Stanislaus River Trout Numbers Decreasing

Photo by user Leonard G./Wikimedia
Photo by user Leonard G./Wikimedia

As we mentioned earlier this week with San Luis Reservoir’s water level woefully low, other waterways in California are struggling as well. The Union Democrat of Sonora has a disturbing report about the Stanislaus River, one of the Valley’s most important rivers, and its trout population.

Here’s reporter Guy McCarthy with some of the depressing details:

Rainbow trout in the Stanislaus River declined 75 percent last year due to drought and warm pulse flow releases from New Melones Dam, a consultant for two water districts said Tuesday.

“If anything, the flows have done more harm than good because we depleted the cold water storage at New Melones,” Andrea Fuller, operations manager for FishBio, said while snorkelers worked in shallows of the Stanislaus to look for scarce trout.

Staff members in wetsuits and snorkel gear surveyed a 59-yard-long pool section of the shallow river upstream from the Sonora Road bridge Tuesday and found one adult trout, 11 inches to 12 inches long, FishBio data collector Colleen Moore said.

“Trout need cool water to survive, not warm,” Fuller said. “Warm water in the river has caused the trout population to decline from an average over six years to about 5,000. It’s a combination of the drought and management decisions that contributed to declining trout populations.”

From Knights Ferry to the confluence with the San Joaquin, trout share the Stanislaus River with salmon, carp, crappie, bass and other species. Fishermen are told that trout and salmon are protected.

“We had a record number of salmon return from the ocean last fall, about 13,000, the highest number in 30 years” Fuller said. “But salmon need cold water too, to spawn, make nests and keep the population going. Cool temperature water is requisite, crucial for these fish.”

The salmon stats are promising, of course, but that’s a drastic drop in trout and something to be concerned about.