The spurdogs in the North Sea area in the Norwegian fishery and observations on changes in migration pattern.
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http://hdl.handle.net/11250/103605Utgivelsesdato
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This report is not to be quoted without prior consultation with the General Secretary.Sammendrag
The Norwegian fishery of spurdog (Squalus acanthias L.), which
started in 1930, has played a dominant part in the fishery for
this species in Europe. During 1963-1968 a change occured in the
behaviour of the spurdog stock. The spurdogs left the traditional
fishing grounds, and this lead to a depression in the Norwegian
fishery. New concentrations were discovered in the southern North
Sea during the autumn 1968. Several tagging experiments, 1975-1979,
indicate that the spurdogs in this area migrate to the area north
of Scotland during the spring. Recaptures from taggings 1959-1966
together with information on Scottish spurdog catches during 1947-
1957, indicate that the spurdogs in the southern North Sea belong
to the Scottish-Norwegian spurdog stock. During the last two years
the Norwegian longline fishery for spurdogs has been greatly reduced.
Length distributions indicate that maturing and mature
females which constitute the main part of the Norwegian catch,
were heavily reduced in numbers from 1975-1979. Research should
be intensified to establish a basis for international regulation
of the spurdog fishery.