This article was published on: 07/13/12 12:00 AM
A big disparity in the sizes of the two salmon runs on the Deschutes is partly due to differences in the two species, fisheries officials say
Out of the first 23 spring run adult chinook salmon to swim above the Pelton Round Butte dam complex on the Deschutes River in 40 years, two are dead.
It is unknown what killed a fish reported dead July 5 near Opal Springs on the Crooked River, while an angler likely killed a fish reported dead July 7 in the Deschutes Arm of Lake Billy Chinook, said Megan Hill, native fish studies team leader for Portland General Electric.
After more than a decade in planning, the first spring run chinook salmon was released by PGE into Lake Billy Chinook in late May.
Caught at a trap just downstream of the dam complex, the adult fish carry tags indicating they were raised at Round Butte Hatchery and released as young fish into tributaries upstream of the dams.
Those tags should also be a warning to anglers to be careful with the fish. “You can’t legally keep them,” Hill said.
While the run of spring chinook on the Deschutes River was well below expectations this year, a record run of sockeye salmon is now finishing its swim into the Columbia River.
The reasons for the difference in run size are many and are based in the differences of the fish themselves, said Cindy LeFleur, Columbia River policy coordinator for the Washington Department of Fish & Wildlife. The different species of salmon go to different parts of the oceans and have different life histories.
“They are all different critters,” she said.
Spring run chinook spend three or four years in the ocean before returning to spawn while sockeye salmon spend a year or two, said Rod French, district fisheries biologist for the Oregon Department of Fish and Wildlife in The Dalles.
Most of the Columbia River sockeye go to the Okanogan River, which runs from Canada into the Columbia in Washington, from which they look for small streams to spawn in immediately after they arrive. Spring run chinook salmon fan into other tributaries of the Columbia, looking for larger rivers to hold in for a couple of months and then spawn.
The fish are different physically as well, French said, with Columbia River sockeye averaging about 5 pounds and spring run chinook averaging about 15 pounds.
Last month, the Oregon Department of Fish & Wildlife ended fishing for spring run chinook on the Deschutes more than seven weeks early after realizing the run was going to be much lower than predicted.
The ODFW expected about 1,800 wild fish and about 5,000 fish from the Round Butte Hatchery to return this year. Counts from early this week had about 50 wild fish and about 1,000 hatchery fish in the run, which typically is done entering the Deschutes by the middle of July.
Overall there were more than 314,000 spring run chinook expected to pass through the fish ladder at Bonneville Dam, about 40 miles upstream from Portland, French said.
The run turned out to be 203,100. Although two-thirds of expected, he said the run is still healthy compared with the runs of the 1990s. Then the Columbia River run regularly was below 100,000 fish.
Why the spring run chinook numbers this year are below expectations remains a mystery, French said. Factors affecting the fish could include ocean and weather conditions.
“We don’t really know how all those things can affect fish,” he said.
In contrast, the reason for the largest run of sockeye on the Columbia since Bonneville Dam was finished in the late 1930s is clear.
Habitat restoration and fish passage improvements on the Okanogan River in recent years have spurred the revival, LeFleur said. The forecast was for 462,000 sockeye to return to the Columbia River this year, but the run has already beat that number with a couple of weeks left.
As of Wednesday more than 504,000 sockeye had been counted passing through the fish ladder at Bonneville Dam. The total run is expected to be a record 535,000 fish at the end of the month.
A small amount of those sockeye will be headed to the Deschutes as part of the first sockeye run in decades. French said there are no predictions as to how many fish will be part of the renewed run.
After more than a decade of planning and more than $100 million spent by Portland General Electric and the Confederated Tribes of Warm Springs on a submerged water tower to aid in downstream migration, adult salmon and steelhead are being returned to the upper reaches of the Deschutes River this year.
The fish are collected at a trap just below the Pelton Round Butte dam complex and then hauled in a truck around the dams. The first spring run chinook arrived in May, and the first sockeye arrived Wednesday, a couple of weeks earlier than expected.
Since the dam complex was built in the late 1950s and early 1960s, the sockeye run was blocked from swimming to the ocean and the fish became kokanee — the landlocked version of the fish. In late 2009 PGE and the tribes completed the submerged tower, creating the option for the fish to migrate to the ocean or stay and spawn in streams feeding Lake Billy Chinook.
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