Variations in the distribution of blue whiting in the Barents Sea: climatic influences or year class effects?
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http://hdl.handle.net/11250/100583Utgivelsesdato
2003Metadata
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Blue whiting (Micromesistius poutassou) in the Barents Sea represent the north-eastern fringe
of the distribution of the species in the Atlantic. Distribution and abundance of blue whiting in
the Barents Sea have fluctuated markedly over the past 20 years: in some years, the species
appears to be very common and widespread, whereas in other years it is much more scarce
and its range appears to become contracted. These variations have at least two potential
explanations. First, increases in abundance may be related to variations in the influx or
distribution of warm Atlantic water in the area. Second, rich year classes may temporarily
expand the distribution area of blue whiting in the Barents Sea (either through direct density
effects or climate-recruitment interactions). We investigate these explanations using data from
scientific surveys conducted by the Institute of Marine Research during the period 1982-2002.
Because of differences in survey coverage, we restrict the analysis to the south-western
Barents Sea. Variations in abundance and distribution are correlated with both recruitment
and oceanographic conditions. Regression analyses suggest that the variations in abundance
are dominated by variations in year class strength, strong year classes leading to high
abundance of blue whiting in the study area one or two years later. However, also salinity in
the Fugløya-Bear Island –section during the previous year has a significant effect, suggesting
that strong inflow of Atlantic water promotes high abundance of blue whiting. Warm years
are associated with the centre of gravity of the distribution being more northern and western
than during cold years.
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ICES CM documents2003/Q:03