The status of the inshore component of the northern brown crab Cancer pagurus fishery, assessed from a time series of LPUE constructed from historical sources

Abstract

A 27 year LPUE series was compiled from daily landings and creel numbers fished, as reported by a processor and by personnel participating in the activities of a small inshore fleet at Malin Head, Co. Donegal. The fleet targeted brown crab in the late summer and autumn months and the series was compared with two other series of LPUE constructed from data obtained from two fleet sources fishing the same stock. The most significant event to have taken place since records commenced in the late 1970s was the introduction in the 1990s of a small vivier offshore crabbing fleet. Competition between the inshore and offshore components intensified and the inshore fleet responded by further capitalising and increasing its seaward range. Since the mid-1980s the number of boats in the Malin Head inshore fleet pursuing the autumn fishery halved while the total amount of gear increased by 29%. The number of pots set by a vessel in a day averaged 600 in 2004 but in 2000 the practice of fishing two sets of gear simultaneously became established. The vivier boats also moved inshore and the ranges of the two fleets now overlap. In the past 15 years there was a loss of between 37 and 57% LPUE, according to the data assembled in this work. Schaefer analyses carried out on the inshore Malin Head fleet’s results and extended to cover the estimated landings of the Donegal inshore fleet, indicate that maximum sustainable yield was almost reached and that the F0.1 point was exceeded by both fleets. Any additional increase in F is likely to further accelerate decline in LPUE. The stock is regarded as being close to over-fished in a regime without effective effort controls. The problems associated with managing a fishery of this kind are briefly discussed.