This article was published on: 10/24/13 12:00 AM
Combination of circumstances led to hundreds of dead Deschutes trout
By Shelby R. King
Fish biologists believe several “unusual” conditions — including drought, fish migrating out of Wickiup Reservoir and better than average rainfall in recent years — contributed to the stranding of about 3,000 fish last week in a side channel on the Deschutes River upstream of Bend.
About 450 trout — including Redband rainbow trout, a species listed as sensitive by the state of Oregon — 1,220 mountain whitefish and a similar number of sculpin were found in a half-mile stretch of the river near Lava Island southwest of town, according to a news release from Erik Moberly, assistant district biologist with the Oregon Department of Fish and Wildlife in Bend.
“It’s an estimate because it’s difficult to count exactly how many,” he said. “Our estimate is probably low.”
Reductions in water releases from the dam operators at Wickiup Reservoir cause river levels to drop at this time of year. The rate of the reduction in water release rates, called a ramp down, is set each year.
Kyle Gorman, region manager for the Oregon Water Resources Department in Bend, said there are no plans to change ramp-down rates.
“Every year we evaluate inflow and use that to forecast (ramp-down) rates,” he said. “We determine what kind of inflow we see and what levels of reservoir gains we have.”
Two good water years in 2011 and 2012 meant the channel didn’t completely dry up, accounting for more fish remaining in the side channel this year than would normally be there, Moberly said.
“With any natural or manipulated flows in rivers throughout the state we can see events like this,” he said. “This shouldn’t create any long-term threat to fish populations.”
Rain walloped Central Oregon near the end of September after a hot and dry summer. Conditions have since become dry, said Kathie Dello, deputy director of the Oregon Climate Service in Corvallis.
“It’s been a really dry year,” she said.
Moberly said reports of dead fish came in last Thursday afternoon. Friday morning, volunteers and ODFW staff rescued about 750 trout (a combination of Redband rainbow and brown trout) and 500 sculpinfrom the remaining pools.
Kim Brannock, who spotted the stranded fish last week while on a run along the Deschutes River Trail, said she questions the numbers given by ODFW.
The state’s estimate for the number of dead trout is “way too low,” she said.
“They are just trying to downplay everything,” Brannock said.
Brannock, her daughter, husband and neighbor, spent about three hours Friday collecting fish from a dwindling pool off of the Deschutes River. They were helped by Moberly and another ODFW worker.
The ramp-down rate this year occurred at a slower rate than in previous years, Moberly said. A slower rate is considered better for fish. Water and fishery managers suspect the ramp-down rate is not to blame for the stranded fish.
“We’re looking at all the information and will use that to determine water management practices in the future,” Moberly said.
“This shouldn’t create any long-term threat to fish populations.”
— Erik Moberly, Oregon Department of Fish and Wildlife in Bend
— Reporter: 541-383-0376, sking@bendbulletin.com
— Reporter Dylan Darling contributed to this report