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134
Densitv estimatgs were very variable and would be a poiotless exercise to take a mean figure
iti
i, ,r,r" country. one fact which emerges liom this survey is that densities
;;;r;i";;;i;;J;.",1 "-it"""i"i" "holJ outsirle pr.tecte.l areas and this was noted tbr a oumber ol rivers (e g
i""*li"t" cr,"o", Rul.rji, Kilombero, Ruaha, Mara, crumeti). This indicates thar protection
is having a beneficial effeot, at least on the cfocodile populatlon
The low densities (often 0.00) tbund outside the protected areas also indicates that crocodile
popriutio". *iff continue to iecline when in competitioo with humans possible way to
.One
im"p tti, A".tin" is to utilize these populations tbr ranching and farming operations Lake
nui*u i, on" ,u"h population that may benefit flom such a management policy'
SPECULATION ON EGG PRODUCTION FROM THE LOWER RUFUI WITHIN TIIE
SEI,OUS GAME RESERVE
The number of breeding females within a population is related tu the total size of that
DoDulation and this fhct is often used to estimate population size tiom counts ot nests
id;;k. ita' Grabam, 1988) Having spe.ulated I'n the l'rtal size ol the p-t'pulation in the
ir*", irtiii it is'then pos;ible to speculare on egg prnrJuttion The numher of.L'rrrcodiles less
thun t.Z oi totnt l"ng,tt is estimated to be alnroxinately 50 % of a Nile rrocodile ppulation'
ftre nu'rter ot treelOing t'emales within an avcrase Nile crocodilc f'ululatioi i\ estiNated to
be y4 of those crocorliGs longer than 1.2 m total length (Games, 1990). Cl tch sizes vary
nr"od, but tt ou",^g" lor Laie Kariba on the Zambezi tiver is 't5 eggs lt' the above tigures
ir" ,ri"t t'U" " t"o."i"nta!ive of the SeloLrs population then egg production for the k)wer Rufiji
within the reservi can be estimated by:
Lower estimate of crocodile numbers
Numbers longer than 1.2 m total length
Number of breeding females
Lower limit fbr average clutch size
Estimared egg Production
5'70',7
2 854
696
30
20 880
ACKNOWLEDGEMENTS
Financial support fbr this survey was provided by Internationaler Reptillederverband E V'
1c",.uny;, 3ou"t. Nouvelle France-Croco (France)' Hambo Crocodile p-roject (Tanzania) and
iu"i" ,qt('Cru*""iul. I thank Dr. Jon Hutton and Dr. Dietrich Jelden ofthe IUCN crocodile
ifeciati"t C'toup fo. initiating this survey and raising the flrnding The assistance of Hashim
l,ituguti nonoe in Dar-es-salaam is gratetully acknowledged Daren Bruessow and Richard
ie.si."on .oae th" night counts possible and James Maynard is tlanked tbr tis participation
iiiiiult *"." ortrv floin by Lorivi Moirana. Gerald Bigurube, Cha(les M'Doe and charles
Trout. Observers were Liiimo, Charles M'Doe, Emmanuel Severre and Cerald Bigurube'
Special thanks to Bakari M'bano who took time olT from his busy schedule to come and rescue
us at Rungwa. The support of the Director of wildlif!. Costa M'lay, especially by making sure
an aircralt was available is Sreatly appreciated