ODFW stocks reservoir with ‘perch killers’

By Jayson Jacoby/WesCom News Service June 28, 2013 10:19 am

The Oregon Department of Fish and Wildlife released 25,000 juvenile tiger muskies, each about 5 inches long, in Phillips Reservoir on Tuesday evening. (Oregon Department of Fish and Wildlife)
The Oregon Department of Fish and Wildlife released 25,000 juvenile tiger muskies, each about 5 inches long, in Phillips Reservoir on Tuesday evening. (Oregon Department of Fish and Wildlife)
 

BAKER CITY — The perch killers arrived at Phillips Reservoir under cover of night.

All 25,000 of them.

A truck emptied its cargo of juvenile tiger muskies, a sterile hybrid fish with an insatiable appetite, into the Baker County reservoir Tuesday evening.

Officials from the Oregon Department of Fish and Wildlife hope the voracious tiger muskies will end the nearly 20-year reign of yellow perch in a reservoir that used to be one of the prime rainbow trout-fishing spots in Eastern Oregon.

Since yellow perch were illegally released in Phillips Reservoir, the number of angler visits there has plummeted by about 90 percent, said Tim Bailey, the district fish biologist at the ODFW office in La Grande.

Tiger muskies, a hybrid of the northern pike and the muskie, have helped trout populations recover in several Western lakes that, like Phillips, have been overtaken by perch or other introduced species, Bailey said.

Releasing tiger muskies isn’t the first strategy ODFW has employed at Phillips, which is along the Powder River about 64 miles southwest of Baker City.

For the past five springs, not including 2013, the agency used a net trap to catch several hundred thousand perch.

Trouble is, the agency estimates the reservoir’s perch population at 1.5 million, Bailey said.

And studies have shown that perch procreate so prolifically that they can recover even if as much as half of the population in a particular waterbody is eliminated.

So long as perch is the predominant species in the reservoir, they will continue to outcompete trout for food and habitat.

“Netting has been somewhat successful but not nearly enough to restore the trout fishery, which is our goal,” Bailey said.

And so ODFW now turns to the tiger muskies which, among other advantages over the net trap, are at work around the clock.

The fish were free, too — they were raised at a federal hatchery near Casper, Wyo. Since fish don’t do well in tanker trucks, they made the trip in a single day, which explains their late arrival Tuesday, Bailey said.

Tiger muskies are particularly ill-suited to being confined for the same reason that makes them ideal for dealing with Phillips’ perch predicament: Their appetite.

“They start eating each other,” Bailey said.

Tiger muskies don’t need to grow into their aggressiveness, either — they pretty much hatch with an attitude.

The bunch dumped into Phillips are about 5 inches long, Bailey said.

“But I think they kind of believe that they’re three feet long,” he said. “They’re bold, and will swim up to bigger fish. At this age they might be the ones that end up being the prey.”

Bass, for instance, would probably enjoy a meal of adolescent tiger muskie, Bailey said.

But it’s their ability to be predator, not prey, that makes tiger muskies ideal for Phillips.

Bailey expects the 5-inch fish will immediately start gorging themselves on this year’s crop of perch, which are smaller.

Tiger muskies don’t know the difference between a perch and a trout, of course, so there’s apt to be some collateral damage.

“We’re not saying the tiger muskies won’t eat trout — they will,” Bailey said. “But it’s really a numbers game.”