| dc.description.abstract | At the Møre coast there are important spawning areas for cod,
coalfish, haddock and herring. As a part of an interaction study of
these species, i.e. the predation of the demersal species on the
spawning stock and the eggs of herring, an acoustic survey for
estimation of the abundance of the demersal stocks was carried out
in the last week of March. During the survey hydrographic data were
sampled by a CTD-sonde.
Acoustic abundance of demersal fish was devided between cod and
haddock as one category and coalfish as another. As biological
sampling by trawling occasionally was difficult because of high
density of fishermens gillnets and rough bottom, biological data
also were sampled from commercial catches in the surveyed area
througout March.
The behaviour of the fish was favourable for acoustic abundance
estimation. However, some informations about haddock, observed as a
heavy predator on eggs of herring, were supposed to be lost because
it often stuck close to the bottom.
The highest densities of cod were observed in the Breisund and at
the Buagrunn, the last area also with the best acoustic recordings
of coalfish and haddock.
The stock abundance estimates of cod, haddock and coalfish were
respectively 32 200, 11 560 and 51 760 tonnes. The experiences from
this investigation indicate the acoustic method to be prosperous in
abundance estimation of demersal fish in the surveyed area during
the winter season. | en |
