Long-term stability in modelled zooplankton influx could uphold major fish spawning grounds on the Norwegian continental shelf
Authored by Frode B Vikebo, Anders Frugard Opdal
Date Published: 2016
DOI: 10.1139/cjfas-2014-0524
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Abstract
Early life stages of fish spawned on the Norwegian continental shelf
have long been suggested to depend on eggs and nauplii from the
crustacean zooplankton Calanus finmarchicus for survival. Calanus
finmarchicus overwinters in the deep basins of the Norwegian Sea, and
gravid females must be advected onto the shelf prior to spawning if eggs
and nauplii larvae are to serve as food for fish larvae. In this study, cross-shelf advection of C. finmarchicus is simulated over 52 years
(1960-2011) using a numerical ocean model coupled with an
individual-based model. The results suggest that cross-shelf transport
of C. finmarchicus is surprisingly stable across years and that
transport is particularly concentrated immediately upstream of the two
major spawning areas for the Northeast Arctic cod (Gadus morhua) and the
Norwegian spring-spawning herring (Clupea harengus), namely Lofoten and
More, respectively. Two large topographical features, the Traena Trough
and the Norwegian Trench, appear to be funnelling C. finmarchicus onto
the shelf in these two areas. This could suggest that the fish spawning
grounds outside More and Lofoten are, in part, maintained owing to
stable interannual food supply in spring.
Tags
Variability
Population-dynamics
Northeast arctic cod
Calanus-finmarchicus
Barents sea
Future climate
Seasonal vertical migration
Overwintering calanus
Atlantic oscillation
Nordic seas