Investigations on blue whiting in the area west of the British Isles, spring 1994

Abstract

From March 25 to April 15 the Norwegian R.V. "Johan Hjort" carried out acoustic surveying and biological and plankton sampling on the blue whiting population congregated for spawning along the shelf edge west of the British Isles. Due to extremely bad weather conditions the survey was notably amputated, causing the rate of area coverage and number of trawl, hydrological and plankton stations to become rather low. The spawning stock size was estimated to 4.1 mill. tonnes, which, however, must be considered as an underestimate. Like last year, the 1989-yearclass was found to dominate the stock. The temperature in the upper 200m layer was generally lower than observed in 1993. Blue whiting eggs and larvae were taken at the shelf-edgs and over Porcupine Bank. Eggs were taken in increasing abundance from he surface to a maximum at 380-400m depth.