Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 9035
Title: Fishery-specific solutions to seabird bycatch in the U.S. West Coast sablefish fishery
Author: Amanda J. Gladics, Edward F. Melvin, R. M. Suryan, T. P. Good, Jason E. Jannot, Troy J. Guy
Publication Year: 2017
Journal: Fisheries Research
Volume: 196
Pages: 85-95
DOI: https://doi.org/10.1016/j.fishres.2017.08.015
Abstract:

Bird scaring lines (BSLs) protect longline fishing gear from seabird attacks, save bait, reduce incidental seabird mortality and are the most commonly prescribed seabird bycatch mitigation measure worldwide. We collaborated with fishermen to assess the efficacy of applying BSL regulations from the demersal sablefish fishery in Alaska to the same fishery along the U.S West Coast. In contrast to Alaska, some West Coast vessels use floats along the line to keep hooks off the seafloor, where scavengers degrade the bait and the target catch. Our results confirmed that BSL regulations from Alaska were sufficient to protect baits from bird attacks on longlines without floats, but not baits on longlines with floats. Longlines with floats sank below the reach of albatrosses (2 m depth) at a distance astern (157.7 m ± 44.8 95% CI) that was 2.3 times further than longlines without floats (68.8 m ± 37.8 95% CI). The floated-line distance was well beyond the protection afforded by BSLs, which is approximately 40 m of aerial extent. Black-footed albatross attacked floated longlines at rates ten times more (2.7 attacks/1000 hooks, 0.48 ¿ 4.45 95%CI) than longlines without floats (0.20 attacks/1000 hooks, 0.01 ¿ 0.36 95% CI). Retrospective analysis of NOAA Groundfish Observer Program data suggested that seabird bycatch is largely confined to a few sablefish longline fishing sectors and a minority of vessels, but is not confined to larger vessels.  Analysis also confirmed fishermen testimonials that night setting reduced albatross bycatch by an order of magnitude compared to daytime setting. Clearly, night setting could be an effective albatross bycatch prevention practice if applied to West Coast sablefish longline fishery and provide a practical alternative for vessels that elect to use floated longlines. These results highlight the importance of understanding region-specific longline gear modifications to identify effective bycatch reduction tools and the value of working collaboratively with fishermen to craft solutions.

Full Text URL: http://www.sciencedirect.com/science/article/pii/S0165783617302291
Theme: Ecosystem approach to improve management of marine resources
Foci: Provide scientific support for the implementation of ecosystem-based management
Describe the interaction between human activities, particularly harvest of marine resources, and ecosystem function.
Official Citation:

Gladics AJ, EF Melvin, RM Suryan, TP Good, JE Jannot, and TJ Guy. 2017. Fishery-specific solutions to seabird bycatch in the U.S. West Coast sablefish fishery. Fisheries Research 196: 85-95.