Criteria for protection: EU Habitat Directive: Sand banks Reefs, gravel Sub-marine structures, gasseeps Species: sea mammals, fish EU Bird Directive: Species and occurrence of 1% of the population OSPAR Threatened and important species and habitats Ecological importance, High biodiversity, Representatively, vulnerability, naturalness
Callianassa Upogebia Quahog Conclusions: Significant difference unfished-fished > shrimps and shelfish > biodiversity Beam trawling causes changes in the fauna, which influences structure, bioturbation and mineralisation. This has large consequences for the functioning of the benthic ecosystem
“Old habitat types” Sand bank Gravel Silt “New habitat types” Ploughed habitat Raked habitat Platforms Wind park Habitat types in the North Sea
Will protection be effective ? Example: the Quahog
Evaluation and targets for the Quahog population Rob Witbaard, IMARES/Royal NIOZ The Frisian Front area has a relatively low abundance of Quahogs (0.06/m2): 20 years ago this was 6 times higher Beam trawl fisheries cause a large additional mortality upon Quahogs Model calculations indicate that the Quahog will basically disappear from the Dutch Shelf in 2017 (Bergman & Sandbrink, 2000) Quahog populations may be genetically different (Holmes, 2003) Climate changes may lead to a change in Quahog distribution To save Quahogs on the Dutch Shelf, fisheries intensities in areas with relative high densities should be strongly reduced What area is most suited to protect Quahogs on the Dutch Shelf ?
Conclusions: An integrated approach of protection, harvesting and building is needed for a sustainable North Sea Fisheries is at the limit of the carrying capacity of the ecosystem: big changes are needed The human pressure is rapidly increasing In 1880, >20% of the Dutch North Sea bottom was ‘hard’, now almost everywhere sand and mud MPA’s should be created