Variability in frontal zone formation and distribution of gadoid fish larvae at the shelf break in the northeastern North Sea
Journal article, Peer reviewed
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Date
1999-02-11Metadata
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http://dx.doi.org/10.3354/meps177221Abstract
Hydrography and larval fish distribution in the northeastern North Sea were studied during
a research programme carried out during the period from 1991 to 1994. The aim was to examine the
connection between frontal zone formation and nursery characteristics of gadoid larvae at the shelf
break. Emphasis was placed on the year-to-year variation in frontal characteristics and distributional
patterns of larvae An area of about 67000 km2 covering the northeastern North Sea, the Skagerrak and
the Kattegat was surveyed by grid or transect sampling. At each sampling station the hydrography was
studied by CTD casts, and the abundance of fish larvae was measured by depth integrating tows of a
2 m ring net. Five species of gadoid larvae and small luveniles were found in the area. cod Gadus
rnorhua, whiting Merlangjus merlangus, haddock Melanogrammus aeglefinus, Norway pout Trisopterus
esmarki and saithe Pollachius virens. Larval abundance differed markedly between species and
years. The abundance of all species was the highest in 1992 and declined during the follo~ving2 years.
In 1994, cod and whiting were the only gadoid species observed. Peak abundance of all gadoids was
found in the vicinity of the frontal zone; however, the relationship between larval distribution and
hydrography differed among species. Correspondence between spatial and interannual variation in
characteristics of frontal zones and larval distributions suggests that frontal zone variability is a central
element in the early hfe of gadoid larvae from the area.