Study first, mine later Until the effects of dredging are better understood, the state should call a halt

State Sen. Jason Atkinson wants to ban suction dredging on Oregon rivers because he says the practice harms fish. Miners - and those who sell them equipment - strenuously object, claiming dredging actually benefits fish.
The evidence - such as it is - is on Atkinson's side, and he's right: Oregon should put a stop to dredging until thorough research can be conducted.
The issue has come to a head because California has slapped a moratorium on suction dredging while the state Department of Fish and Game completes an environmental review of the effects of dredge mining on fisheries. Miners from California have moved their operations across the border into Oregon, causing a spike in the number of dredging permits and a mini-gold rush along the Rogue and other rivers.
The California review was ordered as the result of a lawsuit by the Karuk Indian tribe against a gold-mining club based in Happy Camp on the Klamath River. When the agency missed a 2008 deadline for completing the study, a judge issued an injunction halting dredging. Gov. Arnold Schwarzenegger then signed a bill imposing the moratorium.
Suction dredging is essentially gold panning with a hemi: A gasoline-powered pump sucks gravel and silt through a 4-inch hose from the bottom of the river and runs it through a sluice to remove the heavier gold particles, then dumps the leftover gravel and silt back into the river.
Gold miners and their supporters argue that the effects of suction dredging are minimal at worst, and at best actually help by stirring up food and creating holes fish use to spawn. Dredging is allowed only in the summer months when no spawning is taking place.
But the information that is available suggests Atkinson and other dredging opponents have reason to be concerned.
A 1998 review by two scientists at the U.S. Forest Service's Pacific Southwest Research Station in Arcata, Calif., said little peer-reviewed research was available, but they urged caution.
"In some situations, the effects of dredging may be local and minor, particularly when compared with the effects of other human activities. In others, dredging may harm the population viability of threatened species," the scientists state. "Fishery managers should be especially concerned when dredging ... precedes spawning runs (e.g., fall-run chinook salmon) soon followed by high flows."
The report recommends that each river basin should be analyzed separately, because the effects of dredging can vary widely.
The scientists wrap up their conclusion with this statement:
"Where threatened or endangered species exist, managers would be prudent to assume activities such as dredging are harmful unless proven otherwise," the report concludes.
That's good enough for us. Stop the dredging and bring on the science.
Read the Forest Service report at www.fs.fed.us/psw/publications/harvey/HarveyLisle.pdf.