Preliminary results of investigations on escapement of fish under the fishing line of a Norwegian sampling trawl
Working paper
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http://hdl.handle.net/11250/104119Utgivelsesdato
1986Metadata
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This report is not to be cited without prior reference to the authorsSammendrag
The Institute of Marine Research, Bergen, has carried out combined
bottom trawl and acoustic surveys for cod and haddock in the Barents
Sea and the Svalbard areas since 1981. These investigations have
clearly demonstrated that the currently applied survey methods
in these areas underestimate the young age groups of cod considerably.
One explanation may be a reduced gear efficiency for the smallest
fish.
This paper describes the results of experiments with small bags
under the trawl, designed to collect fish that escape under the trawl.
Considerable catches of different species were obtained in the small
bags. A comparison between trawl and bag catches revealed a strongly
length dependent escapement of cod and haddock under the trawl. The
results explain to some extent the underestimation of young cod.