Rainbow trout back in North Twin Lake
August 25, 2016
BEND, Ore. – State fisheries managers will stock North
Twin Lake with rainbow trout again after tests indicated the water is
safe for the fish. The lake was chemically treated last fall to remove
unwanted brown bullhead catfish.
Beginning as early as tomorrow morning, 2,500
legal-sized and 1,000 trophy trout will be stocked in the lake.
Additional stocking will occur next month.
“It has been a long wait for anglers to get back out on
the lake to fish,” said Erik Moberly, assistant district fish
biologist. “We appreciate everyone’s support...
The plan was to re-open the lake Jan 1, 2016 and
restock with hatchery rainbow trout in the spring. However, the
treatment didn’t occur until late fall due to late delivery of the
chemical by manufacturers. Once the lake was treated, an early winter
storm arrived and froze the lake; high snow levels prevented access,
delaying efforts to evaluate the effectiveness of the treatment and
test whether the waters were safe to re-stock the trout.
“Rotenone breaks down when exposed to heat and
ultraviolet rays, none of which was available at North Twin until
nearly May,” said Moberly.
Over the last few months local staff have monitored the
concentration of residual rotenone every few weeks through collection
of water samples for lab analysis. As a result of the rotenone
treatment, Moberly believes that brown bullhead catfish population has
The treatment of North Twin comes nearly five years
after the successful treatment of nearby South Twin Lake, where
illegally introduced brown bullhead had also decimated the trout
fishery. Today trout fishing in South Twin has fully recovered.
“We have demonstrated that rotenone projects can
improve trout fishing and increase angler satisfaction,” Moberly said.
“We hope North Twin recovers as well as South Twin.”
Rotenone is often used to remove undesirable fish
species because it is an affordable and effective treatment with little
threat of long-term environmental damage. Rotenone has been approved
as a fish toxicant by the Environmental Protection Agency.
Contact: Erik Moberly, Bend (541)388-6145