Reducing seabird bycatch in longline, trawl and gillnet fisheries

Abstract

Introduction 32Results of reviewed mitigation methods 35Mitigation methods relevant to multiple fisheries 35Offal and discard management 35 Area/seasonal closures 36 Longlining 36 Underwater setting devices 36 Funnel (lining tube) 36 Chute 37 AbstractWith an increasing number of seabird species, particularly albatross and petrels, becoming threatened, a reduction of fishery impacts on these species is essential for their future survival. Here, mitigation methods to reduce and avoid seabird bycatch are assessed in terms of their ability to reduce bycatch rates and their economic viability for longline, trawl and gillnet fisheries worldwide. Factors influencing the appropriateness and effectiveness of a mitigation device include the fishery, vessel, location, seabird assemblage present and season of year. As yet, there is no single magic solution to reduce or eliminate seabird bycatch across all fisheries: a combination of measures is required, and even within a fishery there is likely to be refinement of techniques by individual vessels in order to maximize their effectiveness at reducing seabird bycatch. In longline demersal and pelagic fisheries, a minimum requirement of line weighting that achieves hook sink rates minimizing seabird bycatch rates should be tailored with a combination of strategic offal and discard management, bird-scaring lines (BSLs) and night-setting, particulary in Southern Hemisphere fisheries. Urgent investigation is needed into more effective measures at reducing seabird interactions with trawl nets and gill nets. In trawl fisheries, a combination of offal and discard management, the banning of net monitoring cables, paired BSLs, and a reduction in the time the net is on or near the surface are likely to be the most effective in reducing seabird interactions with the warp cables and net. Few seabird bycatch reduction methods have been developed for gillnet fisheries, although increasing the visibility of the net has been shown to reduce seabird bycatch. Further studies are required to determine the efficacy of this technique and its influence on target species catch rates.

Global seabird bycatch in longline fisheries

“…In recent years, an effective response has emerged from the increasing variety and efficacy of technical measures designed to mitigate, and even eliminate, incidental catches of seabirds (e.g. Brothers et al 1999, Bull 2007, FAO 2008, BirdLife International & ACAP 2009. Despite this, there is considerable evidence that many fisheries do not use recommended best-practice mitigation measures (e.g.…”

Stage-dependent distribution of the Critically Endangered Amsterdam albatross in relation to Economic Exclusive Zones

“…In this context, conservation efforts in fishing practice and regulatory meas-ures have been undertaken and/or proposed to mitigate incidental seabird capture at sea (e.g. Bull 2007) within each piece of the Regional Fisheries Management Organisations (RFMOs) world 'puzzle'. However, a specific legal regime applies within a coastal State's Exclusive Economic Zone (EEZ), a marine zone prescribed by the United Nations 1982 Convention on the Law of the Sea and stretching from the baseline out to 200 nautical miles (or ca.…”

Action plan for seabirds in Western-Nordic areas

“…Although some recommendations for mitigation measures are available (e.g. Melvin et al 1999), solutions which are also advantageous for fishers and thus likely to be widely adopted are less obvious than for long-lining (Bull 2007). Trawl fisheries have generally been assumed to cause relatively little bycatch of seabirds.…”