Optimised Codends for an Ecologically and Economically Sustainable Brown Shrimp Fishery

Brown shrimp fishery in the North Sea is an important economic factor in German coastal areas of Schleswig-Holstein and Lower Saxony, where approx. 200 vessels are involved. As for other fisheries, shrimp fishery is criticized for its temporarily large amount of discards of small shrimp and fish. This discussion is amplified since shrimping is often conducted in the Wadden Sea National Park. Consequently, it is agreed between stakeholders that discards in this fishery have to be reduced.

The aim of this study is to determine the catchability as well as the species- and size-selectivity of different mesh types (T0, T 90, square meshes) and mesh openings in the codend. In addition, the theoretical selection potential of brown shrimp was analysed for the different mesh types and mesh openings, using the FISHSELECT method. Measured morphological data, systematic fall-through experiments for defined mesh types, and simulations were used to predict selectivity parameters, L50 and selection range (SR). The specific selectivity parameters were predicted and should be illustrated for defined mesh parameters, such as mesh opening and opening angle.

Furthermore, underwater records of selected different codends were conducted and analysed.