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From left, Nick Leonetti and Bill Jones of the Oregon Department of Fish and Wildlife net stunned fish that have been electro-shocked Wednesday night so they can be marked with an elastometer and later counted in a brown trout population survey for Lemolo Lake.
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ENLARGE
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JON AUSTRIA/The News-Review
Oregon Department of Fish and Wildlife biologists on the prowl on Lemolo Lake Wednesday night in the Predator, an electro-shock fishing boat.
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JON AUSTRIA/The News-Review
At center, ODFW fish biologist Evan Leonetti examines a brown trout netted from Lemolo Lake. From clockwise, left, are Nick Leonetti, Sam Moyer, and Justin Miles.
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ENLARGE
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JON AUSTRIA/The News-Review
Justin Miles holds a brown trout netted from Lemolo Lake.
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LEMOLO LAKE — With the shock and awe a Stealth Bomber might dish out, the Predator stalks and stuns trout in the middle of the night on the North Umpqua River’s reservoirs and Diamond Lake.
The electro-shock fishing boat leaves no brown trout unturned. Belly-side up, fish float just long enough for biologists to net them and mark them before release. The markings, after a certain number of outings, give Oregon Department of Fish and Wildlife biologists an estimate of how many trout are in the Lemolo Lake reservoir.
According to Sam Moyers, ODFW’s mitigation biologist on PacifiCorp’s North Umpqua River Hydropower Project, his crew needs to mark about 300 brown trout in the Lemolo Lake reservoir — the highest on the North Umpqua River — before he can calculate their population.
The electro-shock fishing boat leaves no brown trout unturned. Belly-side up, fish float just long enough for biologists to net them and mark them before release. The markings, after a certain number of outings, give Oregon Department of Fish and Wildlife biologists an estimate of how many trout are in the Lemolo Lake reservoir.
According to Sam Moyers, ODFW’s mitigation biologist on PacifiCorp’s North Umpqua River Hydropower Project, his crew needs to mark about 300 brown trout in the Lemolo Lake reservoir — the highest on the North Umpqua River — before he can calculate their population.
For the past three summers, Lemolo Lake has been tormented by blue-green algae blooms that have incited public health advisories from state and federal agencies. It’s currently under one right now, advising people not to swallow or inhale water droplets and to thoroughly clean fish of skin and fat if they eat one.
The blooms are believed to be caused in part by an overabundance of tui chub, a non-native fish that chews away the bottom rung of the food chain and feeds algae with its nitrogen-rich waste, along with other new management criteria for the reservoir.
The blooms are believed to be caused in part by an overabundance of tui chub, a non-native fish that chews away the bottom rung of the food chain and feeds algae with its nitrogen-rich waste, along with other new management criteria for the reservoir.
In 2004, PacifiCorp began pumping from the reservoir more cold water and sending it into the river at the bottom of the dam. A criterion in its relicensing agreement for the hydropower project with multiple agencies, the jettison leaves more warm water on the reservoir’s surface, a pre-condition for algae, and is thought to suck brown trout down the river as well.
All of those factors are thought to wreak havoc on the population of brown trout, a self-sustaining species in the reservoir ever since the mid-1950s when the dam was built. So PacifiCorp bought the Predator, an electro-shock boat with steel cables dangling in the water from poles protruding from the bow, for the ODFW to use during fish-survey operations.
All of those factors are thought to wreak havoc on the population of brown trout, a self-sustaining species in the reservoir ever since the mid-1950s when the dam was built. So PacifiCorp bought the Predator, an electro-shock boat with steel cables dangling in the water from poles protruding from the bow, for the ODFW to use during fish-survey operations.
On Wednesday night, the five-person crew marked 67 large brown trout by injecting a small string of orange latex behind their eyes and under their skin. Not part of the study, 25 small brown trout and 13 rainbow trout were released and 48 tui chub were disposed of.
Two weeks before, the crew had marked about 40 brown trout with green latex.
“I want to see a green mark, guys,” Moyers said halfway into the outing, long after the sun had set and the lake began to steam slightly with the night’s cooling temperatures.
Two weeks before, the crew had marked about 40 brown trout with green latex.
“I want to see a green mark, guys,” Moyers said halfway into the outing, long after the sun had set and the lake began to steam slightly with the night’s cooling temperatures.
Nary a green mark showed up to help with the calculating.
Because Lemolo Lake is stocked annually with rainbow trout — it’s been stocked twice this year and will receive one more stocking before Labor Day — fishery managers get a good population estimate of their numbers by counting them during electro-shock treatments, rather than marking them.
With future outings, however, green marks should show up with orange marks and whatever color is used during subsequent trips for fish-population calculations.
No longer relegated to trap nets, the ODFW can net just about everything in the path of the electro-shock boat. It glides up to banks, or stumpy fields in the shallows, and pulses water with 120 volts of electricity. In the column of water, it stuns everything in about a 20-foot radius.
The stun can send fish roiling to the surface like boiling rice. In turn, the netters become selective and scoop the largest fish. The procedure is simple and highly illegal for lay fishermen. Not surprisingly, it never becomes dull, no matter how long the hunt. So it went for this reporter and photographer.
“The only thing you got to worry about is falling in while it’s hot,” Moyers said.
Because brown trout are predatory and ambush bait fish under the cover of night, the crew begins work at dusk and doesn’t stop until hours after midnight.
“There’s also a lot of ospreys around, so if the trout move in the shallows during the day they get nailed,” Bill Jones, ODFW’s watershed advisor and member of the hydropower mitigation staff, said.
On Tuesday night, Moyers and another crew roamed Diamond Lake with the Predator and turned up numerous rainbow trout with seven golden shiners.
“It was not what I wanted to see,” Moyers said.
Golden shiners are a bait fish, and live bait fish are banned from Oregon waters.
During a routine net-trapping in July, 11 shiners were caught. The catch came less than two years after Diamond Lake underwent a rotenone treatment to eradicate approximately 100 million tui chub.
Since then, however, tui chub have not been discovered in Diamond Lake. Fishery and forestry managers hope to keep it that way.
Though most of the tui chub in Lemolo Lake are large — evidence, some say, that they washed into the reservoir from Diamond Lake via Lake Creek during an eight-foot drawdown of Diamond Lake before its 2006 rotenone treatment — some small ones also showed up at the same time as large brown trout.
“You can’t tell me they’re not in here eating baby tuis,” Moyers said.
By 1 a.m., Moyers decided to call it a night. The live-well had been filled many times with marked fish and the Predator’s gas tank was low on fuel.
The netters at the front of the rectangular, flat-bottom boat let out a resounding “Awww,” with the announcement.
• You can reach reporter Adam Pearson at 957-4213 or by e-mail at apearson@nrtoday.com.
Because Lemolo Lake is stocked annually with rainbow trout — it’s been stocked twice this year and will receive one more stocking before Labor Day — fishery managers get a good population estimate of their numbers by counting them during electro-shock treatments, rather than marking them.
With future outings, however, green marks should show up with orange marks and whatever color is used during subsequent trips for fish-population calculations.
No longer relegated to trap nets, the ODFW can net just about everything in the path of the electro-shock boat. It glides up to banks, or stumpy fields in the shallows, and pulses water with 120 volts of electricity. In the column of water, it stuns everything in about a 20-foot radius.
The stun can send fish roiling to the surface like boiling rice. In turn, the netters become selective and scoop the largest fish. The procedure is simple and highly illegal for lay fishermen. Not surprisingly, it never becomes dull, no matter how long the hunt. So it went for this reporter and photographer.
“The only thing you got to worry about is falling in while it’s hot,” Moyers said.
Because brown trout are predatory and ambush bait fish under the cover of night, the crew begins work at dusk and doesn’t stop until hours after midnight.
“There’s also a lot of ospreys around, so if the trout move in the shallows during the day they get nailed,” Bill Jones, ODFW’s watershed advisor and member of the hydropower mitigation staff, said.
On Tuesday night, Moyers and another crew roamed Diamond Lake with the Predator and turned up numerous rainbow trout with seven golden shiners.
“It was not what I wanted to see,” Moyers said.
Golden shiners are a bait fish, and live bait fish are banned from Oregon waters.
During a routine net-trapping in July, 11 shiners were caught. The catch came less than two years after Diamond Lake underwent a rotenone treatment to eradicate approximately 100 million tui chub.
Since then, however, tui chub have not been discovered in Diamond Lake. Fishery and forestry managers hope to keep it that way.
Though most of the tui chub in Lemolo Lake are large — evidence, some say, that they washed into the reservoir from Diamond Lake via Lake Creek during an eight-foot drawdown of Diamond Lake before its 2006 rotenone treatment — some small ones also showed up at the same time as large brown trout.
“You can’t tell me they’re not in here eating baby tuis,” Moyers said.
By 1 a.m., Moyers decided to call it a night. The live-well had been filled many times with marked fish and the Predator’s gas tank was low on fuel.
The netters at the front of the rectangular, flat-bottom boat let out a resounding “Awww,” with the announcement.
• You can reach reporter Adam Pearson at 957-4213 or by e-mail at apearson@nrtoday.com.
