By BROOKE SNAVELY
CENTRAL OREGON DAILY NEWS
Some fish species are on the move due to drought conditions in the upper Deschutes Basin.
Biologists are studying how Deschutes River fish populations respond to changes in water management.
They use electrofishing equipment to collect data and establish a baseline against which they can measure changes over time.
“What we are observing here today are good numbers of both brown and rainbow trout,” said Brett Hodgson, Deschutes district fish biologist for the Oregon Department of Fish and Wildlife. “Earlier this week we sampled further downstream and saw fairly good numbers of large adult kokanee as well as a few brown bull head.”
Another objective is to try to determine the number of fish that leave Wickiup Reservoir and see how they are doing in the Deschutes River.
“Brown bullhead could be a big concern if they got established in the river. They are very opportunistic feeders,” Hodgson said. “Basically, anything they come in contact with they are going to eat. That results in competition with fish species. They could, potentially, be a concern for predation on Oregon Spotted Frogs which also reside in this section of the river.”
Hodgson said whitefish, which are native to the river, are the only species that don’t seem impacted by high summer flows when massive amounts of water are released to farmers downstream, followed by minimal flows in the fall, winter and spring when water is stored in Wickiup Reservoir.
Wickiup Dam was constructed without a fish screen, which means when the water drops like it did this year during the drought, a lot of fish leave through the dam and drop into the upper Deschutes River.
That hurts the kokanee, brown trout and rainbow trout fisheries in Wickiup Reservoir but may help the rainbow trout populations in the river.