HAVKYST-Havet og kysten

The northern shrimp (Pandalus borealis) is the most valuable shellfish resource in the North Atlantic and supports one of the world's largest fisheries. The need to establish stock boundaries and study the spatial organization of shrimp has been emphasi zed by the international shrimp milieu. Population structure and spatial organization are keys for implementing a long-term and eco-system basd mangement, and for understanding the effects of fishing on stock dynamics. Given the key role of shrimp in the benthic ecosystem as food for demersal fish, knowledge of shrimp population structure is important also from an ecosystem perspective. Earlier studies have used allozymes to study shrimp stock structure within the Barents Sea, around Iceland and along t he Canadian east coast. This three year project proposes to use more powerful genetic methods - DNA-microsatellites - to 1) investigate the fine-scale stock structure of shrimp in the North Sea, and 2) to place these results in a broader context by compar ing with estimated shrimp stock structure in the species' whole distribution range in the North Atlantic. The former part will focus on demographic and genetic differentiation within and between the presently defined three management units in the North S ea, and between fjords and offshore populations. Microsatellite data will be linked with oceanographic patterns to investigate the influence of larval drift on the population structure and dynamics of shrimp. Microsatellite loci have already been develo ped by Swedish partners and tested in a pilot study. The proposed project is a cooperation between the Norwegian Institute of Marine Research, the University of Oslo, the Swedish Tjärnö Marine Biological Laboratory, and the Greenland Institute for Natura l Resources. The results are expected to be useful for shrimp fishers, the industry and fishery management, and will be received with great interest by the international scientific shrimp milieu.