Effect of a quality-improving cod end on size selectivity and catch patterns of cod in bottom trawl fishery

A new cod-end concept developed and tested exhibited significantly improved quality of caught cod (Gadus morhua) compared with that of the conventional cod end used in the Barents Sea bottom trawl fishery. However, the design of the new quality-improving cod end raised concerns about its size select...

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Bibliographic Details
Published in:Canadian Journal of Fisheries and Aquatic Sciences
Main Authors: Brinkhof, Jesse, Herrmann, Bent, Larsen, Roger B., Veiga-Malta, Tiago
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 2019
Subjects:
Online Access:http://dx.doi.org/10.1139/cjfas-2018-0402
http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2018-0402
http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2018-0402
Description
Summary:A new cod-end concept developed and tested exhibited significantly improved quality of caught cod (Gadus morhua) compared with that of the conventional cod end used in the Barents Sea bottom trawl fishery. However, the design of the new quality-improving cod end raised concerns about its size selectivity and the possibility that higher retention probability could negatively impact the catch pattern by increasing the proportion of undersized cod. Therefore, the goal of this study was to quantify and compare the size selectivity and catch pattern for cod when deploying, respectively, the conventional and new quality-improving cod end in the Barents Sea bottom trawl fishery. The new quality-improving cod end had significantly lower relative size selectivity than the conventional cod end, but no significant difference in the catch patterns was detected in the trawl. Further, estimation of the total size selectivity in the trawl revealed that the increased retention of small cod when using the quality-improving cod end was minor. Hence, despite the reduced selectivity, the quality-improving cod end can be used with low risk of retaining small cod.