Establishing a mark-recapture program for dugongs in Moreton Bay, south-east Queensland

Abstract

This paper reports the commencement of the first mark-recapture program for a dugong (Dugong dugon) population. Moreton Bay, south-east Queensland supported a D. dugon population of more than 800 individuals in 1996 and is close to an urban centre, Brisbane. Several features of this population make a mark-recapture program feasible: a large resident population concentrated over a small and predictable area, a relatively clear water habitat, animals regularly exposed to boating traffic, and an efficient capture method. Fifty-four D. dugon were captured using the ‘rodeo’ method and tagged. Tags applied included a long-term dorsal PIT tag, a titanium turtle tag, fluke notch and temporary paint stick mark. For each D. dugon, body length, anal girth and gender were recorded. D. dugon were biopsied for genetic (microsatellite) analysis. Faecal samples were obtained for reproductive hormone assays. This program has the potential to yield information on trends in population size and distribution, population dynamics, mating strategies, social structure and general health of the population. This is the first season of a long-term project.