State and federal wildlife officials this month are preparing extraordinary measures to protect Chinook salmon returning to spawn in California’s drought-depleted rivers.
Sacramento River fall-run Chinook salmon are making their way upstream from the Pacific Ocean to begin their annual spawning ritual. These fish, primarily produced in hatcheries, make up the most abundant salmon run in California and are the primary catch for an ocean fishery that sustains thousands of jobs.
But the species has had wild population swings over the past decade because of droughts, poor ocean conditions and loss of habitat. Officials are hoping to avoid another wild swing by taking action to help this year’s run, including some measures that have never been tried in California.
At the American River Hatchery near Sacramento, the California Department of Fish and Wildlife is installing water chillers at a cost of nearly $1 million to ensure water coursing through the hatchery doesn’t become lethally warm for salmon and other species hatched and raised there. The chillers, essentially giant refrigeration units, are in place at a few hatcheries around the state but had never before been used on the American River.
And in case Sacramento River flows become too low or too warm, state and federal agencies are considering another new tool: egg injection. In this strategy, salmon eggs would be preserved in a hatchery until river temperatures cool off later this fall, then moved to the river and injected with a hose into gravel beds, where they theoretically would hatch on their own. Egg injection has been successful in Oregon and Alaska but has never been used in California.
Kevin Shaffer, salmon program manager at the California Department of Fish and Wildlife, said egg injection is being “seriously considered.” But it would be used experimentally, not as a broadly applied tool to protect the salmon run.
“We think that’s the best approach, because it’s something really new to California,” Shaffer said. “We could see some significant die-off of natural eggs (due to the drought). But we could also see significant die-off of the injected eggs. We just don’t know.”
The Golden Gate Salmon Association, which represents fishermen, has been pressing wildlife officials to launch the egg injection program. The group’s executive director, John McManus, noted that Sacramento River temperatures at Keswick Dam near Redding are already at 61 degrees, well above the preferred level of 56 degrees, and other tributaries where salmon naturally spawn also are warming up.
“We’re looking at potential loss of an entire generation of naturally spawning fall run,” McManus said.
If that were to happen, it makes survival of hatchery-raised salmon even more important to California’s commercial and recreational fishery, an industry worth about $1.5 billion annually.
The fall preparations are just another chapter in a difficult year. In spring, officials launched their largest-ever salmon trucking operation to move millions of juvenile hatchery salmon downstream instead of letting them swim on their own. The move was intended to protect the fish from predators and warm water. But it is also a gamble, because it may mean the fish fail to “imprint” on their home rivers and won’t find their way back in three years to spawn.
Officials would like to see fall rains arrive early to ease the strain, but that does not seem likely this year. On Tuesday, the National Weather Service predicted Northern California is likely to see below-average rainfall this month, meaning California could be entering a fourth year of drought.
And on Thursday, the U.S. Bureau of Reclamation began reducing water flows in the American River out of Folsom and Nimbus dams. Flows have been near 1,500 cubic feet per second all summer, but by Friday morning were expected to be reduced to 1,050 cfs. Erin Curtis, a Reclamation spokeswoman, said the flow is expected to remain at that level until mid-November.
The aim of the reduced flows is to preserve the cold water that remains in Folsom Reservoir, so it can be used to help the fall salmon run. But several urban areas also depend on that stored water – including Roseville, Folsom and San Juan Water District – and may become even more dependent if fall rains don’t arrive.
Water managers confront a difficult juggling act each fall. Reservoirs often are depleted after the hot, dry summer, leaving relatively little water in storage. Yet they must preserve enough water to release into rivers so salmon can migrate upstream to spawn. That water must be cold, because water temperatures greater than 62 degrees Fahrenheit can be deadly to salmon and their eggs. This conflict is aggravated in drought years.
The water chillers being installed at the American River Hatchery near Rancho Cordova will ensure that water in the hatchery remains cool, even if inflow from the American River is warm. The funding for the chillers comes from emergency drought funds approved by Gov. Jerry Brown earlier this year.
The American River Hatchery is used to breed Lahontan cutthroat trout. Bill Cox, fish production program manager at the wildlife department, said the chiller system also is being designed, if necessary, to serve Nimbus Hatchery, a separate facility next door. Nimbus Hatchery raises fall-run Chinook salmon as mitigation for the construction of Folsom and Nimbus dams, which block hundreds of miles of native salmon habitat.
“If it’s finished in time, it will also be used for incubation of fall-run Chinook salmon,” Cox said. “This year, because of the drought, the water temperature is expected to be a little bit too warm for successful incubation of those eggs. We are racing the clock right now.”
A contractor broke ground on the chiller system Thursday, and Cox hopes it will be operational by mid-November.
In case the chillers aren’t ready, he is making plans to move as much as 4 million Nimbus salmon eggs – half of total production – to other hatcheries on the Mokelumne and Feather rivers, which are expected to have adequately cold water.
One twist this year means American River flows likely will stay higher into November than they might have otherwise.
The Placer County Water Agency is selling 35,000 acre-feet of water to Westlands Water District in the San Joaquin Valley. The price was $325 per acre-foot, or about $11.3 million.
The water, previously held in reservoirs on the middle fork of the American River, will be released from Folsom Reservoir into the Sacramento-San Joaquin Delta. From there, it will be diverted via canal to Westlands, the largest agricultural irrigation district in America.
Water and wildlife officials agreed to delay the transfer until October to provide additional flow for salmon in the American River.
Einar Maisch, director of strategic affairs at Placer County Water Agency, said the transfer is possible because his agency’s American River reservoirs had a surplus available. Even so, Placer County customers have been required to conserve water because they are primarily served by Lake Spaulding on the Yuba River, where there is a shortage of water. Customers also use American River water, but pumping capacity limits how much can be delivered.
“The water sales to Westlands did not in any way diminish water available to our customers,” Maisch said. “We reached a recognition that we have excess water in dry years. And making sure it is released in dry years, so it can provide an environmental benefit in the lower American River, was in everyone’s interest.”