Improved fishing techniques, bigger ships, a rising demand for fish, ... imply that steadily increasing volumes of fish are being hauled up. When more is caught than what is needed to maintain the fish stock, the species is overfished.
Overfishing is one of the most important problems with which the Common Fisheries Policy of the European Union has to contend with. Overfishing is actually not only an ecological problem; it is also an economic problem that the fisheries sector has to deal with.
When a skipper draws in his nets, they may contain unwanted bycatches. These usually involve the target species that are too small to be sold, but also non-target fish species and crustaceans, molluscs, starfish or even marine mammals and sea birds. Bycatch is hitherto usually thrown back overboard and the discarded animals often die from the sustained injuries. When fishing with the beam trawl (a trawl net with a metallic cross bar, the "beam", is kept open), 40 to 75% of the total catch is bycatch. In case of the shrimp fishery, this could run up to 85 to 90%. Particularly the harbour porpoises and the diving sea birds may get entangled in the nets. These animals then drown because they cannot come up to the surface to breathe.
Beam trawl - BMM-UGMM-MUMM
Gillnets - ILVO Visserijj
The problem of bycatch and overfishing cannot be tackled at the level of the Belgian part of the North Sea alone. The European Common Fisheries Policy aims to put an end to both the overfishing and the bycatch.
Thanks to the Common Fisheries Policy, measures have been taken to reduce the fishery pressure such as the Total Allowable Catches (TACs or "Total Allowable Catches"), a restriction of the fishing effort and technical measures with the aim of fishing no more than the Maximum Sustainable Yield (MSY or "Maximum Sustainable Yield " ) by 2020. If one fishes more than the Maximum Sustainable Yield, fish stocks can no longer grow.
The Common Fisheries Policy aims to reduce the bycatch through an obligation to haul all catches aboard and to account these under the allowable catch levels. The recreational gillnet and trammel net fishing is already prohibited now in the Belgian part of the North Sea through the Royal Decree on the protection of species. The Marine Strategy Framework Directive and the Habitats and Birds Directives are also instruments for taking policy measures to tackle these problems through the Common Fisheries Policy. The Directorate Natural Environment (OD Nature) coordinates since ten years the investigation concerning the stranded harbour porpoises in the Belgian part of the North Sea.