Diurnal changes in bottom trawl catches and vertical fish distribution
Working paper
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http://hdl.handle.net/11250/104402Utgivelsesdato
1988Metadata
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This report is not to be cited without prior reference to the authorsSammendrag
Bottom sampling trawl catches and acoustic abundance estimates of North-East
Arctic cod and haddock in the Barents Sea were collected and examined according
to time of day. The trawl catches were at average larger by day than by night, and
there was a larger proportion of small fish ( <40 cm) in the night catches. The acoustic
recordings showed a considerable diurnal vertical migration of cod and haddock.
The fish seemed to stay close to bottom by night and lift off from bottom by
day. Aggregations of haddock were observed up to about 150 m above bottom at
daytime. Fish density in the bottom layer as estimated from trawl catches agreed
closely to echo abundance by night. At daytime no correlation was found.