Arne Eide, Norwegian College of Fisheries Science, UiT.
Previous studies - role of management crucial. Type of management measures is critical. The evolution from subsistence to commercial fisheries. The justification of management. Interaction between economic and biological dynamics in the context of environmental constraints. Shift of paradigms, from protection of fisher(y) to protection of nature. From the development of population models and stock collapses, to the introduction of target and limit reference points which made advice based on analyses of consequences possible. EEZs, limited entry of quota regulations. The precautionary approach - SSB and F parameters. Good indicators critical, and good indicators does not exist. Indicators (can be economic) and Harvest Control Rule (HCR) gives the TAC. Fuzzy sets logic approach, aiming for acceptable (robust) results, rather than the best.
Grete Hovelsrud, CICERO.
Importance of temperature variabilty. Warming and regime shifts. Spawning locations covariation with temperature changes. Stock fluctuations in response to fishing and temperature changes. Fisheries by nature flexible in response to such changes. Many factors affect fisheries - need to distinguish between climate variability and climate change. Societal outcomes difficult to predict. Adaptation measures at one scale - eg national - may affect the local negatively. Increasing temperatures - new species. Various changes observed by fishers. Changes in distribution and abundance. Socioeconomic consequence of CC: outmigration of young people, lack of skilled people, variable access to market, competition w oil industry for skilled labor, etc. Increasing frequency of extreme weather - traditional weather knowledge less valid. Key elements: fisheries management, employment - income - technology, center - periphery aspects - 1-2 degrees warming predicted. Southerly stocks may move north - new opportunities. Weather patterns may become more unpredictable. A range adaptations may be necessary, eg in regulations.
Discussion: complextity of factors affecting communities/individuals. New phenomena. How to distinguish natural variation from CC induced. (Se på utvikling på ulike nivå/skala).
Øystein Skagseth, Institute of Marine Research:
Difficult to distinguish natural and man-made fluctuations. Pathways of Atlantic waters - Icelandic lows major driver. No clear temperature trend 95-06 Barents Sea, increase from ca 1970 to level similar to 50-60´s. Pathway for atmospheric lows important. NAO index = strength of westerly winds. Upstream effects. Greater variability in coastal current in the south. Little variability in the North. Warm period 1930-65, 90-. Barents Sea fluctuations same as the rest of the Atlantic. Prognosis: increasing warming, +1,5 next 50C yr? (Sundby). We are now at a natural warm high, next yrs natural variation towards colder. Summer ice Arctic 2007 rare event, due to local wind conditions caused by highs in the Beaufort. Ensemble of models indicate 2030-40 ca 1 m km2 ice in summer. This statement takes 2007-2008 situation as point of departure. Model predictions depend upon initial state. Norwegian Sea/Barents Sea + 1 - 1,5 in 2070.
Discussion: is the distinction natural - man made important in relation to adaptation? Relationship between different types of fluctuations. Conceptual issues?
Sigurd Tjelmeland, Institute of Marine Research:
Here - changes beyond stochastic fluctuations. The Barents Sea system - interactions make i t difficult to detect changes. Stochastic fluctuations appear non-stochastic - difficult to detect changes through fish stocks. We do not measure the fish stocks, but a virtual population and hope it has something to do with the real population. Capelin: direct measurement. Cod and others: assessment. SSB cod on the rise. More stable, robust year classes since ca 1990 - a regime shift? Earlier more pronounced fluctuations. Haddock very strong growth. Blue whiting down since 2005, low recruitment - disappeared from Barents Sea. Harvesting rules increasingly important in ICES, estimated from population dynamics parameters. Critical: detect changes in parameters. Look at fish stock dynamics, rather than fish stocks. Uncertainties in models, survey indices, catch data. Optimal F depends on the population dynamics - best or robust (in relation to uncertainty)? Need to explore population dynamics space - will the real stock and the virtual stock converge? Use models that are in use today.
Jørgen Schou Christiansen, Norwegian College of Fisheries Science, UiT.
Greenland fisheries project. Arctic FishBase Nordic network project. 70% of polar studies from Antarctica. ca 10% on fish. The Arctic fish fauna unknown to science. Historical data, museums, etc. 95% of Arctic marine fish IUCN DD - data deficient. Need to reduce DD taxa to provide scientific advice. Pressures: petroleum, fisheries, bio-prospecting, invasive species, tourism & cargo shipping - in areas that we do not know much about. Not sure that these areas are species-poor. Arctic fish taxonomically complex, extremely temperature sensitive, key links in food chains, grow and reproduce slowly, have physio-chemical compounds for subzero temperatures - marine bioprospecting. About 37 species, mostly benthic (by NE Greenland?). Lives mostly between -1,5 - 1 C. 87 species by Jan Mayen. Polar cod and ice cod are migrating species, all over the Arctic.