Wild B-run steelhead are getting a needed boost from a program that seeks to capitalize on the species’ ability to spawn more than once.
About 100 repeat spawners were released below Lower Granite Dam on the Snake River Monday, after spending six to 18 months at the Nez Perce Tribal Hatchery.
“The really important part of it is these are wild fish,” said Doug Hatch, a senior research scientist with the Columbia River Inter-tribal Fish Commission at Portland.
Steelhead are unique among Columbia River anadromous fish in that they don’t necessarily die after reproducing. Females of the species have the ability to make their way back to the ocean to feed, regain strength and eventually repeat their spawning odyssey. Those that do it are bigger and produce as many as 50 percent more eggs than first-time spawners.
About 50 percent of wild Snake River steelhead become kelts — those that attempt the post-spawn downstream journey as adults. But almost none of them make it. Hatch said only about 0.4 percent of any given Snake River steelhead run is comprised of repeat spawners.
The commission, along with the Nez Perce Tribe and the University of Idaho, operates a program that seeks to boost wild steelhead numbers by helping kelts become repeat spawners. Instead of letting the fish fend for themselves while trying to reach the ocean, they are intercepted and taken to the hatchery at Cherrylane to be reconditioned.
The fish released Tuesday were in beautiful shape, but when biologists plucked them from a fish trap at Lower Granite Dam in the spring of 2016 they were skinny and haggard. They’d just spent about half a year in fresh water. To reach their spawning grounds, they escaped sea lions on the lower Columbia River, climbed concrete ladders at eight dams and managed to avoid being caught by thousands of anglers. They battled each other for the best spawning habitat, used their bodies to dig egg nests in gravel and did it all without eating.
At the hatchery they were fed a diet high in fat. Biologists monitored their blood to determine when they were ready to spawn again. The program is one of the many steps the federal government is taking to try to prevent steelhead from going extinct. Other actions include spilling water at the dams to help juvenile steelhead survive their trip to the ocean, improving spawning habitat to make it more productive and taking care to reduce competition between fish that spawn naturally and those raised in hatcheries.
Despite those steps, wild steelhead remain in trouble. Predictions vary, but according to some estimates as few as 800 wild B-run steelhead may return to the Clearwater and Salmon rivers this fall. Hatch said about 500 of those may be female. So releasing the 100 reconditioned repeat spawners has the ability to boost wild B-run spawners by 20 percent.
“Certainly in these down years for steelhead, it’s a super safety net program,” he said.
The program, which is limited by a lack of available space at the hatchery, is poised to get a boost. The captured kelts are kept in two small circular tanks at the hatchery. Plans are in the works to construct a new building with six large tanks, which will help meet program target of releasing about 180 repeat spawners annually.
“In the next year, we should have the facility built and we can really attack the project goals,” Hatch said.