Improving the selectivity of beam trawls in The Netherlands: the effect of large mesh top panels on the catch rates of sole, plaice, cod and whiting

This paper presents the results of experiments aimed to improve the selectivity of beam trawls in the North Sea for roundfish whilst minimizing losses on target flatfish. Large-meshed top panels were designed for the tickler chain type of beam trawls used in this fishery. The design process involved model studies in a flume tank, feasibility trials at sea on a research vessel, and comparative fishing trials on chartered commercial fishing vessels. A total of 11 weeks with 450 hauls in total were fished on two categories of vessels, namely 300 and 1500¿2000 hp, representing the major groups in the Dutch fleet. An economic evaluation was also carried out with the landings data from the fish auction. A reduction of 30¿40 or cod and whiting could be obtained with the new gear design, with virtually no losses in flatfish (particularly sole and plaice). The results were communicated extensively with representatives of the fishing industry throughout the project. The new gears were found to be effective and acceptable for the fishing industry. Their implementation would help reducing fishing mortality of these species.