ASFB Home > The effects of spatial and temporal factors on the abundance of seven key finfish species along south-western Australia.

Reduction of Marine Mammal Interactions with Fishing Gear. Addressing Marine Biodiversity Issues

Geoff McPherson, Phil Turner, Craig McPherson, Doug Cato, Denis Ballam and Neil Gribble

THEME: ASFB (Poster)

Interactions between marine mammals and fishing gear is increasing throughout many Australian fisheries. Where interactions are negative to the mammals, the future of each fishery will become increasingly uncertain as biodiversity provisions are threatened. Where interactions are negative to the fishery, the future of the fishery will become increasingly uncertain as financial viability threatens the operators with additional biodiversity issues. Two forms of marine mammal interaction occurs, predation on target catch and bycatch in net fisheries. QFS has developed two monitoring programmes of marine mammal interactions in Queensland based fisheries. Mitigation measures are under consideration. As an alternative method to examine the effectiveness of various mitigation measures, a 3 dimensional acoustic tracking system is under development by QFS, JCU (Engineering) and Defence Science and Technology Organisation. Interactions between false killer whales and killer whales with tuna longline fishery catches in the Coral Sea alone result in losses in the order of $4 million annually. Predation occurs throughout dropline and longline fisheries elsewhere in Australia. Acoustic and mechanical methods to impair the terminal stages of mammal predation are under development with AFMA and Eastern TUNAMAC funding. Interactions between dolphins, dugongs and whales with gillnets occurs throughout Queensland and Australian waters. Acoustic alarms/pingers offer real options to reduce bycatch with NHT funding. However proving alarm/pinger effectiveness through catch monitoring (QDPI and SEANET) and dolphin behaviour (UQld) is difficult due to low bycatch rates. The acoustic tracking system offers an alternative method to examine alarm/pinger effectiveness.