lengthofthe experimentaland control groupsare not significantly diffe.eot at the stalt ofthe experiment. As the experimentprogrcssed we wlre ableto observea constatt increaseill length and weight ofthe group treatedwith steroidscompared to the co rol group. Howeverthis groMh was interruptedfollowing the secondsimple on 5 Januarywhich rezultedin a negativeresult in weight gain in the animalsin enclosure36 (trealedgroup) and39 (Contrcl goup) the reasonfor which is unclearbut may be dueto variationsin temperature.

The action ofthis anabolicandrogen was clearly indicatedby a large increaseweight galn.

Figures I and 2 indicatet]le raie ofweight and lengthgain in the thrc€ feated gtoups. T[e fluctuationsin rate ofweight gain are dueto different causeswhich we were unable to examinegiven the original period ofthe samples.Even so, Ifthe gainsofweight and

354 length arc standardizedas a daily rate (Table4.), we observea gradualincrease between one sampleand the next, obscurcdonly by the sampleof5 Januarypreviously menlioned.

We shouldnote that this steroidwas administered each 2l daysand following the injeaioq provokeda proc€ss,mediated irl eachanimal as it b-ecameaccusto;ed to the effect ofthe hormone,and bega! to gadually looseweight asthe organismcompensated for theseprocesses.

By the end ofthe expeiment, the grouptrcated with steroidhas a meanvr'€ight of 132.6g comparedto l1 L 5 g ofthe conuotgroup. Therate oflength increase was 2183 cm/month In the treatedgroup and 2.4lcnLhonth inthe contrcls.Using anF test,the differencein weight and lengthgain betweer the groupswas significantaithe 0.05 level. Conclusions The use oflaurobolin MD demoNtrateda statisticallysignificant ioqease in the gain in wejght anditcrease in lengh of crocodilesto which it was applied. The primary objectiveofthe experimentwas completedsatisfactorily witirihe gain in animats pr_eviouslywith low gro\ath mtesofaverage growth ofnearly 3 cm and 34g per month. The.actiorofthis steroidlasted approximately 2t daysbut tirisshould pre6iably be appliedevery 15-18days andthe intramuscularroute is very slow when treating a large group ofaaimals. But neverthelesswe recommendthe use ofthis anabolicsteroid when one_hasslow growing hatchlingsor animalswhich are recoveringfiom sicknessor prolongedstress.

All crocodilefarms producesome slow grcwing animalq commonly called runts. The growth ofthese animalsis not normaland commercialfarms haveto finds ways ro improve growth in a good percentageofthese runrs Thosewhich donl die in the first monthsoflife can sometimesovercome this setbackto achievegrolth to commercial size in an economictime period. Our experimentsuggests that treatmentwith ambolic stercidsmay provide a mechanismto achievethis result.

References. JoaneqT., L. McNease& W. J. Ferguson.19g7. Theeffects ofegg incubation te,mperatureon posthatchling growth of Americanalligators. pp.533_537 In WebbG., C. Manolis & P. Whitehead. Wildlife Managernent,Crccodiles and Alligators. Surrey Beatty& Sons.Australia.

Pelosi,S.,R L. Sciorsci& P. I\trnoia. 1994.Somatic influence ofanabolic treatment in calmarl(C.yacare). Pp. 287-29AIn. Vol. 2. Crocodiles. proceedinssofthe 126 WorkingMeetirg ofthe CSG. IUCN- World ConservarionUnion. dland, Switzerla.d.

Whitehead,P. J..1994.Optrmising anificial incubarion regimes for crocodilianeggs. assrgningpriorities. In. Proceedingsofrhe 2"dRegionalMeeting ofthe CSG,Darwn NT. Australia. CCNT, PalmerstonAustralia. TABLA l. Aumeoroe! p€soGr) y longitud(qn) a lo Iargodel e4€rimento.

GRIIPOBiXPERIMENTAL FBC1IA 0&dic-97 26inc-97 0!er*-98 26-s,rf-98 OGftL98 PILETA Peso Peso Peso Peso P€so 66.9 29.03 64.50 29.83 80.45 30.24 1052 127 584 24.29 74.74 29.tl 74.15 29.65 0993 32.t3 \t7 33.52 38 69.2 29-29 94.25 31.15 96.75 32.05 124.9 3443 154 36.13 GRLTPOCONTROL 39 63.4 2anz 29.63 76.60 30-90 09E.1 32-tl rtz 33.rt4

TABI-A 2- Datos grongdios corrEspoodi€at€sa pgsads de cada muestreo e increlncrltosde peso(c,Vresadas e[ gr) a lo largo d€l c&erirtren o.

GRI'PO E(PRIIIENI,IJ- qRUPO COT\TROL

DIAS PISO AOIAL rdEDLC.DESVIS!. NCREMEI{IO PESOIO'IAL MEDIA DESV.IST. NCt&r&tlo to.23 l8 2534.5 t6.02 590.3 076_7 to.o2 129_l 2a 085.1 15.63 0766.0 11.04 3100.J 26.21 0981,0 098.1 11.32 275.O 60 3974.0 132.6 38.40 5715 11r5.0 ltt-t 13,1.O

3s6 TABI-4,3. Datosproneclia

GRUPOg@ERIMENTAL GRUPOCONTROL LONGNUD I'EDIA DESV.ESI lNcREidstcto I'NGIIIID MEDT/{ DESV,EST. INCRIMENTO 865.1 28.87 r.45 246.2 24.62 1.!5 l8 900.9 30,03 l.a0 34.4 296-3 29.63 LJg 10.1 za 9L9A t0,55 13,5 300.9 1.56 992.9 33.\0 2.60 7J,5 32t.1 a2.tl 2.09 1036.l 2.99 331A 3'A L33

TABLA 4. Gaaraoiadiaria €tr p€soGridia) y looginrd(orDldia).

GRLPO CONIROL GRI-FOExPEp.ng.uTAr MUESIREO P€so Logittd P€ro Irqginrd I 2 0.711 0.56 r.093 0.64 -0.010 | )', 0.063 0.62 1.024 0.58 1.186 1.r7 5 1.218 r_21 2.053

35',1 3l:F

o --+-Gpo. ul Confol cto "'F- Gpo.Experimer*o

ffica 1 . Ganansiapronedio en pgso (s.presa& sn g.) p&a et gn4o cgtaol y frabmientoa lio lago del fxfrimrnto. E 'r.s

F zo

Gtritrca2 . Gaaacia pomedio or tqqintd (e,pr€sada€n qn) pata cl grupo cdr&ol y tatamienlo a lo largo del enp€finedio. A Report on the Eelicoptt Swaeysof Crocoillluspolosus in the North€rn Territory of Auslralia

AdamR.c. Britton Brett otdey cnlame G.W.Webb

Wildlife ManageEetulnternationd ry. Ltd., P.O.Box 530, Sanderso4 N.T. 0812,Austratia

Abstrad

Until 1989,oonitoring the poputatioaof the Australiansaltwater crocodile (Crocodtlus porosus) i lhe NorthemTerrilory of Ausfala wasperformed primarily ushg a spodiglt me6od at dghl. The inuoductioDof a regulardaytime helicopter survey programme in 1989providei a meansof surveyiag?0 selectedriver "units" iD a duch shorterperiod of time lhan prcviousspodiglt surveys. Theseafata have provided a relativeindex of abundanceof the populationof c' Porosus. Itt 1997, a tial surveywas performed usiry a subsetof only 21 surveyudts to delerldnewhether a result couldbe obtailed whichprovided a compambleiodex of abunda.oceto the 70 surveyudts at a rcducedcost.

IntIoductioD

Between1945 ad 1971,uDregulated butitrg of c' polorus in the NorthemTeritory of Australia reducedthe populatioDto a.Destimated 5000 individuals. This huntiry wasbamed in 1971,aad the specieswas lisred oD CITES Appendix I h f979. In 1985,c. poro&J wasdo$Dlisted to CITES AppendixII after it wasshown that the populationhas recovered ercugh to begiDcoDEoUed hrn,gement(Webb et cl 1988).A moDitorhgprogranrme was esseodalto exarninethe effec6 of suchmrnrgemeflr, which wasbased around sustainable use of the qrild population.

TheTeritory's moDjtodlgprogamme has relied on both nighFtirnespotlight surveys atrd alay-time helicoptersurveys which arecoltected a!$lally for selectedriver systeDs.Spodight survey data are availableftod 1972(Messel et cJ. 1984),but to covermost of the Territory's fiver systemsthey are costlyad tin€-consuming.In 1989a regularday-time helicopter survey proglamme was initiated at a quarteroftbe costof the existingspodight survey programme. These helicopter surveys cover 70 river units of l0 lan each,aDd they providea rcIativeindex of abundanceof the populatioDof c. POTOS,Sin the N.T, In 1997,the €xistiaghelicopter programme for 70 river u ts wasmodified to 21 ufts on a trial basis.The aim wasto examinethe effecliveDessof rcduciDgthe overallsurvey cosl evenfurther while maintaidrg ar accurateindex of abudarce,

Helicoptersuryey dethod (1989-190

70 surveyud$, each10 I(!r loDg,wele selecledftom 68 river systeDs(Webb ?t aJ. 1988).Durhg JuDe/July,each mit wasflowr odceat or rcar to low tide for maximumbaDk exposure. As the helicopterflew at a coDsra speed(60 - 70 !ph) ad heigh (20 m) abov€the mainstrenm,the trumbe$of $ocodilessigbted werc recoldedinto four generalsize classes (small, medium, large, x- large).The combircddata ftom theseunits have been used to calculatean index of docodile abundance(Webb & Malolis 1992)which catrbe appendedto historicaldaa to providean indicationof populationchaDge over time.

360 Resultsof helicoptersurveys (1989-1996)

Historical(i.e pre-1989)population dara from sporlightsurveys w€re converted to helicopter densityequivaletus (Webb a, 1988)ro whichactual dara fr;m helicoptersurveys (post:1988) wereappended (Figure t). ".

.8 oo .7 too

aa ov

a aa

.1 o 7.5 10 12.515 17.520 22.5 25 27.5 Y€alsSinceProreciion

Figure L Crapb sbowiDt rh. r.larioDsbpb€rpen nce dcrsi.y of c. ?oro'ir .xprcsscda bclicoDrer cou cquivnan$, &d yca..ssilcc lrotccrior (25 = 1996,ctci. rrlto;,c-3l d.la ,i.r..,.a Io hcli.i"io delsiry cquiviialB dc ildicat d wI! ed circlcs, aciur bcliclpr.r dalaeirh op.c citclcs.

Theequation for thisrelatioDship, desctibed by lhear regrcssion,is: y = 0.182+ 0.023x@ = 0.0001,I = 0.7)

Froo^rhis equatiotr(where x = yea$ silce prolectiol, y = 61q.od1. densig, the predicted deDsiry ror ly9l {to years srnceprorection) is 0,767 crocodilesr(m. Tbare dafa suggestthat the geaeral populadon of c. porofiA i! the NortheE Tenitory ha.sshow! a significad-;d dra::oaticncovery since prorection in 1971.

Trial helicopter survey method (19?

Although rh€ N.T- Ielicoprer survey prcgruDBrebas satisfied its original inteftio! (to conthue ro provide.an index ofpopularion cha[ge), rhe cost ofperformiag the suweys is stilt high. Therefore, a trial helicopler survey ,ras conductediD 1997 wiA tUeaim ofieducing cos*, yet mattaining acara@ relatiye index oI abundance. To rc&Jce costs, surveys calt eiiher be performed less often,"u or the number of uni6 (area) iDvolved caII be decreased- hence reducing coOy netoprei nign Iime. we examined rhe la[er oprion, takiog co$ialerable care to crcate tsubsel of dver u ts wtuch reflectedaccurarely tle densiryand size disnibudon of crocodilesseeD in all70 utrirs.

361 Crerting a subset

Riverswere select€dinitially by coffidedry !hei. knowncrocodile densities, paltems ofgrowlh, and their location. This produced a subsetof 49 river u ts (Subset49)which was caPableof predicting the mean densily of crocodiles in 70 uDits vert successfully (using lined regression: p < o.o0o1,I = 0.9?0)(Figure 2). These49 units weredivided into high, dedium andlow densityunits (following the classification used by Webb et al. 1988) and a mulriple regressionperfomed against the 70 uni6 to account for biasescaused by varialion in different deDsityutrits. This showedthal orUy high aDdmedium density rivers were contlibuting to the relatioDship, and so all low density rivers werc excluded f.om the subset.The new 21 unit subset retriDed the propenies shown by Subser4gand appearedlo be a very good predictor of the deDsity iD 70 units (linea! regression:p < o.o0o1, r? : 0.993) (Figure 3). Size strucNe of crocodiles is alnost identical berweenlhe different subsets(Table l).

A secondsubset (Subse!2la) was devisedby replacing the Roper river with the Kalarwoi river - bolh medium density rivers - iD order to rcduce helicopter flight time. Subs€e1a is also a good predictor of the crocodile densiry in 70 utrits 0ine:lf regression:p < 0.0001, I = 0.979). Tlt fiul survey ircluded both the Roper and Xrlarroi dvels to compare Subset2l witi Subsel2la. The Rope. is charict€rised by high variability ia numbe$ of qocodilcs sighted, a.!d we felt that Subserla might provide a better long-term solutioD.

i -61s t

d

.56.53 .6 ,62.64 .66 .63 -1 .12.14 ,16 l,o5 l.l r.15 !.2 1.25l-r 1,351.4 1.45l5 Sqb*r2l

Figlr. 2. Glaph sbowilg tb. tclalo.sbip Figur. 3. G.aph s!o*i.g llc rcladoDship b.tvd @a! delsity of c. por46 itr !.tec.D Eca! d!i!s,ry of c poerzr in subscr49agai$r lhe n 70 uit dalaer I! a sr$s.ot ae!i!$ rb. n 70 uit dat&lcr ln p.rfed rclaliolshi!, alt poiDb would lic o! a pcrfcct Elatio.sbip, all poilti podd lic

N''d.L4.fo'14.4x14.N'.L .7 245 29.6 1076 47.7 t731 t6.0 542 6.J 159 28.9 726 46.3 tZt4 16.4 4\2 7.1 tst 28-8 611 473 tO79 ]62.:..34t. 7.t \50 2g.o 6\-t 47.7 rOO4 16.1 339

Table 1. Size srBcl@ of rhe diff..elr sub*rs cxlra.d at lusbcB ald p.rc. rgcs of crocodild c&h or fou sizc classes GFall, roediln, ldgc, i-largc). Results:predicted v. actual

After performin-g-rhe rriat helicoprersurvey, the fire3suled detsity for Subseela(rhe Dreferred suoseuw:15 l.)JJ crocodil€s/kn. Using the followiDg equatioD(ob6ined ftom a regr;ssion between Subset2laand rhe70 unit dataseD: densityTo- 6.4699* 6..sity2r" + 0.0632 the corrected density for 70 uniis derived fiom Subset2la is 0.782 crocodiles/kjn (Figu.e 4).

The-me€sureddeDsiry for Subsel2l (using rhe Roper river) was 1.490 crocodiles/hl. Usilg me

dersityTo= 6.5299* 4"nsiql; + 0.0149 the correcred densiry for 70 utrits derived frod Subseel js 0.791 socodiles/kn.

The predicied density fo! 199? was catcuratedar 0.767 crocoariles/km.subseola gave ar error m predicri!tr of ody 0_015crocodiies/L:d, or 1.9%. Subse€1 gave an error ia pr"aiStioi ii o.oz+ crocodiles/kd,or 3,1%.

CoEclusioEs

Tbe chrnge b crocodile densitiesover time derived iolo helicopler coutrtsdescribe atr ove&ll recovery of,rhe geDeralpopulicion of C polo$l', in Oe Norttm ferritory. tlis u"oa,"fi"* ,a. succss or rDe comrrcrcnl utillsaion progamee wNch b35 beeo operatiry for over ten ye3rs. Arroougtr ure Destb(ticators of deEsiriesand popularioDtrends coBe udtub@dly ftoDr deBned aud survey showsthat cost+ffective aad accuraie alernatives may tE:ry]I,y:?: oenveo D0E an-{s..:"t,.TlicoI!er erusutrgdrtaser

t.5 5 7,5 l0 12.5 l5 t7.5 20 22.5 25 21.5 yean Sinc. p.orccdon

Figurca. crap! sbowi,rglbc relarioBtupbcrwccD !rc.! d.lriv of c. prrora.xprcsscd s hclicoorc. cosr .quivild6, 4d yc4 3c. prcrccdon(26 = 199. crc)_ Acknowledg€ments

Dataare preseDteal courtesy of the Park ad Wildlife CommissioDof the NorthemTer tory (PWCNT),who alsoprovided turding for the helicoptetsulveys. SimoD Stirmt (PWCNT)asslsled in collectionof datafor the 1997survey.

Refeaences

Messel,H.. Vorlicek,G.C., Green,W.J., & Onley,LC (1984)Suneys of tidaldver systetnsin the Nod}lemTeritory of Australiaand their crocodilepopulatioDs- MoDogtaph 18 Popllarion dyiamicsof Crocodtlusporosa aDalstatrs, rnanagedeDt and recovery. Update 1979-1983' PergamonPress, Syalney.

Webb,G.J.W., Dillotr, M.L., Mcf,ea!,G.E., Marclis, S C & Ottley,B (1988).Moniioing the recoveryof the saltwatetcrc.odie (CrocodrlusPoro&J) populationin the NorthemTeritory of Australia.f Wo*ing MeetingoI the IUCN-SSCCrocodile SPecialist Group. I'ae' PapLa New Guinea. webb. G.J.w. & Manolis, S.C. (1992).Motritoring saltwater crocodiles (C/acodYlus porosw) istje NorttrelDTerritory of Ausualia.ln: WiWiJe2001: Populations (eA. By Mcculougl' D R & Barlen, R.H.). ElsevierScience Publications Ltd PP 404418

364 APPLICATIONOF GEOGRAPHIC INFORMATION SYSTEM (GIS) TECHNOLOGY TO CROCODILERESEARCH AND MANAGEMENTIN QT]EENSLAND.AUSTRALIA, J.D. MIer, M. Read& P-Kotoi pO Que€nsladDeFrtment ofEnvircnment and Heritage, Box 5391,To$.rs.ille, eueenslan4 Australi44810.

ABSTRACT The use ofceogaphic Information S)stem (GIS) technologyto addressbiological, conservationand m,lnagementissues has two additionalbanefits over moreconveDtional mapprngand aralysis methods. First, GIS technologyallows ihe pr€sentationofcomplex, and sometimesdisconnected, data in a visually s).nthesisingmanneq seconal, use ofa GIS enables spatia.l(e-g. position of crocodil€,ttpe ofvegetation) andnon-spatial data (e.g. size of crocodile,Einfall) to be analysedin combinationwith topographicinformation (e.g_eleration, drainage)and attribute infomation (e.g. infiastmcture). The traasition from moretraditional stylesofdata a.Dalysisand presentationrcquires training in the use oftle GIS progEm but relatively little adjustrnentto dalabasefiles. The greatestcbange occurs in recordingthe position. The position ofthe crocodilc is rlow recorded via a GPS(Global PositioDingSystem) ir degreesand minutes oflatitude and longitude which are ihen convertedto decimaldegrees for use in the GIS program. the generalapproach combines the use of digitized topographicmap layers of athibutes (suchas *aterw,Lys,roaals, infrastructure, vegetation q?e) andimages (aerial photographs,digitized maps,or satelliteimages) suppoltld by statewide aerial ard stratrtied \rate!-way surveys. Standarddata collected during surveysincludes positioD, estinrate of size, date,time, babitat andactivity ofcrccodiles sighted.This apFoach allows for a linkage through time of attributescontained in culrent and older datasets and analysisvia Bootean logic.

INTRODUCTION A Geogaphic Irfornlation Systern (GIS) is a computer-basedsystem by which spatially (geographically)referenced data can be oryanised,interogated and displayed(Koeln er'-al.,1994).The useofa GIS allows integrationof spatialand attdbute datathat is nor availablevia papermaps. Because a GIS can presenta view ihrough multiple dafa layerso. themeswhile maintainingpositional relationships among them, analysisof datavia a GIS slFtem allows five basicquestions to be addressed(Walker ajd Miller, 1990): l. Wlat exists at a specifiedlocation? 2. Whereare particular conditionsmet? 3. Wllat changeshave occurredthrough time and wherehave these occurred? 4. What arethe impactsofchanges in Iand usepattems (social, economic, environrnental)? 5. $tlat will be the likely result of furrher changesin land use pattems?The answec to thesequ€stions have direct beadngon the consenation nurvtgementofa speciesand its habitat.

365 BUILDING A GIS A natuml resourceGIS is usualtyconstructed for an areafrom existing data including satelliteimages, topographic maps, aerial photographs, digitized rnapsofinfrastructure, administrativeboundaries, inventodes of flom andfauna, vegetation maps, soil mapsand drainageoutline maps(Combs et al., 1996)(flg- l). Eachlayer or themepresents information on a parhcularaspect ofthe arca ard its flora andfauna (e.g.v€getation, soil, slope,aspecr, elevalio4 topography,rainfa.ll, infia$ucture, etc.). Data may take the folm ofpoints, lines or polygons. The bas€rnap (or image)serves as both a backdropto the presentationand an active layer in the analysis. New data obtainedfiom recentresearch can be incorpomtedas an exta lay€r. The infoflrDtion themesaro interrogatedvia Booleanlogic to describetheir intel- relationships(Sillq l9?9). The currentmidmum standardfot a PC computerused in supportof GIS work is a Pentium 150(or geater) processorwith 54 (preferablyor mor€) megabytesof RAM; the GIS softwarebeing used is ArcView (EnvironmentalSystems Research Institute, Inc.) but other softwarcpackages are alailable.

GIS DATA In order to be usablein a GIS, the minimum data setcollected in the field should include:position of eachsocodile in decimal degeesof latitudeand longihlde,a descnptlon ofhabitat, dateand time, estimatedsize ofeach crocodile;these attribute data are linked by the position. Additional data shouldbe obtainedon the exactstarting point and exactfiaishing point ofthe survey,distanc€ surveyed, route surveyed,duration ofsurvey, season,moon phase, wate! and/ortide level, $ater andair temperaturcs,wind strengthand the numberand species of crocodilessighted as well as otherspecific data required in supportofa particular study. One ofthe a&mtages ofusing a GIS is gainedwhen digitisedmaps ofthe habitat beyondproximity oflhe docodile areanalllsed. The variousthematic layers often revealmorc aboutthe suroundrng areathan canbe observedduring the survey Colour aerialphotographs arc a souce ofactual and detailedspatial infomation. Colour aerial photogaphsmust be digitisedor scarmedand the imagesmust be rectified (conected)to reduceerror from the camerabefore positional datacan be overlaid. Digitising the boundariesbetween various parts ofthe image(i.e. river banks,veg€tation t?es, roadways' etc.) to makeclose up outline (polygon) mapsmay introduceerrors of l0 to 20 metersin actual positio! (Grossand Adler 1996). In Queensland,digital map coverageis Fovided through Auslig on a scaleof 1:100000.The coveragesinclude primajy featuressuch as rivers, wetlands,roads, and other infi:ashucturein eachtheme layer. Theseinrages ale as aocrmteas a l:100000 papermap. Th€ digitised naps allow examinationoflarge areaswith a relativ€ly high atcuncy. Covemgesat other scalesare becominga!?ilable. Satelliteirnages are very good latge scalepictures; however,the imagesmust be rgctified (corrected)beforc positionaldata can be overlatd.Because ofthe spectralbands captued in the image, sateltiteimages are very useftl in broad-scalehabitat mapping Unfortunately,magdiring the imageto examinea portion ofa river, for exarnplg revealsthe coars€nessofthe pixels which may representan areaon the ground of30 x 30 metersor more as a unifom entity. Eachtlpe of thematiccovemge provides infoination that can contribute to th€ overall analysis,however, each has its s&engthsand weaknesses and they shouldnot 'thrown be together'; a clear unde8tandingofthe impact ofaddiDg errorsto fhe analysisis requiredto selectappropriate inages, themesand data.

DATA POSITIONAL ERROR The key characteristicof dataused ir a GIS is position; all other athibutesare related tlrough their positions. DeterminiDgthe position ofpoint is relatively simple using a Global PositioningSystem (GPS) unit. Howevef GpS units havean acknowledgederror associated with the accuracyand precision ofthe position. The positiou given by tie GpS may havean error of+/- 30 meterson the ground,sometimgs less. Grosserro6 are usually eliminated tlrough training and careful operationofunits. Sysrematicerrors remaiq particularly with the use ofnondifferentially correctedpositions as a result ofthe intentional introductionof positional eror from tre satellites;these can usually be identified by displayingthe data.The developmentof differential GpS hasreduced the error to lessthan I meier in somecases. althoughthese units arc still expensive.R ndom efiors occuroccasionally without ole3r explaration; thesecan sometimesbe idertified by displaing rle data. EstablishiDgthe position ofa line or a polygon requiresthe datato be digitised agains a rectified map base which is slightly more complicated(see Koeln et al., 199{ for discussion). Becauseall methodsused to obtain a position containero$, tho conceptof what 'aca€ptable constltutes error' is impoltant. Acceptableellor must be definedin terms of the biological cha€c€ristics ofthe spcciesb€ing studied. In the caseofdocodiles, a GpS pornr error of+/-30 metersin position during a suney is probably acccptable.For example,ifa qocodile is spottedamong vegetation at the edgeofthe water alongthe left ba* ofa river, the error in the position is 30 metersalong tle bank. The GpS position in conjunctionwith the obse@tion ofthe actualposition meansthat the crocodileis not at tie right bank or in the middle ofthe river or on the mud ofthe left bank. Givel a circle oferror aroundthe clocodite of+/-30 metemand the observationofits phlsical positior! tle real error is along the bank.

DOANDING Tl{E SPATIAL AND TEMPORAL SCALES The conceptofscale in ecologicalresearch contains t!r,o dirnensions:spatial anal tempoEl (Cody, 1996). Expandingthe spatialdimersion is easy(albeit possibly difficult logistical9; for example, inc.rporating morercplications in a wider rangeofbabitats extends tbe spatialdimension. Expandingthe temporalscale is morc difiicult; it simply t kes time. The only way to incorponte an expimdedtemporal scale is through long-term studies(Cody, 1995). Ideally, ecologicalstudies, particutarly those dealing wirh changesin populiationsof long-lived species,community structurg and/orecological sJrstems, incorporatg epansion in both dimensions. Scateis also irnportantin the atalysis andPrcsentation of dala b€causoa GIS allows manipulationof spalial dat4that may not bejustified by the natureofthe data (Goodchildand 'zooming-in' Gopal, 1989). The abiliry to changetie scaleof a map by is tempting but often not support€dby the accuracyofthe cartography(Goodchild and Gopal, 1989) Enors on mapsinvolve both the attributesand tleir relativepositlons. The efiors compoundwhen the scalesofseveral layersar€ violated; as a resultthe accumcyofthe analysisis compromised For exarrple,a line on a computermap may havea width tllat representsone to severalmelers (evedtens ofmeters) in the real world, dependingon the scaleofthe rnap. Magnirying the image(zooming-in) will reducelheperceived width ofthe line but doesnot improvetlre accuracyand/or ptecision ofthe line. Similarty, the dot that repres€ntsthe position ofthe crocodilea.lso changes size as dle map image is magnified. When vie\aed in the conte\'tof a largearea map, the dot may represertthe total error ofth€ GPSposition (+/- 30m or moro. wlen viewed on a magdfled map,the dot rnay repr€sentonly a few metersand give the impressionof accuracyand precisionthat is not containedin the data for example,the dot may be positionedon the q{ong sideofthe river aacordingto tle obsenationalDotes. Expandingthe temporaldimension into fie future takestime but GIS anal'6is can be edend into the pastthrough the computerisatio!ofpreviously collecleddata sets. Theseolder datasets contain information reletant to both the tsnporal andspatial conponents to the over all project, evenif different methodsanayor persontel wer€ usedto obtain the data. The practical aspectsofincorporating older data s€tsform a tlm€ consumingprccess that involves severalsteps, i&luding the identificationofdata sources,acquisition ofthe data (i.e. obtaining oopiesof datathat must be t?ed or scannedinto electronicfomat), rnanipulationto be compaliblewitl the necessarycomputer format(s), checking a.nd cofiecting befoie the data canbe displayedas a tleme (maplayer) and analysed For example,MagDusson et al. (1980)conducted a broad_scaleaeria.l survey to assess estuarinecrocodrle nesting habitat along the westemsids of CapeYo* Peninsulafiom the Norman River to th€ tip of CapeYork Peninsulain 1979. The surveynotes contained several attributes:the AMG positior! a descriptionofthe habitat andvegetation, comments oI! actual nests,and a rating ofthe quatity ofrhe habitat in a Par-agraphper site fo.mat The data obtahed ftom Magrusson€t al. (1980)provide a snap-shotofibe location ofrests, the number ofcrocodiles seenand an eva.luationofthe habitat at the time ofthe surv€y (1979). As future surveysare conducte4many ofthe sitesand all oftle identified aestswill be revisited. As witi all previouslycollec{ed alat4 som€t}?es of compatisonsmay not be possiblefor a numberof reasorsbut beingable to examinethe distribution ofnests and nesting habitat along specfic watenara,sseen in 19?9in the conte* of1le resultsofmore curent survels doesallow assessmetrtofchange iD nestinghabit4t andnest distribution. Without older data sets,broad-scale ecologica.l and population research is alwaysjust begluring using older data setsallows researcheffort to be betterfocused and build on existinginfofination.

368 SIJMMARY GIS approachallows the combinationoftemporal andspatial componentsofdaja and their display. The ana.l'sisand modellingavailable through the application of GIS tecbaology becomestempomlly dFamic and spatially descriptive(Ctessie, 1996). However,as with any computer-basedsystem, the rule of,garbage in - gadage out' applies. In tems ofGIS arulysis, this conceptrefers to the quality ofthe data collectedin the field, the us9 of appropdatescales and the sum (and s).nergism)of all errols.

LITERATIJRECITED Cody,ML. 1996._Introductionto long-terln commuity ecologicdstudies. pp. t_lj. In: Long-renn studiesofvertebrate corDmunities. (M.L. Codyaod J.A Srnalwood,ids.). Acarfemic_press, NewYork. Combs,R Stridf J. andBolsta4 P. 1996GpS \.s Traditional melhods of dataaccu.acy input improving s?atialdata accuract? pp. 359-365.In: SpatialAccura€y Assesunent in Naturalitesource and EnvironmentalSciences. (H.T. MoFTe., RL. Czaplewsl4RH. Hamre,eds.) USFS General TechnicalRepoft RM-GTR-277. CressisN 1996Statistical modeling of environmentaldata in slac€and time. pp. l -3. In: Spatial AcqrlacyAssessmen in NaturalResource and Envircrunental Sciend;_ (H.T. Mo;er, RL. Czaplewski,RIl Hanre,ed!.) USFS General Techical ReDo(RM-CTd_277. Goodchild,M. altdcopal, S. (eds-)1989. The acflracy of spariatdal2bases. Taytor and Francig Lonalon, U.K.290p. Grcss,C"ld Adler,P. 1996Reliability of Area\4appin8 by delineationh AerialphotoEmphs pp. 267. 271.In: Slalial Accur,acyAss€ssment in Natural Resource and Envirorunenraf Sci;c€s. (H.T. ,- _ l-{owrer,Rr. Czaple*ski,RH. }Ianre, eds.)USFS Oeneral Technical Report RM_CTR-2??. Koelia 9T., Cos€rdia_L.M. and Saon& L.L. 1994.pp. 540-566.Ilj Researchar; rr,lanagement Techniquesfor Wildtifeaad Habitats. Cf.A. Booknou! ed.) The Wildtife Soci€ty;Bethesda, Md. L{agnusson,WE., cdgg, c. C. andTaylor, I A. (1980).An aeriat$lr!e} ofpor€mialne$ing a&as of Crocodyluspomsus on thewest coast of Capeyork per ns,na_iu$;alan Witdlifeiesearctr, 7,4654',78. Silc J. 19t9. Suri*icat conceprsin geog.aphyCeorgE Allen andUnwi4 London.276p. Walker.T C andl\4|ler. RK. 1990.Geographic infomation syslems: an assessmentofiechnok:gy, applcarionand producrs. Vol. I SEAITech. publ. , Madisoqca I66p.

369 Figue 1- A GIS is constructedfor a definedarea from a seriesof themes(layerc), eachofwhich pr€sentsinformation on a palticular asp€ctofthe infrasauchue, physicalstrucbre, flora andfauna. Datamay be points,lines or polygons.

View throughthemes

CrocodileSightings

WetlandBouodary

Rivers & Roads

Vegetation

Land Ownership

. Topographyof Catchment pre-hatch method for influencing the diet eaten aft€r tatching in Saltwater crocodile (Croco.lylus porosus) II. Sneddonl, P. G. Hepperr & C. Manolis2

I School ofPsychology, Queeo'sUnive$ity ofBelfast, Belfast, N. keland 2 Wildlife ManagenentIntemational Pty Umited, Darwin, Australia

ABSTRACT Oueobjective for thoseresponsible for raisingcrocodiles in captivity is to emurethat lhe admals producedare healthy. Consequetrdyit would be benehcialto feed animalsan optimal diet as soonas possibleafter hatching. However,hatcblings catr sortrctimes be choosyabout what they eat andit hasbeen suggested tiat odous may play an impotart rcle in diet s€loction io both youngerand oldepnimdq. Wo* in sp€ciessuch as chickeN, rats and humanshas shownthat when an embryois exposedto a substancebefore bifth or hatching,it will prefer tiat substancepostDatally. This piecoofrcsearch examined whether it waspossible to influencelhe postlatal dietarygefererces of lhe Saltwatercrccodile (Crccodylus porosus)by exposue to a chemos,ensorystimulus (strawberry) during incubatiotr.

Embryoseither rcceived no prenatalstimulation or wereexpos€d to eittrerstawbery or water during the last 18 daysof iacubationby wiping the stimulusonto the surfaceof the egg. After hatchiDgthe qocodiles' consumptionof strawbery flavourEd,orange flavoued atrd unflavouredfoods wasBeasu!9d in a vadety oftwo choicetesb. Results(takisg clurch valiation diEcdy into accouBt)showed ttrat crocodiles who hadbeeD exposed to strawb€rry beforc hatchingshowed a signihcantpostnatal prcference for strawberryflavourcd food, This preferencedid not generaliseto novel stimuli suchas orange and was specifrcto the stimuls usedfor embryonicexposure.

The preliminaryrcsults from this studyshow that when crocodileeggs are coat€d with a chemosensorystimulus dudng tie last stagoof itrcubation,the hatcblilgs will subsequetrdy prefer food flavouredwith that stimulusafter hatchitrg. Io termsof husbandryit rnay be possiblethelefore to 'prime' the qocodiles to be more receptiveto thgir diet after hatching. This in tum may resultin healthier,stronger rn;mels. Furtherresearch is cufietrdy underway to examinehow this embryoric learningmay idtuence the developnentand gro\r't! ratssof exposedanimals. 37r INTRODUCTION Researchhas previously suggested that newly harchedSaltwater crocodiles (Crocodylus paro.rzs)show distinct prefercncesfor particularfood types. Therc aremalked drfferences bctweenclutches in the food prefercrcesshown and also oo the exteatof feedingand growth (Webb,Manolis & Cooper-Prestotr,1990). It is not clearwhat exacdyinfluences these preferences,although in adult crocodiliaosit is known that chemosensationplays an impodant role in fe€diBgbehaviour (Weldon & Ferguson,1993; Weldon, BriDkmeier & Fortunato, 1992:Weldoo, SweDson,Olson & Brinkmeier, 1990;Scott & Weldon, 1989). It may be possiblethat the food preferencesshown by newly hatchgdciocodiles are also inlluenced by chemosensation.

Although it hasnot beenpreviously studied in teptiles,evidenc€ from other speciesmay offer a novel techniquefor iDlluencidgfood preferencesi-u crocodiles affgr hatching. Studiesof rnarnmals(Hepper, 1988), birds (Sneddon,HePper & Haddetr'i.B press), amphibians (Hepper & Waldman,1992) and eveninsects (Isingdni, l-enoir & Jaisson'1985) have all showntlat stimuli which ar€experienced before bir0r or hatchiogcan iD{lueoce preferences after birth or hatching.

The majodty of tlEse studiesof prenatalleaming have examined exposue leaming' In thes€ studiesanimals arc expos€dto a stimulus(usually chemosensory or auditory)before bifth or hatching. After emergence,lhe animal'sresponse 8o this familiar stimulusis comparcdeither to their respoDseto an utrfamiliarstimulus, or to the r€slroDseof other individualswho were not exposedto the familiar stimulusprenatally (e.g. Hepper, 1988)- Thesefindings suggest that embryoniclearnidg of chemosensorystimuli by simPleexposule may be commonto all anhlal groups. Basically,if an animalis exPosedto a particularflavour beforebtth, theDit will preferto eat food of that pafiicularflavour afterbifth.

This study examinedwhethet crocodile hatchlings who were exposedto a chemosensory stimulusbeforc hatchingwould show a subsequentPreference for that stimulusafter hatchiDg' comparcdto hatcblingsfrom the sameclutches who hadr€ceived no e4)osureto the stimulus' It was alsoinvestigated whether any responseobserved was sperific to the stimulus gxpe.iencedbeforc hatchingor a generalisedrespoNe to othet chemosensorystimuli'

312 METHOD Subjects Ctocodlles(Crocodrlut porosus)were suppliedby Wildlife MalagementInterDational, pty. Ltd. in Darwin, Australia. In total 180hatct ings werc usedin this study,taken from lO clutches(i.e. 18 eggswere used from eachclutch). Atl the eggswere collected flom nestsiD the wild soonafter beinglaid. They werethell tansferred to waterjacketedincubators. Mean temperaturein the incubatoNwas 3 loc.

Proc€dure Trcatmentin this studytook plac€during the last stageof incubationbeginning on Day 65 accordingto the bestestimations of age. Exposureceased 3 daysbgfore the eggswere expectedto hatch. On averageeggs werc exposedto the stimul.ifor 16 days. Humidity was 99% and tle temperatureia all of the ircubaton was 3loc on average.For eachtleatlnent group (describedbelow) 10 clutcheswere used,with six eggstaken from eachclutch. To minimiseclutch effects betwgen gloups, clutches were split evenlybetween differetf exposue conditions. Thercwere no differcncesin mortality betweenthe differenttreatmeot goups.

Treatmentgroups for the posttrataltests were as follows: l. Strawberry,eiryd onto the Eggshell: Stawberry essence(commercially available food flavouring) was wipedonto the top surfaceof oae end of the egg using a cotton wool swab daily from Days 65 to 87 of incubationhclusive. Around one sixth of the eggshellwas covered. The sbell lvas stainedpink and otr averageeach egg was coatedwith 0.25m1 Strawberryeach day. Every day, beforethe stnwberry was applie.d,the end of the egg was wiped usiag distiled waterand a cottonswab to removeany odour left ftoD the pEvious day's application. This helpedto minimiseblockage ofthe porcsin the eggshellthrough stimulus build-up. Treatmentedded 3 daysbefore hatching was due (Day 87) aDdeggs were cleaned thorcughlywith dechlorinatedtap waterio orderto r€moveall yisible trac€sof strawberry esseoce.The eggswere then transferedto a different incubatorand left undisturbeduntil hatching. In total 60 hatcblingstaken from 10 clutcheswere tested in this group

2. Waterwiped onto the Eggshell: Decbloinated,tap warerwas wiped onto the shell using a cottonwool swabdaily from Days 65 to 87 of incubationinclusive. The techlique of applicationwas the sameas that usedin Group 1. On averageeach egg lvas coatedwith 0.25m1water each day. Treatmentended 3 daysbefore hatching was due (Day 87) and oggs werecleaned thoroughly with decblorinatedtap water. The eggswerc thetrtransfened to a different incubatorarld left utrdisturbedudil hatching. In total 60 hatcblitrgstal(en ftom l0 clutcbeswerc testedin this group. 3-t1 '[17ese 3. No EtnbryonicTreatment: eggswele given no extraprcnatal stimulation but instead $e!e left utrdisturbeduntil 3 daysbefore hatching when they were transferred to a differcnt incubator. In total 60 hatchlingstrken from 10 clutcheswele teskd in this $oup'

A.fterhatching crocodiles were housed in grcupsof six in fibreglasspens which consistedof a land areaa|rd a waterarea. The hatchlingsfrom differeutexposure groups werc alwayshoused sepantely. To mitrimis€any clutcheffects, each pen held animalsfrorn two clulches(th€e gach animalsftom eachclutch) andttrc samecombination of clutcheswere housed together io exposuregrcup.

Ilatcbtings wereraised in darkrcssapart from whenthe lids wele lifted for cleaningand putting food into the petr. Hatchlilgs werefed daily at 4Prr; the food was left il rhepeo ovemight. Food was presentedotr two plates,each containing 75 grans of meat' At 8'30am the next moming any ungatenfood wasrcmoved, the waterdrained, pen cleanedand refilled' Crocodileswere fed a mixture of mincedbuffalo' kangaroo,and chicken rneat which was fodified with vitamins.

Each penof hatchlingswas given a two choicefood plefereocetest 12 daysafter hatching' Half the qocodiles in eachtreatment grcup weregivetr a choicebetwe€n St'awberry flavoured and Unflavouredfood, wbile the otherhalf wele given a choicebetween Orange flavour€d aDd UDflavourcdfood.

Regardlessof test the procedurewas the sane. Two Platesof food, eachcontaining 75 grams were prepared.This food wastbe sameas the batcblingswere nomrally fed To eachofthese 3ml stimuluswas added(either orange, strawberry or distiled water)alld mixed throughoutthe food. The st'awberryard orangefood flavouriDgswere a similar colour' Esth Platewas theo placedin the land areaon eitherside of tbe raisingpen andthe hatchlingswer€ Ae€ to sample oither q?e offood. The side ofpres€ntationfor eachof the flavous wascounterbalatrced' The food was placedinto the pensat 4 p.n on the day of testing,the lid wasclosed and the crocodileswere then left undistulbedovemight- At 8.30 a.rL the next moming the remaining food in eachdish wasrgmoved to be wgigbed. The amountof eacht)?e of food eate[ was calculatedby weighitrgthe remaioingfood andther subtractingfiis amountftom 75 grams'

For analysesa preferencescor€ fo! the amountof flavouredfood eatenwas calculated as a percentageof tbe total amountof food eatenaccording to the following fomula: (Amount flavouredfood eatetrX l0O) / (Amount of flavoued food + unflavouledfood eaten) RESULTS Studiesof the saltwaterc\ocodile (Crocodllus poros&r) haveprEviously foutrd that neonates exhibit clutch-speciflcfood preferences(lVebb, Manolis & Cooper-preston,1990). Thereforc for the purposeof analyses,two tailed pair€dt-tests wele cardedout malchedon the basisof clutch.

As can be seenin Figure 1, crocodileswho had beenexposed to strawberrybgfore hatching ate significaltly mole strawberryflavoured food (nean 63,26Vo!s.d.24.16) than thosewho had receivedno embryorictreatment (mean 3l -72%!s-d-21.O2) (t= 2.8 (df 4), p = O.O49l). The hatcblingswho hadbe€n expos€d to strawberryprclatally alsoate signifrcaotlymore strawberryflavoured food (mezn 63.26%f s-d..24.16)thatr crocodiles lvho had water wiped ontothe eggshell (meaJr28.4l% !s.d,.16.4) (t = -3.13(df4), p = 0.0353).Therefore the preferenceshown for strawberryflavoured food was due to &e embryonicexposue to strawberry,and not to the mechadcalstimulation of wiping the substatrceonto the eggshell.

100

?-^z'" !F60 E $mwb€rryon sheu NoT.r.hent e,^ A I Waicrotr Shelr !20 10 0 Trcatme.ntGroup Fieure I The amounlof sFawberrJ,flavoued food shownas a percentageoi the loral amounr offood eaten(t S.D.) by th3 crocodileswho had no embryonictrearnent or had either suawberryor water wip€d onto their eggshellsduring incubation

However,when the preferencescores for the olangeflavoued food wete analyseda different picturc emeryed(Figure 2). Therewere no sigtrificantdiffereoces between tlle groups,snd embryonicexposurc to strawberrywas found to havgno effect. The crocodileswho had beeu exposedto strawberrybefore hatching ate similar amountsof orangeflavoured food (mean 45.51%! s.d- 14.53)compaled to thosewho had Do embryoDictreatmetrt (meaD 31.05% 1 sd. 26.37) (t = LA (df 4), p = 0.356). Therewas also !o significant differenceobserved botweentho amoutrtof orangeflavoured food catenby the crocodileswho had beetrexposed to sbawberrybeforc hatctng (mean45.517o + s.d. 14-53)and hatchlings who had water wip€d onto their eggshell(mean 41.38% a s.d. 17.39)(t_= -0-43(df 4), p = 0.6887). 100 90

a E Stnwbeny on Sh€ll t60 a n I i30

lo 0 TrteimentGrcup

Fipure 2 The amountof o€ng€ flavoured fmd shown as a p€rcentageof th€ total amountof food ea&nCt S-D.) by the crocodileswho had no embryonicEejanent or had eiiher st awbery or wat€i wiped onto their cggsh€llsduring incubation

DISCUSSION Pr€Dalalexposure to st awbetryrcsulted in a postnataldietary pr€ference for st'awberry flavouredfood in Saltwatgrcrocodile hatchliDgs. It was also showDthat the preferencefor stlawberrywas due to the embryonicexposule to strawbrry atrdnot to the extrame.hadcal stimulatiol of wiping the stimulusonto tie eggshel during iocubatiotr.The effectwas specifrc to the stimulusexpelieDced by the9mbryos and did Dotgeneralise to otherflavours such as o&nge.

This studyprovides the fust evidcncethat embryonicleaming occun in a reptilianspecies aad that embryonicgxposule catr be usedto hflueoce Posrnatalbehaviour' By exposingthe that qocodiles to a chemosensorystimulus their Postnatalhtake of a food flavouredwith stimuluswas inc!€ased compaFd to hatcblingswho had receivedno embryodc exposureto the stimulus. WhereaspFvious rcsearchhas shown that chemosensationitr crocodilescao be importad for manydifferetrt behaviourspostnatally, this study sholvstbat chemoseosory abilitiesmay emerge much earlier than waspleviously believedand futtlel investigationsDeod to be caried out into how this embryonicleaming trray natually occurand how it may influencr different behavioursafier batching.

Given the curent statusof manyspecies of crocodiliansas endaagered oa protected' these 'pdne' rcsultsare importad in suggestingthat it may be Possibleto crocodilesto be more rec€ptiveto their postnataldiets by exposingthem to a chemosensorystimulus before they hatch. By ercouraginghatcblings to eat optimal diets soonafter hatching, it maybe possibleto 376 raisestlooger, healthier animals. Furtherstudies are cuEendy underway to examitrethe growth lates of embryonicallystimulated crocodiles in orderto seeif this is the case.

REFERENCES HeppeaP. G. 1988.Adaptive fetal leaming: prenatal exposue to gadicaffects postnata.l prefelences.Anim. Behav. 36 (3\:93+936

Hepper,P. G. & B. Waldman.1992. Embryonic olfactory learnnglnfrcgs. Quarter$ Joun&l of ExperinentalPsychology, 448 (314).179-197

Isingrini, M., A. Irnoir & P. Jaisson. 1985. Preimaginalleaming as a basisofcololy-brood recognitioni.q the ant, CataglyphisCursor. Proc. Nat.Acad- SCLUSA,82]-8545-854'l

Scott,T. P. & P. J. Weldon. 1989. Chemoreceptionin tle feedingbehaviour of adult Americanalligato$, .4lligator mississiryier8is. Anim. Behav.39:. 398400.

Sneddotr,H., P. G. Hepper& R, Hadden. Itr press. Chemos€nsoryleaming in the chicken embryo. Physiol. Behav.

Webb, G. J- W-, S. C. Maaolis & H. Cooper-Preston.1990. CrocodileMamgement and Researchin the NorthernTeritory: 1988-90. Proceedingsof the lhthWo*ing Meaing IUCN-SSCCrocodile Specialist Grotp Apnl l99{: 253-273

Weldon, P. J., W. G. Brinkmeier & H. Fortunato. 1992. Gular pumpi[g respons€sby juvenile Americanalligto\s (A0igator mississipp,"nrit to neat scetrts.Chemical Setses, 17 (l):79-83

Weldotr,P. J. & M. W. J. Ferguson- 1993. Chemoreceptionin qocodiliaDs:anatomy, naturalhistory atrdempiical results. Brain, Behaviour& Erolutioa 41t239-245.

Weldon, P. J., D. J. Swensotr'J. K. Olson & W. G. Brinkmeier- 1990- The Arnerican Alligator detectsfood chemicalsi.B aquatic and terrostrialetrvironments. Eth.logt, 85:.l9l-198 CROCODYLUSACUTUS !N TARCOLES RTVER.COSTA RICA

by

GerardcAbadia and Itario Femandoorjuela

tllTE atnt li-tlalll

TheTarcoies River lows iritofie PacificOcean in CostaRica. in spiteof heavyorganic and chemicaiconlaminaioir it is hometo a large-*ild population cf crocodylutacutus. '1998 A longterm study oi ihe crocodilepopulaiion has been underway since February. to add ic pre-existingdata cn fie populaion. lY|EI l-r\rutt

Three differentmethods are beingused to surveyihe crocodiiepopulation. Tl'lese are day counb,night ccunts, and aeriel surveys- An 18-lootlong fiberglass boat with a YAMAHA85 HP ouiboardis usedlor day and nigtrtcounts along a distanceoi 6.8 km upsaeamfrom the river mouthurhich has beengone over 12 times.An AUToMARLong Range Mod. 453 - 12 v lamp is used for night counts.For aerialsurveys an ultralightDelta TRIKE ifpe plane. Philippine mcdelwith a RoTAx 503 - 52 HP engineand SlRlo wing is used.Flights are 70 m above groundai an averagespeed of 55 kmlhour.

Eachcrocodile seen is plottedon a mapto determinespatial distribution of the PoPulation.

RESULTS

Datacoilected so far yieldan estimatecf 21.4 lndividuals,/kmfor a crocodileDcpulation which is notrandomly nor evenly distributed. Recentigures indicatea greatnumber of hatchiingsare iostshorty afier birth,prcbably due io ,/aterpollution. Sc far. a ccmparisonof the threecensus techniques indic?ies a 2.3:12propotf'on oi sigl''fngs for aeriaisurveys:dayliglrt counts: niglrt counb.

Aerialsurvels enableone to see very largecrocodiles lvhich cannot be spotteaitrcm a boal givenihei!' extreme wariness. Night counts are usefulin determiningthe amountcf smalisize crccodileswithin ihe popuiation,whereas daylight counts allow one tc registersand-bank siides.

Additionaldaia on the populationis stillrequired before atteFlpting to draw definiteconclusions population. aboutthis crocodile 378 TEIE Caiman latirostris RANCHING PROGRAM IN SANTA FE. ARGENTINA. The first conmercial rearing (1998)

Alejandro Laniera Pje- Pvdo, 4455, Santa Fe - 3000,Argentina E MNit I'[email protected],ar"

Abdr"Nct

In the lart Coderenceof the Parti€3of CITIS (COP 10), C4nran,rzto!tris rrgentine populetiod was trr4ferred from Appendir I to Appcndir II under Oe n rching Rsokfioa. SiDceits beggitritrgiD 1990,the Sada tr'eeryerimentat ranching prograD did barv€lcover thrtr 40Obrlad- sDoi{cd c'in4n mst3 .nd did r€tourn hto tle witd rlmoat 8,000yearlitgs, &!d fitrndly tbir y€ar (1998),for the very lilst time, cotrmercid rerriag rtans. About ihe 50% of the aninds h{ch€d Oir year (750hefchldgr) fmm the harrcatedeggr, arc cnrre ly rrilcd for r comdercirt purpore aDdthe prosp€ctic that ihe numberwil incrcdc itr the rcrr futur€-

Background

The Expedmental Ranching Program ofbroad-snowtd Caima'|.(Cainan lafirostris)bega'l^n Simta Fe provitrc€ ofl 1990, tom an agre€mentbetween the Instituto Nacional de Tecnologia Agropecuaria (INTA) and the Ministedo de Aglicaltun_ Gaaaderi4 Industria y Comercio (MAGIC). From 1992 and bas€d o! other age€rnent with the Mutual del PersonalCivil de la Naci6n (MttPClg, the amountofthe eggs harvestwas increasedand the level ofthe work improved.Sitc€ its beginningthe aim of the progam was to det€rmineifthe Ralching techniqueis an usefulltool for direct cons€rvationofcairDan populations and (indir€ctly) cons€ration ofthe local wetlands (cainan habitats)through the economicvalorization ofdut lands.

The philosophyofthe work is very simple,the eggsare collectedfiom the wild by the prograrn'sstatrand caried to the ircubator in SantaFe Ciry the hatohlilgs af,e reaxedunder contolled conditionsin nurseriegand after the winter the yeadings (befrveetr8 to 10 month old) are releasedinto the wild in the sameplace wh€re the €gs were harvestedt}le seaso[before. The statusofthe studiedpopulation is monitoredby night couds and all the infornation is statisticallyanatyzed. From this year (98'), we did keepthe 50% ofthe animalsfor a commercialrearing purpose.

Due to the in6easedamount ofthe harvestduring this years,the program becamein a pelmanelltsoulc€ ofimportant andus€full iofodnatiotr about tle latural history ofbroad snoutedcaiman on one hand andthe captiv€readng techdques on th€ other.

319 Despitethe differencesamong species. the zuccessofthe crocodileranching period' is progr"."-;,; a;t*red almost all over the world and,in its Q4erinmental with over.rhan7'800 lerriost at.A fo, Cdimdnlatitostlis too Affer eight yearsof work eggsharve* uf, (exc€pt^ttn:]astyear yearlingsrcleased into the wild ard with the -go.rng. the transferof santa 6ouu;;ft Nino' ptr.nomen),in COP 106 Argentinadid obtab the ;;e-i*irt t p&"lation fiom tlrc AppendixI to AppendixIl of ClTE-st,rlnd:r offie i. r i n"*f"ti"". iitt summercommercial rearing did starl keepingthe-sO%o for releasing fratchlings(about ZSOanimals) for commercialpurpos€, and the othet 5070 ioto the wild on lext November'

Metodolosv

The metodologyofthe work was displayedextensively in the lastsCrocodile here: SpecialisGroup Working Meeting,but we can makea summary project Ness are rnarkedfor I I Eess are harve$edAom the wild for the peopleof tbe *t ranchemployosJ *ithin th" foteston the bat*saf rlJ"tiioi tt"",rycattle landsare narrowstreams o; smalllakes, or arrouniswampy lands Nests within swampy markedby ourselveswith an helicopter' place wirb horsesin 2) The rransportofthe eggsis carriedout dependiagthe harvest lakeEanc wlln rne tlle cattle ranchs,witi boatsin a few occasionsin brooksand helicoptarin swampylands. with a 95% of 3) lncubationis carriedout in the artifrcial incubatoral 3l 5o C ad hulrnidity. water in a s|lohof ils 4) Ifutchlingsare r4red in concretepools in rurseties,covered by The anirnatsar,e f:ed three siuface.fhle are a basicternperature control duringwinter'. vitaminicmrneral rnrxtute ti-es u we"k *itft ntinc€dchi;ken heads.bran c€real and a fust years'but Dow 5l The vearliDesare identiryedby nestand harveslyear during the teo.momhsof ;:;;dt"td;ir-#d"tile animas*ittr metattictags Afler about wild at thesame .*ti"g *i"t *lnt"ff"a tnaitions, the animalsare released into tbe placeofthe eggsharvest the year before'

6)Molirorinsiscafiedoutwirhstandarizednightgcoultsinthesrrrv€yedplac€sand -atvred uno (d€pendinsthe water temperatue) on ;"^;;;1" ;;;;;t "ooetted thebasis of ourwork from 1992(Ladera €t al)

hatchit is slsodetennined the pocentageofth€ hatctings.to 7) Afte! 9.elTTr"iauy in the field' ;;;;il;;;J" be keepedfor rel^easingdeppending on thesituation Thisyear for examplgwell keepa 50% Updated Results

Table#l showthe numberofharvested nests,the numberofeggs and the halchedanimals year by year sincethe beggioingofthe work.

TABLE I

90/91 10 372 237

91/92 25 903 701

92/93 24 926 589

93/94 50 1936 1196

94/95 60 22ll t646

9st96 84 3120 2262

96t97 97 3572 2394

97t98 58 1954 L448

38I Table#2 showthe numberofanimals (ten month old) rcleasedyear by year srnc€ the begginingofthe wo*.

TABLE2

The First Commercial Rearitrq

Even thoughthis yearthe eggsharvest was lower becausethe difrcult accessto the working placesdue to the unusualyhight rainy seasonatributed to "El Niflo' phenomen,we did sendto commercialrearing about the 50oloofthe hatchlingsfrom this '€ar, for the very first time.

A total of58 nestwele harvestedin the provilc€, with a total of 1,954eggs and 1,448hatcl ings. Sirce last April, 750 youtrgCaiman latirostris {e rearedfor a cornnercialpurpose at the ee€rimental breedingstation. The animalsbelong to the MUPCN andwill havemarketable size on the niddl€ of 1999.

The ody differenceon the rearingconditions ofthe commercialyr€ared admals comparedwith thosereared for releasingis the tempertureduring winter. Wbile the 382 hatcl ings for releasingin the could days(Ju.ly and August), could receivetempertures of about 20'C, th€ admals for commercialpurpose, never do receivetenpertues under 28oC.This is possiblebecause conmercial facilitieshave a doublenurserie system with electicheaters 24 hoursa day during the critic period.

Cotrdusions

l) Eggs harvestand reari€ conditions:

The amountof eggsharvested is increased€very year, with the o

2) Statusin samplingareas:

After arl spectacularpopulational recovering the thrc€ frst yearq the situation looks now stabilizedin the working areas.On the other handan expansionon the disribution areasof C. Iqtircstris is detrtf1-. The proportion of the markedaoinals (farm-released)in the feld studiesis 607oofthe total. An explanationabout it could be tha! onesth€ capacityoftle enviroment is rised a migrationoccur to borderingplac€s, what is suggestedfo! the recaptureoffarm-released animals 12 kilomexersfar &om the releasingpoiqt. Anyvay, the incidenceofthe hidrologicalsituation in eachpanicular year app€r as the mainthing to be considere4so in this way flood causesdispersrorl dry produceconcentratiot and extremedry. migrations.

3) Prospects:

A caracterizationoftie areaswhere broad snowtedcaimaa occur, showsthat tie 4eZ ofthe populaaionlives on heterog€oeousenvirolDents (forest, strearns,lakes, narrow rivers and aftificial poads),and the remaining60elo occur orr homogeleous envimments(inacessible swampy land). An study ofthe salelttal irrnges(SPOT) on the basisofthe field works showsthat in the 80% ofthe swampylands bigger than 300 has, nofhem than 31" S in SanJavier st3tg SanCrist6bal state and dle cenfial portion of VeIa andgeneral Obligado states, is posibleto find broad snowtedcaimans. The progam at the momentis canied out in the 54% ofthe swampyland surfaceof San Crist6balstate (5,875 has.of 10,747has. a\nilables),ir.the 27yo ofthe swampylad surfaceofSan Javierstate (4,813 has.of 17,809has. availables), and did not start yet in tlle other studiedareas (25,1 17 has.).This meansthat without consid€rtie rest ofthe nolt ofthe provinc€,the currentworking areais the 19%ofthe availableswampy land surfaceavailable. study alea was dividedinto diferent Secto6, to accommodatetbe couotsarld for com;adson. Secto!E was left out dudngthe counts,as it is in an inaccessibleterrai! andit is a yearfor not ;ossible to get to the river as certail parts. This sectorwas only searchedotrce nestsand this was doneby helicopter.

3. OBJECTTI'ES of the PROJECT

The project hasas it's objectivesthe following four aspects:

/ Movemeds itr the river systemi.e. tim€, extent,location andreasoN

/ Nestingdata h respectoflocatio4 flumbets,enviro nentalParameters, clutch sizeand eggdimensions.

/ A study ofthe water qualitiesand a moDitoringofwater quartities. The quality aspect will be limited to industrialpollution and heary metals.

/ The updateof a databaseon the toxicity and pathologyin C nilotias as andwhen samplesor materialbecome availablg.

4. MOVEMENT The total nutnberofqocodiles in the whole ofthe KNP hasdeclined since 1994' Thereis too little dataavailabte to explainthis declinein trunbersas yet This declinewas reflectedin the study areaas well. For tiie purposeofthe snrdy,individuals were classedac4orditrg to total length(TL):

Sizel: 0-1,5m Size2.1.5 - 2-5m Sizet 2,5 - 3,5m Size4, >3,5m

Besidesnoting t}e numberofindividuals per sector,tlrc numberofgroups was also noted lf atrytwo indi;dusls were closerthatl their o$n body lengthfrom another,f,heywere seento beiongto u gro,lp. Group sizesranged from I iudividualto as manyas 40 animals'

Countswere doneduring May, Aug Dec and Janevery year. The Jancount wasto determine the Nmber ofhatchednests. A count would tnical startbefore suffise andfollow a predeterminedcoulse. The odective was not to do a c€nsus,but rsdrerto detenDitrea iendency. Certainsectors could not be coveredcompletely as rururerousislands in tlrc stream obscurei the view. sectoGBp and G could be covered100% vizually Two or *ree goups' observerstook part in the countsand all usedstaqdard 8X 32 bitroculars lvith larye is on" the highestaverage was noted. This study showedclearly that there Pot"-lry rnoveirentdurloittre year, and it is io coffiast with the findingsofPooley Q969) Breeding areasditrered fro'm beiore and afterthe flood of 1996. Before 1996two areaswere identifed andphysical mating in boti areaswere observed.There was a definitemovemeot during May to thoseareas, and presumably ftom it duringAugust. 384 Bibliosraphv

Lanier4 A. 1990.A programofootritoring and recoverfug of1Yild populaliots ofcair@Ds io ArgetrtrDa with the aim ofoanagementpp.(f-5) In: ploce€ditrgsofthe foli Wo*ing meetiryoftle CrocodileSp€cialist Group ofthe IUCN.The world colservatiotr union- Glaad- SwitzrrLnd.Vol. 2 ISBN2+327-0023-X vi+ 345p.

Ia.rrier4 A. 1992 A programofmodtoring andrecovering ofFdd pofljations of@im,n. itr Argentid wirh the aim ofEaragemeBrThe secondy€ar. pp.: 261-269. In: Oocodiles.proaeedi[ss oJtheI lth Wo*ing Meeti4 ofthe CrocodileSpecialist croup ofthe SpeciesSurvivat Comni..ion ofihe ruCN TheWorld ConservatiotrUnio4 Glrrd_Switz€rland. Vol. I ISBN2-83174132-5.

Iarriera, A. 1993.I,a cotservaci6ny el Eatrejode Cainanl,atirostris elr Sa.olaFe, Argedi@. pp.:(61- 69). En: Anaisdo m Wo*shopsobre CoDsenagao e L{rnejo dojacare do papoanlarelo. Eds.:Vedade e outros.piracicaba, Sao padq Brasil.

Iffrier'4 A; I$.hof,A. And C. von Fimk 1996.The exp€riEeDtal raDching prog!:am ofbroad-sDowted cai]n,tri! SantaFe, Argeftina Itr: Crocodiles.hoceedings of the 136 WorkingMeetitrg ofrhe CrocodileSpecialirt croup. IUCN - TheWo d ConseF€rionUdoD' clallc_ Switze.landISBN 2.83174327 -1. 5t6D.

385 CCNSERVATIONSTATUS OF CROCODILESIN INDIA! A CO[lPrilrATt'ltE ANALYSISIN PROTECTEDAND UMROTECTED RIVERS

R. J. Rlo

Schoolofstudiec h zoolo6r Jiwaji UnivenitY Gwrlior'M.P.4?0ll

ABSTMCT

A comparativeaccounl on the conservationefforts and management statusof crocodilesin the ChambalRiver (NationalChambal SancnEry) and wherelarge GangaRivcr is Fesented.The Chambal River is a Fotectedarca scalercleasing of gharialis rakingplace. All rhe aquaticanimals inctuding crocodilesarc well presewedin this plotectedarea ln contrary'crocodiles havercachcd !o neatextinction in the GangaRiver dueto humanactivities like waterdryelopm€nt programmes' pollution, commercial fishing e& lt is recommendedto take management actions to protectthe aquaticresources in th€Ganga Rivet.

INTRODUCTION

ln tidia manyrive6, lakes ard narshes offer a wtiety of habirarsfor 'Ihey rhree spcci€sof crocodifes arc gbanal (G"vialis Sansetictls),w)gger (Crc.dytus ',ry't/J;trk)and saltwatercrocodile (C.ocdyltls '{/roslls)' Of all llE rhreeslecics ofcrocodiles, gharial and mugger arc pres€ntin Nonb lndia ard th€ rhird species(i. pcrrorz.rlive in b|ackishvratets in the coastalSbres The €ady recordsreveat tt|at th€seaquatic reptiles at one time' llerc very aburdant trcughout their disEibulionrange (Smith' 1933). Howevei' dueto commstcial

t4d' IUCN/SSCCSC working ne€ting at SinSapore'Julv 1994.

386 exploirationand habitatdeseuction populations of crocodilespesies uiere reducedto nearexinction (FAo' 1974). In manyof drehabitas the crocodile populationswere otally wipedo$ (Rao'1994).

Duling 1975,the Governmentof lrdia has taken up a consewation plogran for all rhreespecies of crocodilespreselr in diff€rentSlai6 (FAO' 1975). The CrocodileProjcd in Indisis bqsedon the potectionof rernaining wild crocodilepopulations and rchabilitationof crocodilesin rheir former distribrnionrangc. Srrh a progam requircscomirbBbls howl€dge on thc biologr and habirarrEquir€tnqfs of crocodils All ttuce spesiesof Indian crocodilcshad been extstsively sudied in differentcom€rs ofthe clunty (Singl! l9?8- 1985:Brstald, 1974;Kar' l98l; Choudhury'l98l: Whitakerand Basu 1983:Rao, l98E; Whiuter ard Whitaker,1989)' ba dl€ micro'habitatof &e crocldil€swas not studiedin deraits Shdicson the waterquality in crocldile habitatsare lacbng (Rao and Sharma' 1994)

Crccodilehabitsl reoairerru8:

R€searchstrdies haw be€nundertaken to identiSdre habitas occupied 'Ihe by rh€crocodiles (s€€ Rao, 194 for rwiew). Ganp Riveris a majorhabitat for boththe s?€ci6 oft€shwa&r crocodiles. The saltwatcr crccodile occut in lhe tait endofthe Ganga river in Sude66ns'West Bengal (FAO' 1974)'

Crocodilesare amphibiousvenebrar€s spending pan of rh€ir lives in waterand p6tt on &y land lt is knownthat habilat is a natunl homeofatimals andsupports aninul populations primadly tbr spoce'lbod and sheltet tlabitNb areusually dewribed in termsof saliertphysical and chemical features of lhe environmentSince, the ph}sicaland chemical characteristics of rater atrcct habiratDrefetence, seasoml tatiations do havebearing on the habibr'prefer€rEe of a pdrticu.laicrowdilc spccics.On a{)oourt of this,tho habilatin a panicular searonmay receive a prcferEntialt€atn€nt froma crocodilespecies over some odrcrhabirat Conclusively,the bener the habitat, th€ geater are the chancesof suvival. TheFcscnt habitat ofany liviry qocodilesp€ci6 dors not rcflcatthc diversityof possiblebabitats for tht $eciesb$ merclyirdiclres dre habitatin whichit tEsmanaged to survii€(A.lcala ad Dy-Liacco,1989).

Old recordsindicate 0Er the crocodiles abounded in all thegr€at riven of Nonhemlndia includingGang riv€r (Short! l9l; I.AK l9l; Rao, 1933). Howweqby early1970's populations ofcrocodiles have been very mrrch rcduc.ed (FAO,1974). There are m repodsofoccurrence ofcrocodiles in theGanga rir€r, particularlyin the upperstetch (Ku*po pers.cornrnu Mzrch 1992). Variou humanactivities like huntingald tabibt destuctionin the GangaRiver have an impocron Ulepopulation decline of crocodiles.lt is necessaryto waluatethe cxistingideal habitat corditiom of crwdiles in rheGang River.The preserr.e ofcrocodilesin rheGanga River may indicate the river quality suitable for these higheraquatic animals, which are eorEidercdas top predatosin th€ aquaric €cosystem.

CrocodilePrcied;

Crocodilesin manyriven includingGaaga fuver havebeen illegally huntcdfor hidcs,mcat and mcdicin€. This 'harvesr',the lossof habitatfrorn alterationand human senlernen! ard lhe u.seof nylonset netsfor lishingrnay havebeen significrnt in reguluingsome local populations.Wth a view to qrnservelndian Crwrxlile spcies whocepopulatiors were depletcd throughout their distributionrange, a Nation-widecrocodile consertation Foject was initiatedin thecountry by tlre Govr of Irdia (BusrarCa1974). Urx.ir:r rhe Crocodilc hoject manycrocrxllc habitas vrcre identified and prorcctcd by declaringas crocodilesanctuaries lrfiere captive r€ared qocodiles are releasedsince |fi. TheUttar Pradesh Forcst Deparfinent has taken a leadingrole in releasingcapivc rearedgharial in variousrivers ipclding thc Ganp river (secbble 4) Majority of the crocodilereleasing sites have received protection undu Indiur Wildlife (Protection)Ac! 1972Hou/ei€r' ibe Gangariver s'Eetchin whichgharial have beenrelcased is not a Fotec{edarea Periodicand annualslrv€ts h3veb€€n to caniedout in difcrent Staksby ihe respoctivcState ForEst Depaftnents maior monitorthe populations. These swveys rwealed tbat the Charnbal tiv6' I ributary in the Gangariver sysiem'is oneof the bestcrocodile habitat in drc present countrywhere large nunber ofcrocodiles especially Gbarial arc

Sdadvareos:

ChambalriYer:

The Chambalriver flonisthrougir the Statesof MadhydPradest\ Utar N Pradeshand Rajastran between lhe psrallelsoflatitude 250 52' N ard 29023' soutF andloogitude 760 28' E ard d 0l' E. It is a deepfas riverlowing from Pradesh westto notth-eastAffer originating fiom VindhyanRange in Madhya rivcr the river ru$ tltrowh Raja*lEtt From Pali (Charnbaland Padati RheouFo confluence)il bor&rs MadtryaPtad€slt and Rdastltanand ftom nvet Barechait bordersMadhya Prad€sh and Uttar Pradesh Down Ba&cha the a flowsentirely througtr Unar P6desh until it join Yamua at Bareh Ttrcrearc and seriesof thee dans at GandhiSagr (l"fadhyaPtadesh), Rana Pratap Sagar Ja*aharSagar and a bamgeal Kotra(Rajastltan)'

The averageamut dischatgeof the river is about4193 million cubic metresfiom its largeGafthment area of 22'533sq km fuver guging indicares metrEs that the armualrun off r'ariesftom a minimurnof 1450million cubic goodyears During duringdrought years to 10'900million cubic metresin monsoonthe river floods nanrally and high exte s of erosionard depositionof soil uke plac€.

A maJorportron drc Chambsl fuver is d€clatedas National Chambal Sancnraryfor thc protectionofthe Gharialand orher aquatic animals like mugga, ftesh*aterturtles, wedand birds ard dolphinsad oten.

Cangarner:

Thc Garlgarises at 7010meters in Gangoui,Uttar Kashi Dstict, U.P, Indi4 on the Southemslopes of the Himalayanmnge, It flows throughthrEe differcr Stales- Uttar PEd€slt BitEr and West Bengalcovering a distanceof 2525 hn. beforeit joios the Bay of BeDgel.During irs long cot|Iseit embrac€s manysrnall lonents and tibuwies ofvaricd origin

The presentstudy hasbeen caried otn in rhe GangaRiver in a stretch betweenRishikesh and Kanpurin Utlar PEd€slL The total lengthof thc rivcr undersudy is 645 krn. All $e way fiom fushikeshlo Kanpurmost ofdE ghats have religious imponance. brge number of pilgrims takes holly badu do cremationand posi crematiooactivities and thus become major sourcesof pollutionto the river.

ln the sudy area large numbcr of factories like IDPI- BHEI. sugar, chemicals,fenilizers, engineering coton and tarmeriesare situatedon the bsnks of the riwr- Thedischaryes from th€seinduslries enter the Cangafuver direcdy or indircctlyand pollute the river to a corniderableextent. The naturalflow ofrhe Gang River hasbeen checked due to consluctionof baragesin the uPstream. Thes€bqmgcs als corEtnctedeitlEr fot po\r€r gcn€rationor for inigationto the agriculnrrallands. A seriesof barrageshave been consfiuded al Rishikesh Haridwar,Bijnor and Narora- Amongthem the barragcat fushik€shryas speciallyconstructed to supply$'arer b theChilla Power slation Theriver rrater at Narorawere diverted both for inigation(l,ower Ganga Cansl) and for Atomic PowerPlant located at Narora-Other two banagcsat Haddvarand Biinor are meantfor inigationthough UpperGanga caml ard lvladhyaGanga Canal, respec'tivelY.

Crocdilg inthe Chambaldwr:

In th€Chambal river t\No species of crocodiles,the gharialard mugger arepEs€rlt (Singb 1985tRao, 1988).Unnological sludies caded out it! $e Chambaldver rcv€aleddBt the rii€r is not polhld (Shann4l9l). No major citiesor townsarc situated for morethan 600 kn oDeither side ofthe Cbanbal riveftanlcSo dte Chatr$slRiver is comparativelyan unpollutedriver in rhe GangaRiver systern. Pan of th€ river hasbeen declared as NationalChambal Sanctlaryduring 1978 for eruuringprotection to theGl|arial, which is considerEd asendangacd crocodile species- Being an irnpoia gharialhabitat in thecounty theChambsl fui€r hasbeen identified as a majorriver for gharialrehabilitatiorl '1788 In this river around capivereared gharial have been released- Capive rearedmuggas were also released in thisriver. The slatus surveys conducted in theChambat river rwealed thal larye groupE (more thsn 20) of gharialarc prcsent in differentareas (Table 2) (Raoand Singiu 1994). The gharial population in the Chambalrirer is increasingdw to releaseof capivereared anirnals and highly protectedhabirat with security against poasible dange.s (Rao, et o/., 1995).

CrocodilTin theGarAa iver

The rcsulrsof th€ suveysin the studyar€a sllow thal gharialand mugger sympatricallyin the Gangafuver. The number of anirnalssighted ir diferent js sites shownin table 3. Significantrccord of occuIrcoceof adult gharialin thestudy $Etch ofthe GangaRiver was the repon &om Anupsahar in Dstrict Bulundsahar. On 14January 194 on€adult female gbadal (3.8 m) u/its founddead in theGanga River at AnuFahar(Dainik Jagara& Hitdi Newspaper l5 Jan194). posr-morrom The rcponindicales that tlle ardmalwas died due to "inflanmationof liver andcongestion of tlmgs",pe6ap6 a cs-!eof downing deathin fishingner DuringOcrober 1994, thee gharialnare reportedin the GangaRiver downsreamof Narora barrage. Th€ Utbr pndesh Forest Deparbnent hadreleased a total of 225capiv+reared gharial in tbeGanga River upstreamofBijnor barragenear Hastinapur (Table 3 and4)-

Duing the$udy penod no released gharial *rs found"Thc gharials have becnrel€ased in anunFotected arc4 wherelarge-scale fishing has been noticed. Dueio rhefishing activiti€s in rhissuelch all gharialmigh havekilled in fishing nets.Possibility of migrctionof thesercl€ased ghadal may be anorhqfacior for not locatingthem in $e srudyarca- Theseanimals always avoid hrunan interferencein their habitats.

In thestudy arca mugger have been reponed from many places (Tablc 3). At Naroradownstrearn of banagea oul of 20 muggerharchling5 have been located Amongthem one harchling v/as caught and brough to th€ labomloryir theJiuaji UniveDity.This shorla Out thsre is a goodnesting site for muggerar Narora" One4' mugger\ras caught in a fishingnet on 17 November1994 at Narora-AnodEr case of muggeraftacking a manal Ranghatwas also repon€d Sincethere is heavyhuman aaivities alorg the Gang River,it wasobserved thar muggoprefer living in thelower Gangacanal. Crocodilehabitaa:

Althoughditrerent parameten of Gangafuver are exeruively studied no studia havebeen undenakcn on habid cquircmentsofcrocodilcs. By thetime rescarchsadies on I'ariousaspecs ofcrocodilcs bave besn initiared during l8E 1970'sthc crocodileshave drcady been rEduced in nurnberin the Gangariwr. Due to lcssor negligiblcpopulations no g.rdieshave b€en cari€d ot.t in thc Ga$gariver. However, detail€d sMics onbabitat rcquiEmeEts of socodil€sbave beel undertakenin tbe Chanbal dver, a majortibuary in theCangs riv€r syssm (SingL1985 and Rao; 1988).

Duringrhe presenrshdy the inbabitedas uell as pol€miafhabibts availablefor crocodilesare recorded Thc undistub€dsandbanks are most preferredttsking sit€s for qocodilcs. Steepsar$aDl(s are rhc major rcquiFmentsfor gharialfor nestingHo*evcr, in tbe sudy areano swh steep sandbenkshave been rccorded irdicating that n€sring sit€s for gharialare tacking how€ver,mugger rnay usehad nuddy banksfor nesting The fesence of hatchlingsat Narorais a goodindication of potontialnesting sites for mugga.

Threq6:

A shdyon til€ impaclofhurnan activities in the sudy areaon crocodile populatioruand their habitathas been made- Crocodile populations of both0re specieswere heavily exploited for skirsduring 1950's and 1960's. Though levels ofexploitationhave not beendocumente4 nwnbers harc declinedin theGanga riverto nearextinction Thehabiat desmrcdon in rie form of lo6sof suirable nestingsites, which have ben changedinto agriculturelands, caused no natural regenerationof wild populationas the remrantsurviving br€eding adults have lost suirablebreeding ateas. The largescale fishing all alongthe Gangariver is a great rlreat to theseanimals. Crocodileseither killed in the fishing nets by drcwningor dIe fishermenkilled them intentionallyto avoiddanage to their rc6 and alsoconflict for fid! resources.

Corcenution:

The muggerand gharialare listed in AppendixI of CITES. Under the Nationallegislation, these s?ecies arc prol€cteddmugh wildliG (FotcctioD)Ac! 1972ard alsoconsidered as cndangered in IUCN RedData Book AltboughoFy arc protectedmder Nationallegislation their habitatsin the GangaRiver are not protect€d No sanduaiesand proectedareas are declarcdover the GangaRiver in the studysE€tch. This resultedin lossofsuirable habitats for crocodilcs.

Marueenent ?Nls:

Tip crocodilesin the Chambalriver areprotected as ths river is uder th€ managernentof National C-lunbal Sarctuary.Sightings of crocodiles in the Gangariver are very rare,but they arc plenty in the Chambalriver Undertbe 'Grow and Releaseprognm' largerumber of captiverearcd ghadal havc been releasedin the Chambalriver. Tlrc popdationestimales rcv€aled thar tre glnriat populationin the Chambalriver hasbeen recortring overthe pastdecade from an earlierdeclining $,aels New neslingsites ofghadal havebeen esablished in the highlyproEcrod Chambal sancnery. Oocurerce of largenumbcr ofoocodiles in $e Chanbal Riwr is dw to the protectiongiven to thc habitatsb dE Shre ForesrDeparEnents. The situationin rlE Gang river is completelydifercnt l"arge-scalefishing a major tk€ar for aquaticanimals, is going in the river. In addition,lhe river is usedfor manyplposes includingreleasing of industial ard domesticpolluranb, which nakes the dv€r unsuitablcfor the aquaticanirnals. Thereare no protectedareas in the Gargariver betweenfushikesh and Kantrn

394 Aquaticlife in somestsetches in rheGarga river is Fotect€das tltese sEetches rec€iveFote€tion ftom the rcligiouspeople on the river gbats.Howwcr, such areasare few andcontibute little protection to theaquaric anirnals-

Adion plan:

lfcrocodilesin theGanF riv6 arcto bc troece4 it is €ssentialto take uprhe following actions. l. Detailedsrweys are n€eded to idsrtifyrorr habibrsard populations ofthe qocodiles. 2. Efforrshave to belak€n to givelcgal proteclion to th€suibbl€ habitats in theGanga river to accommodatethe surplus soc& held in catrivity.

ACKNOWLEDGMENTS

The studyin tlre Charnbalriver was caniedout wilh the finaDcial alsistanceftom the Wildlifs Institut€of lrdi4 Dehndm The Gang!Projcqj Direcronte,MinisEy of Environnent& Forcsais the fuiding agencyfor the Gangadv€r study.I am vay nwh thanldi to tlFse frmdingagencies- I also tha* lvt-P.Forest Deportuant Lrigatioo DeporuD€o! Naror4 U.P., ny studenb andother field srafffor theirhelp during tlrc field stdics. REFERENCES

Alcal4A.C. andDy_Liacco, M.T. 19g9.Habitals: In crocodilesand allisatoB. Ed.Ross. Fac6 on file, New york.

Bustar4ftR- 1974.A FrcliminarysurvEy ofthe pospectsofcrocodile hrming ruCN, New serics"41. 45-47.

Choudhuy, S. 1981. Some sll}(lr'esoo the biotog and @olo8- of Gaviatis Eqnge,icntt\e k&,ai g,arial(Crccodili4 ca;a[ a*1 inb. ,n^i,Gi. Lucknow.

F.AO. 1974- prelimuBry A survcyofrlF prospectsfor crocodilcfarming (Based onthe work ofBustan( HR). F.OIndtll033,66. F.AO. 1975.hd1 .fu1og9 potentialof gharialand saltwa,rercrocodile sch€rnesin Orissa-F.O.lt:dnlh33- l_124 I.A-K f 92l_ Crccodileshooting in Nepal.l aozrbsy Nat.Hist- $c 28:291. Kar, S. 1981. Stlrdieson $e salt$/aler(/'i(r.jdile, Goa>dylwporaro Scheidae. PhD. rlests.Utkal Univ. Orissa-

Rao,C.J. I 933.C,avid on fie lrdus.J St d .rr'ar.Hist. So(-l(4): 37. Rao, RJ. 1988.Nesting ecologr ofGharial in theNationat Charnbal Sarrcnrary. Studyreport, wII, mimeo,pp. 105.

- 199 Ecologlcalsctdies oflndian Crocodiles. An overview.proc. l}h workingmeetjng ofrh€ ruCN,ASCyCSc, Thailand Vol. I : 25!273.

and Sharm4H.D_- 194- Limrplogica.tsMies and their afplication ro rhe coruervationard marugemsntofcrocodiles. ln: Crocodiies2d Ree Conf ruCMSSOCSC,Ausoalia Vol. l:317-361.

_ andSiDgh LAK 1994.$atus andconserv-ation ofthe Gharialin India Proc-12$ }ofting m€etingofrhe IUCN/SSC/CSO,Thailand Vol l:&L 97.

- Basq D., Hasaq S.N.. Sharn4 B.8., Walker,S and Molur, S, t995. Population and ltabitat Visbility Assessmentfor Indian Gharial. Wo*shop Proc. Shalma.H.D. l99l. Lirurological str.diesof aquatic ecosyslEmsin Gwalior regionrvith specialrcferenc€ to crocadilehabitals. rf4PDtl th€sis'Jiwaji Univ. Gwalior.

Shortt,N. l92l- A few hints on qocodile shooting J. Bonbay Nat Hist. 9c 29'.n.

Sindl LAK l97S. Ecologicalsbdics on thc Indiangharial Gaeialit ga'getiaa (Gmelin) (Reptilia. qocodilia) PhD. thlsis, Utksl UniveEity' Bhubaneswar.

19s5.Gharial poprlation terd in NationalChambal Sanctuary. wilh noteson ndio uacking StudyEpon CRC/WLmimeo ppl67.

Smittl.lvtA 1933.The buna of British India' includingCeylon and Bwnta. Reptilia and Anph$ia. Vol I, I-odcab' Testudi!rcs.Tod.y aod Tomono$sPriners ard hrblislrers,New Delhi

Whilak€r,R. andBasq D. 1983.Thc gharid (Gaialis gangeticls)A' 'rnie' ' J' BodbayNat. Hist. Soc 80(3):53I -518. ruCN Publ' --New ard Whitaker,Z. 1989.Ecolo6/ ofthe muggprcrocodile series.pp. 27G296. Tsble l. Sslieot featurB ofthe study srcas itr the Ch8mbsl river rDd Gargr river. s. Features Grlgs river Cbsmbalriver No l. Riverstatus Mainriver lvtajorTnbdary of Yamuturiwr (Gaog€snv€r s)stcm) 2. Studyarca fushikesh- Kanpur Pali- Pachbmda 3 Riverlength urder Approl 645hn Appro>c400 hn study Territory RajasthaaMadhya UttarPEd€sh Pradesh& UttarPradeslr Majorcities & Rislrikes[Harid\rar, Nil Towns(wilhin 2 kn GaImuktcsirar, fromthe river bsnk) Anupsahar,Narora Farukhaba{Kanpur 6. Distncts Dehradu4Haridwar, Morena,Bhind Bijnor,Gaziaba4 (M.P.), Buludsalnr,Badauq Sawailaadhopr, Famkhaba{Kanpur DholFr Eaj.), Agra lta$ah(U.P.) 7. Barrages/Darns Rishikestt,Haridwar, Nil Bijmr andNarora Tributaries SuslMa,Song Kuno,KutMari, Banang4Malin Sonali, Aasun,Sndh, Pahuj Mohara,Sol, RangpngaIsaa Kalinadi,Kal)nni nven 9. Humanactivities Commudtybathing al Agriculh[E,sand religiousgluts, collectio4 bathing Cremation& Post- canle*ashing crernationactivities, illegal fishing agricultue,Iishing dischargeofdomestjc & Ldustrialpollutants, vaterregulafion 10. Conservationslans Unprot€c1cdarca (small Proteclcdarca strachis passingthrough (Sanctlary) ChillaSanctuary between fushikeshand Haridwar)

39E Tsble 2. Drta or currert crocadilepopuhlio! i! thc Protcct€drr€as itr M.P. Crccodile popul8tioD

Prolectedsr€a NationalChambal Sanctuary 120 t2l4 SonGharial Sanchrary ll 35 KenGharial Sanctuary 3 22

Gharisl lopul8tion in tbe ChrEbal fiver (19t96)

Total populstioD No, ofaduh No, ofrdrlt No of No. of femeles Ed6 D€stiog relts sit€s

t2t4 n+ 2l.r ')l 75

399 Tsble 3. l,ocrtion record! of frBbwater crocodilesin thc Gaaga river b€tw€eoRtuhik6h trd Kenpur.

Znne Mugger Gharid

Reported Sightcd Reported Siehted

Rishikesh -Oneadult was Nil NI MI killed by local ..'. Hanowat policemenin I99l Hariduar -2 subaduls NiI One juvenile Nil - Bijnor upsteam (released?) Btnor Bamge upstrenm Bijnor Bamge - 225captive reared gharialwere released Bijnor- Yes Nil Yes Nil Brijghat Brijghat- Yes One adult Yes -l adult Narora duringMay and femaleat SeptemberI 994 IGshipur4 -2 adultsin May 194 Anulpahar One adult dudngFeb. and fenale dead Marcht994 at Anupsahar -l adultfemale during at Karnavas January1994 during November, DeoenberI 994 NaloE - Yes -4 adulrsand Yes -2 adula aDd Kachla oneJuvenileat onejwenile Ramghat ir! Nov. 1994 -20hatcblings at Narcra at Narora downsueam barrdge Nil Nil Table 4. Year wise ghlri8l relealesio lDdiar riversr

River State No.ofGharials

1979-93 C.hambal MP./Raj.ru.P. 1788 1985-93 Son lvIPru.P ln 1986 Rapti U.P l0 1979-94 Gilwa U.P 399 1986.92 Cttaghra U.P 45 1982-94 RangaDga U.P 257 t98G92 Sharda U.P 2& 1985-93 Ksn M.P 35 1977-89 lv{atranadi Orisa 609 19G93 Betira U.P 55 l99G.9l D"dhwa U.P 5 1990.93 Ganga U.P 225

'After Raoand Singlr (1994) MADRAS CROC BANK; AN UPDATE.

Nikhil $/hittker alrd EaraT Andrews Madras Crocodile Bank P.O. Bor *4 Mahabilipurll8 Ta.nil Nadu 603104 India

ABSTRACT.

The M{draa Crocodile Bxnk was strrted in 1976to rave tbe three IndiaD cro€odilesfrom almost certain eninction, Problems fac€d were habitat loss and the illegal st

INTRODUCTION.

At pres€nt the Mndras Crocodile Bank has s totat siock of about 3,000 crocs, of which 2t00 rne Muggers Steps hav€ been taken to reduc€ the annuat output oI around 2,000 viable eggsfrom these profific breederi, si there is limited sprce to hotd the hdchliDg& Ther€ rre two all maley'all female pits where rcsting activities bave ceased. Unfortunately, ther€ are other enclosureswith 450 miI€d ser Mugger in th€m which makes the probleo a little more complel, Sadly, ev€rf, year around 1700-1800egs go the compostdue to the confined space,lack of identificd suitabte habitats Ior release,and the prevailing negative attitude towards comm€rcial farming. In rdditiotr to the three speciesof Indian crocodil€s, we have Morclet'! crocs, Siam$e crocs. rnd the common Caimad, all which have successfullybred herc. Our Dwarf crocs, NiI€ crocs, false Gharials, and Amedcan Alligatorr are showing bre€ding interest, and we hop€ these goups erccessfully repruduce in lhe near future.

trew habitats rernaircd by the late 60s' for rll of Oe three endemic crocodilian lpecies. Ile lutur€ looked bletker, a3 more ofthe prcciow walerbodies were converfed into agriculfural latrd ,!d human settlement& Crocodiles were shot on sight, ard the skitrs taDned in private tanneries witbi[ India, or erport€d to be tadned €hewh€re. By the lat€ 1930s', the Saltwat€r crocodile was rcar extinct id South Indi& the lrst known tesidedt' Soltsater crocodile was rhot in 1940( R Whifrker, personal comm). Mugger, known to travel long distancesover ladd looking for waterholes in the d.y sea$on,were opportutristicalty killed for their hides. Eowever, the hdian gbarial wa! the most critically lhreataned at this point, th€ir habitat being alt€red €itedively by ihe drmming of riverN, r€sulting in consecutiv€floodin& Additional lactors contributing to drastically declining numlrers w€re hunling for th€ gharial's rki& meat, body partsj coll€ction of €ggsfor human codsumption, atrd incidental droffning in fishing nets. MANAGEMENT; PROS AND CONS

The Croc Bank h!3 23 enclosurcsfor th€ ten sp€ciererhibited, ofshich ? enclosuresar€ occupiedby Mugger. Sev€nenclosurc! utilize utural acquifierponds (ic no itrlot or outlet for water, potrdsare mlde by digging10-12 ft bclowthe groundsurface and tapping the saler table). Th€ othcr syslemis cotrcretizedpond& complet€ with r wder inlet atrd d.aitrag€system. The natural acquifierslre clor€to 64 ft deepduring the rainy searoB( Nov.-Feb)itr Madras Eo*ever, duridg the dry s€as,on,w{ter l€vclsdccrreale rrpidly and pondshrve to be dr€dgedfor &e benefil of the crocs,as at ruch low water levelsof 2-3ft deep,water tempenturcs occasiondlyerceed 35 d€gre€sCelsius at peakt€mpenture, in the middleof the .ftemoon It is noled,that under thesecircumstancB wh€rc e numberof crocodilesar€ givcnan insuffrcientbody of water,two or thre€ dominantcrocodiles Bill not allowsmall€r srbordinate individuals to enter the weter. To dr€dg€a mtural acquifierto atleast4-{ 1/2ft of standingsat€r tak€stwo 10three drys, dependidgon lh€ waier body'sarea, wbich mtkeathis opemlion a costlyannual priority, a6 mosaof the pits hrv€ to be dredgedthre€ to four tim€aevery dry leason.

Each€nclosurc whicft houserpotentidly d!trg€rouscrocodiles has a rafetywall, abouttwo feet awayfrom the main enclosurewrll (on the itrside),and fi{o and a half feethigh. Tbis to give peoplea s€condchance if they do lall into a croc pit, bop€fullythe unfoftunaletourist getsover the €ncloslrewall beforethe crocsget overthe srfety wsll! Th€re are grles behycentbc eDclosurewall and safetywall to g€t any crocsout oftb€re thsl hrve climbedover the srfety wall at night When itritialty planningihe safetywalls, we fouDdtbat consideralionshad Xobe made ap€ci€awise. Some species were troto ous6tun&lers' ( suchar th€ Mugger),which had s t€ndeacyto dig at the ba!€ of the salls and try end get pastthe b{rrier, Deeperfoundations had to b€ d|rgfor thes€crocs. Other crocs( ie. Saties),dont showmuch tunncling activity, making a de€pfoundrtion untrecessary.

The period betweeawater chmgesin lhe crocodileponda raries betweenspecies, season (e.g. wcudry), averagesize of the goup, and density. It hasbeen observed that the poDdsin etrcl$ures contrining caima[ h:rveto cleanedfr€quently, aJ Ois sp€cresha! a tcndencylo def€cttein the wat€r a lot of the time In etrcldurescontaining 2-5 cr.ocs, sater needonly b€ flwhed and refilled every4-5 months. However,enclosures which bold 450or soMugger, with r large water ane& can only be cleanedevery sir monthsor sodue to a water shortagemost ofthe year. The advrdtageof beitrgable to consarucfcemert pords is th€ lbility lo vary vater levels, ihereby creating3-4 different temperaturcgmdicnt!. Eventualy, the CrocodileBank hopesto be ableto g€t togeth€rth€ fundsto concretiz€ell of the remiining mtural acquinerponds. We have obs€rved,that in the llst few yearss€veral constrnction sites tave comeup aroundth€ Crcc Brnk, andthe water table,at peak dry sea$d, dropslorer everyyear'. Occasionallyit is necessaryto createa Shadedar€a over a portionof the pond to lowd water temperaturesin the aftemool. ID a Saltwatercrocodile pit with 55 adults(11.44.0), a femalewar obs€rvedto be guardinga nest rbout 20 ft fmm the sater. A cattl€f€€d lray wassunk into the sard ^6 ft from her n€stand filled with water, but shewasn't noticeddrinlung During p.ticuraly stre$ful dsysfor ihe crocs( e.9 Beaiuridg, drcdgid& etc.)when 'Xile ups'occur,the crocsrr€ sprayeddown *ith wrter, atrd an elfort is Dmdeto not rllow atrycruca gd 'buriedl I! oDeof the higher {tensityMugger enclosrrese105 femdes),two concretiz-€dponds separate fmm the main hrge poolprovide weak and str€ss€diddividuals r necoveryare&

Fe€dis dividedinto thr€e crtegories,dependfug oD the cro$ sizaand species.SdaI lirr lish a|ld finely mincedfish are fed to halchlingsuader eightycentim€ters in lotal length. Large fish go to the subadult crocs ( 1.2-1.75ms) and the specieswhich r€quire a fish diet Thcs€ inctude the false gharials and the Ilrdian ghfials. Tbe adutt Mugger, Salties, Nile crocs, rnd other speciessith stronger snout and jaw builds arc fed hrge piecesof be€f composedof appmrimately 75yo bone ^nd 2so/ome t The crocodiles ar€ fed in the tate aftenoons, with an attendant miking srre th€ food is spread out evenly in the enclolures, to prer€nt pile-ups, and to also giv€ the srbordinate individuals s chanceto feed. The n€xt moming the enclosuresare swept clean, and th€ remaining me is buri€d. A[imtls in individual breeding pe|rr (Falsc ghariat& Siam€se crocs, Nile cmcs) are given mixed fced during th€ir r€spective breeditrg lea$ns This coDprises mts, frogs, and crabs It was observedthrt the quality, qurntity, time bctwe€n fceds, and tlp€ of fced ofTeredplayed a large role in a given individuals gronth rate, paticurartJ in the tirst fcw years. A5 the crocs grow larger, additional factors (e.g sex ratios) whicb don.t afl€ct th€m much at juvenile stages,aremore evidmt and presumably play r mle in modelitrg hierarchy pyramid& As batcl ings, cmcs seemlo do belter bcing fed at 2-3 day intervals, aDd for th€ first few months growth mtes ar€ fast Eowever, oncea croc reachg srb-sdult siz€ (€-g. 1.2 ms in Mugger), it only reeds to consumeabout 8-10%0of its body weight in r w€ek Ke€ping a rEcord ofihe feed for s€veral hundred crocs of vrrying size! ca|r ev€ntualty maierializi into discovering an optimum teed consumption p€r. individual Tb€ time sprced behr€en 2 feeds is det€rmided by the animals gboosters,, siz€ atrd cud€nt bodJ cotrdition. Gravid femalet may r€quire additional aJ a lrrge amount of time and energ/ is put into courtship, mrting, providing calciun to shell follicl€s, eggayiag, and guardirg of the nest site(s). Approximately 2 tones of beef, sir hundred kilos of large fr$hwater fish, and 300-500snnll live lish is brought to the Croc Bank bi-w€ekly.

WEAT DO WE DO WITE ALL TEESECROCS?!!

Cle{rly lhe Muggen are dominanl at the Cmc Brtrk, in terms of sheer numb€rs (-2,800 crncs). Up utrtil four yean ago, the Croc Bank w'r playhg al| active rolt in restocking t]€ f€w remaining viabl€ babitats with Mugger. Unfortunately, r! in other third world countries with similar croc reinlmductiod strategies,people haw problems rppreciathg the concept ofsildlife manrg€ment when th€y themselvesare pov€rty stricken. The local politicians frown on hLing crocodiles releasedinto waler bodis which are also used by their poteDtial voters, tocrl fisheman coEplrin sayitrg the crocs competewith them lor comDercialty valuable fish, atrd pcople setded along riv€rine habitats sry crocs are a lhreat to tb€ir cattle, and a nuisance to them. Th€ concept of sustainableuse has been put forwrrd several times, but hr! been rejected m*inly du€ to Dmblems of maintaining eflective poaching controls

Tw€nty yearf, ago, miintritridg a larg€ number of h.tchlings atrd yearling! wa! Bot r pnobleo. Eow€ver, thes€ cr.ocr ar€ now adults, atrd with lb€ pr€sent situation of having not enough releaae rit€a, this posea . mrjor problem. dthough Mugger breeding has come to a itandrtill her€, the grFadult! accumulated ov€r the last few yerrs (-1020 no6) will be reachiDg adulthood in the nell few years, end the juveniles (-990 Dos) will be growing idto sub-rdutts This *ill put an exti& very large straitr on holding spaceand feed bills for the!€ croc$ a{d w€ hope to find r solution shortly. Zoo €xchangesbelp a bit, but subtrrcting 3-5 Mugg€r from this bmmidg population would-nt make a noticeabl€ differcnce. We havc put in alr rpplication to do a on€ tim€ cull of around a thousand sub-adult mugger. The strain on adult cmcs being mtintaiBed in high dedsity pits b all the mor€ notic€ebl€ now. There is r conn€ction between mortality rates and enclosure d€nsities, higher mortali8 in the deNely stocked pits, dropping down to almost 0olo in the enclosrres with ad€quate rrea per. individurl We've discovered that stocking deDsity is also dependefl on general teBp€ram€nl Specier like the Salt-Ifater crucodile would maim each other if housedin high rtocking densities. On the other hand, specieslike tte Mugg€r and American alligltor ere more socirble rnd The idea of startitrg !

PUBLIC REI,ATIONS

lAe Madrrs Crocodil€ Blnk is playing atr rctive mll in educating lhe general public on lhe mady tasci ting and idtriCale ml€s crmodiles play in our eco-systems.Sign borrds in the Croc Bank describe lhe spe.i$ e ibit€d, its gcogrrphical range, marimum lcngth, atrd addilioBal facts of €cological atrd morphologicsl intercat to the public. VisitoN crn pay lhe equivalent of 60 cents to watch the crccodiles beidg fed & half kilo of beef, get s chance to louch a smrll crocodile, and har€ lheir questionsrtrswered by Cmc Bank staft A problem in g€tting acr6s to lhe public od lh€ €cological value of crocs, is thaf there xr€ no real vdu€s that th€y can relde to Outside of th€ Crm BBnk they are tr€at€d as nuisance a[imals. Il has b€en kdown for scveml years that a wildlife resource can be conv€rted to the calegory of'livestock", and crn be legrlly farmed witt elTectivecontrol measuresto sustrid a healthy wild population. Unforhru ely, mrnaging such an op€mtion in a third world country would mise several problcmr reld€d to religion, poaching contmls, and sentim€nt Thfu is a coudtry in which millions of rtp€es p€r adnum. is spent on saving cockroachesatrd rats from diss€ctio! labs. Tte Croc Baltk has an advafiage of being located id an ar€! which has a hrge trumber of daily visitors wbo stop by, tourists visiting from difierent strtes in Indi& and foreigners from mainly Europe atrd tbe U.S. The cost of enlranc€ ticketr ar€ kept low so as to allow people from nrral areasto get to view and l€am about lhele fascidrting reptiles. Tte .r€. iD which the Croc Bank is locrt€d a.lsobenifits, e3most of the stalf employed are from a nearby village, and locat ihops and rtalls thrive on the large numbers ol visitors, paticularly od the weekends"

UPDATEON TFE PRESENT

The Croc Bank has come a longwal' since it began in 1976. Wenow have 10 oflhe 23 sp€cies of crocodil$ of which 6 cpecieshave successfullybred here. Tho6€first few chtches of Mugger eggr produced itr thc late 70s' were hddled with ertreme c!re, although now, with hundreds of vitble €ggsbeing laid annually (in somec$€s, bi-arnually) there fu frutaiingly little we cln do to r€solv€ the situation The cnrr€nt stock of crocodiles being h€Id al (he Madras Crocodile Bank is displayed bclor. Particular int€r€sf is being prid lo ile false Gharirls and dwarf croca, which rre saaritingio sbow sigos of breeding activity, .nd we hope lo get someviable €ggsin the not too far away future. Someol our surplus exotics' have goneto reveral zoosin Iddi& shere they aeem to be doing moderately well We ultimltely wish to acquire all the 23 sp€ci$ of crocodiliaB and creale a genepool, end breed and supply endangeredcrlcodilians lo weII reputed zoological collections, ther€by easing the pressurc on the wild populations. Table 1 PresentCrocodilian Stock at Madras CrocodileB.nk

Species Total Stock Adults Sub-adults Juveniles Cpdltlrb 2,196 775 1023 998 t41 41 ll 20 5 z 58 2 2a 2 2l t4 E 9 3 T. s.hlzgelii 5 5

Oagoing res€arch focuss on temperaturc s€r deter.mination, veterinrry $p€cts of crocodile farmin& and growth rates in hatchlingc.gangdi.utrLitedh rrtificial enviro[ments An rddilional proposal to do ,nother survey for possibl€release babitst for Mugger t{i soonbe rtarting and hopefuly a large number of crocodil€s car be releasedat various locations in and around Tamil Nadu as in the prsL Basevnlu$ rrc currentty beiDg anal],Z.d for the Mugg€r in conjudction {ith a nesrby diagno$tic lrb, *hich will be useful h setting stxndard vdue3 flith which susp€ct€ddiseased aDimals catr be compar€d witb. A[nual mealurements are taken of almost all of the itock of crocNat Croc Bank, and gro$.th rates are carefully modtored lh€r€by givitrg w alt ides of how were doidg in terms of managiDgthe crcca Surveys add populatiotr monitoring of the Saltwater crocodile ia the Ardalasd end Nicobar isladds continues Th€ Croc Brrk (also call€d tbe Centre for Eerpetolog/) i! in its 22nd year of publbhing its Sci€trtil-rc Jourrrd, E madrylil This is r peer r€viewed joumal tLat gr€w from r simpl€ newslEtt€r to wbat ebecomiDg is now deNcribedas lhr premier herp€tological jour.nd ofA3ia". W€ end Ois update by suggajtitrg ltat researcherr interested in C&codiliarr use the Cmc Bank as a basefor their studies! . f€w which have al.eady done so arc the University of Nonh Dakotr, Lafyatte Coll€ge, .nd the Smilhsonian Idstitution The Trouble With gigh Density.... Bdln Stlcy Vderina'r Aspectsofrte Mad s Ctocodile Bank bus 200JBrill.y Pira Cmrsbg WoodrtocLGeorgi! 30189 USA brt8c'@arch$.ugredu Intmduction Ide3lly, tlrc veterinary aspectsofMadfis CrccodileBank Trust could be surnftarized into a seriqsof prel€ntirc rlvrnageme measu€s,including diet stocking densityand preferredenvironmenlal conditions. When applie4 this regimer would result in a healthy,prospering population ofcrocodilians rcquiring little intervention other than feedingard enclo$ne maintenaDce.However, the high stoaking densitiesoccuring in someofMCBT's enclosureshave re$tted fu i&reased levels ofstress as animals struggleto fee4 thermoregulateand raint in socialorder. Stresshas long beenrecognized as a key prcdispositrg_faclorro di9ase in crocodilhns that maniks itselfas a decline i! the generalhealth ofa popdatiotr '" . This causeand efect relationshipbe$r€etr o\€rcroqdiD& stressand diseas€can b€ clearly conelatedwith the incidencesof mobidity and mortality at MCBT.

Trcnds Thelre s ir the incidenceofdisease at MCBT arc easilyobserrable. Almost all casespresented can be tmced back to one of fve enclosuies,each vith the commonproblem of high populal.iondensit (S€e Table 1). The deathrccords that exist for pastthree ye$s at lh€ MCBT indicate C/ocodyluspalustris as le predominatespecies afec1e4 s.ondRtW Caiman cro.odibs crocodilus. Funhermore,wilh fe exc.?tion ofhatchling deadE,there hasbeen almost no motulity in 6ny other species.These two a.trecredspecies share a comfton facto., both are resideatspecies ofthe pils with the greatest overcrowding. Unfortunately,the deatl recordfor the past thre€years is limited to a comparisotroftolal pr,stand Fesent inventoriesand only rEflecisthe numbersand specieslost with no accuratedata oDother faclors suchas the lime ofyesr and post-monemfindings althougbplevious die-otrslnve occurred. Howsv€r, a detailed recordofmortality has b€enrecendy implementod as well as a uniform necropgy procedwe. The numben of rccent deathsin the afiecled pits (Jan. f6-Jtny 2) are giv€n in Table I and tlrc post-mortemfindings are discussedbelow.

Table 1 Atlected DensitiestrC De.lhs Pit nu|fber Stock Total rumber of Ilensity (p€r square Deaths D€xcriDtior rnimals (Jan 16.tulv 2) 1 Sub-adult 321 1,18 C. Dalustris 8 Large adult 1lE 0,06r. ,lFenale

10 Large adult/Male 53 0.004*t 2 C.Dqlustris 16 AdlultC. palustris 450 0.99 21. Adult & Sub". 700 1.13 30 ail.ult C. palltstris

'?eptile '" Ilne T.J., 196: Crocodilians. Pp 336-337,, Medicine and SurgeD/ by D.R Itader. W.B. SaundeNCrmpany: Philadelphia. '" Lare T.J., 1996: Crccodilians- ?p 337-339t' 'RQtile N{edicineand Suge.r" by D.R I,fader. WB. SaundersCompany: Pfuladelphja 'Ihe majorityof C m.odtl6 wqe formsly hous€dh a nixed pit (21)with c' "/codtl6 ?a!$ru-r an4 onthe basisofbodv condition and mortalitv, were clearrv not @m!.ringeff@tiverr Theyhrve sine b€o movearto an all-

5

..While lhesedensities ee not ase*reme as rhose of theother enclosures, both pits containlarger animars, n ny wellover-tlebnete . In addirion,a sisnific&t lonion ofthesepirs is norused for actualdaily ;rivity ad rhe densigof artjr''|,rlsper xtilizen4@ \rbuld be9r@16.

Stockitrg Dcnsity High lDpulation densitieslead to a declinein th€ quatity ofa number ofenvironmmtal faclors and interferEwith the carrying out ofroutine fivuragementopemtions, both rcsulting ir severehealth_rclated consequences.While the direct etrectsofor€rcrowding mry s€emquite obvior.Band havebeen reponeal marrytimes beforo,the folowing is a brief sl|mmaryof obsenatio$ rnadeat the MCBT. Every major environmentalrequirement for normal crocodiliangmwth and maintenanceis afrccted by ove.crowding. The continual excretionofw"ste by literally hun&eds of crocodilesinto a limrted volume ofwater hasthe inevitablercsult ofpoorwater quality. The organic-rich potralsthen servEas arl optimal environmentfor a eriety ofmicroorganisiDs,thus e\Tosing th; chronicaily stresseda&mats to potential pathogens.Profiding eveniood distribution also presentsproblems. While every attemptis rnade1o sFesd the food as equally as much aj possible,with suchnumbem, it is doubtfrl that the weaker animals crn competeeffectively. In addition, the oclurrenceof dominancehienrchies has showDto Dlav a signifrcant role the daily life ofcaptive crocodiliansr. Thereforc, it can be assumed$at social srress as animals uder high densiE c@pete for food basking spotsand renitory could havenegative impli.ations on healtL panicularly during the beeding seasonwhen such jnteraclionsarsmagnfieal Regular managementard maintenarceof someenclosures is also hampeled by high density. Th€ lo€ical solution to poor ri?ter quality would be to increasethe llequencyof cleaning wfich is donein pits (th!6e ofsmaler aninals) that are desiFed for efrcient draining and rcfilling. Xowever,too ofthe s.rfi_:ring ircrssed lits morfality arc dug into the natu:al aquifer, rnaldng completecleaning impossible. A lbird c€mentpil which housesroughly 800-900sub-adult and addt c palrstis presenrs a numberproblerns due to its sheernumbers. Deathsdue to pilin& the stressofmoving the aninuls during cleaningad lhe high ahbient temperaturesare dimcdt to avoid. Furthermo.e,the acl of clsning its€fpooes Foblems with s€fely manewering such a large nunber ofnature ardmalswhile the quadities l€st of sedimentand exdement are manuallydredged fiotrr the enclosureF,ond. lh€ recognilion of all adrnals exiibiting s)dptoms ofmorbidity among srrcha large numberof crocodilesis difficult ad in many incidences,impossible. Someailing ani[uls cal be identmed by their \r"sting body condition or, as discussedbelow, the deElopmedt ofdermatitis or clrta&ous abscesses.A few ofthese animals havebee! removedand isotatedwhen possibte,but lack ofenclosure sf,ac€fmits the trUtrIberthat ca-ube accoftnodated.

'" Campbell,T.W., 1996:Clinical Patlnlos/. Pp253 ,,? "Repdle Medicine and Surgery.', by D.R N{ader. . W.B. SaundersCompa[y: Philadelphia. " Muray, M.J., 1996:Pneumonia and Norrnd RespiraloryFunction. pp 402,', ..ReptileMedicine and . SurgEry''byD.R l4ader W.B. SalmdenCompary: philadelphia. " Itossi,J.V, 1996:Dermatolory. Pp lll ;4 "ReptiLMedicin; and Surgerl,byD.R Mader.W.B. SaundersCompany: Piiladelphla. _- LanglW., 1987:Crccodilian Behaviou: Implications for Management.pp 280-282t "Wildlife Mal|agementCrocodil€ and AlligatoE" edby cW Webbet at. Surr€yBeatty & SoDspty Limited: Australia e Foggi4 C.M, 1987:Disqses ard Di$ase Coftrol on C&codileFarms in Zimbabwe.pD j, 'Wildlif€ 351-362 ManagernentCrocodile and AlligatoK' edby cW Webbel al. SureyB€cy & Sonsprt Limited:Australia. 408 Post-Mortem Findings A uniform rcgrmenfor post-modemexamination was beelln in May of 1998using a formatted data sheetincluding date of deatb sigralment, and pit number. Every animal prcsentedis measur€dfor total tengtb, snout-ventleng&, headlengd\ headvidlh and taif girth. The lattel measurementis a lalue tlnt will be attemptedto be corelated witb that of healtly animalsonce a sufficrent saftPle size is acc.ued. Shouldthere be si€lificant corelauon, this measurem€ntmight be of benefit in a applying a rmifom methodof body condition scoring. In addition, eachanimal is given a body conditiol scoreon a best- worst scaleof one to ten. Each Estem is then syftlMtically evaluatedfor exraordiMry findhgs, wilh obser%tionsbeing rccordedon the datasheet. All adrnals are fully er"luated reeiardlessobvious e{emal tiauma. Almost every incidenceof animalsbeing presefted$dth exlernal wounalswealgd si8trficant internal findings, suggestingthat rhe damagewas inllicted 3fter deathin most cases

As sfakd previously, c. palrsti.t hasb€efl the sp€ciesmost often prcsentedfor post_mortemwith C c. crocodilitls&ing str).jfd,. In the pastfew months,to which thesepost-monem flndings apply, these havebeen the only two sp€cies$rfrering mortali9. All aiimals presentedhave been of $e sub-adultto adult srzeclass e I meter). Body condition is mostoftetr in the lowe. end ofthe |ange (<5), with vertebraand linb girdles appearingprominently benealh the ski . Anore{ia or diminished food intake are suggestedbased on the poor body cudition and lhe absenceofdigesta in post-moneds perforrned ftcently after the feeding of an enclodure.In addition, the moribuid animals in isolation haverefused food as t'€ll alld appear10 be exhibiting behavioralfever 6s tlrcy neverente! the rrater' The most commonffnding upon intemal cyaminationhas beencongested, hypel€dic and often gl:rnulonratous lungt suggestingrespiratory ftilue as the fioal causeofdsth in most cases.In adchtio4 the intestines are often presentedin various degr€esof h}?eremi4 trith hperemia or petechealhemorrhagB ofthe itrtestinr.lmucosa. Severalofthese animals,tlose ofpit 16 in particular, ha\€ also exhibited mu$focal, a{rdati}€ c-utaneouslesrons to larious e{ents on both the do$al and ventral s1ldaces Two aalditional anin ls with the abov€findings ha!€ beenpresented with large subcutaneousabsc€sses, one and t$o per admal. Also, two animals exhibiting the samefindings werediagnosed with hperuricemia and severe visc€ral gou! which hasbeen reported as a sequelaof renal disersein reptiles srlfering from septic€oiar". Basedon theseindirys, it has beenassumed that theseaninlals are stfrering from genemlizedseplicemia as all fndineF coincidewith previouslyreported inforsution on septrcemiain crocodiliaisrb ?b. The MCBT has recedly establishedrelations wit! the post_gBduateftedical science division ofMadias Udversig for anall$is ofpost-mortem samples.Protew spp. Oulgaris ani- nt\ofacie s, werc is{,latedfiom lung tiss:ugperitoneal lluid ard ime$inal mucosagmples along with Gro.up!, Sreptococci. P/ote6 spp. hav€beed a reportedopportunitic pathogensin rcptiles, ideniified in septicemias,pneumonia and dermatoses;in additior\ Slreptococci has oflen beenimplicated as a '' secoodarypa|}rcgenrd The lesionson the pit 16 animals werealso culrured a St?p/ococcl specieswas identified and findin€F were ne€ativefor mycosrsand intmcltoplasmic inclusion bodiescharacteristrc of caimanpox. Additional samplesfrom a numberof animals havebeen sribmitted and resr'lts are awaited

Managem€nt Unfortunately,until a solution to decressethe numbeE ofcrocodiles at MCBT is presente4therc is little that can be done. Isolatirg and medrcatingsuch a volume ofclocodrles is impossiblq due to shortageofenclosues for the fomer and the latter being prohibiti!€ly e)vensive. Funhelmorq it is difrcult to justify tr€tne4t when the animals wiU er€ntually b reintroducedto rhe salne6owde4 siressedpens. Measues to continueimproving the animals' mvironmen! $rch as water changesand equal food distributio4 and closemonitoring of mortality will continue_Th€ p.oblem ofthe fugh incidenceofcainan deathshas hopefully beenEmedied by the rec€ntconstruction ofan al-carnan eaclosr e- In regard1o tnaintaining isolation ofafrectedpits alld nininizing the risk oftt-ander of pathogensto other enclosffes,none the afiectedponds dmin into other pensand it hasbeen rccornmendedtlutt an antimicrobial footbalh be usedbetween enclosures before rrc*ers carry out daily clsning A definitive diagnosiswill be pursuedin eachcase as the occrrence ofany infectiousagents musl be irnmediatelyidentified due to potential dsk to other residentsF,ecies at MCBT. In additiorl a blood study of is prcsendyundeNay to determirc henatologicrl and biochemicalbseline rangesfor the MCBT'S C palrsti.r populationfor ule in frture diagnostics. As for the present,there is ftustrating little elsethat can b€ done other than hopefor relief in the form of the following: requests for C. palustris at otherf^cilities and relase sites:the establishmentofa seco.d Oocodile Bank to which someallimals car b€ transfened;or a changein govemmentpolicy regarding slaughteror q ling.

410

study area v6 divideal hto difetent Sectots, to accodmodate the caunts and for aom;adson.Sector E wasleft out dudngthe counts,as it is in 8ninaccessible terrai4 andit is a yearfor not iossibleto getto the riveras certaio larts. Thissector was oDly searched once nestsand this was dolle by helioopter.

3. OBJECITT/ESofthc PROJECT

Theproject has as it's objectivesthe followingfoul aspects:

/ Movementsia theriver systemi.e. time, exted, location ar1d r€aso[s'

/ Nestirydata in respectoflooatiorL numbers, environmeutal parameters, clutoh size aIId eggdimensions quartities'The quality aspeot / A studyofth€ waterqualities and a monitortngofwater *i belimited to irdustdslpollution and healy metals' andwhe'r / Theupdate ofa databaseon thetoxicity aodpathology in C niloticusas samplesor materialbecome available.

4, MOVEMENT Thereis too Thetotal numb€rof crocodilesin thewhole ofthe KNP hasd€clitred since 1994 in the tittl" i"tu u*itoUtuto explainthis decline in trumbersas yet Thisdecline-was reflected to total rt rav-ar* * *"U For tie purposeof the shrrl1individuals were clsssad sc ording lenglh(TL):

Size1: 0-1,5m Slze2t1,5 - 2,5m Size3.2,5 - 3,5m Size4: >3,5m trot€d If Besidesnoting the nuober ofindividuals per sector, the numberof gt-oups.wasslso seetlto anvtwo indivi'dualswere closer tban their owu body length fiom anoiher,they were [.ir"gi" gt"w Groupsizes ranged fiom I individualto asmany as 40 animals " to delertrline Countswere done dudog May, Aug, Decad Janevery year' TheJan oounJ -was a thenumber of hatchednests A ooult wouldtyPical start before suDrise and touow a oredetermined-C;;.hcourse Theobjective was not to do a census,but ratb€!'to determtde in tb€ stream ;il;""J. ;ors couidnot becovered completely ss nuo€rous islads a" ti"lv. seotorsB,D 8trdG eouldbe covered 100% visually Two or three o-Ur"*.if groups, i""t p* rr,the cor:atsard all usedstandard 8X 32 binoculars.witb large one O""i."** hlgh"rt ** noted.This study showed clearly that thoe is morethan (1969) Br€edhg -.t"il*, a-i"iO""u"t€" year,and it is in coatrastwith the findingsofPool€y wereidentified areasaifereo t-in UiUre andafter the flood of 1996 Before1996 two areas movementdutitrg May -a pGJ t"ti"g i" bothareas were observed There was a defnite to thosealeas, and presunably from it dudngAugust' 1999 222 ' Thtt p'$ otlvtt'otly @it!d t@ 6rr Fidi" Jdrtv the fi.rllextend ofthe movementsare not yetundetstood See appetdix I for Sraphsoo numbersaod groups.

5. I{ESTING Eachyear during December the numberofnests h the studyares was courted on foot' but in 1997a helicopxerwas used. The following table shows the nunbers.

able l. Nesrsin sludv orca. SecA SecB SecC SecD SecE Gorge Totd 1993 2 l 9 I 22 54 1994 3 l0 5 29 t0 6 199t 4 5 5 12 t5 t9 60 1996 2 2 3 7 4 41 1997 0 1 3 17 0 20 4l

Someoests was opeled towards the eltdofthe nestiagseason (late December) aod the eggs wereoounted, measurcd and weight before retum€d to the [est. Thisis thefrst aodotrly data availablefor KrugerNatioaal, and it comparesfavorably with Loveridge(1992). Altbougb uo indicationofcommunal ncsting areas (Pooley, 1969) rvere found, some s€otors were rnore utilizedthan others. Except fot one,all the neststist wereopetred, hatched successfitllt one trestwas abaodoned. No aggressivebehavio! was €ncountered (Koftoq 1989),(Pooley, 1969).

Table 2. Esp dst.t colleded olots the olifants r, Nest no Eggs Length width MassG) Spoiled Depth Female '19 54 JI t27 3 D6 20 1q 49 110 5 270 3,t2 '75 ', <| D't 49 )t lll 4 D9 39 49 109 0 230 2,94 Dll 43 49 106 250 2,10 D12 4 47 t02 1t0 3,t2 D13 30 t0 232 3,65 GI 46 74 49 106 2 310 1{t 38 7l 48 109 I 490 2,99 G3 45 78 52 143 5 2.40 3,25 '16 Average 37 49 114 263 3,02

222b Thit 0.8. id&et n ly ooin d f@ ftr printr.SJtN'ry !999