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88 The endocrine ph1'siology of the adult also appears to bo influenced by the temperature experienced during incubation (Gutzke and Crews, 1988). Overall, &culating conc€ntratiols of an&ogens are significantly higher in adult Eales compared to adult femalos Within females, however, androgen t€v€ls ai€ significantly higher, and estrogen levels sieEificantly lower, h females ftom high tempciatures compared to females ftom low incubation temperatur€s. Indeed, most fenales from high temperatures appear to be functionally sterile, sugg€sting that tho primary alteration is at the neuroendocrine level as it is in androgenized female rodents A.EFFECTDUE TO D.ICUBATION -, TEMPIRATI'RE AND -E! T p..o s 005 GONADAL S EX p-, s .ool E do b0 Male32.5'(n=10) Male 30' (n=5) Female 32.5'(n=8) Female 30. (n=25) € B, EFFECT OF CONADECIOMY Y ON DA Y OF H ATCTI / Z Zf -
89 The sexual behaviors of irdividual leopard gcckos ftom dificrcnt hcubation tomperatures varies in a systcmatic ma!.oer, witt thc rcsponses offomales to malc courtship stowing the greate,st difercnce (Gutzke and Cre'; , 1988), FerMles ftom low ircubation tempratues readily cfibit receptivity whetr courtod by a Balo. Or the oth€r hard, females fiom high hcubation tempcratures r€spond more lile males tha! lite feEales fton low teEperatures. Ttey often lf,il aggessively reject the malc or attack him as would occur in a dale-Ealo encouDter. This effect ofa Dale-ploducirg temperature oD tbe feEalc phenotype is iemidscent of the well-tnown masculinizirg effecLs of a.Dalrogen treatment ilr leonatal feEale mamDrals. In other wordE high i.ncubation teEperature Eay be acring in a fashion aralogous to a.ldroge! duriDg developmeut in mamDrak. Captive Ma&gement of Reptiles with TSD Thc occurence of TSD io rBalry reptiles affords thc udque opportu.nity to artifici.lly codtJol sex detcrmination lrithin a c.ptive populatioD" However, several basic questiols must be addlessed to optid;ze thc captive DraDageEent ofrepdles qit[TSD. These questions include: (i) Whictr temperaturcs produc€ a particular s€x? (ii) Do a[ temperatues producing a particular sex r€sult iD iadividuals of equd sexual competeDce? (iii) Wlich sex ratios are best for a captive populatiotr? The ftst questio! is b€giljlilg to bc arswered in a number of species. It is beaomiDg dear tbat species which show sioila! patterDs of'ISD car bave different pivotal temperatures ( = idcubation temperature p.oduciDg a Ll sex ratio) (Bull et al., 1982; Mrosoisky et al., 1984a; Wibb€ls et al., 1991). Becausc of this variability i! tle patterns a.ud pivot3l temperatures of TSD, masipulatiry the sex ratio of a given species qould r€quire ttrat a variety of incubation lcmperatures be studied simultaa€ously to determine whid sFd6c teoipcratBro langes ploduce a giver sex ratio. Are there ccrtair optimal temperatures for producirg sexually coDpetelt indrviduals? Itr the leopard geckq the ocssional femalas resulting ftoru relatively high Eale-produciog hcubatron temp€ratures are lrot reproductively c&petent (s€€ above). Futher, the "sexual poterq/ of alr incubatiotr teEperature car vary (BDI et al., 1990; Wibbels et al., 191), For example, ia the red-eared slider tlddtl (Tru.hemrs scliprd), shiftilg eggs to a higher (fenale-producing) or a lo*er (Draleproducilg) tenperature wil rcsdt;n more stewed s€xratios. Such studies could prove difficult using turdes becauso of thc length oI time sepa.rating ircubation and adult rcproductive success. However, a liz-ard such as the leopard geckq wbich matures mpidly aDd adapt6 *€ll to captivity, could plove to be a 6odel species for such studies. The ability to ma.!.ipulate sex dete.mjlatiotr by temperature nccessitates tle choosiag of ar appropriate sex ratio for a g1vetr c:ptive reari.Dg progr6m. This issue car be approached using two distinctly differert strategies. In the 6lst approach, one could attempt to duplicate the sex ratio of naturally o..urring populatios. Thc sex ratios in natual populations of leptiles witl TSD do Dot al*?ys conform to tle L1 ratio suggested by sex allocation tleory (reviewed by BuI ard Chanov, 1988; see also Limpus, 1985; Mrosorsty and Provancha, 1989; Wibb€ls et al., 1991). In facl rnary feloa.lebiased sex ratios have becn dotected as well as at least one Drale-biased sex ratio (Linpus, 198t, The evolutionary basis of skewed sex ratios i6 ulkrcwq although Bu[ and Chamov (1989) have proposed that factors such as tberEal envirooment prefererces and/or postLatchling groi+,tL rate,s could afiect the fitoess of a particular sex ald thus selcct for biased 6e.( ratios. Regarau€ss, our presert knowledge of TSD ard the resulting sex ratios pre!€nt us ftom .*ig"i"g a! evolutiorarily stable sex ratio to a give! populatiod of reptiles *ith TSD. Wlile lhe effects of sex ratio on the reproductive output of a population of reptiles witl TSD has lot bee! empirically addrc,se4 it se€&s that h situatiols ir which reproductio! is female-limited, an iocreased production of fenale offspring could signiEcardy i.ncrease the reproductive output of a captive populatio& Thus, a.n altematirc 6trategt would simply be to disregard s€-r ratios that o€cur in the wild a.rd Ea.oipulate the sex ratio of tle captive population i! order to msxiEize reproductive sucacss. If ole decides to generate a biased sex ratiq what ircubation temperahles should be used? That is, should an iDcubatior teEperature that producls the desired sex ratio be utilizrd or should a proportior of tbe eggs be incubated at a male-producing tempelature aDd lhe renfider incubated at a female-ploducirg teEperafiirc? Thesc questiors ca! be addr€ssed by studies investigating t[€ effects of hcubation temperature olt sexual colrpetence (as discuss€d above fo! lhe l€opard g€cko).
Page 1 and 2:
CROCODILES Proc€€dings of the l
Page 3:
FOREWORD The two volumes of this PR
Page 6 and 7:
Elsey, R M, McNease, L & Joanen, T:
Page 9 and 10:
CFAZ CIIAIRMAN'S OPENING COMMENTS F
Page 11 and 12:
PRESENTATION FROM THE MINISTER OF E
Page 13 and 14:
Fitting Curves to crocodilian Aqe-s
Page 15 and 16:
7 a.set of uniforrn random nunbers.
Page 17 and 18:
2. VON BERTAI"ANFFY MODEL FOR GROWT
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11 The -following four tables give
Page 21 and 22:
UNIFoRU sarnpling MEDfUM sahpl ing
Page 23 and 24:
15 Sectior IV: Actual Croc Data, l,
Page 25 and 26:
1'l (ii) Linear regressron. same ra
Page 27 and 28:
1,9 rejecting nufl hypotheses that
Page 29 and 30:
21 Brisbin, I.L., Jr., c.c. White,
Page 31 and 32:
Iength lthich corresponds to the ni
Page 33 and 34:
25 Because of lack of funds Eo carr
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27 Despite the fact that during a p
Page 37 and 38:
29 FIGURE N9 2 BLACK CAIIIAN POPULA
Page 39 and 40:
I'Effect of diets conplenented vith
Page 41 and 42:
3i Two of the 6 x 2 m. tanks four e
Page 43 and 44: : .i ; -3, E .-1 t FFdF !_9 + + + +
Page 45 and 46: 10 Table IV : fl aernathological Re
Page 47 and 48: 4l 4.- CONCLUSIoNS 1) The most favo
Page 49 and 50: 43 THE INVOLVEMENT OF RURAL COMMUNI
Page 51 and 52: 45 the rainy season and, in conhast
Page 53 and 54: 47 difficulties and the isolation o
Page 55 and 56: 49 Eacb time that one of the villag
Page 57 and 58: 51 CONCLUSION Naturally, these rcsu
Page 59 and 60: 53 LONG-TERM POPUT-A.TION S'ruDIES
Page 61 and 62: 55 'Ile study reporled here was des
Page 63 and 64: 5'7 made of transmilteFequjpped ndm
Page 65 and 66: 59 wilhin the reservoir was lypific
Page 67 and 68: 6l However the use of such winter d
Page 69 and 70: 6.1 surface to breathe (Kellogg 192
Page 71 and 72: 65 ACKNOWLEDGMENTS This work was su
Page 73 and 74: Murphy, T. M., P. M. Wilkinson, J-
Page 75 and 76: 69 t 3 ^ 3 :9s 3P o ;x !B 'rr.l9 3e
Page 77 and 78: 7l FoDd B + i Poud C I Pltllr. l. U
Page 79 and 80: 73 9 October 1991 L t' I L t' 26 Ma
Page 81 and 82: 75 80 -r- 1987-88 + 1991-92 t -40 .
Page 83 and 84: 77 GROWTH RAIE OF CAIMAN (Caiman cr
Page 85 and 86: 79 Values of the life lable paramet
Page 87 and 88: 81 REFERENCES Craig. G.C., D. Si.C.
Page 89 and 90: 83 CUMATIC F{w L Stirldi .6.aiDS EF
Page 91 and 92: 85 2. Behavioral facilitation of re
Page 93: 87 TeEperature, hy&ic coaditionq aa
Page 97 and 98: 9l 2o I E F conuor o.r r.0 r0.0 a0.
Page 99 and 100: 93 Referetrces Ber!, H.A. (1990). T
Page 101 and 102: 95 GROWTH RATES AND BODY CONDITION
Page 103 and 104: 97 LIPID AND FATTY ACID COMPOSMONAL
Page 105 and 106: 99 be removed sustalnably, provided
Page 107 and 108: 101 necessary as the endurance of t
Page 109 and 110: 103 Table 2. The ratio of first sig
Page 111 and 112: 105 3) Movement and dispersal The r
Page 113 and 114: 107 Disease Trend$ on Crocodite Far
Page 115 and 116: 109 Fuigol and other dermar,?ir - d
Page 117 and 118: 111 THE FEEDINC ECOLOGY OF TWO NILE
Page 119 and 120: 113 areas outside the National park
Page 121 and 122: 115 been done for a tlpical populat
Page 123 and 124: 117 ACKNOWLU)GEMENTS This study was
Page 125 and 126: 119 THE STATUS AN'D DISTRIBUTION OF
Page 127 and 128: Figure l: Crocodile Survey - Tanzan
Page 129 and 130: 123 :rD ES e € a 69 PE e 3 Er t !
Page 131 and 132: 125 Ruaha River (Figure 2) The Ruah
Page 133 and 134: 127 lake Mtera (Figure 4) This is a
Page 135 and 136: t29 with 6shermenand subsistence f'
Page 137 and 138: lil Kilimmjaro/Tanga Region Pa gani
Page 139 and 140: 133 The numbers of crccodiles durin
Page 141 and 142: 135 REFERENCES Chabreck, R.H. 1966.
Page 143 and 144: l -37' 3.1.4 lagal Trad.e Local tra
Page 145 and 146:
l.l9 In order to gecure credibility
Page 147 and 148:
l4l 'rould apply to 6kins of good h
Page 149 and 150:
143 This infdrrDation cduld be supp
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l.l-s ].nternational reEplfnstbitit
Page 153 and 154:
t4'/ illegal sttjns in their pr,r,d
Page 155 and 156:
149 CROCODILE SKIN INDUSTRY IN ETII
Page 157 and 158:
l5l Table 2. Ouotas for Ethiopian c
Page 159 and 160:
153 depriving EWCO of incentive for
Page 161 and 162:
155 A PRELII{] NARY ASStsSS!.IENT O
Page 163 and 164:
15',7 Origin l Payert lltosk Breedi
Page 165 and 166:
159 dropped, producing 23 and l9 eg
Page 167 and 168:
l6l This figure ts even lorrer than
Page 169 and 170:
163 =z 3F \riciNoraj {
Page 171 and 172:
165 References EArr,ER, R.D. ( 1976
Page 173 and 174:
t6'1 IPPIIDIX tt BtoBtE cI0@(DILX n
Page 175 and 176:
l()t/ Backqround l,lelano5uchus nio
Page 177:
t7l The numbers of black cainan c'b
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