Using small meshed collecting bags on trawls to quantify trawls seabed disturbance of aquatic organisms

Research output: Contribution to conferencePosterResearch

Abstract

NGOs have become active at uncovering and illustrating potential problems of the environmental and ecosystem impacts of fishing activities, especially demersal trawling, exerting considerable pressure on decision makers and subsequently, fisheries. The environmental impact of demersal trawling activities has been documented by collecting samples before and after the fishing process or by comparing areas of different fishing intensity. These investigations are expensive and labor demanding and are inappropriate for documenting effects of smaller technological changes aimed at reducing trawling impact on
commercial fishing grounds. In this study we develop and test small-meshed collecting bags designed to retain juvenile fish and benthic megafauna. The collecting bags are mounted in the wings and body of the trawl. The catches in the collection bags provide information of the species and size of organisms that encounter the trawl, but are not retained by it. Such catch represents an unaccounted trawl disturbance of the organisms associated with the
seabed. In combination with knowledge on behavior and habitat utilization of these organisms, their presence can be used to indicate differences in the mechanical effect, such as penetration depth of the ground gear of different trawl designs. Collecting bags are also mounted to the different sections of the trawl in pairs, one to collect the organisms that pass through the trawl meshes and one to collect the population. Standard selectivity analyses thereby allow us to estimate the size-selection of the caught organisms in different parts of the trawl
Original languageEnglish
Publication date2014
Publication statusPublished - 2014
EventICES Symposium 2014: Effects of fishing on benthic fauna, habitat and ecosystem function - Tromsø, Norway
Duration: 16 Jun 201419 Jun 2014

Conference

ConferenceICES Symposium 2014
CountryNorway
CityTromsø
Period16/06/201419/06/2014

Cite this

Krag, L. A. (2014). Using small meshed collecting bags on trawls to quantify trawls seabed disturbance of aquatic organisms. Poster session presented at ICES Symposium 2014, Tromsø, Norway.