Distribution of hake ( Merluccius merluccius, Linnaeus, 1758) in the Bay of Biscay and the Celtic sea from the analysis of French commercial data

Abstract

Hake landings and effort data provided by the French otter trawl fleets exploiting the Celtic sea and Bay of Biscay fishing grounds were used for years 1992–1994. Monthly catch rates of five hake weight market categories were calculated and used as input in a correspondence analysis and hierarchical ascending classification procedure to describe the spatio-temporal distribution of hake in the Celtic sea and the Bay of Biscay. Results show a great difference in hake catch composition between the two zones. The higher proportion of small hake in the Bay of Biscay can be explained by the use of a minimum mesh of size 65 mm instead of 80 mm in the Celtic sea and the existence of a hake nursery coinciding with the muddy bottom of Nephrops fishing grounds in the northern part of the Bay of Biscay. Adult hake were found relatively more abundant in the shallow water of the eastern Celtic shelf from April to November. Oldest fish seemed to move westwards at the end of the year. They congregate for spawning along the slope and on the shelf in the north-western part of the Celtic sea from February to April–May. There is no evidence that young adult hake follow the same migratory pattern but they were found in abundance along the slope in the north of the Bay of Biscay during autumn and winter months.