The AusTED II, an improved trawl efficiency device 2. Commercial performance

An Australian-designed bycatch reduction device (BRD), known as the AusTED, was modified to improve its efficiency and simplify its design. The modifi ed version (the AusTED II) was tested under a range of conditions typical o f prawn trawl fisheries of north eastern Australia. Trials occurred during commercial trawling operations to heighten industry awareness of research i nto BRDs and improve the credibility of research results to industry. Avera ge bycatch reduction ranged between 15%? and 49% depending upon fishery con ditions, and the capture of large animals such as stingrays and sea turtles was significantly reduced. The AusTED II had a variable effect on prawn ca tches depending on trawling, conditions, ranging from no significant differ ence to a 36% loss. The AusTED II offers commercial fishers the benefits of large animal exclusion plus reduced bycatch. Reductions in bycatch were ex plained in part by the exclusion of fish species with "fusiform" and "later ally compressed" body-forms. Unexpectedly, "weak swimming fish" were also e xcluded consistently by the AusTED II. The trialing of a single BRD across a range of trawling conditions in north eastern Australia demonstrated the variability in BRD performance that can be attributed mainly to the quantit y and composition of bycatch species. It is highly likely that other exclus ion systems like the AusTED II will not be immediately suitable to all nort h east Australian trawl fisheries. The acceptance of BRDs by the Australian trawling industry will depend upon efficient and pragmatic designs coupled with industry confidence in research results. (C) 1999 Elsevier Science B. V. All rights reserved.