~ Alaska

AlaskaAlaska will experience a variety of climatic changes, from warming temperatures that prompt shifts and expansions in species ranges to acidifying waters that may cause declines in shellfish production. Since the 1950s, statewide average annual air temperatures have increased by 1.7°C (3°F) and are projected to increase another 1.1-2.2°C (2-4°F) by 2050 (Stewart et al. 2013). Melting sea ice driven by warming air temperatures may expose potential new habitat and/or fishing grounds, and northern range expansions may lead to increased abundance of new species and therefore new fisheries (Chapin et al. 2014).

For some species, such as walleye pollock (Gadus chalcogrammus) and juvenile salmon (Oncorhynchus spp.), warmer ocean temperatures may lead to reduced health and abundance (Chapin et al. 2014); thus, it is unlikely that current levels of fishing and harvesting pressure of these species in the region will be sustainable over time. Compared to other regions of the country, the effects of ocean acidification may be stronger in Alaska due to its cold, CO2-rich waters (Walsh et al. 2014) and low salinity levels (Chapin et al. 2014).

Impacts on Commercial Fisheries

The major impacts of concern for the management of commercially important species in Alaska, such as salmon, cod (G. macrocephalus), and walleye pollock, are ocean acidification, warming temperatures, and melting sea ice. In the Bering Sea, Chapin et al. (2014) suggest that ocean acidification will decrease pteropod (zooplankton with calciferous exoskeletons) population size, limiting prey availability for key species such as pink salmon (O. gorbuscha) and thus causing reduced abundance (Aydin et al. 2005; Fabry et al. 2009). Increasing temperatures may cause northward range shifts of several key species, such as sockeye salmon (O. nerka) (Roessig et al. 2004; Chapin et al. 2014).

Warming temperatures also cause melting sea ice, which increases freshwater runoff to important coastal habitats (Johnson 2012; Chapin et al. 2014), leading to decreased salinity levels (e.g., the Gulf of Alaska) (Royer and Grosch 2006) and potential alteration of primary and secondary productivity. Newly ice-free areas may create new habitat and fishing areas for stocks such as cod, herring (Clupea pallasii), and walleye pollock. However, the North Pacific Fishery Management Council prohibited fishing in U.S. Arctic waters until research is conducted to determine the potential effects of new fishing activity in the region (Fluharty 2011; AFSC 2012). In July 2015, the United States, along with the other four Arctic countries – Canada, Greenland, Norway, and Russia – signed a joint declaration to prevent high-seas fishing in the central Arctic Ocean until science-based management mechanisms are in place (U.S. Department of State 2015).

Impacts on Recreational Fisheries

Major target species for recreational anglers include salmon, halibut (Hippoglossus stenolepis), shrimp, rockfish (Sebastes spp.), and shellfish, and the industry nets approximately $500 million per year (ADFG 2014). Unlike commercial fishermen, recreational fishermen cover a more limited range and may no longer be able to access traditionally fished species due to shifting species ranges, leading to potential economic declines for recreational boat operators and decreased catch for individual recreational fishermen. However, with expansion of other species’ ranges, there may be new species available to recreational fishermen.

Impacts on Subsistence & Traditional Fisheries

Fishing is an integral part of the lives of Alaskan Native communities, and they are dependent on fishing for subsistence, livelihood, and culture (Chapin et al. 2014). In addition to facing health and safety risks due to rising temperatures, melting sea ice, and permafrost thawing (Bennett et al. 2014), Alaskan Native communities are likely to see declines in traditionally fished species, such as salmon. In general, subsistence and traditional fishermen are geographically limited and tend to harvest species close to home. Changes in species ranges (e.g., northward migration of sockeye salmon) or migration routes could limit access to traditionally fished species (Roessig et al. 2004). While northward expansions of species may help compensate for the loss of traditional species by providing new fishing opportunities, switching to new species could be a cultural challenge and may require changing fishing gear, a costly expense for small-scale fishermen (Roessig et al. 2004).

Impacts on Aquaculture

There is limited information available regarding the impacts of climate change on shellfish and salmon aquaculture operations in Alaska. These are likely to be affected by the same stressors that will influence open-water populations, such as ocean acidification and an increase in hypoxic areas. In order to manage for these impacts, it will be necessary for aquaculture operators to closely monitor ocean conditions and intake waters and potentially consider relocating operations to sites with more favorable conditions (e.g., areas with less upwelling of cold, low CO2 waters) (Johnson 2012).

Alaska Table 1Alaska Table 2