Salmon: No dam difference?
by The Editorial Board October 29, 2008,
Yes, there are many differences between the Columbia and the Fraser, which has its own problems with pollution and development, as The Oregonian's Michael Milstein reported. And there's nothing about the Fraser River's survival rate -- only about 25 percent to 50 percent of its young salmon make it down the river to its mouth -- that should be the ultimate goal of those trying to restore the Columbia runs.
But the study, which carries the overly provocative title "Dams Make No Damn Difference to Salmon Survival," should at least force all the interest groups in the Northwest to pause and consider whether they have too quickly and easily dismissed the effects of hundreds of millions of dollars of fish passage improvements installed at Columbia and Snake river dams.
It's considered bad form in the Northwest salmon debate to say anything positive about the Bonneville Power Administration and the Army Corps of Engineers, but it does appear that the fish-friendly improvements at their dams have helped counter the harm of the power-generation structures. It also appears that efforts to control squawfish and other predators in the Columbia system, which isn't done on the Fraser, might be helping the salmon.
Dams do kill young salmon trying to survive their journey downstream. We'll never believe anyone's claim that they "make no damn difference" to salmon. But this study, and other lesser publicized findings, have shown a marked increase in downstream smolt survival on the Columbia.
Again, we're in no way suggesting that all's well with Columbia and Snake River salmon. Young salmon mortality is still unacceptably high. The study, which used young salmon implanted with acoustic tracking devices, showed that about half of spring chinook that start from an Idaho hatchery on the Snake River made it all the way to Bonneville Dam. Many more of those fish disappeared in the last stretch of the Columbia near its mouth, eaten by seabirds.
Adult returns are anemic, too. It's surely possible, as some researchers argue, that young smolts may survive the long run through the dam system so weakened and stressed that they will die later.
The latest study won't be the last word on the subject of Columbia salmon. But it provides an interesting comparison to a river without dams, and provides support for the huge and continuing investments in dam modifications and predator control efforts meant to protect migrating salmon on the Columbia. They are making a difference for fish.