Oregon Hatchery Takes a Tip From Mother Nature

The Parkdale Fish Facility is not your father’s fish hatchery.

Run in partnership by the Confederated Tribes of the Warm Springs and the Oregon Department of Fish and Wildlife, it is trying to rebuild dwindling stocks of salmon and steelhead in the Hood River by making fish spawned in hatcheries behave more wild.

“In order to do that, we feel we’ve got to imitate Mother Nature the best we can,” said Mick Jennings, a former state fisheries biologist now working for the Warm Springs tribes. “These fish have adapted over thousands of years on their own. The problems in this basin are man-caused activities.”

That concept colors the way they gather brood stock, raise young fish, even how they release them back into the river that is born in the snows of Mt. Hood and empties into the Columbia River.

At Powerdale Dam, the brood stock for summer and winter steelhead and spring Chinook are drawn from across the breadth of the run by taking every 10th to 15th wild fish that comes up the fish ladder.

Fisheries technician Terry Guisto anesthetizes the fish and takes scale samples to figure out their ages, so that they can mimic the age mix of the wild run in the hatchery stock. For steelhead, for example, they want 80% 4-year-old fish, 16% 3-year-olds and so on.

“It allows for more resiliency in the population,” in case of a drought or some other natural disaster, Jennings said.

To make fish feel more at home, holding ponds at Parkdale are painted camouflage, and old Christmas trees are thrown in for cover. Pools are 12 feet deep at one end. Sprinklers spray the surface to keep fish on the bottom.

“They have a completely different behavior than traditional hatchery stocks,” said state fish biologist Jim Newton. “They’re a lot more flighty. We try to minimize contact with humans. Things are as wild as they can get.”

Like chameleons, young fish will take on the color of their environment. When traditional hatcheries raise young fish in light-colored pools, they come out lighter than their wild cousins and are easier targets for predators until they turn darker over a couple of weeks.

Rather than dump the fish into the river from a truck all at once, Parkdale puts them out in riverside pools where they have a chance to imprint longer on the scent of their home water, and migrate out when they choose by jumping over a stop-log.

It is too early to see an impact on adult returns, but the changes seem to be having an impact on the survival of young fish, Jennings said.

Sampling shows that between 76% and 81% of the fish raised to be wilder and allowed to go out when they choose are making it to the mouth of Hood River, compared with 32% to 38% of fish treated the old way.