About the Alaska complex

The Alaska Complex LME is made up of 5 distinct ecosystems: the Gulf of Alaska, the Aleutian Islands, the Eastern Bering Sea, the Beaufort Sea, and the Chukchi Sea.

The Gulf of Alaska LME is characterized by cold nutrient rich waters that support moderately high productivity and high biological diversity. This region experiences climatic regime shifts that affect productivity and zooplankton species composition as well as productivity of important species. Commercially important fisheries include crab, shrimp, rockfish, salmon and halibut. Stressors on the ecosystem include fishing, invasive species, oil discharges, and industrial contaminants.

The Aleutian Islands LME is part of the Aleutian-Commander Island archipelago that extends more than 3,000 km between Alaska and Russia, and forms the southern border of the Bering Sea. The islands are mostly peaks of steep submarine volcanoes, with exposed portions surrounded by narrow shelves descending to a steep drop-off. This subarctic region is moderately productive with strong interactions between shelf and deep-sea habitats. The richness in marine life includes large concentrations of seabirds, marine mammals, sessile invertebrates, and fish. Commercially important species include crab, Atka mackerel, cod, and other groundfish.  Stressors on the ecosystem include shipping, military operations, climate warming, and fishing.

The East Bering Sea LME is a high productivity system characterized by both an extensive gradually sloping shelf and a deep-sea basin. Productivity is influenced by temperature, currents and annual cycles of sea ice formation and fresh water input. The region has experienced multiple shifts between warm and cold water regimes in recent decades. Commercially valuable fisheries include salmon, herring, rockfish, skate, sole, plaice, pollock, shrimp and crab. This system, while having a relatively low human population density, experiences fishing, logging, mining, oil and gas development, low level pollution, and industrial and urban development as stressors.

The Beaufort Sea is a moderately low productivity, high-latitude region with an Arctic climate that is highly influenced by seasonal conditions. Much of the region is ice-covered throughout the year and light limitation reduces productivity except during the summer season. The coastal region supports a variety of organisms and provides habitat for water fowl, shorebirds, marine birds, anadromous fish. Offshore resources include Arctic cod, saffron cod, eelpouts and sculpin which along with smelt, provide support for populations such as beluga whales, seals and seabirds. The region is sparsely inhabited and several indigenous peoples practice subsistence whaling and fishing. Main pressures on the system include oil and gas exploration, pollutants, climate warming, sea ice loss and potential for establishment of shipping routes through the Arctic. 

The Chukchi Sea LME is dominated by a high-latitude and relatively shallow sea with an extensive continental shelf. This LME experiences the Arctic climate and primary productivity is heavily influenced by seasonal ice formation and melt; the range of primary production estimates for this ecosystem encompasses both low and very high productivity, depending on conditions. Important species are salmon, herring, sea birds, walrus, seals and whales. The region is remote and sparsely populated by indigenous peoples. The ecosystem is very lightly exploited and the coastal areas are relatively pristine. Stressors on the ecosystem include oil and gas production, persistent organic pollutants, seismic exploration, and climate warming.

Source: www.lme.noaa.gov and Alaska Fisheries Science Center