Spring Chinook Return to Columbia
by Kristina Brenneman
CASCADE LOCKS, Ore. -- They may have gotten a late start, but the number of spring Chinook salmon passing through Bonneville Dam was 30 percent higher than last year's count, fishery experts said.
An estimated 124,000 chinook made their way upriver at the official close of the season, up more than 29,000 from 2005 and higher than initial projections this season, according to Brian Gorman, a spokesman for the National Oceanic and Atmospheric Administration's fisheries service.
Spring chinook typically start returning to the Columbia River in late February or early March. But, for a second straight year, the fish didn't appear in substantial numbers until May, he said. Fishing experts were uncertain why they have been late for the past two years.
"This year's spring run took its time, but it crossed the finish line with a very respectable showing," said Bob Lohn, head of the Northwest region of the NOAA's fisheries service.
He said he's convinced that recent efforts to improve fish passage through the dams, as well as significant investments to enhance fish habitat, hatchery and harvest management "will help salmon recover for the long term. "
Typically, salmon runs are variable. Improved in-river conditions do not always translate into larger runs because the ocean plays a greater role in salmon survival, Lohn said.
"The poor ocean conditions we observed in 2004 and 2005 lead us to expect lower rates of return for spring chinook in 2007," Lohn said. "The counts of jacks, the early-returning fish from the juveniles that migrated to the ocean in 2004 and 2005, are about two-thirds of last year's number."
NOAA Fisheries continues to work at making hatcheries more compatible with efforts to conserve naturally spawning salmon. Gorman said in the next few weeks the agency will identify several hatcheries in need of reform.
NOAA scientists also are wrapping up research on the influence of changing ocean conditions on salmon from the time they migrate as juveniles through the estuary into the ocean to when they return as adults, Lohn said.
"This ongoing research will help future salmon management decisions," he said.
Moreover, the U.S. Army Corps of Engineers has plans to install a fish slide at Lower Monumental Dam in 2007. Such slides, which provide safer, faster passage for young salmon through the dams' spillways as they migrate to the sea, are already in place at Ice Harbor and Lower Granite dams, Lohn said.
The Corps has also added electronic detectors for both adult and juvenile salmon at the dams, including a recently installed juvenile fish detector at Bonneville Dam.
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