A compilation of length and species selectivity improving alterations to beam trawls

The increasing concern about the ecosystem effects of fishing on the marine environment and particularly, the impact of trawling on benthic communities is reflected in numerous publications. The weight of this concern will very likely only increase in management decisions in the near future. Beam trawling has a negative reputation with regard to discarding and seafloor impact and may be confronted with further constraints imposed by the fisheries management. The fishing industry has, however, the opportunity to anticipate management decisions and to adopt improved fishing gears, i.e. with reduced discarding and reduced environmental impact. A pro-active attitude and a voluntary uptake of improved gears allows the industry to shape the alterations to the specific conditions of the fishery and the fishing grounds. For the chain matrix beam trawl, many studies have been carried out on a wide variety of technical alterations to the beam trawl to improve the length and species selectivity, to reduce ecosystem effects and to reduce fuel consumption. The ILVO-Fishery institute has carried out many of these experiments and has recently been testing and promoting a combination of successful alterations. The improved trawl has been called the “alternative beam trawl” and has already been commercially tested for two years on a beam trawler. It consists of a number of simple and cheap alterations to the beam trawl. This report is a compilation of the most successful technical alterations for the beam trawl. The alternative beam trawl is not strictly defined and can consist of any combination of selective devices presented in this report or even new devices that prove to be successful. The basic idea is that each device that has undergone scientific scrutiny can be further developed by the industry in close cooperation with the fishery institute