According
to Levin et al., 2009, a key component of ecosystem based management
is a holistic assessment of the status of marine ecosystem, and an integrated assessment
is a formal synthesis and quantitative analysis
of information on relevant natural and socioeconomic factors. It is WGINOR’s role to develop an operational approach for integrated
assessment of the Norwegian Sea ecosystem based on the common framework that is
starting to emerge as a result of integrated assessment groups
operating in several ICES areas in the Norwegian Sea for some years.
The biomass of
planktivorous fish in the Norwegian Sea seems to have been close to or above
the carrying capacity for some time (Skjoldal et al., 2004; Huse et al., 2012), and there has consequently been a lot of focus on the interplay
between zooplankton production and fish biomass and predation. WGINOR will also
look at the consequences of potential interannual variability in the area’s
primary production. This will indeed be a key topic for the working group, and multispecies
and ecosystem models will be used to investigate this issue further along with
the integrated assessment. Fishing, despite some petroleum exploration in the
outskirts of the Norwegian Sea, represents by far the most important anthropogenic
impact on this ecosystem. The model analyses will be an integrated part of WGINOR’s
assessment.
In traditional single stock
assessment the focus is only on providing an absolute abundance estimate of the target species. However, when addressing multispecies interactions and
carrying capacities of different trophic levels in ecosystems, it becomes important to establish
absolute abundance levels for the different components in order to quantify the
combined effect of consumption and flows between the different trophic levels.
WGINOR will therefore put an effort on providing estimates for absolute abundance
of the key components in the Norwegian Sea ecosystem. WGINOR will also focus on
addressing the survey data collection for such an analysis and requirements for
performing integrated assessments.
The Norwegian Sea
is a deep water basin with an average depth of 1800 m and is situated between
Norway, Iceland, the Faroe Islands, Jan Mayen, and Spitsbergen. The area holds
great zooplankton biomassess and is a key feeding area for planktivorous fish
stocks such as Norwegian spring spawning herring, blue whiting, and Northeast
Atlantic mackerel.