Sterile Lunker Likely To Improve The Fishing Record Rainbow Calls Attention To Fish Farms

It’s old news that huge rainbow trout have been caught on Rufus Woods Lake. But biologists are still staggering from the piggish size of the Washington state record rainbow caught there last month.

“That was a sterile fish, and I’m astounded at what they can do compared to native fish,” said Ken Williams, Washington Fish and Wildlife Department biologist.

Robert Halverson of Republic caught the 25.45-pound lunker on the Columbia River about halfway between Grand Coulee and Chief Joseph dams on Feb. 23.

“I’ve been fishing there for years,” said Halverson. “The fishing had been pretty slow, but my luck sure changed that day.”

Indeed, the luck of all Washington anglers could change now that biologists are seriously peering into the genes of this abnormal fish.

Williams and other biologists hope to step up their efforts to stock the sterile rainbows in prime fishing waters, such as Aeneas and Chopaka lakes in Okanogan County.

But for now, anglers are intensely interested in Rufus Woods Lake, the Columbia River upstream from Chief Joseph Dam.

Until the last two years, the reservoir has been lightly fished, a perfect hideaway for local anglers such as Halverson, a 57-year-old retired Air Force master sergeant.

The pressure was light for obvious reasons:

Trout limits on Rufus Woods are restrictive - only two a day compared with five upstream on Lake Roosevelt.

Boat access is difficult, with only two public boat ramps - one at each end of the 53-mile-long lake, and one dirt launch in between.

A few years ago, anglers didn’t think much about Rufus Woods because the upper Columbia was still open to steelhead fishing, and they were enjoying sensational catch rates for kokanee, rainbows and other species at Lake Roosevelt.

The deterioration of fishing success at Roosevelt in the past three years has given more anglers reason to explore Rufus Woods.

“There’s more and more fishermen there, even though you have to run a boat about 20 miles upstream or downstream to get to the good fishing,” Halverson said.

He’s referring to one of two areas where commercial fish farms use net pens in the lake to raise sterile trout for sale to restaurants and markets.

Rainbows native to the reservoir are long and slender like steelhead, Williams said. “Rufus Woods isn’t tremendously productive water for trout.”

But fish that occasionally escape from the net pens have been providing a trophy-trout bonanza for anglers, he said.

“These are sterile fish that put all their energy into growth instead of wasting it on forming gonads and eggs,” he said.

The record fish could be the result of a 1995 pen failure that dumped a large number of trout in the lake, said Ed Shallenberger, manager of Columbia River Fish Farms. That was the year after the operation switched from normal hatchery trout to genetically altered sterile fish called “triploids,” he said.

Shallenberger’s net pens are 16 river miles downstream from Grand Coulee Dam.

The triploid fish are well-fed, so they grow to more than 3 pounds in about a year before being shipped to market.

“Fish that escape tend to hang out near the pens, where they can eat feed that goes through the nets, as well as food that’s in the river,” Shallenberger said.

“These fish tend to be short and stocky, so when they get large, they get round,” he said.

Another triploid characteristic is fat around the viscera.

“The record fish had 4 to 5 pounds of fat in its cavity,” said Curt Vail, the state biologist who verified the fish for the records. “That seems to indicate it wasn’t working too hard for its food.”

Halverson said the male fish was so fat, it didn’t put up much of a fight after it was hooked.

Halverson could be playing games in order to protect his lunker fishing hole. He told The Spokesman-Review he caught the record fish roughly 25 miles upstream from Chief Joseph Dam. But he told state biologists he caught the trout while trolling a Rapala in the forebay just above Chief Joseph Dam.

Biologists have documented catches of big trout in both places.

Halverson said his partners caught a 9-pounder and a 12-pounder the same day.

Most of the fishing action has occurred near the two net-pen farms, where anglers can fish from shore as well as by boat.

In addition to Columbia Fish Farms, there’s Chief Joseph Fish Farm, 26 miles downstream from Grand Coulee near Benson Spring.

With the campground at Bridgeport State Park scheduled to open Friday, angler numbers are likely to increase even more on Rufus Woods.

“My experience is that the crowds will come too late for the best fishing,” Halverson said. “The big trout usually bite best in the winter, when it’s cold and few people want to fish.”

He said the big fish already were getting harder to catch two weeks ago. “Later in the spring, you still catch trout, but they’re smaller,” he said.

A huge release of water over Grand Coulee Dam on Tuesday night could be another setback for anglers heading to the lake this week.

“A big spill creates dissolved gases in the water that kill the fish in our pens,” Shallenberger said. “You can bet it kills other fish in the river, too.”

State Fish and Wildlife Department budget shortfalls pose another setback for anglers.

“We were talking with Fish and Wildlife to buy about 100,000 of our sterile fish for them to release in fishing lakes,” Shallenberger said.

“We were going to give them a deal, a buck a fish for 1-1/2-pounders we didn’t want to hold over this year. They liked the idea, but with the budget deficit, I hear the deal’s off.”

, DataTimes ILLUSTRATION: Color photo Graphic: Rufus Woods Lake