Coho Salmon Run Sets Modern-Era Record on Clackamas River

Portland General Electric, which owns and operates the North Fork Dam, says more salmon are returning because the utility has increased the number of juvenile salmon that make it past the dam and into the ocean.

While Oregon’s salmon runs are so depleted by drought that the governor is seeking a federal bailout for fishermen, there is a silver lining along the Upper Clackamas River.

A record number of adult, early-run coho salmon returned to the Upper Clackamas River by Nov. 9 this season. Nine thousand fish made it past the North Fork Dam, the highest number recorded since the dam was built and record collection started in 1958.

Portland General Electric, which owns and operates the dam, says more salmon are returning because the utility has increased the number of juvenile salmon that make it past the dam and into the ocean.

“Survival rates through the bypass pipeline are around 99%, and collection rates are among the highest in the region, if not the world,” says Garth Wyatt, PGE’s senior fish biologist. “Using our new facilities, the time that it takes juvenile coho to pass the dams was reduced from as many as 12 days down to only two and half hours.”

That’s because of new innovations made to the dam, especially a floating surface collector in North Fork Reservoir that “captures more than 90% of oceangoing juvenile fish in the reservoir.” The system relies on a pipeline for fish to maneuver past the dam—as opposed to using transport or trucking like other dams in the region.

“This allows coho to arrive in the Lower Willamette River a bit earlier in the spring,” a Portland General Electric press release, “when water temperatures are cooler and predators are less active, increasing their odds of survival to the ocean.”

By Tori Lieberman