As the climate warms, some native species are undergoing population decline. Others are adapting to new environmental conditions. While still others push further north toward cooler temperatures. This ability to acclimatize depends on the species’ adaptive capacity, or respond to change. A new framework for assessing the adaptive capacity of various species of plants and animals offers some projections. But in northern regions, where climate warming is occurring at a rapid pace, animals’ adaptive capacity are already being tested.
On July 29th of this year, Pacific walruses began to amass onshore near Point Lay, numbering about 5,000 by August 5th. Walruses have been gathering on a Chukchi Sea beach in late August or early September since 2007, when sea ice extend hit a record low. Now, diminishing summer sea ice seems to be driving an earlier congregation, as with last year when walrus took to the beach on July 30th. Pacific walruses, primarily females, utilize sea ice as platforms for foraging and to rear their young. Densely congregated animals, sometimes as many as 40,000 to 50,000, risk crushing their young if they are disturbed by overflights or boat traffic. Advisories and new protections are in effect.
In western Canada’s Fraser River, sockeye salmon are returning to their spawning grounds in record low numbers. According to the Pacific Salmon Commission, the early Fraser River run will number about 283,000 fish, far less than the previous low in 2019 of 493,000 salmon. Researchers blame the decline on warming ocean and river temperatures.
Closer to home, salmon runs in Alaskan waters have been uniformly poor except in Bristol Bay. Cordova’s City Council declared disasters for the Cooper River and Prince William Sound sockeye, chum and chinook runs. In Chignik the runs are so small the sockeye fishery remained closed for the third year in a row. Cook Inlet had a healthy run of pink salmon but the sockeye and silver salmon runs were disappointing. And in Haines, sockeye, coho and chum runs up the Chilkat River are unlikely to reach escapement goals. The low runs there have resulted in a scaled back drift gillnet season.
Meanwhile, Pacific salmon are finding cooler waters in the far north. Chum salmon are showing up in Cambridge Bay in northern Nunavut Canada. Records from 2019 tallied some 2,000 Pacific salmon (including some sockeye) in the region, a three-fold increase from years prior. Moreover, they are arriving up to three weeks earlier than in years prior and are now harvested across northern Canada.
And Pacific pink salmon are finding their way into the waters off Quebec, Canada. During the summer of 2019 and again this summer, pink salmon were netted in Ungava Bay. Considered an invasive alien in Quebec waters, pinks, with just a two-year life cycle, are adapting rapidly and nosing further east as Arctic waters warm.
This begs the question, will the shellfish, krill and forage fish these animals depend also adapt to changing ocean conditions? And if not, will other food resources shift northward to fill the void?