Summary
Bycatch of seabirds during longline fishing operations is listed under Australian legislation as a key threatening process which could endanger 14 species of seabirds. In 1998 a Threat Abatement Plan (TAP) was finalised to manage this threat. The TAP is essentially Australia’s NPOA and requires all fisheries to reduce seabird by-catch to below 0.05 seabirds per thousand hooks. Since 2001 the performance of three measures — an underwater setting chute, and two line-weighting regimes (38g and 60g swivels used on snoods 6m from the hook) used in combination with twin bird scaring lines — were trialed in Australia’s Eastern Tuna and Billfish Fishery. These trials did not involve experimental manipulations, but were tests to ascertain if the measures could achieve the TAP’s performance indicator of 0.05 birds/1000 hooks. All three measures failed to achieve this level — at the completion of the trials a total of 278 seabirds had been caught in 461,311 hooks observed (overall bycatch rate 0.6 birds/1000 hooks). The principal species caught was the flesh-footed shearwater, which comprised 91% of all birds taken. Reducing bycatch in pelagic fisheries, particularly where seabirds with diving capabilities are commonly encountered, poses significant challenges for gear technologists and fisheries managers. Finding solutions requires a mix of legislative and political measures to ‘soften up’ industry, combined with sound science to define problems and develop technological answers. Educating fishers in the use of mitigation measures in the absence of appropriate incentives and compliance is unlikely to lead to uptake of those measures and a subsequent reduction on seabird mortality levels. This is particularly the case in fisheries dominated by a fishing fleet that is largely owner-operated where immediate financial imperatives take priority over longer-term industry sustainability.