Impact of codend mesh sizes on selectivity and retention of Acadian redfish Sebastes fasciatus in the Gulf of Maine trawl fishery

Published source details Pol M.V., Herrmann B., Rillahan C. & He P. (2016) Impact of codend mesh sizes on selectivity and retention of Acadian redfish Sebastes fasciatus in the Gulf of Maine trawl fishery. Fisheries Research, 184, 54-63.
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This study is summarised as evidence for the following.

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	Use a larger mesh size Action Link

Use a larger mesh size

A replicated, paired, controlled study in 2013 of a fished area of seabed in the Gulf of Maine, Atlantic Ocean, USA (Pol et al. 2016, same experimental set-up as Pol et al. 2016) reported that larger mesh sizes in a bottom trawl codend improved the size-selectivity of commercially targeted Acadian redfish Sebastes fasciatus compared to smaller mesh sizes. Data were not tested for statistical significance. The length at which redfish had a 50% chance of escape was 33.6 cm with the largest mesh size (165 mm), 29.2 cm with an intermediate mesh size (140 mm) and 22.3 cm with the smallest mesh size (114 mm). Data were collected in March-April 2013 from 56 trawl deployments (average 0.5 h duration) on a commercial bottom trawler using a trawl net with two diamond mesh codends (trouser trawl). One of three experimental codends with different diamond mesh sizes (165 mm – the minimum required mesh size, 140 mm, and 114 mm) was fished on one side, and a small diamond mesh (64 mm) codend on the other to sample the whole length range of fish. Each experimental codend was used for three days before being switched for a different mesh size (16–22 hauls of each pairing). Catch weights and the lengths of a random subsample of at least 100 redfish where possible from both codends were recorded each haul. Full gear details are provided in the original study.

(Summarised by: Leo Clarke)