Climate Change Poses Complex Array of Issues for Fisheries

A juvenile Chinook salmon swims in the Chena River, a tributary of the Yukon, during the summer of 2023. Photo by Erick Schoen.

The Department of Commerce and the National Oceanic and Atmospheric Administration (NOAA) have announced plans to allocate more millions to address how climate change affects Pacific salmon and steelhead in the Columbia River.

This $60 million investment from the Inflation Reduction Act would also play a role in addressing deferred maintenance and repairs at Mitchell Act-funded hatchery facilities across the Columbia River Basin, the Biden administration said March 22.

The funds were first announced in June 2023 as one component of the historic $3.3 billion in investments focused on ensuring the nation’s communities and economies are ready for and resilient to climate change.

Of that $3.3 billion, $240 million goes to support Pacific coastal salmon restoration and recovery through investment in non-Mitchell Act hatcheries, while $42 million would support Pacific salmon populations through the Pacific Coastal Salmon Recovery Fund and expanded research programs to identify and prioritize restoration strategies.

Continuing Work

The impacts of climate change and their adverse effects on fisheries have sparked action for researchers and regulators alike. Academics are intensely engaged in collaborative studies on fisheries and the economy while the federal government invests millions of dollars in restoring wild fish and hatchery facilities.

NOAA is also continuing work to re-open migratory pathways and restore access to healthy fish habitat by the removal of projects ranging from culverts to huge dams.

The Iron Gate Dam on the Klamath River near the Oregon-California border is one of four dams slated for removal from that area by the end of 2024.

The first of the four dams on the west Klamath River was destroyed in the summer of 2023, unleashing a torrent of water that had been held back for a century. The river was once the third-largest salmon producer on the West Coast, but in the time since the dams were constructed, the Klamath’s coho and Chinook runs have dwindled to a fraction of their historic abundance, National Public Radio reported in January.

The Mitchell Act was passed by Congress in 1938 for the conservation of salmon and steelhead fishery resources in the Columbia River Basin, in light of hydroelectric, irrigation and flood control development projects across the basin.

It authorized the establishment, operation and maintenance of hatchery facilities in Oregon, Washington and Idaho, as well as other fishery conservation activities. Since 1946, Congress has annually appropriated Mitchell Act funds. That legislation currently supports roughly one-third of all of the hatchery production in the Columbia River.

“Climate change impacts every corner of our science-based marine conservation and management mission—from managing sustainable fisheries and aquaculture to conserving protected resources and vital habitats,” NOAA Assistant Administrator Janet Coit said.

Action Areas

Action areas for NOAA in 2024 range from investment in cooperative partnerships with the fishing industry, academia and state partners to improving overall science and survey enterprise to better address ecosystem changes. Investments include $42 million announced in 2023 as part of the funding for Pacific salmon earmarked for the Pacific Coastal Salmon Recovery Fund.

Sen. Lisa Murkowski, R-Alaska, said federal funds totaling over $205 million have been allocated for fisheries data surveys and assessments via the fiscal year 2023 budget signed into law in mid-March.

During a March 22 interview, Murkowski said that there is no catch-all answer to the challenges facing Alaska fisheries, from global economic competition to climate-related issues, but that she feels Alaska will come out of it intact.

“Nothing is ever guaranteed in fisheries,” she said. “They have seen good times and bad times. The people in this industry are pretty resilient. There is no one single answer and that is the challenge we’ve got here. Everyone has different resources that they can bring to the table.”

The economic and climate change challenges are a trend that will continue and we need to figure out how to adapt, she said. 

Public awareness of climate change on fisheries and ecosystems has heightened in recent years, but fisheries scientists who had seen the early warning signs were already doing research and trying to alert the fishing public of the coming impacts from a warming planet.

In 2011, an article on climate change in Fisheries Magazine, an online publication of the American Fisheries Society, noted that forecasts of climate impacts on ecosystems are far more challenging and their uncertainties even larger because of a limited understanding of physical controls on biological systems.

“These uncertainties in forecasting biological responses to changing climate highlight the need for resource management and conservation policies that are robust to unknowns and responsive to change,” the study’s authors, led by Daniel Schindler of the University of Washington’s School of Aquatic and Fishery Sciences, said. “We suggest how policy might develop despite substantial uncertainties about the future state of salmon ecosystems.”

Ongoing Studies

Fisheries biologists at the University of Alaska in Fairbanks meanwhile have collaborated with the Alaska Department of Fish and Game, NOAA Fisheries and the University of Washington in ongoing studies of the divergent responses of western Alaska salmon to the changing climate.

“The main point is looking at how these climate changes impact downturns in Chinook and chum salmon,” said Erik Schoen of the International Arctic Research Center at the University of Alaska in Fairbanks. He collaborated with five other researchers, including UAF colleague Peter Westley and Schindler on this study.

Their report, released in the late summer 2023 in Fisheries Magazine, focuses on four major points:

Western Alaska salmon abundance reached historic extremes during 2021-22, with record lows for Chinook and chum salmon and record highs for sockeye salmon.

Salmon are maturing at smaller sizes. Since the 1970s, Yukon River Chinook salmon have decreased an estimated 6% in mean adult body length and 15% in fecundity, likely exacerbating population declines.

Salmon population declines have led to fishery closures, worsened user conflicts and had profound cultural and food security impacts in Indigenous communities that have been tied to salmon for millennia.

Changes in abundance and size are associated with climate changes in freshwater and marine ecosystems and competition in the ocean. Changes in predators, food supply and disease are also likely important drivers.

The study notes that waters in Western and Interior Alaska are warming nearly four times faster than the global average and twice as fast as waters in the continental U.S., with the impact of the Pacific Marine Heatwave of 2014–2016, the Pacific Marine Heatwave of 2019 and an air temperature heatwave and drought in 2019.

This warming is believed to have negatively impacted Chinook salmon, which would represent a fundamental departure from previous decades of salmon ecology research, which consistently found that warmer conditions improved salmon production in northern regions.

Changes in growth and age of maturity of western Alaska Chinook salmon have been linked to changes in ocean climate, and selective predation of larger individuals also may be contributing to accelerated maturation, the study said.

Chinook populations in the area are influenced by changes in demographics and food webs and are susceptible to bycatch and interception in other fisheries, researchers said, including the Arctic-Yukon Kuskokwim (AYK).

Warming waters also contribute to greater rates of infection by pathogens and parasites, such as Ichthyophonus, due to increased rates of disease progression at higher temperatures. The impact of disease–climate interactions was identified by participants in this report as a critical unknown.

While extreme environmental events have become common in recent years, poor returns have impacted communities since 2003 and some participants have stated that they feel bycatch in commercial fisheries have exacerbated the problem.

They also noted that allowing bycatch prioritizes commercial interests over subsistence opportunities, which are protected by the Alaska National Interest Lands Conservation Act. 

Researchers said these negative impacts on AYK salmon may be further exacerbated by an increase in hatchery production across the North Pacific Ocean.

In years when chum salmon originating from hatcheries in Japan were more numerous, some Chinook salmon populations in the Yukon River have been less productive, they said.    

Margaret Bauman is an Alaska journalist and photographer with an extensive background in Alaska’s industries and environmental issues related to those industries. A long-time Alaska resident, she has also covered news of national and international importance in other states on the staff of United Press International, the Associated Press, and CBS News. She can be reached at