Stanislaus River's salmon eggs lost after dam releases
John Holland
The Modesto Bee
11/27/2011
People working on behalf of Stanislaus River salmon were none too pleased with what happened early this month.
Excessive water releases from New Melones Reservoir resulted in the loss of perhaps 12 percent of the newly laid eggs, fishery consultant Doug Demko said.
"If you're not going to provide the appropriate flows, why spend millions of dollars restoring salmon habitat?" Demko said during a visit to the river Friday.
He is a consultant to the Oakdale and South San Joaquin irrigation districts, which tap the Stanislaus and are under pressure to help rebuild its depleted salmon population.
This was not a matter of a big surge of water washing out the eggs. Rather, Demko said, the high flow forced the river into a side channel that is usually dry. Female salmon laid eggs in the channel, but they were lost when the water receded and the eggs were exposed to the air.
The U.S. Bureau of Reclamation has to balance the needs of salmon with other demands in operating the reservoir, spokesman Pete Lucero said.
They include keeping New Melones fairly high for summer recreation, creating flood-control space in the reservoir to prepare for the storm season, and enhancing water quality in the lower river.
"It's an unfortunate situation," Lu-cero said of the egg loss. "We do the best we can to balance our releases with the demands downstream and the fish."
Salmon used to number in the hundreds of thousands in the Stanislaus and other rivers on the San Joaquin Valley. They dropped to a mere 443 on the Stanislaus in 2007, according to one count by the California Department of Fish and Game.
Environmentalists mainly blame water diversions. Irrigators point to other stresses — water pollution, predation by nonnative striped bass, and conditions in the Pacific Ocean, where salmon live for two to four years before returning to spawn in valley rivers.
The numbers have rebounded slightly the past couple of years, but salmon advocates say much more needs to be done.
Demko said the reservoir operators should have released the water more slowly, allowing the river to stay in its main channel, where salmon could spawn successfully.
The estimate of a 12 percent loss came from an examination of redds — the gravel beds shaped by female salmon to receive their eggs. Demko said his company, FishBio, found 36 "de-watered redds" in a seven-mile stretch from Knights Ferry to east Oakdale.
