Bull trout bonanza.
COVE PALISADES STATE PARK - Throughout most of the Pacific Northwest, bull trout are so scarce it's against the law to kill a single one.
Here at Lake Billy Chinook, however, big bull trout are so numerous - and so voracious - that anglers may soon be asked to kill more of them, for the species' own good.
The reason? There are signs that the bull trout, known for its size and predatory ability, might be eating themselves right out of its most-hospitable homewaters in Oregon.
"We have an extremely large population - we're a little worried that we're over the sustainable level," said Don Ratliff, a fish biologist for Portland General Electric, which operates the dam behind which Lake Billy Chinook is formed by the waters of the Crooked, Deschutes and Metolius rivers.
PGE agreed to pay for additional monitoring of fish populations in the watershed, after a sharp drop in the number of kokanee spawners was noticed last year.
Kokanee - landlocked sockeye salmon - are the primary food source for bull trout. If the kokanee population crashes, biologists worry that the bull trout population could crash right behind it.
Only 9,419 kokanee adults spawned in the Metolius watershed last year, the lowest number since counts began in 1944. As recently as four years ago, the kokanee spawner count was estimated at more than 555,000 adults.
After gathering more data about the bull trout and kokanee populations, biologists are expected to decide whether to recommend liberalizing the bag limits on bull trout in hopes of reducing the pressure on kokanee.
Currently, anglers in Lake Billy Chinook are allowed to harvest one bull trout per day, with a minimum length of 24 inches.
A bull trout that size typically weighs 6 or 7 pounds, or more. But they get much bigger than that.
Many anglers here say they routinely toss back 7- and 8-pounders in hopes of catching a much bigger one. The state record bull trout, weighing 23 pounds, 2 ounces, was caught here in 1989.
The scope of bull trout fishery at Lake Billy Chinook is difficult to believe, considering how rare the species has become in every other Oregon waterway where it once flourished.
"There's a tremendous fishery here," said Ratliff, who has followed the bull trout's progress for more than 20 years.
"Last year they harvested 500 fish, all trophy-sized," Ratliff said. "Twice that many were caught and released."
Indeed, an Oregon Department of Fish and Wildlife creel survey taken in March and April 2004 shows that 3,061 boat anglers harvested 510 bull trout and released 1,013 legal-sized bull trout.
Another 4,000 bull trout less than the 24-inch minimum were released by anglers.
Ratliff said bull trout "have just gone bananas" as the harvest pressure on them has been reduced over the years.
Juvenile bull trout were the "main beneficiary" of a 1983 regulation change that banned the harvest of all wild trout in the Metolius River, Ratliff said, even though that rule was intended to benefit rainbow trout.
The Metolius and its tributaries - fed by snow melt that seeps thorough deep deposits of porous pumice on the east slope of the Cascades before emerging as springwater - provide the unusually cold spawning and rearing waters that bull trout require.
In 1992, the bag limit on Lake Billy Chinook was reduced from 10 trout per day to five, only one of which could be a bull trout.
In 1998, the 24-inch minimum size provision was added. In addition, a bull trout "staging area" near the mouth of the Metolius was closed to all angling by the Warm Springs Tribe, which controls the Metolius Arm of the reservoir.
As a result of all these protective measures, bull trout numbers have exploded. A record 1,045 spawning "redds" were counted in the Metolius basin fall, compared to only 27 redds counted in 1986.
Biologists estimate that 2,403 adult bull trout spawned last fall. Unlike salmon, bull trout can spawn several times during their lifetime.
"This sort of thing hasn't happened anywhere else," Ratliff said.
"What the bull trout have here is a unique situation with so much good spawning area we're liable to overwhelm the system with 'em."
Steve Marx, the ODFW district biologist in Bend, said bull trout in Lake Billy Chinook "have been a great success story."
"We keep wondering when the population is going to top out, and trying to figure out what the limiting factor will be," Marx said. "Perhaps it's food, perhaps it's habitat."
The decline in kokanee numbers can't necessarily be blamed on the bull trout, Marx said, because kokanee populations are notoriously cyclical.
Kokanee spawner counts in the Metolius were as low as 17,175 in 1995, then shot up to 550,000 in the year 2000.
Still, seeing a low ebb in prey numbers coincide with a peaking of large predator's population has some scientists concerned.
Adding to their worries is that a recent count at a "downstream migrant trap" on the Metolius found juvenile bull trout fry outnumbering kokanee by a large margin.
Creel checkers are weighing and measuring all bull trout harvested this season. Any drop in the weight-to-length ratio could be evidence of a developing food shortage.
The U.S. Fish and Wildlife Service plans to convene an independent scientific panel to review all data regarding the Lake Billy Chinook fisheries.
Should that lead to liberalized bull trout harvest rules, there's no guarantee the situation would change because such a large percentage of the fish caught are released. Remember, creel surveys indicated that two-thirds of all legal-size bull trout caught in 2004 were set free.
And on opening day of the the Metolius Arm fishery this year, creel checker Haley Huntley said anglers reported catching 56 legals "but we saw only 10 fish" because most people were releasing them.
"A lot of people think, `Oh, they're endangered and if you catch one you should definitely let it go,' ' Huntley said. "So part of my job is to educate people that the bull trout are doing quite well - to the point that they're eating all of the other fish species in the lake."
If you want to fish for bull trout, the Deschutes and Crooked river arms of Lake Billy Chinook are open year-round, but the fishery is at its best during March and April. That's when the fish tend to congregate in the Metolius Arm, in preparation for moving into the river as the reservoir water warms.
The Metolius Arm is open to angling March 1 through Oct. 31. In addition to a state fishing license, a Warm Springs Tribal angling permit is required to fish in the Metolius Arm.
The most popular method of fishing for bull trout at Lake Billy Chinook is probably trolling in shallower water close to the shoreline, where the big bulls are looking to gobble up smaller fish. Use large lures - "something that you'd go marlin fishing with," Ratliff suggests.
Big bull trout are easily spooked while in shallow water, however, so some anglers prefer to use electric trolling motors to move quietly while casting and retrieving their lures. Others suggest trolling with a "side planer" so that the lure covers water not churned up by the boat's passage.
This year, however, some Lake Billy Chinook veterans report catching fish where they've never caught them before - right out in the middle of the lake.
As one man put it, "Now they'll go anywhere there's kokanee."
BULL TROUT BASICS
Bull trout are the largest native trout in the Pacific Northwest; the state record is a 23-pound, 2-ounce fish taken in the Metolius Arm of Lake Billy Chinook in March 1989. The world record bull trout was caught in Idaho in 1947; it weighed 32 pounds.
In 1998, the U.S. Fish and Wildlife Service listed bull trout as "threatened" under the Endangered Species Act, triggering protective and recovery measures.
Only four places in the Pacific Northwest - Oregon's Lake Billy Chinook and Montana's Hungry Horse Reservoir and Koocanusa and Swan lakes - boast bull trout populations healthy enough to allow fishermen to target them.
March and April are the peak of the bull trout fishery in Lake Billy Chinook. The limit is one per day with a minimum length requirement of 24 inches.
Large bull trout are thriving in the waters of Lake Billy Chinook near Madras. The lake is the only place in Oregon where's it's legal to harvest bull trout, which are protected under the Endangered Species Act. Bull trout in Lake Billy Chinook are tipping the scales in double digits, including this 14-pounder caught by Kirk Dennis. Brett Dennis / Central Oregon Fishing Mike Stahlberg / The Register-Guard Haley Huntley, a creel checker at Cove Palisades State Park boat ramp, weighs a bull trout. `A lot of people think, `Oh, they're endangered and if you catch one you should definitely let it go.' So part of my job is to educate people that the bull trout are doing quite well - to the point that they're eating all of the other fish species in the lake.' HALEY HUNTLEY CREEL CHECKER
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|Title Annotation:||Recreation; Lake Billy Chinook's protected bull trout thrive, but are they eating themselves out of a home?|
|Publication:||The Register-Guard (Eugene, OR)|
|Date:||Mar 24, 2005|
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