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Snake River Fall Chinook Return To Lower Granite Shattering Record; Fishing Not So Great
Posted on Friday, October 22, 2010 (PST)

The 2010 fall chinook return to the Snake River basin is huge, more than two times the modern-day record. But, it is not catching on very well with anglers who recently have had their first opportunities in decades to catch and keep the prized late season salmon.


Through Thursday a total of 41,526 fall chinook had been counted this year climbing over Lower Granite Dam’s fish ladders. That’s already well above the previous high for an entire season, 16,624 in 2008. The record goes back to 1975, the year the dam was completed. Lower Granite, located in southeast Washington on the lower Snake River, is the eighth and final dam the fish pass on their spawning journey.


The big return was portended by last year’s record return of jacks, young fish that return to their natal waters after a little more than one year in the Pacific Ocean. The jack count last year was 41,285, four times the previous record of 10,228 in 2008. The broodmates of those big jack classes are now returning as mature spawners.


Returns in recent years represent a big rebound for a species that veered toward extinction in the 1960s and 1970s. The naturally spawning fall chinook run to the Snake River returned an average of 41,000 adults annually during the 1957-1960 period, according to the “Status Report: Columbia River Fish Runs and Fisheries, 1938-2000,” compiled by the Oregon and Washington departments of fish and Wildlife. Returns were reduced drastically with 1967’s completion of the Hells Canyon Complex of dams, which flooded spawning reaches and blocked upstream passage. Construction of federal dams on the lower Snake also flooded historic spawning habitat.


The Snake River wild fall chinook were listed as threatened under the Endangered Species Act in April 1992. Returns dipped to as few as 78 wild fish in 1990, though the total count at Lower Granite that year, including hatchery fish, numbered 383 fish.


Sport fisheries on fall chinook had not been allowed for a couple decades. But given a relative rebound in returns -- in large part fortified by hatchery programs -- the retention of fall chinook has been allowed for the past two years and again this year on the Snake where it is the shared Idaho-Oregon border.


The “take permit” provided by NOAA Fisheries “is designed so that fall chinook that are caught during our standard steelhead season can be retained,” Sam Sharr, anadromous fisheries coordinator for the Idaho Department of Fish and Game said. The ESA permit also covers the 1.6 miles of the Clearwater River in Idaho. Both Idaho and Oregon boat anglers can catch and keep fin-clipped hatchery origin steelhead and fall chinook.


But, Sharr said, “we haven’t seen that high of a catch.” Through Sunday a total of 380 clipped fall chinook were caught and kept, as were 190 jacks. Anglers caught and released 2,566 unclipped fish that are either of wild origin or are fish born in hatcheries but not fin clipped before their release. The IDFG estimates that anglers fished 95 hours on average for each kept fall chinook.


Fishing was, however, a little better this past week (Oct. 11-17). Anglers caught and kept 163 clipped fall chinook and the average on the Snake was 59 hours per kept fish.


It is also the third year of allowed fall chinook retention on the stretch of the Snake in Washington from Lower Granite up to the Idaho border.


Again, “the catch rate has not been good at all,” said Glen Mendel, district fish biologist for the WDFW. He theorizes that a warmer than normal Snake River may be dampening the fishes’ desire to bite. Mendel also said that people may be catching and releasing chinook that they could have kept because the fish are in the very latest stages of their spawning journey and changing physically, making them less desirable for the dinner table.


Fish that are not harvested, or trapped at Lower Granite to infuse the Snake River fall chinook hatchery program at the WDFW’s Lyons Ferry Hatchery, continue their journey. An as-yet-undetermined portion of the run is of wild origin. The rest are the product of Nez Perce tribal supplementation program and other hatchery program.


Lyons Ferry, long the standard bearer for the threatened Snake River stock, raises the bulk, 4.4 million, of the juvenile fish released into the Snake and tributaries either directly or from acclimation facilities that allow the young chinook to receive their final rearing near sites where they might return to spawn in the wild as adults. Another 1.4 million subyearling fall chinook are reared at the Nez Perce Tribal Hatchery in Idaho and released either directly on-station or from acclimation sites in the Clearwater drainage.


The Idaho Power Company, which owns the Hells Canyon Complex, began its fall chinook program spawning flow regime on Oct. 11 to protect redds now being built in the Snake River below Hells Canyon Dam.


The program is part of Idaho Power’s commitment to protect and preserve the environment surrounding its dams and generation facilities, which Hells Canyon Dam, which is 66 river miles downstream of Oxbow Dam, which is 12 miles downstream of Brownlee Dam.


The spawning flow will be held flat at a constant flow of approximately 8,700 cubic feet per second and will be maintained through approximately the second week of December. After this time normal operations and flows will resume.


As a result of this year’s fall chinook program, Brownlee Reservoir was drawn down to 2,041 feet elevation by Oct. 11. That is 36 feet below full reservoir.


The draft of Brownlee was necessary to make space in the reservoir to capture inflow to Brownlee in excess of the flat spawning flow release. Due to the temporarily low water levels, the only Brownlee Reservoir boat ramps available in October will be at Hewitt and Woodhead Parks. Additional ramps will be available as Brownlee fills during the fall chinook spawning period.


As mitigation for dam impacts on salmon populations, Idaho power funds the production, at its Oxbow Hatchery in Oregon operated by the IDFG and at the ODFW’s Umatilla Hatchery, of about 1 million juvenile fish which is a part of the overall production target of 5.9 million fall chinook. The IPC fish are released directly into the Snake from the boat ramp just below Hells Canyon Dam.


The eggs for the IPC production come from Lyons Ferry, which has long been the repository for the Snake River fall chinook egg bank, which was begun in 1976 to preserve a vanishing genetic stock.


“Genetically, they’re considered to be the same” wild Snake River stock, IPC biologist Paul Abbott said of the eggs received from Lyons Ferry that are hatched out at Oxbow and Umatilla.


Forecasted inflows are managed so that Brownlee Reservoir is full, around 2,075 feet above sea level, by the first week in December. It’s anticipated that the minimum flow set during the spawning period can be maintained until fry emergence (when the young fish leave the redds, or nests) in the spring without emptying Brownlee Reservoir.


Later this fall surveys will be conducted to determine how many redds have been established in the Snake and tributaries -- Grande Ronde and Imnaha rivers in Oregon and the Clearwater in Idaho.


Redd counts monitor redd locations and establish the location and depth of the shallowest redd. Idaho Power and the U.S. Fish and Wildlife Service do counts via helicopter during the spawning period over the Snake River. In addition, the Nez Perce Tribe conducts aerial redd counts on the Clearwater, Grande Ronde, Imnaha and Salmon rivers.


These survey flights account for the majority of the redds observed. However, in the Snake River, many redds cannot be observed from the air because they are in deep water. So, deep water redd searches using underwater videography occur during the spawning period as well as the aerial surveys. Redds as deep as 22 feet have been observed in the Snake River using underwater videography.


The number of redds have steadily risen since the counts began in 1991 with a total of 55. Last year’s count was 3,464, the highest ever.


Many of the spawners are of natural origin. Some are fish acclimated by the Nez Perce Tribe at Pittsburg Landing, Captain Johns Landing and Big Canyon before their release. About 650,000 yearlings and subyearlings are now released each year at both Captain John Rapids and Big Canyon and 550,000 are released at Pittsburg Landing. Roughly 40 percent of those tribal releases are marked.


There is also direct release of 200,000 marked subyearlings from near Captain John Rapids and another release of 200,000 marked subyearlins in the Grande Ronde River.


Other spawners may be returns from fin-clipped fish released by Idaho Power.


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