Tracking free-ranging sharks with hand-fed intra-gastric acoustic transmitters

To estimate tag retention time, 39 acoustic transmitters were hand-fed to bull sharks Carcharhinus leucas, lemon sharks Negaprion acutidens and tiger sharks Galeocerdo cuvier, in the Shark Reef Marine Reserve, Fiji. Minimum tag retention times ranged from less than 24 h to 34 days, and bull sharks could be tracked for a minimum mean duration of 6.8 days. Feeding acoustic transmitters wrapped in bait to free-ranging sharks is an alternative and viable method to obtain presence�Cabsence data from free-ranging sharks.