Effect of gear design on catch damage on cod (Gadus morhua) in the Barents Sea demersal trawl fishery

Jesse Brinkhof,Bent Herrmann,Manu Sistiaga,Roger B Larsen,Nadine Jacques,Svein Helge Gjøsund

doi:10.1016/j.foodcont.2020.107562

Jesse Brinkhof, Bent Herrmann + Show 4 more

Open Access

https://doi.org/10.1016/j.foodcont.2020.107562

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Abstract

Damage incurred during the catch process is an indicator of the overall quality of fish and fish welfare. Because catch quality is difficult to improve once it has deteriorated, it is important to preserve quality during the catch process. Atlantic cod (Gadus morhua) is the most important species in the Barents Sea bottom trawl fishery. Bottom trawling is a non-benign fishing method, and it is therefore considered important to reduce damage imparted to fish during capture, and subsequently improve catch quality and fish welfare. In the present study, the levels of damage on cod captured with a new gear design were assessed in the Barents Sea bottom trawl fishery. Furthermore, this study investigated to what extent the compulsory sorting grid and diamond mesh codend configuration employed in the fishery is responsible for the damage incurred by cod during the capture process. In total, 750 cod captured over 25 hauls were evaluated for catch damage (marks, ecchymosis, exsanguination, and scale loss). The results showed that substituting the grid and codend configuration with a four-panel selective knotless section followed by a gentle codend increased the probability of cod having no catch damage by 6.00% (CI: 0.6%–11.41%). Moreover, the gentle codend led to a significant reduction in the severity of all catch damage categories.

Highlights

The high densities of gadoid fish in the Barents Sea (Norwegian Directorate of Fisheries, 2018; Yaragina et al, 2011) have led to an increased focus on two main areas in the demersal trawl fishery: i) improving catch quality, and ii) improving size selectivity
Damage on cod captured with the grid and 130 mm diamond mesh codend configuration
Fish caught with bottom trawls often show marks, scale loss, internal and external ecchymosis, and poor exsanguination, all of which contribute to a reduction in overall quality (Esaiassen et al, 2004; Ingolfsson & Jørgensen, 2006; Digre et al, 2010; Rotabakk et al, 2011; Olsen et al, 2013, 2014)

Summary

Introduction

The high densities of gadoid fish in the Barents Sea (Norwegian Directorate of Fisheries, 2018; Yaragina et al, 2011) have led to an increased focus on two main areas in the demersal trawl fishery: i) improving catch quality, and ii) improving size selectivity. Improved catch quality results in increased revenue and improved fish welfare. The latter is a factor that is subject to increasing attention by NGOs and consumers (Veldhuizen et al, 2018). Brinkhof, Larsen et al, 2018 presented a new codend design, termed a sequential codend, which significantly improved the catch quality of cod without compromising size selectivity (Brinkhof et al, 2019). The fish are kept in the quality preserving codend segment only during haul-back and can still be subject to severe damage during towing

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