Counting Salmon On The Stanislaus River
Salmon have spawned this fall in the Stanislaus River in numbers not seen in three decades – 11,629 of them as of Monday by one count – but the outlook is worse to the south.
The Tuolumne River had an estimated 350 fish Monday. The Merced River was at about 800 late last week. Both streams have had much less water released from upstream reservoirs during the spawning than the Stanislaus.
“We’re nearing the end of the run and it’s looking pretty bleak,” said Peter Drekmeier, policy director for the Tuolumne River Trust.
Concern about the chinook salmon has reduced water diversions to farms and cities in recent decades. The supplies could drop even more if the fish’s long-term prospects do not improve.
Salmon hatch in rivers up and down the Central Valley, then spend a few years in the Pacific Ocean before returning to reproduce and die. Along the way, they face reduced flows, high temperatures, non-native predators, degraded spawning gravel and other challenges. Add to that a four-year drought that has further strained the habitat.
“Water is extremely limited this year, and we’ve been trying to make what water we have work well for fish,” said Rhonda Reed, branch chief at the National Marine Fisheries Service for the San Joaquin River and its tributaries.
Salmon numbers in the San Joaquin Valley are relatively small compared with the Sacramento Valley, but they nonetheless approached 70,000 in 1985. The spawners that year included many that were born in a two-year stretch of very wet weather.
Reservoir managers have to release minimum amounts to help lower-river fish at key points in their life cycle. The amounts are relatively low on the Tuolumne and Merced, but that could change in future years under new federal licenses for hydropower, along with state mandates.
Releases on the Tuolumne peaked this fall at 183 cubic feet per second as measured at La Grange, according to the California Department of Water Resources. The peak for the Merced, as measured at Snelling, was 589 cfs.
The Stanislaus ran as high as 1,335 cfs, as measured east of Oakdale at the Orange Blossom Bridge. It has higher flow minumums because it is part of the federal Central Valley Project, along with supplying the Oakdale and South San Joaquin irrigation districts. This fall, the districts boosted the river with water being sold to distant farmers by way of the Sacramento-San Joaquin Delta. The sale drew fire from critics who said it was not approved in the open, but the results for salmon look favorable.
The 11,629 fish were tallied at a weir operated by Fishbio, a consulting firm with an office in Oakdale. Spawning will continue further into December, so the number could approach the 13,473 recorded for all of 1985 by the California Department of Fish and Wildlife.
The fish spawn in about 25 miles of the Stanislaus from Riverbank to Goodwin Dam. Last week, The Modesto Bee got a look at the upper end of that range with Domenic Giudice, an environmental scientist with the state agency.
“This is good habitat,” he said of a stretch just east of Knights Ferry. “We just added gravel. The water temperatures are right. It’s fresh out of the dam. Velocities are high.”
Their power and determination are amazing, They’re going to fight to spawn and then lay down and die. It’s a pretty impressive life.
Domenic Giudice, state Fish and Wildlife
Giudice and his co-workers estimate the numbers in part by counting the carcasses of fish that died soon after spawning. They take specimens that go to their La Grange lab to determine the age and native stream. They then chop each fish in half with a machete so they do not count it twice.
What looks like a rotting mess is a source of food for raccoons, foxes, vultures and other riverside wildlife —including insects that will be eaten by young salmon next spring.
“It’s a very gruesome representation of the circle of life,” Giudice said.
Earlier this fall, Stanislaus water temperatures were too high for spawning, but that has improved, said Fishbio senior biologist Andrea Fuller in an email.
“However, there is not enough room for all of the fish to spawn in the Stanislaus River, and we are seeing fish spawning on top of each other,” she said. “When a salmon creates a new nest on top of an old nest, the old nest is destroyed.”
Reed, with the federal fishery agency, said that could be solved by increasing the Stanislaus habitat. She also said the Merced spawning, while still low, is an improvement. It is the only one of the three rivers with a hatchery to supplement the wild salmon.
The fish on the Merced and Tuolumne also contend with water hyacinth, a non-native weed that has clogged the lower rivers and parts of the Delta during the drought. The Stanislaus, with its higher flows, has not had a problem.
Water suppliers contend that greatly increased flows are not the answer for salmon. They call for gravel replenishment and other habitat improvements, suppression of striped bass and other nonnative predators, and cleanup of tainted rivers.
The suppliers include OID; SSJID; and the Modesto, Turlock and Merced irrigation districts. Their farmers say they use much less water than before, but environmentalists would like to see even more conservation.
“I do think that through water use efficiency, we could have a thriving agricultural economy while reviving the Tuolumne,” said Drekmeier at the Tuolumne River Trust.
The salmon industry also seeks increased flows on Central Valley rivers to help the little fish that will become the big fish it catches off the coast.
The Golden Gate Salmon Association projects that healthy conditions could generate $5.4 billion in annual economic activity in California, compared with $1.4 billion now, Executive Director John McManus said. It sees the potential for close to 100,000 jobs, including commercial and sport fishing, boat and gear suppliers, and other businesses.
McManus, based in Petaluma, said the total rises by about 50 percent if it includes the part of the Oregon coast where Central Valley salmon swim.
The eggs laid by female salmon this fall, then fertilized by the males, will produce juveniles that will head out to sea in the spring. They could be helped along by reservoir releases, or by strong natural runoff if El Niño continues to bring storms to California.
Longer-term efforts could help, too, such as at Dos Rios Ranch, where the Tuolumne meets the San Joaquin and natural floodplain is being restored. Drekmeier said the food and other conditions could help young salmon grow fast and be ready for the hazards of the Delta and Pacific.
Giudice, the state fish expert, also talked about the prospects as he searched for salmon carcasses near Knights Ferry.
“Their power and determination are amazing,” he said. “They’re going to fight to spawn and then lay down and die. It’s a pretty impressive life.”
John Holland: 209-578-2385