Hatchery Fish Play Big Part
by Mike O'Bryant
An average of 8.63 percent and as much as a third of fall chinook that spawn naturally at Hanford Reach September through November begin their life in a hatchery, according to a report by the Columbia River Inter-Tribal Fish Commission.
The findings came after 20 years of marking and tagging 200,000 juvenile fish per year at Grant County Public Utility District's Priest Rapids Hatchery in an attempt to quantify the hatchery contribution to the health of "upriver bright" stocks.
"Our belief is that salmon reared at the hatchery are contributing to the productivity in the reach," said Dani Evenson, ecological interactions specialist with CRITFC. "In effect, that is supplementation." She added that biologists still need a better understanding of that contribution "to evaluate the performance of hatchery-reared fish, refine goals for returning runs and direct artificial production."
"Our results show that fishery managers should consider the potential for hatchery-reared fish to contribute to the productivity of natural stocks in the development of recovery goals and management practices, and that the fraction of the returning population from the hatchery must be considered when estimating natural population parameters," the report says. It goes on to say "The failure to account for hatchery fish in these calculations can lead to incorrect perceptions of natural stock performance."
The study found that the proportion of Priest Rapids Hatchery fish spawning in Hanford Reach ranges from a low of 4.64 percent to a high of 60.57 percent, averaging 29.83 percent between 1979 and 2000. The proportion of Hanford Reach returns attributable to Priest Rapids Hatchery ranged from 1.33 percent to 33.05 percent, to reach the average of 8.63 percent.
However, the Priest Rapids Hatchery, which releases 5 million fall chinook smolts in mid-June each year into the Columbia River, and 1.7 million smolts for the John Day Dam mitigation program for the U.S. Fish and Wildlife Service, was designed to mitigate for salmon losses due to the construction of Priest Rapids and Wanapum dams, not for supplementation. To act as a true supplementation hatchery there would have to be some changes, said Doug Hatch, CRITFC fisheries scientist and a co-author of the report with Evenson and Dr. André Talbot. One change would be to set up an acclimatization facility for releases of juveniles below the dam and another involves building raceways filled with gravel to mimic the natural river terrain of wild salmon.
"The Priest Rapids Hatchery has been very successful," said Hatch. "We are not questioning that success. Our research simply offers suggestions on how to make further improvements at the facility."
The hatchery already is using brood stock indigenous to the reach, Hatch said. "There is no genetic difference between hatchery and wild stocks," he said. "They are a single stock."
Hatch said supplementing stocks in streams and allowing hatchery fish to return and spawn naturally has been successful in a number of tribal operations. Those include the reintroduction of steelhead and salmon by the Umatilla Tribes in the Umatilla River in Oregon, the reintroduction by the Nez Perce Tribe of coho salmon to the Clearwater River in Idaho, and the reintroduction of coho by the Yakama Tribes into the Wenatchee, Yakima and Methow rivers in Washington. However, that's not to say that supplementation will work or is appropriate to all rivers, he said.
"We're very interested and concerned about salmon recovery and want to keep all options open," Hatch said, adding that the tribes want to take a scientific approach to fish recovery. "What works on a case by case basis should be what we use."
"Hatcheries are not the solution for fish recovery, they are a tool," Hatch said. The problems with habitat, hydro and harvest all have to be fixed. Once those are fixed, he said, then there would be no need for hatcheries. "They are a way to allow us time to fix those problems."
The 51-mile long Hanford Reach begins at the foot of Priest Rapids Dam and is the only free-flowing stretch of the Columbia River in the United States. It provides the last significant fall chinook spawning habitat in the mainstem river, according to CRITFC.
"CRITFC's research continues to lend credence to our belief that hatchery salmon are integral to natural spawning grounds not only in the Hanford Reach, but throughout the Columbia River Basin," said Sam Jim Sr., chairman of the Yakama Nation's Fish and Wildlife Committee. "This further proves that hatchery supplementation must be an essential tool for rebuilding natural spawning populations to meet the goals of the Endangered Species Act and tribal treaty rights."
Native Fish Society executive director Bill Bakke said the findings in the report do not support the "political claim" that hatchery-reared salmon contribute to the productivity of natural stocks.
"The report fails to compare the recruits per spawner for both hatchery and wild spawners in the river. This measures the productivity of the two groups to produce adult spawners," Bakke said. "Lacking that kind of information, the natural productivity of the hatchery salmon cannot be determined. Therefore the claim that hatchery fish contribute to the natural productivity of the river is only speculation, not a fact."
He said that the fact hatchery salmon return and contribute to the catch is not a new finding, but it doesn't support the report's conclusions.
Columbia River InterTribal Fish Commission: www.critfc.org
Native Fish Society:home.teleport.com/~salmo/
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