A salmon embryo starts life in a fertilized egg.

NASELLE — The cycle of rebirth and renewal is underway at the Naselle Fish Hatchery, aided by an exceptional fall coho return.

On Monday, Dec. 19, several Washington Department of Fish and Wildlife hatchery technicians, fish specialists and biologists were busy handling hundreds of adult coho and steelhead that will help fuel future fish runs.

Hatcheries have provided a boost to salmon and trout reproduction since the 19th century. They’ve taken on added importance in the 21st century as habitat losses, ocean conditions and other factors have made it more difficult for salmon to spawn on their own. The Naselle facility is one of three state hatcheries in Pacific County and among dozens in Washington state.

Virology and genetic testing

Pacific salmon and steelhead — a seagoing trout species — famously return to spawn and die in the rivers where they were born. The fish being processed in Naselle now started their lives there, typically about three years earlier, and then spent most of their lives growing up in the ocean.

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‘From the time the river opened, we’ve had people sport fishing here, too. It’s been a really good year.’

Naselle fish hatchery specialist IV John Larson

Once the adult fish return to the hatchery, the work on spawning future generations begins.

“We do a baseline on all stocks we spawn,” said Naselle fish hatchery specialist IV John Larson as he cut samples of spleen and kidney from dozens of salmon, one of the first steps in processing spawned adult coho.

“We grab a piece of the spleen and a piece of kidney out of each fish, and they run that for viruses.”

The samples are plated and examined at a fish virology health lab in Olympia to test for any potential pathogens that could impact salmon stocks.

“They’ll let us know if they isolate anything, but no news is good news,” Larson said.

“Normally, we don’t find any viruses. We had one about 10 years ago, just a random thing that popped up, but it went away as quickly as it showed up.”

Working near Larson was Willapa Bay fisheries biologist Barbara McClellan, who was busy collecting genetic data from adult coho.

“I’m taking fin clips for a genetic sample,” McClellan said.

“These will get analyzed to assess stocks and determine if they’re Willapa fish, or from outside [of the Willapa watershed]. They’ll break down the genetics to make sure they were brood here. If they’re not brood here, they’ll determine where they’re from because they have baselines for everything. This is part of the baseline for just Willapa. We did Chinook [salmon] a couple years ago, so now we’re doing coho.”

More than 100 late-run coho and a couple of dozen steelhead were processed Monday, part of a process hatchery workers will repeat in two weeks. Their individual lives are cut short, but all would soon die anyway in a natural spawning situation. Adults expend everything in their drive to produce a new generation of their species, their bodies then fertilizing the forests and streams where they originated.

Manually expressing the milt

The job of removing the milt from male coho and eggs from females is a messy one, but essential to sustaining and preserving future salmon runs.

“Right now we’re expressing the milt out of the bucks [male fish] manually. It’s part of the fertilization process. We’ll then go back up and mix the eggs with the milt,” said Naselle Fish Hatchery Specialist III Brady Foreman.

“We put four into a bag so that we can get our [genetic] crosses. We have eggs from 20 hens [females] in each bucket. We put that into five buckets, then cross it with the bags so we get the right cross.”

The next step takes place in the incubation building.

“Once we get them all spawned, we mix the milt with the eggs and put them in the incubator,” Foreman said.

Into the incubator

The eggs are temporarily extracted into five-gallon buckets and the milt is squeezed into quart-size plastic bags. Each five-gallon bucket has eggs from 20 females, which are then combined with a bag of milt from four males, a ratio that helps promote genetic diversity.

“Basically, you have up to 20 females getting fertilized by up to four males, then they’re all combined at the end. It’s more representative of what’s happening in the wild. It’s good for genetic diversity,” Foreman said.

“This is how we’ve been doing it for the past six or eight years. It only takes one male to do all the work, but then you don’t have the good genetic diversity. Doing it this way, we’re able increase gene flow through the population. By mixing in wild brood stock, we integrate wild brood stock into our parent fish and we’re able to keep the genes stronger.”

This innovation is among several developed in recent decades to enhance the odds that hatchery fish will be strong enough to survive the hazardous life cycle that lies before them.

Carcasses complete the cycle

Carcasses from the spawned fish will help support the next generation. Once the eggs and milt have been extracted, the salmon carcasses have their tails removed before the regional fisheries enhancement group distributes them in higher-elevation tributaries “to feed the system.”

The tails are removed so field biologists will be able to easily see they were intentionally planted.

“That way they know that they didn’t spawn in the wild,” Larson said.

Coho returns by the numbers

An exceptional coho run this year is rivaling that of 2014, a record year for the Naselle hatchery.

A total of 31,972 adult coho have been counted at the hatchery this year, according to the latest in-season hatchery escapement report by WDFW, published Dec. 15.

“The two years before it was about 20,000 [coho]. In 2014, we had about 43,000 back,” Larson said.

At the Forks Creek Hatchery, near Raymond, which flows into the Willapa River, approximately 20,000 coho have returned so far.

The exceptional coho returns have made for a prosperous commercial season and successful fall for sport fishermen.

“The bulk of the gillnet fishery is those hatchery-bound fish,” Larson said. “The gillnetters got about 47,000, so they made some money. From the time the river opened, we’ve had people sport fishing here, too. It’s been a really good year.”