Photo courtesy of the Native Fish Society
The Willamette Falls, which feeds into the Molalla River, has seen record numbers of Coho salmon this season.
The Molalla River saw a record wild Coho salmon run this fall that even trumps the numbers seen when hatchery Coho were still stocked in the river.
In the last five to 10 years, the average annual run of Coho salmon over the Willamette Falls has been about 3,000, said Todd Alsbury, District Fish Biologist for Oregon Department of Fish and Wildlife. This year, the count for adult Coho reached 25,000, shattering the record high of 17,902 set in 1970.
The fish are counted as they go through the fish ladder above the Willamette Falls, Alsbury said. Coho are not an indigenous fish to the Willamette and did not use that habitat until a fish ladder was constructed in the late 1800s.
Alsbury said it’s difficult to estimate how many of those fish actually come through the Molalla River, but he said it was likely 20 to 30 percent of the Willamette Falls total.
ODFW stopped stocking hatchery Coho in the 1990s, so the current Coho population is wild, Alsbury said.
“What I find fascinating about it is the previous high was all hatchery fish,” said Russell Bassett of the Native Fish Society.
Alsbury credits the population rise to various factors, but said ocean conditions play a key role and improved greatly after several bad years. Another reason is the habitat had become relatively vacant in the upper Willamette, Alsbury said, because they had stopped stocking hatchery fish where fish were naturally spawning. In addition, fishing limitations have reduced the number of fish being harvested.
“They all kind of combined together to produce a phenomenal run of Coho,” Alsbury said.
In response to the growing population, ODFW increased the bag limit for wild Coho from two to three fish. They also worked with Clackamas County to temporarily open Wagon Wheel Park in Molalla to give anglers access to float the river.
The park has been plagued by vandalism and off-road vehicles in the past, and Alsbury said the county told him they would close down again if those problems returned.
Fishing opportunities were good during the season, Bassett said, especially along Milk Creek. But now that the spawning season is coming to an end, most of the Coho are no longer good to eat.
During the season’s peak, about 900 Coho passed through the falls in one day. In recent weeks, the pace slowed to about 30 to 50 fish a day, Alsbury said.
While the Coho population has been impressive, other fish populations continue to struggle.
Bassett said that while the Coho could be viewed as competition for steelhead, the Coho can also benefit the other fish populations by adding nutrients to the water as they die. Bassett said he hopes winter steelhead numbers are on the upswing and that this year’s population could double from last year, which was the second worst on record.
“The Spring Chinook population is completely in the tank,” Bassett said. “Our native population was pretty well gone by the 1970s. The only ones left are hatchery fish. We’re just not seeing a lot.”
Spring Chinook are the only hatchery fish currently being stocked in the Molalla River. ODFW stocks 100,000 Chinook annually in the Molalla.
“We are going to be potentially changing that program to improve harvest opportunities in the Molalla,” Alsbury said. “Right now the stock that we use is from South Santiam. We’re hoping to change to a different hatchery program to increase the number returning, producing more spawning and producing naturally in the Molalla … We hope that a different stock, perhaps from the Clackamas River, would be more successful.”