Relative Importance of Abiotic and Biotic Factors to the Management of the Northern Shrimp (<i>Pandalus borealis</i>) Fishery on the Scotian Shelf

Abstract

The biology of the northern shrimp, Pandalus borealis, on the Scotian Shelf is discussed in relation to the Gulf of Maine and Newfoundland Shelf stocks. The Scotian Shelf is an area of transition for P. borealis with a change in oceanographic characteristics in the mid shelf area that has resulted in populations with characteristics of both more southern and more northern stocks. The commercially important population on the eastern Scotian Shelf is restricted to small areas of suitable habitat despite favorable temperatures over a wide area. On the western Scotian Shelf a small population inhabits relatively small areas of marginally suitable temperatures, despite large areas of suitable habitat. Commercially important concentrations in this area appear only rarely after temperatures decrease to more favorable levels. Differences in migration patterns between the Scotian Shelf stock and stocks to the north and south are related to differences in temperature regimes. While shrimp populations on the Scotian Shelf are influenced by water temperatures and habitat availability, predation pressure is also a significant determinant of abundance. The implications for the management of shrimp fisheries in the area are discussed.