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98
A RADIOTELEMETRY AND MARK.RECAPTIJRE EXPERIMENT
tO ISSTSS TIIE SURVIVAL OF JUVENILE CROCODILES RELEASF]D
FROM FARMS INTO TIIE WILD IN ZIMBABWE
R. A. FERGUSSON
P.O. Box HG 1l
Highlands, Harare
Zmbabwe
ABSTRACT
Irrge numbe$ of Nile crocodile eggs arc collected by crccodile ranchers from Lake Kariba'
Zim-babwe. A small p€rcentage of this harvest is retumed to the wild at 1 to 1-5 m TL'
This paper describes ihe initial stages of a survey to monitor the success of this process'
nadioteiemetry and mark-recapture techniques are being used to estimate survival, growth
and dispersal of the captive raised animals comparative to that of the wild population - There
are indications of considenble mo ality caused by cannibalism and human interference'
Pattems of growth and dispersal after rclease are apparent. The rcsults of this investigation
have imolicitions for sustainable harvesting programs for crocodiles throughout Aftica and
also for conservation programs in which rcstocking of depleted habitats is concerned'
INTRODUCTION
This project originates from CSG research objectives. The objective is to evaluate the
,u""ot of th" release prognm that is the current policy of the Crocodile Farmers
Association of ".o.odile Zimbabwe (CFAZ) and the DePafiment of National Parks and wildlife
Management (DMWLM). The background and relevance of this project are outlined
bdefly;
- Commercial crocodile ranches collect eggs from the wild and rear these animals in
captivity. I-ake Kadba is the focus of these activities in Zimbabwe'
- Prior to 1987 each of the 5 crocodile mnches collected less than 3000 eggs each
year - the quota being set by DNPWLM.
- Since 1987 unlimiled egg collection has been encouraged, pardy to estimate the size
of the adult population and uP to 40 000 eggs ate collected each year'
-Empirical evidence and modelling indicate that a very large proportion of eggs can