Selectivity and retention of pollock Pollachius virens in a Gulf of Maine trawl fishery
Published source details
Pol M.V., Herrmann B., Rillahan C. & He P. (2016) Selectivity and retention of pollock Pollachius virens in a Gulf of Maine trawl fishery. Fisheries Research, 184, 47-53.
Published source details Pol M.V., Herrmann B., Rillahan C. & He P. (2016) Selectivity and retention of pollock Pollachius virens in a Gulf of Maine trawl fishery. Fisheries Research, 184, 47-53.
This study is summarised as evidence for the following.
Use a larger mesh sizeAction 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 non-commercially targeted saithe Pollachius virens compared to smaller mesh sizes. Data were not tested for statistical significance. The length at which saithe had a 50% chance of escape was 52.4 cm with the largest mesh size (165 mm), 45.6 cm with an intermediate mesh size (140 mm) and 34.8 cm with the smallest mesh size (114 mm). Data were collected in March-April 2013 from 21 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 (six to eight hauls of each pairing). Catch weights and the lengths of a random subsample of at least 100 saithe where possible from both codends were recorded each haul. Full gear details are provided in the original study.
(Summarised by: Leo Clarke)