Growth, size- and age-at-maturity of shrimp, Pandalus borealis, at Svalbard related to environmental parameters

Abstract

Modal analyses of carapace length frequency distributions reveal differences in growth and age at first female maturity of shrimp, Pandalus borealis, at Svalbard. The shelf slope west and north of Svalbard within a depth range of 200-600 m was divided into seven Areas. Between seven and ten age groups of shrimp were identified in each Area. The slowest growth was observed in Isfjorden. Age at female maturity (L50) varied from six to eight years between Areas. The differences in growth and age at female maturity between Areas could be explained by differences in bottom temperature. In Areas dominated by cold water, and where Atlantic and Arctic water alternate causing variations in the environmental conditions, shrimp showed slower growth and a higher age at female maturity. To ensure that inter-annual variations both within and between Areas are revealed, we suggest that shrimp ageing should be done separately for all seven Areas defined in this paper.