Yakama Nation’s Innovative Techniques to Rebuild Salmon Runs In the Yakima River Basin
- October 29, 2013
- John Harrison
The Yakama Nation is working to restore extirpated runs of summer Chinook, coho, and sockeye salmon to the Yakima River and experiencing what the tribe’s senior fisheries research scientist, Dave Fast, calls “pretty good success.”
“Reintroducing species of salmon to the Yakima River Basin is very important spiritually, culturally, and economically to the Yakama Nation members,” Fast told the Northwest Power and Conservation Council in July.
The Yakima River Basin is one of the premier agricultural areas in the nation, and also historically a great salmon river. Large-scale, commercial agriculture in the basin dates to the early 1900s. Over time, dam construction, habitat loss, and overfishing took a toll on the fish.
“Initially, it was apples, but today a number of crops are raised, including tree fruits, grapes, hops, and many others. These are made possible by the rich volcanic soil in the basin, but also by irrigation from the Yakima River, and this has come at some cost to the salmon,” Fast said.
“We’ve been working on coho the longest in the basin,” Fast said. “The goal is to re-establish a self-sustaining, naturally spawning population.”
From annual historic runs of 44,000 to more than 150,000 fish, coho returns steadily dropped to zero by the 1980s. Today, the tribe is experimenting with three innovative techniques to rebuild the population. First, adult fish are captured and transported to tributaries that once supported coho, then studied to determine whether and where they spawn, and whether their offspring interact with other species, such as trout. Second, the tribe uses mobile acclimation ponds—small raceways that can be moved from one tributary to another—to release juvenile coho into tributaries. And third, juvenile fish at the parr stage are planted in tributaries to determine whether release at that life stage is preferable to releasing fish as smolts when they are older.
Fast said the mobile acclimation ponds will help answer one of the persistent questions about using supplementation to rebuild naturally spawning populations.
“The question is, if you stop supplementation, will the population continue or will it plummet back?” Fast said.
“It’s a really neat system where we can move these in and out quickly, and we will eventually get to all of the tributaries as we remove barriers,” he said.
A hatchery at Prosser Dam is the main coho production facility at the moment, but the tribe plans to add a small hatchery at the Holmes Ranch upstream of Rosa Dam. The tribe currently operates an acclimation site there. In August, the Council’s fish and wildlife committee received a positive review of the project from its independent science panel. The facility would produce 500,000 coho parr and 200,000 smolts for release in the upper Yakima and Naches rivers using broodstock collected at Roza and Sunnyside dams.
“We’ve gone from well under 1,000 coho adults returning per year to where we had a total of more than 10,000 fish in 2009, hatchery and natural combined,” Fast said.
The tribe is also working to restore summer Chinook salmon, extirpated in the basin in the 1970s.
“We’ve made tremendous progress to improve the mainstem river for spawning,” Fast said. “The objective is to see if we can restore early-run fall Chinook between Sunnyside Dam and Roza Dam, and also in the lower Naches River. We also hope to increase the number of natural-origin summer Chinook for harvest.”
But sockeye restoration may be the biggest success story. From historical runs of more than 200,000 adult fish, the number dropped to zero by the early 1990s, largely because the river was impounded behind dams and fish passage for both juveniles and returning adults was impossible.
Using two donor stocks, sockeye from Lake Wenatchee and Lake Osooyoos on the Okanagan River in British Columbia, the tribe has been trapping adult fish at Priest Rapids Dam and transporting them by truck to Cle Elum Lake.
“This isn’t really a hatchery program,” Fast said. “The adult fish spend the summer in the lake and then migrate up into the Cle Elum River to spawn in the fall.” The tribe is working on a new design for a juvenile fish bypass system to improve sockeye passage out of the lake and into the river.
From 1,000 sockeye captured at Priest Rapids in 2009 when the restoration effort began, the number of adults transported to Cle Elum Lake has increased steadily to the allowed maximum of 10,000 in 2012. From the 1,000 adult fish released into the lake in 2009, the first smolts—the tribe estimated there were 80,000—passed over Prosser Dam on their way to the ocean in 2011. This year, the first adults from those smolts were collected at Rosa Dam and transported with other sockeye trapped at Priest Rapids to Cle Elum Lake.
It was cause for celebration, and on July 10 the tribe held its first “Return of the Sockeye” celebration at the lake. By the first week of August, 575 adults had returned to Prosser Dam in the lower Yakima.
“Hopefully, we’ll get to the point where we don’t have to use out-of-basin stock,” said Fast. “We can take all the fish that were naturally produced in the basin and release them back into the lake.”