A PRELIMINARY EVALUATION OF THE PERFORMANCE OF PASSIVE INTEGRATED TRANSPONDERS AND METAL TAGS IN A POPULATION STUDY OF THE FLATBACK SEA-TURTLE (NATATOR-DEPRESSUS)

Marking of nesting female Natator depressus with passive integrated tr ansponders (PITs) at the major eastern Australian rookery of Wild Duck I. was initiated in 1989. The failure rate of PITs after two years wa s calculated and compared with loss probability estimates calculated f or conventional metal tags on the basis of 1979-91 data. PITs compared favourably in the short period of evaluation with an 8% loss of ident ification after two years (n = 37). Loss of metal tags was variable be tween metals and tagging positions, with titanium tags applied to the axillary position of the front flippers being the most effective in th e long term. Factors peculiar to this species that affect loss of meta l tags and prospects of PIT performance in the long term are discussed .