U.S. Fish and Wildlife Service officials work at the Ouray National Fish Hatchery in Utah. (Photo provided by U.S. Fish and Wildlife Service)

U.S. Fish and Wildlife Service officials work at the Ouray National Fish Hatchery in Utah. (Photo provided by U.S. Fish and Wildlife Service)

Analysis of Northwest, other salmon hatcheries finds nearly all hurt wild salmon populations

More than 200 studies across 40 years reveals impacts of large-scale hatchery programs

For much of the last century, fish hatcheries have been built in the Northwest, across the U.S. and around the world to boost fish populations where wild numbers have gone down.

But an analysis of more than 200 studies on hatcheries programs meant to boost salmonid numbers across the globe – including salmon, trout and whitefish – shows that nearly all have had negative impacts on the wild populations of those fish. Most commonly, hatchery fish reduced the genetic diversity of wild fish, leading to poor health and reproductive outcomes.

The findings weigh into a sensitive topic with a big price tag. In the Northwest, hatcheries are supposed to be a solution to declining wild salmonid numbers, caused in large part by hydroelectric dams, overfishing, irrigation and climate change. In the Columbia River Basin alone, officials have spent billions of dollars on nearly 200 hatcheries as well as habitat restoration projects during the past 50 years to improve wild numbers, but research shows those programs are having an opposite effect.

The global studies, all undertaken between 1971 and 2021, were analyzed by scientists at the nonprofits Trout Unlimited, based in Virginia, and The Conservation Angler, out of Washington, along with the University of Washington, the University of Montana and the Université Laval, in Quebec, Canada. Their analysis was published in July in the journal Fisheries Management and Ecology.

Of the 206 studies the team analyzed, more than 80% revealed hatcheries programs had adverse effects on wild salmonids. Of the 3% of hatcheries globally that were found to benefit wild populations, the majority were stocked with wild fish who were bred and released in small numbers to boost severely depleted wild populations.

John McMillan, science director at The Conservation Angler who worked on the analysis, said the team wanted scientists all over the world who are studying the same fish species to see the impact of hatcheries programs beyond their regions of study. He said despite an overwhelming body of research showing most hatcheries programs hurt wild fish populations, it’s often controversial to criticize such programs.

“It’s frustrating from a scientific point of view, because you can see what the science suggests, but it’s understandable why we’ve been reluctant to move our position on hatcheries, because of the social implications,” he said. “This is one of those things, like climate change, where we have to sit back and think about our relationship with the animal, what it means to us and how much we want to give up so these animals can truly, potentially rebuild themselves.”

Effect of big hatcheries

This year the Oregon Legislature passed Senate Bill 5509, which includes $1 million for a third-party assessment of hatchery programs in the state, including analysis of their costs and benefits.

Hatcheries programs in the Northwest and globally that release hundreds of thousands of fish each year had the worst effect on wild salmonid populations, according to the analysis.

“When you see really large releases of fish, they tend to swamp out the wild population,” McMillan said.

An example is pink salmon released from hatcheries in Alaska. Unlike most salmon species, pink salmon spend two years rather than one in the ocean feeding before returning to their spawning grounds in rivers. They enter the ocean almost immediately after being released, and feed on vast amounts of microscopic plankton, which are the food for larger plankton that other fish species such as Chinook, coho, steelhead and sockeye eat. When hundreds of thousands of pink salmon are released from hatcheries each year, they upset the balance of food available in the ocean for all those other species.

“It’s not leaving enough food for other salmon in the ocean,” McMillan said. It’s even negatively impacting orca populations, who feed on those other salmon species. You consume so much at the bottom of the food chain that it cascades to lower production at the top.”

The best hatcheries, McMillan said, rear fish from wild stocks and release small but effective numbers to provide a short-term boost to the population.

McMillan said the analysis shows a need for more study of fish epigenetics – the study of how the environment a fish develops in can change and affect the way its genes work, the way it behaves and its ability to survive.

“There has been research coming out in the last four to five years indicating that even though hatchery fish are representative of the population at large from which they’re from, they’re undergoing epigenetic changes due to the hatchery rearing process,” he said.

Some of those changes are passed along to offspring. Scientists are trying to study that process and discover whether those traits are passed to wild species and whether that affects the ability of wild fish to survive, he said.

Recent studies found that some hatchery fish struggle in waters heavily affected by climate change. Wild fish have had millions of years to evolve through conditions that, at times, have resembled the present. Though they may have similar DNA, the influence of hatchery conditions on fish could make them less prepared to survive in volatile ocean conditions than wild fish.

“Many of these wild fish have the genes to deal with these changing environments. But it’s unclear whether the hatchery fish do,” McMillan said.

• This story was original published in the Oregon Capital Chronicle, which is, like the Alaska Beacon, part of the States Newsroom network.

More in News

(Juneau Empire file photo)
Aurora forecast for the week of April 15

These forecasts are courtesy of the University of Alaska Fairbanks’ Geophysical Institute… Continue reading

Rep. Sara Hannan (right) offers an overview of this year’s legislative session to date as Rep. Andi Story and Sen. Jesse Kiehl listen during a town hall by Juneau’s delegation on Thursday evening at Juneau-Douglas High School: Yadaa.at Kalé. (Mark Sabbatini / Juneau Empire)
Multitude of education issues, budget, PFD among top areas of focus at legislative town hall

Juneau’s three Democratic lawmakers reassert support of more school funding, ensuring LGBTQ+ rights.

Rosemary Ahtuangaruak, mayor of the Inupiaq village of Nuiqsut, at the area where a road to the Willow project will be built in the North Slope of Alaska, March 23, 2023. The Interior Department said it will not permit construction of a 211-mile road through the park, which a mining company wanted for access to copper deposits. (Erin Schaff/The New York Times)
Biden shields millions of acres of Alaskan wilderness from drilling and mining

The Biden administration expanded federal protections across millions of acres of Alaskan… Continue reading

Allison Gornik plays the lead role of Alice during a rehearsal Saturday of Juneau Dance Theatre’s production of “Alice in Wonderland,” which will be staged at Juneau-Douglas High School: Yadaa.at Kalé for three days starting Friday. (Mark Sabbatini / Juneau Empire)
An ‘Alice in Wonderland’ that requires quick thinking on and off your feet

Ballet that Juneau Dance Theatre calls its most elaborate production ever opens Friday at JDHS.

Caribou cross through Gates of the Arctic National Park and Preserve in their 2012 spring migration. A 211-mile industrial road that the Alaska Industrial Development and Export Authority wants to build would pass through Gates of the Arctic and other areas used by the Western Arctic Caribou Herd, one of the largest in North America. Supporters, including many Alaska political leaders, say the road would provide important economic benefits. Opponents say it would have unacceptable effects on the caribou. (Photo by Zak Richter/National Park Service)
Alaska’s U.S. senators say pending decisions on Ambler road and NPR-A are illegal

Expected decisions by Biden administration oppose mining road, support more North Slope protections.

Rep. Sarah Vance, R-Homer, speaks on the floor of the Alaska House of Representatives on Wednesday, March 13. (James Brooks/Alaska Beacon)
Alaska House members propose constitutional amendment to allow public money for private schools

After a court ruling that overturned a key part of Alaska’s education… Continue reading

Danielle Brubaker shops for homeschool materials at the IDEA Homeschool Curriculum Fair in Anchorage on Thursday. A court ruling struck down the part of Alaska law that allows correspondence school families to receive money for such purchases. (Claire Stremple/Alaska Beacon)
Lawmakers to wait on Alaska Supreme Court as families reel in wake of correspondence ruling

Cash allotments are ‘make or break’ for some families, others plan to limit spending.

(Michael Penn / Juneau Empire file photo)
Police calls for Wednesday, April 17, 2024

This report contains public information from law enforcement and public safety agencies.

Newly elected tribal leaders are sworn in during the Central Council of the Tlingit and Haida Indian Tribes of Alaska’s 89th annual Tribal Assembly on Thursday at Elizabeth Peratrovich Hall. (Photo courtesy of the Central Council of the Tlingit and Haida Indian Tribes of Alaska)
New council leaders, citizen of year, emerging leader elected at 89th Tribal Assembly

Tlingit and Haida President Chalyee Éesh Richard Peterson elected unopposed to sixth two-year term.

Most Read