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The Spawn is On

by Greg Stahl
Idaho Mountain Express, April 29, 2005

Steelhead season comes to a close

Female steelhead trout are killed to extract eggs from their bellies. At the Sawtooth Fish Hatchery south of Stanley, Randi Hufford collects eggs and deposits them in buckets. On Thursday morning, Roger Elmore made life happen.

As assistant manager of the Idaho Department of Fish and Game's Sawtooth Hatchery, it was Elmore's job to mix eggs and sperm, called roe and milt, from steelhead trout that returned to the Sawtooth Valley from the Pacific Ocean.

As he poured a Dixie cup of milt into a bucket of eggs, he also squirted water from a hose. The water helped trigger fertilization.

"This is where the birds and the bees are," he said. "Fertilization takes place in less than a minute."

By late this week, 1,400 steelhead returned to the weir at the Sawtooth Hatchery on the Salmon River, approximately 45 miles north of Ketchum. Thursday morning, biologists removed 141 of the anadromous fish from the hatchery's trap, and 50 were processed for fertilization the same day.

Fish and Game biologists estimate that each female carries about 4,500 eggs, meaning up to 225,000 eggs were fertilized on Thursday.

Elmore's work was the last stop on an anadromous assembly line, in which steelhead trout are trapped and then separated into raceways according to their sex. Females are clubbed and gutted to remove the roe. The bellies of males' are massaged to extract milt.

After fertilization is complete, the fertilized eggs are taken to an incubation building. About 50 days after fertilization, the eggs become "eyed," which means the egg contains an embryo that has developed enough so the eyes are visible through the egg membrane.

From fertilization to the eyed-egg stage, success rates hover between 85 percent and 88 percent, Elmore said. From the eyed-egg stage to the smolt stage, success drops another 15 percent.

Steelhead are an anadromous breed of rainbow trout. They spawn in freshwater streams but live most of their lives in the Pacific Ocean. The fish returning to Central Idaho this spring entered the Columbia River last summer or fall. The fish winter in the river system, usually downstream from the city of Salmon.

Steelhead, unlike anadromous salmon, don't die after spawning, but hatchery fish are nonetheless killed. Despite the fact that steelhead live on following their spawning activity, the 900 miles between upper Salmon River steelhead spawning habitat and the Pacific Ocean makes multiple spawning trips unlikely.

The Sawtooth Hatchery, the farthest anadromous fish hatchery from the Pacific Ocean, is the destination for steelhead that were naturally born or released by Fish and Game in the Sawtooth Valley.

Historically, thousands more wild steelhead returned to the valley each year. Now, very few of the upper Salmon River's wild steelhead remain, with only 19 unmarked (potentially wild) fish returning so far this year.

Fish and Game's steelhead hatchery program is intended to maintain populations for sport fishing, said Sawtooth Hatchery manager Brent Snider. Chinook and sockeye salmon hatchery programs, he pointed out for comparison, are conservation-oriented.

Breeding and raising fish is a fairly lengthy and complicated process. Thursday, nearly each step of the steelhead breeding and rearing process was evident in the Sawtooth Hatchery's operations.

When fish reach the hatchery's weir, which prevents any more upstream migration, they instinctively swim upstream and climb a fish ladder, entering a holding pond. The fish are sorted and processed each Monday and Thursday during the season. It's a process hatchery personnel call "moving" fish.

Moving fish consists of collecting eggs and sperm, fertilizing eggs, placing the fertilized eggs in incubation trays, raising young fish’Äîcalled smolts’Äîand returning smolts to the wild river system when they're about 1 year old. Between incubation and the age of 11 months, steelhead are raised in separate, warm-water hatcheries, primarily at the Hagerman Hatchery in the Hagerman Valley.

On Thursday, 1-year-old steelhead were returning to the Sawtooth Valley from Hagerman in large silver tanks towed by trucks. The tanks each hold about 20,000 fish. Once in the river system, it takes the smolts less than a week to make it to the slack water behind Lower Granite Dam, the first of eight reservoirs they will encounter. After that, their progress slows considerably.

Steelhead spawning will conclude this week, about the same time the steelhead sport fishing season ends. The migration generally ends about the time the spring runoff begins to really pump, Snider said.

"Usually we have to shut down the trap because of high water about the first week of May," he said.

For Twin Falls resident Gary Woodland, steelhead fishing has been an Idaho pastime for 20 years.

"Some years you catch 'em; some years you don't," Woodland said. His rod leaned against a tree, and he sat in a lawn chair next to a fire near the confluence of Redfish Lake Creek and the Salmon River.

Woodland fished the Salmon River all week. He said he saw a handful of fish but caught none. Fishing, however, is only part of the reason to be there.

"If I catch fish, it's just a bonus," he said.

Greg Stahl
The Spawn is On
Idaho Mountain Express - April 29, 2005

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