Long-term effects of local scale OIL pollution on fish Populations and COMmunities in the Lofoten-Barents Sea system (OILCOM).

Oil companies are currently extending their search for new oil deposits to areas that have previously been sheltered from oil exploration. This is controversial and has led to an extensive scientific and public debate especially over opening the ecologically vulnerable Barents Sea (BS) and areas around the Lofoten Islands of northern Norway. The area is important for the survival of eggs and larval of several commercially important marine fish, including Northeast Arctic (NEA) cod, NEA haddock and BS capelin. The functioning and resilience of the entire Barents Sea ecosystem may rely on these species. A major concern is the possible impact on the fish populations from an accidental oil spill. In the OILCOM project we have investigated how potential population level effects on zooplankton may propagate to the capelin and cod stock in the Barents Sea. We show that effects may be large, but at the same time the effects are associated with high uncertainty. Furthermore, we have investigated how an oil spill that affect only parts of a year-class of fish may increase or decrease over time due high or low concentration of eggs and larvae in years with small or large spawning fish. We have also investigated the possible effects of spatial structure in mortality on survival in early life stages and how this affects the potential outcomes of an oil spill. We digitised historic data on jellyfish and arrow worms bycatch that can be used in statistical analysis to reveal possible explanations of why mortality varies in space.

We have been able to better quantify key uncertainties associated with the upscaling to population and ecosystem levels of an potential oil-spill in the Lofoten area. These can have impact on how we precieve the probability of an adverse event associated with oil related activities. Through the OILCOM-project (and other related projects) we have built up a significant expertise on topics related to oil-spills and effects on populations of fish in the Barents Sea. Moreover, a strong connection between highly qualified scientific environments both in Norway (IMR, NIVA and UiO) and abroad (PINRO and University of Washington) has been achieved.

In this project we propose to develop and analyse empirically based models for quantification of possible effects of accidental releases from petroleum activities at the cohort, population and community level for several fish species in Lofoten-Barents Sea system. At the cohort level, a key uncertainty in quantifying the possible impacts is the considerable variability in the natural survival of the fish eggs and larvae in time and space. We propose to investigate the different factor shaping the spatial and temporal variations in natural mortality, by combining state-of-the-art models and data. At the population level, a major uncertainty has been to quantify the combined dampening effect of intra- and inter-cohort density dependence in the pre-adult stages and the effect of highly variable recruitment. We will address and quantifying the impacts at population level from cohort loss across several species. In addition, we will quantify community level impacts from loss of prey or predators. The project will produce highly valuable new knowledge on ecologically and commercially important species. We expect the outcome to significantly improve our ability to assess the long-term effects of oil compounds on the health and development of these fish stocks. This is important, not only for our understanding of these fish stocks, but also for an ecologically sustainable development of the petroleum industry.