Hatcheries Impact Naturally-Spawning Salmon Populations

Emily Nuchols is a senior environmental journalism major at Western Washington University. She’s managing editor for The Planet magazine.

In Puget Sound and coastal Washington, the Washington State Department of Fish and Wildlife (WDFW), Puget Sound and coastal Indian Tribes and the U.S. Fish and Wildlife Service operate more than 100 hatcheries. The majority were built to compensate for habitat loss and to produce fish for harvest in response to declines in naturally-spawning salmon populations.

Hatcheries provide 75 percent of salmon caught in Puget Sound fisheries and are an essential element to an $854 million annual recreational fishing economy in Washington state (ranked eighth in the nation), and a $145 million annual commercial-fishing economy (seventh in the nation), according to the Hatchery Scientific Review Group data.

“Hatcheries are a tool, they can be good or bad,” Heather Bartlett, hatchery reform coordinator for WDFW, said. “It depends on how they are used.” In recent years, however, hatcheries have been identified as one of the factors responsible for the decline of naturally-spawning salmon populations.

In 2000, an independent group was selected by Congress to review the benefits and risks of hatcheries in the Puget Sound and Coastal Washington hatchery reform project. Congress designated Long Live the Kings (LLTK) as the project’s independent, third-party facilitator and established the Hatchery Scientific Review Group, an independent panel of nine scientists to review hatcheries. It was the first ever, system-wide review of the hatchery program.

“Hatcheries used to be seen as a magic tool to immediately produce more fish,” Michael Kern, LLTK project coordinator, said. “But they only provide benefits if operated in the right way.” He said the largest risks of hatcheries are loss of genetic diversity, competition and over-harvesting.

Steve Seymour of the Watershed Stewardship program for the WDFW said there must be a fishery to harvest the hatchery salmon. He said the goal is to harvest 90 percent of the hatchery fish, but in doing so 90 percent of the wild salmon are also being harvested.

The coho salmon of the Nooksack River are a good case study, he said. The Skookum Creek hatchery releases 2.3 million yearling coho salmon each year for harvest. He said the hatchery is viewed as a success because the coho return in large numbers, but with a large hatchery there are consequences. The harvest of hatchery fish through the past 20 years has caused the decline of the wild coho population.

Seymour said the largest impact of hatcheries on wild salmon is from over-harvesting.

He said ideally managers should plan for the escapement goal, which is the return of spawning fish to hatchery racks or traps, before setting the harvest goal to ensure maintenance of fish populations. There is no escapement plan for coho on the Nooksack; the hatchery is managed with the main goal of harvest.

Seymour said 60 percent of the natural spawning population has to return to the river to maintain a population. Not as many are needed to maintain a hatchery population.

Seymour said hatchery fish don’t have the same genetic makeup as wild fish, because the manager selects traits that are altered for survival in the hatchery. He said 10 percent of all salmon, including hatchery fish, stray and spawn in streams other than that of their birth. When hatchery fish stray their traits are combined with the wild traits and affect the genetic fitness of the salmon stock that has adapted over time to survive in the wild.

“We don’t know the point that genetic mixing is deleterious to the natural population, but we know it is happening,” Bartlett said. She said it is unacceptable in a hatchery program to have more than 5 percent hatchery fish spawning in the wild.

Two genetically different species of chinook salmon inhabit the Nooksack River—the spring and fall chinook. Fall chinook are not native to the Nooksack, but were introduced from a hatchery in the 1920s to supplement the river’s native spring chinook. It was later realized that the two were genetically unique.

Kendall Creek hatchery releases approximately 500,000 fall chinook each year specifically for harvest. Seymour said smolts are released in the lower Nooksack and Lummi Bay. He said many fall chinook return to the south fork to spawn. Because the fall chinook spawn only a few weeks later than the spring chinook, hybridization is a risk. The larger fall chinook also compete for limited spawning habitat and food in the river, which exceeds the river’s carrying capacity.

“Hatchery fish are bigger and more aggressive,” Kendall Creek hatchery specialist Ed Argenio said. “Heck, we hand feed them, of course they can outcompete wild stock.”

Seymour said this year’s escapement is the lowest he’s ever seen. The decline in population is not entirely because of competition from fall chinook, but it definitely has an effect, he said.

Next year, he said, WDFW will start up a spring chinook hatchery on the south fork of the Nooksack River and will remove a large portion of the wild population as brood stock. This is the second attempt at a chinook hatchery on the south fork. In the early 1980s, the Lummi Nation launched a hatchery that failed less than a decade later.

“Risks go with all components of hatchery production,” Seymour said. “We could lose the population either way.”

He said that any time a hatchery begins with small brood stock population, inbreeding is a risk.

“It could be 2020 before the south fork can support a healthy population of springs, or maybe it never will,” he said.

Seymour said several years ago a low of 30 threatened native spring chinook returned to the north fork. He said the population has increased, but the number of natural origin recruits has stayed about the same. The conclusion, Seymour said, is that hatchery fish are straying into natural populations and the habitat is not able to maintain a population of wild fish.

Kendall Creek hatchery, located on the banks of the north fork of the Nooksack, releases 750,000 spring chinook each year—half of the 1.6 million it released before hatchery reform. Seymour said to be successful the wild population should outnumber the hatchery population, but most fish in the river have hatchery ties. The objective, he said, is to keep a population of wild stock in the river until the habitat can support more fish.

In the early 1980s hatchery managers looked to the founding population of spring chinook, Seymour said, and studied the genetic makeup through scale samples. The present population of spring chinook is similar and representative of the founding stock.

The one factor all sides can agree on is habitat.

“Habitat is key, if there is a good habitat the natural spawners can withstand more,” Bartlett said. “With a degraded habitat, the ability to rebound is limited and the scope of error is small.”

Seymour said loss of habitat and riparian zone degradation is definitely impacting salmon populations. Out of the five species of Pacific salmon, spring chinook and coho spend the most time in freshwater habitat. He said chinook fry spend four to five months in the river before migrating to the ocean, while coho fry spend up to 18 months in the river.

“In the old days, it was simple to raise and release millions of fish and that was it,” Seymour said. “We didn’t think about what it was doing to the wild fish in the river.”

He said times are changing and hatchery managers will be forced to think more broadly of the impacts on wild salmon.

“As ‘risky’ as hatcheries are, there are rivers where we wouldn’t have fish populations without them,” Bartlett said.

One such stream is Whatcom Creek in downtown Bellingham.

“This was a dead creek,” hatchery manager Earl Steele said of Whatcom Creek when he arrived at the hatchery in 1978. “There were no fish, so we weren’t displacing any native species when we introduced hatchery chum.”

Whatcom Creek is now the largest sport fishery for chum salmon in the state of Washington. But, the hatchery is unique because it revived a barren stream with fish and essentially started with a clean slate, with little risk to wild stock involved.

Bartlett said hatcheries will always be present on some level in the future, but what that is will depend on habitat. She said the state may reduce hatchery programs or their reliance on them, but if the population of Washington continues to grow, there will continue to be more destruction of habitat.

“As long as we as a society continue to make political decisions to build malls, roads and developments that cause a loss of habitat,” Bartlett said. “There will always be a role for hatcheries.” §