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NW Fishletter #392, April 1, 2019

[7] Tribes Helping Repeat Spawners To Boost Idaho's B-Run Steelhead

Columbia Basin tribes have been working for 20 years to capitalize on steelhead's mystifying ability to repeat spawn, and recently got final recommendation from the Bonneville Power Administration (BPA) to build a new reconditioning facility to boost the Snake River's famous B-run steelhead returns.

Repeat spawning is an odd little survival technique that only steelhead possess, of all the anadromous fish in the Columbia Basin.

The reconditioning facility is for kelts, steelhead that have already spawned and are on their way back to the ocean to feed, remature and gather strength for another return to their spawning grounds. But few make it back.

After years of research to develop the best methods to boost those returns, the tribes have been catching these post-spawn adults at juvenile bypass systems, holding and feeding them until they remature, and releasing them back in the river to spawn in the wild again.

The Columbia River Inter-Tribal Fish Commission and the Nez Perce Tribe believe that giving Snake River steelhead a second shot at spawning is one way to help increase the numbers of the larger B-run fish.

"Our research has shown that when they do spawn again, they're larger, and they produce more eggs and larger eggs, which is associated with better survival," Doug Hatch, a senior fisheries scientist for CRITFC, told NW Fishletter.

At an estimated cost of roughly $2 million, the facility to recondition Snake River kelts still needs a preliminary design and an operation and maintenance plan before CRITFC returns to the Northwest Power and Conservation Council for final approval. Construction of the facility, as part of the Nez Perce Tribal Hatchery new Lewiston, Idaho, should begin next year.

Their goal, once it's built, is to increase ladder counts of B-run steelhead passing Lower Granite Dam each year by 6 percent--an extra 180 adult females--released and ready to spawn again, Hatch said. According to the Bonneville Power Administration's environmental analysis of the project, "A kelt reconditioning program in the Snake River Basin is believed to be critical for increasing the returns of these fish to this level."

Idaho is well-known for its steelhead fishing, especially its B-run, which mostly return to the Clearwater River and are generally larger and come back later after spending two years in the ocean, compared to the A-run steelhead that return after one year.

Fish managers and others have been concerned about recent low returns of these larger steelhead. Last year, conservation groups threatened to sue the Idaho Department of Fish and Game to stop the harvest of hatchery steelhead until the agency promised tighter controls on steelhead fishing, and applied for an incidental take permit of wild steelhead from federal agencies.

Programs to recover the Columbia Basin's declining steelhead runs have included limits on fishing, restoring habitat, improving passage at hydroelectric dams, and developing hatchery programs. Currently, only the tribes are attempting to improve runs by boosting the number of repeat spawners. "It's a novel approach, and I think it has a lot of promise--particularly when the runs get into these low status positions," Hatch said.

He said that the return rates for repeat spawners vary. In the Yakima River, repeat spawners make up about 3 percent of the adult steelhead run, while in the Snake River, kelts returning to spawn a second time account for only about 1 percent. Partly because return kelts are so rare, the reconditioning program has the potential to vastly improve repeat spawning in the Snake River, he said.

In a 2016 letter to the Northwest Power and Conservation Council, the Fish Commission noted, "Based on the 1-percent return rate in the Snake River, collecting and reconditioning kelt can provide over 100 times greater benefit to the population in terms of fish on the spawning grounds than their potential contribution as natural repeat spawners. Kelt reconditioning not only increases spawners on the spawning grounds, it plays an important role in the spread-the-risk strategy for steelhead; it helps to preserve the diversity of life history pathways in steelhead and can be used as a restoration tool for at-risk steelhead populations."

Hatch said that, historically, more steelhead returned to the Columbia River and its tributaries to spawn a second time, but downstream passage at hydroelectric dams is designed for juvenile fish, making it difficult for adult steelhead to return to the ocean and attempt another return. "The passage facilities are making improvements, but they were never envisioned to pass adult fish. They have small piping, which cause problems for the adults," he noted.

In 1999, CRITFC and the Yakama Nation began looking into methods to recondition steelhead in the Yakima River, to see if they could get kelts to remature and rebuild their strength without making a return trip to the ocean.

Over time, the tribes developed a successful method that involves capturing adult steelhead as they migrate downstream after spring spawning and transporting them to a reconditioning facility.

While held, they are fed a diverse diet that includes krill and squid, and are treated with antibiotics to help rebuild their immune systems. Some are held for about six months, until October, and then released into the stream where they were collected as the new steelhead run is returning. Those that do not remature in six months are held for 18 months before they are ready to be released, Hatch said.

The reconditioned fish--both at six months and 18 months--do not go to the ocean because they've already rematured before they're released, and instead join the run as it heads to their natal spawning grounds to lay eggs, Hatch said.

The program in the Yakima River was so successful, similar programs have been developed by Colville, Warm Springs and Nez Perce tribes in the Methow, Okanogan, Hood, Deschutes and now Clearwater basins.

Hatch noted that while the reconditioning generally occurs in a hatchery, the program is different from conventional hatchery programs. "These are wild fish that we're bringing into the facility. They've already spawned, and we recondition them and put them back out into the run at large," he said. "You're increasing the natural run with natural fish. There's a lot of upside, and not very much downside."

More recently, researchers have been working to determine which fish will require a full 18 months--known as skip spawners--and which will be ready to spawn again after just six months.

Hatch said that in nature, these skip spawners are more likely to occur in years when conditions were difficult for adult migration, whereas consecutive spawners happen when they've completed spawning and are still in relatively good condition. "It does vary annually, but it also varies by location. In the Snake, we do see higher rates of skip spawners than in the Yakima," he noted.

He said it's more cost-effective to recondition those that take only six months. But, he added, "There are tradeoffs because skip spawners are even larger, so you have even more eggs and bigger eggs, so there are some advantages."

The Columbia Basin tribes have been at the forefront of the research and are currently the only fish managers with kelt reconditioning programs, but Hatch believes that may change. "I think as the steelhead populations continue to go down--the most recent forecasts look pretty bleak--this becomes even more important, and there may be greater interest by others," he said. -K.C. Mehaffey

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NW Fishletter is produced by NewsData LLC.
Publisher/Editor-in-Chief: Mark Ohrenschall, Editor: K.C. Mehaffey
Phone: (206) 285-4848 Fax: (206) 281-8035

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