The reservoirs behind Priest Rapids, Wanapum and Rocky Reach dams in central Washington got an infusion last week with the release about 15,500 hatchery-raised juvenile white sturgeon that it is hoped will form the foundation for habitat-filling, self-sustaining populations.
The young fish represent a big step toward implementation of the hatchery supplementation provisions of white sturgeon management plans for the Chelan and Grant county public utility districts. Both were developed as a follow-up to federal hydro project relicensing processes that were completed in 2008 (Grant) and 2009 (Chelan).
The relicensing orders from the Federal Energy Regulatory Commission include requirements that the dam owners mitigate for dams’ impacts on fish and wildlife, such as salmon, steelhead and white sturgeon. Grant PUD had its Priest Rapids and Wanapum dams relicensed and Chelan PUD completed the process for Rock Island Dam. All are on the mid-Columbia River.
The releases were celebrated Thursday by federal, state and tribal officials during a special ceremony at the lower Wanapum boat launch. The Wanapum and Yakama tribes and Grant PUD staff, along with other tribal and agency partners, believe releases will one day become a part of a self-sustaining populations.
There were 3,000 9- to 10-month-old fish released into the Wanapum tailrace during the Thursday ceremony and about 6,000 more were planted in the Grant PUD reservoirs earlier in the week. All of the fish were outfitted with PIT tags and about 1 percent were also equipped with acoustic radio tags so their movements can be tracked to evaluate how they do, and what they do.
Chelan PUD last week released 6,500 of the 10-inch long, 4.4-ounce sturgeon into the river about 35 miles upstream of Rocky Reach. Biologists (PIT and acoustic) tagged fish as well as marking the plates or scutes that cover the fish instead of scales, said Josh Murauskas, the biologist in charge of the Chelan PUD white sturgeon program.
The goal in releasing the fish near traditional spawning grounds is to rekindle flagging natural populations. It will be 20 years before the fish are mature enough to spawn.
This year’s and succeeding years’ releases are aimed at achieving the goal of ensuring the longevity of the species, and ultimately allowing increased tribal and recreational fisheries.
Increasing the number of naturally spawning white sturgeon in the Grant PUD reservoirs is a joint effort that includes the Wanapum Band and the Yakama Nation and others. Likewise, the Chelan effort involves the help of tribes, state and federal agencies and others.
“There’s a lot of people in play here,” Murauskas said of the sturgeon recovery effort.
The sturgeon culturing process begin in early June 2010 when tribal fishers captured two female and eight male adult sturgeon in the mid-Columbia reservoirs to use as broodstock for the program. Eggs and milt were extracted for use in artificial propagation at the Yakama Nation’s Marion Drain Hatchery and the broodstock were released back into the river, according to Daonella Miller, who heads the Yakama Nation sturgeon program.
“In another month we’ll be back out on the river trying to catch broodstock to start the process all over again,” Miller said.
Given the fact that fewer sturgeon were captured than desired to produce a diverse genetic mixture in the hatchery, some eggs and milt were used from captive broodstock that had been held in the hatchery for the past 15 years. The captive brood added an additional three “families” to the gene mix.
The tribal hatchery produced 13,000 juvenile fish, 6,500 each for the Chelan and Grant PUDs. To meet its release goals Grant got an additional 2,600 juvenile sturgeon from a British Columbia source.
The tribes are enthused about the rebuilding program.
“They are in bad shape. In some areas there are only a few remnant adults,” Miller said of the remaining populations of naturally produced fish. There is evidence of some natural spawning and recruitment into the white sturgeon populations. But there also seems to be some relatively blank spots among the various age groups of fish, Miller said.
Miller guided the development of sturgeon facilities at the hatchery, acquired holding ponds, filters, plumbing supplies and surplus hatchery equipment on a spare budget.
“The tribe saw the need to take the lead” on the sturgeon recovery program, Miller said.
The PUDs and tribes intend to continue supplementing the white sturgeon populations for at least three years, while evaluating the impacts the program is having. The idea is to size the population to the amount of suitable habitat. It will be a long process, given the fact that sturgeon take at least 20 years to reach productive maturity, and can live for up to 100 years.
“You can’t just wait two or three years to see if it works” as can be done with other species, Murauskas said. “It’s not such a quick turnaround with sturgeon.”
The development of Columbia River hydrosystem has resulted in the relative isolation of white sturgeon in regulated and impounded reservoirs.
“All of these populations experience complete or frequent recruitment failures that are likely related to river regulation, flooding of historical critical spawning and rearing habitats, increases in predators due to habitat alteration, introduction of exotic species, and pollution,” according to the Priest Rapids Project White Sturgeon Management Plan. “At present, what limited natural recruitment does occur is likely insufficient to maintain existing population levels.”
The overall goal of this Rocky Reach White Sturgeon Management Plan is to promote white sturgeon population growth in the Reservoir to a level commensurate with the available habitat based on monitoring results.