Idaho Kokanee Population Declines

The kokanee fishing was crummy last year and this coming season is shaping up to be even worse, according to the Idaho Department of Fish and Game.

“It’s kind of like we’ve taken a step backwards,” said Melo Maiolie, a department biologist.

Kokanee numbers are down dramatically from last year. Biologists estimate the population has dropped 40 percent, plunging the fish back to a population low experienced in the mid-80s.

Maiolie and other fisheries biologists suspect the cause of the decline was the heavy spring run-off last year. The fish may have washed over the Albeni Falls Dam on the Pend Oreille River, or been killed by dissolved gases created by the spill from upstream dams.

“As fish breath that water, it’s like a diver getting the bends,” Maiolie explained.

The decline comes at a poor time for the wildlife agency, which is in the second year of a three-year experiment with the Pend Oreille Lake level.

The U.S. Army Corps of Engineers usually keeps the winter lake level at 2,051 feet, but has kept it at 2,054 feet for the last two years for the sake of the experiment.

Fisheries biologists believe that long-term declines in the kokanee population are due to the loss of gravel spawning beds caused by the dam drawdown. By keeping the lake level higher in winter, the kokanee salmon have 2 million more square feet of spawning beds.

But with so few fish available for spawning, biologists will have a difficult time knowing how effective the dam drawdown is.

“We lost a lot of fry from the first year of the experiment,” Maiolie said. “Each age class declined, so we’ll start this year with a lower number of eggs.”

In the ‘50s and ‘60s, anglers used to pull about one million kokanee from Lake Pend Oreille each year. The numbers started to decline in 1966, when dam operators started drawing the lake down 11 feet each winter.

Now a normal harvest is 200,000 fish. Biologists would like to recover the kokanee so the annual harvest is about 750,000 fish, which would take a population of 3.75 million adult fish, Maiolie said.

, DataTimes