Bycatch reduction in the deep-water shrimp (Pandalus borealis) trawl fishery with a large mesh top panel

Ólafur A. Ingólfsson,Manu Sistiaga,Eduardo Grimaldo,Jesse Brinkhof,Dagfinn Lilleng,Jure Brčić,Bent Herrmann,Nadine Jacques,Hermann Pettersen,Roger B. Larsen,Kristine Cerbule

doi:10.1016/j.jnc.2021.126001

Abstract

In the Northeast Atlantic deep-water shrimp (Pandalus borealis) trawl fishery, the bycatch of juvenile fish and shrimp represents a problem. This study evaluated if inserting a 200 mm mesh size top-panel in the last three sections of the tapered upper belly section of the trawl could reduce bycatch of juveniles while maintaining the catch efficiency for deep-water shrimp. The bycatch species investigated were Greenland halibut (Reinhardtius hippoglossoides), redfish (Sebastes spp.) and polar cod (Boreogadus saida). The bycatch of Greenland halibut and the smallest polar cod was significantly reduced, while no effect was found for redfish. The large mesh panel did not lead to a significant loss of deep-water shrimp. The results of this study illustrate how a simple modification of a fishing gear can mitigate the bycatch problem in a shrimp fishery, without significant losses of the target species.

Highlights

Trawl fisheries targeting shrimp are often associated with high levels of bycatch due to small mesh sizes, which lead to the capture of species that are similar in size to the targeted shrimp (Broadhurst, Brand, & Kennelly, 2012; Campos & Fonseca, 2004; He & Balzano, 2013; Polet, Coenjaerts, & Verschoore, 2004; Sistiaga, Herrmann, Larsen, & Brink hof, 2019)
In the Barents Sea deep-water shrimp (Pandalus borealis) trawl fish ery, the bycatch of juvenile fish and shrimp represents a problem for fisheries management and commercial fisheries
We examined whether the use of a large mesh panel compro mised catch efficiency for deep-water shrimp

Summary

Introduction

Trawl fisheries targeting shrimp are often associated with high levels of bycatch due to small mesh sizes, which lead to the capture of species that are similar in size to the targeted shrimp (Broadhurst, Brand, & Kennelly, 2012; Campos & Fonseca, 2004; He & Balzano, 2013; Polet, Coenjaerts, & Verschoore, 2004; Sistiaga, Herrmann, Larsen, & Brink hof, 2019). Current gear regula tions for this fishery include the mandatory use of a Nordmøre sorting grid with 19 mm bar spacing and a codend with a minimum mesh size of 35 mm (Norwegian Directorate of Fisheries, 2018a). With this gear, large fish are unable to pass through the narrow bar spacing of the grid and are released through the fish escape opening over the grid (Eayrs, 2007; Larsen, Herrmann, Sistiaga, Brinkhof, & Grimaldo, 2018). A range of sizes that are small enough to pass through the bar spacings of the Nordmøre grid are too big to subsequently be released through the codend meshes and are retained (Herrmann, Sistiaga, Larsen, & Brinkhof, 2019; Larsen, Herrmann, Sistiaga, Brinkhof, Brinkhof et al, 2018; Larsen, Herrmann, Sistiaga, Brinkhof et al, 2018; Sistiaga et al, 2019)

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Conclusion