Effectiveness of fish waste management strategies in reducing seabird attendance at a trawl vessel

Abraham, Edward R.; Pierre, Johanna P.; Middleton, David A. J.; Cleal, John; Walker, Nathan A.; Waugh, Susan M.

doi:10.1016/j.fishres.2008.08.014

Cited by 36 publications

(40 citation statements)

References 20 publications

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“…Strict discard policies employed by trawl vessels operating in waters within the jurisdiction of CCAMLR have minimized exposure of birds to warp cables by retaining discards on-board until after shooting or hauling of fishing gear; consequently, the occurrence of incidental mortality is close to zero (CCAMLR, 2014b). Implementation of improved discard management measures around the Falkland Islands will be essential to reduce incidental mortality in trawl fisheries in the future (Abraham et al, 2009;Pierre et al, 2012).…”

Section: Overlaps Between Commercial Fisheries and Albatross Dietmentioning

confidence: 99%

“…Seabird survival and breeding success can be reduced by competition with fisheries (Furness and Tasker, 2000;Frederiksen et al, 2004), and incidental mortality in fishing gear can be a major cause of population declines, particularly of albatrosses and large petrels (Weimerskirch and Jouventin, 1987;Barbraud et al, 2008;Phillips et al, 2016). Physical and operational mitigation measures have been developed to reduce seabird mortality (Løkkeborg, 2008;Phillips et al, 2016), including the reduction of fishery discards, which decreases the attractiveness of vessels (Abraham et al, 2009;Pierre et al, 2012). Scavenging birds are attracted to the supplementary food source provided by discards, which may consist of (i) the head, tail and offal of retained catch (commercial species caught at commercial size); (ii) whole fish of commercial species but caught at a non-commercial size; (iii) non-commercial species and (iv) unused baits (in longline fishing).…”

Section: Introductionmentioning

confidence: 99%

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DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

et al. 2017

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Almost all of the world's fisheries overlap spatially and temporally with foraging seabirds, with impacts that range from food supplementation (through scavenging behind vessels), to resource competition and incidental mortality. The nature and extent of interactions between seabirds and fisheries vary, as does the level and efficacy of management and mitigation. Seabird dietary studies provide information on prey diversity and often identify species that are also caught in fisheries, providing evidence of linkages which can be used to improve ecosystem based management of fisheries. However, species identification of fish can be difficult with conventional dietary techniques. The black-browed albatross (Thalassarche melanophris) has a circumpolar distribution and has suffered major population declines due primarily to incidental mortality in fisheries. We use DNA metabarcoding of black-browed albatross scats to investigate their fish prey during the breeding season at six sites across their range, over two seasons. We identify the spatial and temporal diversity of fish in their diets and overlaps with fisheries operating in adjacent waters. Across all sites, 51 fish species from 33 families were identified, with 23 species contributing >10% of the proportion of samples or sequences at any site. There was extensive geographic variation but little inter-annual variability in fish species consumed. Several fish species that are not easily accessible to albatross, but are commercially harvested or by-caught, were detected in the albatross diet during the breeding season. This was particularly evident at the Falkland Islands and Iles Kerguelen where higher fishery catch amounts (or discard amounts where known) corresponded to higher occurrence of these species in diet samples. This study indicates ongoing McInnes et al. Fishery Discards in Albatross Diets interactions with fisheries through consumption of fishery discards, increasing the risk of seabird mortality. Breeding success was higher at sites where fisheries discards were detected in the diet, highlighting the need to minimize discarding to reduce impacts on the ecosystem. DNA metabarcoding provides a valuable non-invasive tool for assessing the fish prey of seabirds across broad geographic ranges. This provides an avenue for fishery resource managers to assess compliance of fisheries with discard policies and the level of interaction with scavenging seabirds.

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Section: Overlaps Between Commercial Fisheries and Albatross Dietmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

et al. 2017

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“…The presence of offal in the discharge is a major factor affecting seabird numbers around trawlers (Weimerskirch et al 2000) as well as fishing areas, discard volumes and condition (e.g. Abraham et al 2009). …”

Section: Seabird Assemblagementioning

confidence: 99%

Estimating mortality of black-browed albatross (Thalassarche melanophris, Temminck, 1828) and other seabirds in the Argentinean factory trawl fleet and the use of bird-scaring lines as a mitigation measure

Tamini¹,

Chavez²,

Góngora

et al. 2015

Polar Biol

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“…It is generally acknowledged that the most effective way to reduce seabird mortality resulting from contacts with warp cables is through preventing or reducing the discharge of offal (Wienecke and Robertson 2002;Watkins et al 2008;Abraham et al 2009;Bull 2009). Discard management, however, is complex, and retrofitting vessels is costly.…”

Section: Discussionmentioning

confidence: 99%

Refining Tori lines to further reduce seabird mortality associated with demersal trawlers in the South Atlantic

2011

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Fisheries-related mortality of globally threatened albatrosses and petrels in the Falkland Islands is largely attributed to collisions with warp cables on stern trawlers. Following the introduction Tori lines, also known as bird-scaring lines, in 2004, incidental mortality has been substantially reduced. However, there is still a requirement for further development and optimisation of mitigation methods. In this paper, we present results of sea trials to compare the efficacy of a modified Tori line design with the initial (2004) design. The modified design resulted in 28 and 33% fewer warp contacts than the 2004 design for all species, and high-risk species (black-browed albatross and giant petrels), respectively. Surprisingly, these differences were not found to be statistically significant. However, the modified design was more effective at reducing interactions with the Tori lines themselves. The modified design provided better coverage and protection of the warps, particularly in crosswinds, and was safer for the crew to use. Our study highlights the importance of continued research and development in the field of bycatch mitigation and has relevance for trawl fisheries globally.

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Effectiveness of fish waste management strategies in reducing seabird attendance at a trawl vessel

Cited by 36 publications

References 20 publications

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

Estimating mortality of black-browed albatross (Thalassarche melanophris, Temminck, 1828) and other seabirds in the Argentinean factory trawl fleet and the use of bird-scaring lines as a mitigation measure

Refining Tori lines to further reduce seabird mortality associated with demersal trawlers in the South Atlantic

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