Choosing anteriorgear modifications to reduce the

Authors: Matthew J McHugh Matt K Broadhurst David J Sterling

Publish Date: 2016/11/12

Volume: 27, Issue: 1, Pages: 111-134

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Abstract

Globally penaeidtrawl fisheries are faced with three broad sustainability issues 1 large bycatches 2 acute benthichabitat impacts and 3 high energy consumption Most resolution efforts have focused on i above and via bycatch reduction devices BRDs installed in the posterior trawl codend which typically reduce total bycatches by 30–70 but are poorly adopted owing to few perceived benefits by fishers While mandated BRDs will remain a feature of selective penaeid trawling solutions to habitat impacts and high energy consumption require changes to the anterior trawl including the spreading mechanisms eg otter boards beams and sleds ground gears and net designs Further because such components ultimately determine which organisms enter the codend it should be feasible to structure anteriortrawl modifications to address all three sustainability issues including improving selection We sought to review the feasibility of such an approach here and located fiftyeight relevant articles of which 45 11 and 23 directly or indirectly focused on reducing bycatch habitat impacts and energy consumption respectively Considering these articles we propose a protocol for holistically improving the environmental efficiency of penaeid trawling involving 1 selecting the most appropriate multinet configuration 2 reducing otterboard angle of attack to ~20° 3 minimising twine area and 4 optimising horizontaltrawl opening Compared to conventional configurations choosing alternatives within the above protocol could reduce total unwanted bycatches and habitat contact by 70 while concomitantly lowering drag/fuel costs by 20 The latter outcome might improve selective penaeidtrawl adoption among global fishing fleets

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