Population-Dynamics and Status of Crocodylus-Porosus in the Tidal Waterways of Northern Australia

Abstract

The results of 10 years of systematic, standardized, night-time surveys of C. porosus in c. 100 tidal waterways in northern Australia are presented. One group of waterways in Arnhem Land has been studied intensively, especially over the last 4 years; others have been surveyed at least once and many several times. The results indicate a basically steady total population, with some signs of an increase in the proportion of large animals. As total protection has been accorded C. porosus since 1972, these results are perhaps surprising. The results of our surveys and studies have allowed a picture of C. porosus population dynamics in northern Australia to be developed, and this is presented in some detail. It enables us to account in a consistent fashion for the results of the surveys and to predict results to be expected on future surveys. The results also enable us to make an assessment of the overall status of C. porosus in northern Australia, and of the prospects for recovery of the population. Management implications of the results and population model are also discussed.