Arctic marine mammals and fish populations on the rise

Arctic marine mammals and fish populations are on the rise, according to a report released on Monday by the the Arctic Council's biodiversity working group at a Montreal conference. In fact fish populations have risen dramatically, according to the findings of the Circumpolar Biodiversity Monitoring Program, the Zoological Society of London, and the World Wildlife Fund. The three organizations collaborated on the analysis, looking at 890 populations of 323 species of Arctic vertebrates. The Arctic wildlife population changes, they said in a statement, are linked to "Arctic climate oscillations and changes in commercial harvest" in neighboring waters. The report identified that fish living close to the surface of the water as opposed to near the ocean bottom were most susceptible to climate change, including such commercially important species as Pacific herring, ocean perch and Arctic cisco. Some mammals were found to be recovering from exploitation, but rising populations of gray whales, bowhead whales and Greenlandic walruses have not returned to historical levels. Sea ice species ringed seal, beluga whale, and thick-billed guillemot, meanwhile, have declined. As well, marine birds continued a slow and steady decline that started in the late 20th century. The report said this "may be related to changes in climate, sea ice and food availability" and may be the beginning of a longer-term decline. The effects of Arctic warming also were not restricted to the far north. The Atlantic Ocean is experiencing a decline in vertebrates thought to be driven by Arctic climate shifts, as well as commercial fishing. In contrast, the Pacific Ocean has experienced a dramatic increase in vertebrates, amid warmer sea temperatures.