Water Spills At Grand Coulee To Kill 5,000 Fish At Aqua-Farm

The death toll at an Okanogan County aqua-farm likely will hit 5,000 fish, due to massive water spills over Grand Coulee Dam.

Ed Shallenberger, vice president of Columbia River Fish Farm, predicted last week he’d lose 3,000 of the steelhead he raises to sell to restaurants.

But divers had pulled 4,771 dead fish from the farm’s net pens by the end of the day Thursday. Fewer carcasses are found each day, Shallenberger said, and few of the 170,000 surviving fish show signs of gas bubble trauma.

“It’s an incredible difference,” this week compared to last, he said. “We don’t have any fish (swimming) on the surface,” which is one symptom of the illness.

Shallenberger’s 1- to 3-pound fish started dying April 16, the day after the U.S. Bureau of Reclamation increased water spilling over the dam as a flood control measure.

The rush of churning water super-saturated the river with nitrogen, causing gas bubbles in the fish 16 miles downstream from the dam.

State standards call for nitrogen levels no higher than 110 percent, meaning 10 percent of the gas is undissolved. Readings at the fish farm hit 135 percent on April 16.

The readings have fallen, but still top 120 percent on occasion.

Dam managers say they are sympathetic to Shallenberger’s problems, but can have little control over the spills.

The dam has been ordered by the U.S. Army Corps of Engineers to release water from Lake Roosevelt to make way for a larger than average runoff expected later this spring. Lake Roosevelt is the reservoir above Grand Coulee.

Until the late 1980s, big spills were a spring event most years. A persistent drought made the spills unnecessary for nearly a decade.

The fish farm opened in 1990, so Shallenberger was caught off-guard by this year’s spill.

Shallenberger said Grand Coulee officials have talked with him several times, trying to find ways to spill water without killing his fish.

, DataTimes