Pop-up archival satellite tagging of Carcharias taurus
Otway NM and Ellis MT (2010) Pop-up archival satellite tagging of Carcharias taurus: movements and depth/temperature-related use of SE Australian waters. Presentation given at the Sharks International conference, 6 – 11 June 2010, Rydges Esplanade, Cairns, Queensland, Australia.
Mitigating anthropogenic threats to the critically endangered Carcharias taurus requires a detailed understanding of the shark’s movements and depth/temperature-related use of coastal waters. Initial information was obtained by tagging 15 C. taurus (8 males, 7 females) with pop-up archival satellite tags programmed with varying deployment durations (60 – 150 days). Double tagging with acoustic tags linked to our SE Australian coastal acoustic monitoring system (SEACAMS) provided accurate geo-location of individual sharks. Distances moved by individual C. taurus ranged from 5 – 1,100 km and varied according to gender, sexual maturity and season. Migratory movements (north and south) were punctuated en-route via the occupation of aggregation sites for differing periods of time. The deepest depth recorded was 232 m off SW Rocks on the mid-north coast of NSW. Movements of C. taurus were restricted to waters with temperatures ranging from 14 – 26°C with males and females exhibiting similarities in their depth and temperature-related use of coastal waters. On average, male and females spent 71% and 78% of their time, respectively in waters < 40 m and 95% and 96% their time, respectively in waters 17 – 24°C. By occupying inshore waters, C. taurus is more exposed to potentially adverse fishing-related interactions.