Influence of some physical and biological factors on the density and vertical distribution of Atlantic halibut Hippoglossus hippoglossus eggs
Journal article, Peer reviewed
Permanent lenke
http://hdl.handle.net/11250/108633Utgivelsesdato
1986-10-27Metadata
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Originalversjon
http://dx.doi.org/10.3354/meps033207Sammendrag
ACT: Atlantic halibut Hippoglossus hippoglossus (L.) eggs were sampled using a Tucker trawl
and a MOCNESS-sampler at 3 selected localities in North Norway. The specific density of the eggs was
determined in a density-gradient column. The eggs were found to achieve higher specific density with
increasing age. In areas with a horizontally stable, clearly defined pycnocline (Andfjord and Seraysund),
the vertical distribution of eggs was characterized by a unimodal egg distribution. Furthermore,
the older eggs were found at higher average capture salinities than younger eggs, i.e. they were
distributed in relation to their neutral buoyancy. In an area with a horizontally more variable and less
defined pycnocline (Malangen), the pattern of vertical distribution of eggs was less distinct, often with
polymodal egg distributions. In this hydrographically variable system, no heterogeneity in the distribution
of the various egg developmental stages could be discerned. In Malangen, thus, it is proposed that
the vertical distribution of halibut eggs is most strongly influenced by physical factors.