Summary
Passive acoustic deterrents in the form of chains of metallic beads and air-filled plastic tubing attached to gillnets in Australia did not reduce bycatch of two small cetaceans: the Atlantic bottlenose dolphin (Tursiops truncatus) and spinner dolphin (Stenella longiristris). A sub-surface set gillnet (set 4.5 m below the surface) in Australia reduced cetacean catch rate [Atlantic bottlenose dolphin (Tursiops truncatus) and spinner dolphin (Stenella longiristris)] when compared to a standard surface set net. The sub-surface net decreased total fish (teleost species: tuna, mackerel, billfish) and shark catch approximately 25%.