An annual report released by NOAA warns of significant changes happening in the Arctic due to a changing climate, with impacts even being observed in the critical salmon population.
Decades of depreciating sea ice, reduced snow cover and warmer temperatures have pushed the region into what experts described as “uncharted territory” with more weather extremes and changing ecosystems.
In the more than 100-page report card, scientists highlighted a summer season of record warmth, significant ice melt, a low spring snowpack and historic wildfires as being some of the driving forces behind ecosystem changes.
“We’ve seen heat waves in the ocean and heat waves on land, and salmon populations have been responding with extreme ups and downs,” Erik Schoen, lead author of the salmon chapter of the report and a fisheries scientist at the UAF International Arctic Research Center, said in a statement.
The report found that both Chinook and Chum salmon have greatly decreased in population while the western Alaska salmon have reached record levels.
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Observations also indicate that the fish are maturing at a smaller size, leading to reduced reproductive capacity.
In addition to direct climate changes, authors said predators, food supplies and diseases are likely also playing a role.
“We know that king populations on the Yukon do worse when the adult salmon swimming upriver to spawn experience high river temperatures and low flow, which tend to be correlated with hot, dry years,” Schoen said. “There’s also a disease called Ichthyophonus that can interfere with a salmon’s ability to swim.”
Where populations of salmon are growing, biologists have linked warmer bodies of water to a faster growth rate.
According to the University of Alaska, some species previously spent two years in lakes before migrating and now may be down to just one year.
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Low amounts of salmon in the Yukon and Kuskokwim River basins have resulted in significant impacts.
Several fisheries and popular casting spots have faced closures and limitations due to the dwindling species.
Indigenous people face the harshest impacts, with fishermen not able to teach techniques to younger generations and have lost an important source of economic development.
The report card has been produced annually since 2006 and is meant to serve as a guide to stakeholders, agencies and the public on the changing landscape around parts of the Final Frontier.