On the biology of Pandalus borealis Krøyer, with reference to a population off the Northumberland coast

Abstract

The deep sea prawn, Pandalus borealis Krayer, is fished extensively in Norwegian, Swedish and Greenland waters, some 4000 metric tons being caught annually, having a value of about £800,000. Its biology has been investigated by various workers in these countries. Comprehensive accounts have been given by Wollebaek (1903), Hjort & Ruud (1938), Rasmussen (1953)and Horsted & Smidt (1956). Despite this, relatively few populations have been sampled at regular intervals throughout a year. In high latitudes where much work has been carried out, ice, for varying lengths of time, prevents stocks from being sampled. Rasmussen (1942, 1949, 1953) has shown that the life history of P. borealis varies with locality in a range from southern Norway to Spitsbergen. When P. borealis was found in numbers in deep water off the Northumberland coast advantage was taken to investigate the biology of the species at the southern limit of its eastern Atlantic distribution and to compare the results with those of other workers. Knowledge of the biology of the prawn now covers the whole of its north-south distribution and some account of this is given. In addition, the study gives information on a population that has not been fished commercially and provides a more complete picture of sex reversal than has been obtained hitherto.