Atlantic Fisheries
Research Document 1996/009

Aspects of the biology of northern shrimp Pandalus borealis on the Scotian Shelf

By P. Koeller

Abstract

Information from groundfish and shrimp trawl surveys, commercial samples, logbooks, and experimental trap fishery and published geological/oceanographic reports were used to determine some basic biological parameters on Scotian shelf shrimp stocks. The main concentrations of Pamdalus borealis are found on the eastern Scotian Shelf, in the Louisbourg, Canso and Misaine Holes. Secondary concentrations are found inshore off southeastern Cape Breton (The Noodles), on the Scotian Slope near The Gully, in Roseway Basin, in the vicinity of the Fundian Channel and at the head of the Bay of Fundy. Shrimp in the Noodles appear to be relatively isolated, but some degree of exchange with the offshore concentrations takes place via larval drift and migrations of juveniles into deeper water. Most movement is more local: for example, inshore, larger animals move between Chedebucto Bay and the Noodles; offshore, shrimp move into deeper water as they grow; larger animals congregate on the southern edge of the holes. Shrimp on the Scotian Shelf, as elsewhere, undergo an annual reproductive cycle with spawning (egg extrusion) in the late summer-early fall and hatching in the late winter-early spring. Local differences in this cycle are evident, particularly between the inshore and offshore areas. Year class strength varies considerably between the offshore holes. Growth rates appear to be slightly slower on the Scotian Shelf compared to Newfoundland stocks. Growth rates were slightly faster in Louisbourg Hole, which tend to have warmer temperatures.

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