Study

Efforts to reduce Chinook salmon (Oncorhynchus tshawytscha) and rockfish (Sebastes spp.) bycatch in the U.S. west coast Pacific hake (Merluccius productus) fishery

  • Published source details Lomeli M.J.M. & Wakefield W.W. (2012) Efforts to reduce Chinook salmon (Oncorhynchus tshawytscha) and rockfish (Sebastes spp.) bycatch in the U.S. west coast Pacific hake (Merluccius productus) fishery. Fisheries Research, 119-120, 128-132

Actions

This study is summarised as evidence for the following.

Action Category

Fit large, supported escape openings (such as Fisheyes, Bigeyes and radial escape sections) to trawl nets

Action Link
Marine Fish Conservation
  1. Fit large, supported escape openings (such as Fisheyes, Bigeyes and radial escape sections) to trawl nets

    A replicated study in 2009–2010 of a fished area of seabed in the Pacific Ocean off Oregon, USA (Lomeli & Wakefield 2012) found that fish trawl nets fitted with large escape opening systems (two designs) allowed the escape of unwanted Chinook salmon Onchorynchus tshawytscha in two of two designs and widow rockfish Sebastes entomelas in one of two designs. Results were not tested statistically. In trials of two pairs of escape openings, 80­–100% of Chinook salmon observed to enter the net escaped (escaped: 1–8 fish, entered: 1–11 fish) and 19–33% of rockfish (escaped: 4–8 fish, entered: 21–24 fish). In trials of a single pair of escape openings, 50% of salmon escaped (escaped: 8 fish, entered: 16 fish), but of the 53 rockfish that entered the net, none were observed to escape through the openings. Data were collected in September 2009 and May, August and September 2010 from video footage recorded during 32 trawl deployments (113–259 m depth) on a commercial vessel targeting Pacific hake Merluccius productus. Two designs of net were used, with either one (14 h video) or two (17 h video) pairs of large escape openings cut out of the netting on the upper portions of both side panels. Two square mesh ramps in front of the openings acted as a guide to actively swimming fish towards the escape openings (see original paper for gear specifications). A total of 23 tows were done with an open codend, the other nine with a closed codend. Fish entering and escaping through the large openings were identified and counted from the video recordings.

    (Summarised by: Leo Clarke)

Output references

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