The catch composition of a sole net (8 cm mesh opening) was analysed according to the catch of benthos and undersized fish. Five different methods to decrease the catch of benthos and undersized fish were researched: fewer tickler chains, brushes in stead of ticklers, larger meshes (9 in stead of 8 cm), a double “Anti-Discard” net (AD-net) and a net with very large meshes (200-480 cm) in the upper side of the net (GM-net). Only the AD-net and the GM-net gave clear possibilities to decrease the unwanted by-catch. None of these methods, however, can prevent the damaging of buried benthos. Protection of the coastal area, where undersized fish and vulnerable benthos can be found, is possibly more effective than discard-saving technical constructions. The intensive beam trawling in the southern North Sea, probably already caused changes in the composition of the soil fauna, reducing the numbers of vulnerable benthos and larger fish species, while less vulnerable benthos species and smaller fish species have increased in number. |