Report on herring acoustic surveys in northern and central North Sea during summer 1987
Working paper
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http://hdl.handle.net/11250/104523Utgivelsesdato
1988Metadata
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This report is not to be cited without prior reference to the authorsSammendrag
Acoustic surveys covering the Northern and Central North Sea were carried
out by Scottish and Norwegian vessels during the period 24 June to 11
August. The estimated biomass of mature herring was 817 000 tonnes. For the
area north of 57°N the estimate was 553 000 tonnes compared to 534 000
tonnes estimated in July 1986. For this area the estimates by age groups
indicate a high mortality on the 1981-1983 year-classes. The estimated
number of the 1984 year-class was about twice as large as the estimate for
all older age groups together. The 1985 year-class was estimated to be quite
strong (13.7 · 10[9]).