Fish and Fisheries in the Chukchi and Beaufort Seas:
Projected Impacts of Climate Change
A.B. Hollowed1 and M.F. Sigler2
1Alaska Fisheries Science Center, National Marine Fisheries Service,
National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115
2Alaska Fisheries Science Center, National Marine Fisheries Service,
National Oceanic and Atmospheric Administration, 17109 Point Lena Loop Road, Juneau, AK 99801
November 11, 2012
- Efforts to project how shifts in environmental conditions in the Arctic Ocean will affect the distribution and abundance of marine fish have yielded different outcomes depending on the region and modeling approach.
- Current prohibitions on commercial fishing in U.S. Arctic waters provide an opportunity to design a management strategy for future fisheries that is rooted in an ecosystem approach to fisheries management.
- In support of the management strategy design, the Arctic Ecosystem integrated survey (Arctic Eis) was initiated in the northern Bering Sea and Chukchi Sea in summer 2012.
The impacts of global warming portend that U.S. Arctic (defined here as the Beaufort and Chukchi seas) marine ecosystems will experience significant change, including loss of sea ice in summer (see the Sea Ice essay), increased stratification (see the Ocean essay) and shifts in the timing and intensity of the seasonal production cycle (Slagstad et al., 2011; Wassmann et al., 2011). Several authors (Cheung et al., 2009; Hunt et al., in press; Huse and Ellingsen, 2008; Mueter et al., 2011; Sigler et al. 2011) have attempted to project how these shifts in environmental conditions will affect the distribution and abundance of marine fish in the region, with the outcomes differing depending on the region and modeling approach. Cheung et al. (2009) projected that expanding bioclimatic windows would result in increased biodiversity in the Arctic, whereas Sigler et al. (2011), projected that the shallow sill separating the northern Bering Sea and the Chukchi Sea, and the persistent presence of the cold water over the northern Bering Sea shelf (Stabeno et al., 2012), would serve as a barrier to invasions of fish species into the region. Pre-cooled water entering the Chukchi Sea from the south, and winter mixing of the Chukchi Sea as it becomes ice covered, result in water temperatures below the physiological limits of the commercially valuable fish that thrive in the southeastern Bering Sea (Hunt et al., in press). Other studies found that key life history features, including slow growth in the first year of life, fidelity to spawning grounds, limited larval dispersal and narrow food habits may impede colonization of the Arctic (Hollowed et al., submitted). Additional monitoring and research is needed to reconcile conflicting outcomes and to improve the accuracy of projected impacts of climate change on the distribution and abundance of Arctic marine fish and shellfish.
Currently, prospects for commercial fishing in the U.S. Arctic are limited by regulation. In 2009, the National Marine Fisheries Service developed an Arctic fisheries management plan (FMP) (Wilson and Ormseth, 2009). For most fish stocks within the Chukchi and Beaufort seas, stock size was insufficient to support commercial activity. For the three stocks (snow crab Chionoecetes opilio; Arctic cod Boreogadus saida; and saffron cod Eleginus gracilis) of sufficient size to support commercial activity, additional information is needed to design sustainable harvest strategies within an ecosystem context. Further, Arctic cod and saffron cod likely would remain off limits because of their ecological importance as key prey of marine mammal and seabird predators, leaving snow crab as the only likely candidate for consideration for commercial fishing once additional information is obtained. In light of this uncertainty, the North Pacific Fishery Management Council closed the region to commercial fishing for fish stocks other than Pacific salmon and Pacific halibut (Wilson and Ormseth, 2009). Pacific salmon fisheries in the Arctic were already closed under a separate FMP. Pacific halibut (Hippoglossus stenolepis) fisheries in the Arctic are prohibited by the International Pacific Halibut Commission.
The existing prohibitions on commercial activity within the U.S. Arctic provide an opportunity to design a management strategy for future fisheries that is rooted in an ecosystem approach to fisheries management. In support of this long-term goal, NMFS (National Marine Fisheries Service) scientists are designing and implementing baseline surveys to gather information needed to develop age or length-based stock assessments for fish and shellfish in the Arctic (Fig. 3.8). Similar fish surveys are also being undertaken in the Canadian Beaufort Sea as part of the BREA (Beaufort Regional Environmental Assessment) program (Fortier, 2012; Reist, 2012).
The U.S. surveys gather oceanographic measurements, abundance, stock structure, growth, food habits and bio-energetic data to identify the mechanisms underlying fish responses to changing oceanographic conditions. These measurements will enable scientists to develop an integrated ecosystem assessment (Levin et al., 2009) that will project the present and future status of marine resources under changing climate conditions as well as potential new anthropogenic stresses emerging from increased shipping, oil and/or gas development. These ecosystem models will allow scientists to inform managers and society of the implications of different options for marine resource use in the Arctic.
Recent reviews of the global status of commercial fish and fisheries reveal several factors that contribute to the achievement of sustainable fisheries (Gutierrez et al., 2011). These factors include leadership, social capital and incentives as well as a commitment to the collection and assessment of high quality information on the fished populations. It is not clear how the governance structures that contribute to sustainable fisheries will work under changing climate conditions within a multinational context (Arnason, 2012). However, if at some point in the future, fish or shellfish stocks increased to a level that could sustain commercial fisheries and knowledge of the life history and population dynamics was sufficient to manage the fishery sustainably, then a comprehensive management plan would have to be developed for the region (Fluharty, 2012).
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