Acronym NA
Category
Fisheries
Title Utvikling av artsselektiv tråling etter hvitfisk - Development of species-selective trawling for whitefish Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Arill Engås Coordinator email arill.engaas@imr.no
Coordinator institution
IMR - Institute of Marine Research (Norway)
Institutions involved
NA
Start year 2012 End year 2014 Funding (€) € 332,735 Website https://www.fhf.no/prosjekter/prosjektbasen/900773/ Summary Cod and haddock often occur together on the fishing grounds in the Barents Sea, and with today's trawling techniques, this results in a mixed fishery. This is not always optimal, based on rational operation and environmentally friendly harvesting of the stocks. In the early 1980s, Scottish researchers conducted experiments that showed that cod and haddock had different behaviors in the trawl opening of bottom trawlers, in that cod tried to dodge towards the bottom and haddock in the opposite direction (Main and Sangster, 1981). On the basis of this behavioral difference, several projects were initiated, including at the Institute of Marine Research, to develop bottom trawl technology to separate these two species during trawling. The background for the Institute of Marine Research's projects was to develop a system that made it possible to fish more strategically in relation to quota / market and not least with a view to optimizing selection for different species. The best result was a system with a horizontally divided extension that ended up in two trawl bags (Engås et al., 1998). The experiments showed that for haddock, an average of about 90% of the catch was in the upper bag and the proportion was relatively stable from hay to hay. For cod, the picture was not as clear. On average, 65–70% of the cod was caught in the lower bag. However, the haul to haul variation was greater than for haddock. In connection with the development of resource- and environmentally friendly trawl technology within the Center for Research-Based Innovation for Sustainable Catch, Catch Quality and Catch Economy (CRISP), a cruise was carried out this year where a combined information from sonar (operated in sonar mode) in the trawl opening (pelagic / semi-pelagic trawling) with video observations at the back of the extension. The information from both sonar and video was directly transmitted to the bridge via probe cable. Differences in behavior between cod and haddock were observed both in the trawl opening and backwards in the extension. By combining information from sonar and video with the technology that is being developed within CRISP, one sees a potential for developing species-selective trawling for whitefish, for example to catch only one species or distribute cod and haddock in different bags. In the 90s, the experiments were very much characterized by trial and error, as one did not have access to the same instrumentation and camera system as today. The industry is developing and using new types of bottom trawls (for example semi-pelagic trawling where the doors do not have bottom contact) where probe cable is an important element for, among other things, achieving sufficient vertical opening on the trawl. Such a development means that the concepts of, among other things, instrumentation / active selection (transmission of signals via cable for control and reception of information) intended in the development of species-selective fishing can also be used not only in pelagic fishing where probe cable is standard equipment, but also in bottom trawling. The project was planned to be carried out in two phases. Only phase 1 of the project has been carried out because there was no research quota available for the implementation of phase 2. During phase 1, fish experiments were carried out with a horizontal split extension (net line made of 300 mm mesh size, square mesh) which ended up in two separate trawl bags. The experiments showed that the bulk of cod was caught in the lower bag, while the bulk of haddock was caught in the upper bag. The distribution of cod and haddock in the two trawl bags varied greatly from hay to hay. The behavioral observations that were carried out indicated that the variation in the distribution between haul was due to the variation in the vertical distribution of fish in the trawl opening. Attempts with a guide panel in front of the divider panel to guide cod down under the divider panel and with a divider panel of elongated meshes (15 cm across and 50 cm lengthwise) to make haddock easier to pass through the divider panel from below, were carried out, but did not significantly improve the separation. of cod and haddock between the trawl bags.
Keywords
Trawling;
Cod;
Fish;
Fishing technology;
Haddock;
Gear selectivity;
Marine Region
13
Northern North Sea (27.IVa)
42
Barents Sea (27.I)
14
Skagerrak, Kattegat (27.IIIa)
41
Norwegian Sea (27.IIa)
4
Marine Region Map
