Sampling herring in the Norwegian Sea by pelagic trawl
Original version
This report is not to be cited without prior reference to the authorAbstract
When the stock of Norwegian spring-spawning herring is distributed in the Norwegian Sea in
summertime, pelagic trawl sampling may be rather challenging because of substantial
variation in vertical distribution (from surface and down to 400 m depth), and avoidance of
vessel and trawl gear. In this paper the operation and performance of the «Åkratrål» during
pelagic trawl sampling of herring by R/V «G.O. Sars» on cruises in the Norwegian Sea 1996 -
1997 are described. The sampling results with regard to capture success, catch size and
geograpically segregated length distributions are presented. The implications of the sampling
results on the reliability of the acoustic estimate of stock size are discussed.