Reducing bycatch in beam trawls and electrotrawls with (electrified) benthos release panels

Abstract

Benthos release panels (BRPs) are known for their capacity to release large amounts of unwanted benthos and debris, which can decrease mortality on these animals and eases the on board sorting process aboard demersal beam trawlers. They can reduce the bycatch of undersized fish, which is desired once the European discard ban is implemented. However, unacceptable commercial losses of sole (Solea solea L.) and damage to the BRP as a consequence of suboptimal and unsuitable rigging in the traditional beam trawl with chain mat, is hampering a successful introduction in commercial beam-trawl fisheries. To eliminate these drawbacks, square-meshed BRPs with different mesh sizes (150, 200, and 240 mm) were rigged in a trawl with square net design as used in electrotrawls and tested for selectivity. In addition to this, the effect of electric stimulation at the height of the BRP to eliminate the loss of commercial sole was examined. According to our observations, no abrasion of the net attributable to suboptimal rigging occurred in any of the BRPs tested. The catch comparisons showed significant release of benthos and undersized fish in all panel mesh sizes, but there was always a significant loss of marketable sole in the 150, 200, and 240 mm BRPs. Adding a 80 Hz electric cramp stimulus to the BRP, resulted in equal catches of sole larger than 25 cm as the standard net, without negatively affecting the release of benthos and most undersized commercial fish. This clearly demonstrates the promising potential of electrified BRPs (eBRPs), but further optimization by using smaller BRP mesh sizes or optimized electric stimuli is warranted to retain all marketable sole.

No Injuries in European Sea Bass Tetanized by Pulse Stimulation Used in Electrotrawling

“…; Soetaert et al. , , ). Nevertheless, tetany did not induce severe lesions in flatfish such as Sole (Soetaert et al.…”

Netinnovatie Kottervisserij II

“…Onder een volledige invoering van de aanlandplicht (European Union, 2013) wordt in deze visserij vooral de bijvangst van ondermaatse schol (<27cm) en wijting (<26cm) als problematisch ervaren. De voorgestelde en ontwikkelde innovaties richten zich dan ook voornamelijk op het voorkomen van de vangst of laten ontsnappen deze soorten (Van Marlen et al 2013;van Marlen et al 2016;Soetaert et al 2018). Bij het voorkomen van de vangst wordt gezocht naar een oplossing waarmee de ongewenste vis niet in het net komt.…”

Interactive effects of fishing effort reduction and climate change in a central Mediterranean fishing area: Insights from bio-economic indices derived from a dynamic food-web model

“…In addition, bottom trawling is the only activity specialized in catching highly valuable demersal species such as shrimps. However, since 2000's experimental technological advances have made progressively available potential options to reduce the impact of trawling due to unwanted catches (small-size individuals of commercial species or non-commercial species), for example by means of net modifications or benthos release panels (Soetaert et al, 2016;Vitale et al, 2018).…”