Amid a brutal heat wave and a worsening drought, California’s wildlife agency made a dire prediction in July: “Nearly all” of an endangered salmon species’ juvenile population was likely to be cooked to death on the Sacramento River in 2021.
It turned out to be true. Only an estimated 2.6% of the winter-run Chinook salmon juvenile population survived the hot, dry summer, the state Department of Fish and Wildlife said.
The fate of the winter-run salmon has profound implications for California’s chronically overtaxed water supplies, even as recent rain and snowpack levels suggest the drought might be easing. Environmental restrictions aimed at propping up the fish populations could deprive cities and farmers of water deliveries this year.
At the same time, fishermen and environmentalists say the salmon’s pitiful survival rate, among the lowest on record, is a disaster that should have been prevented – and raises questions about California’s and the Biden Administration’s commitment to the environment.
Regulators, however, said the survival figures reflect the severity of one of the worst droughts ever, as well as other factors.
The massive fish kill, unveiled in a New Year’s Eve letter to the federal government, came in spite of warnings that a catastrophe was coming.
Last spring the National Marine Fisheries Service said the survival rate could be as low as 12%. Then the Department of Fish and Wildlife said it could be worse, predicting that “nearly all” of the juveniles were at risk.
Environmentalists argue the massive fish kill was caused by state and federal mismanagement of the river last spring.
Salmon are disappearing from the wild
The winter-run salmon – which actually spawns in the heat of summer in a small stretch of the Sacramento River in Redding – has been listed as endangered since 1994 by the federal government. Because they have just a three-year spawning cycle, environmentalists and regulators fear a single disastrous season could put the salmon on the brink of extinction in the wild.
At this point, the winter-run is now almost entirely kept alive by workers at U.S. Fish and Wildlife Service, who collect eggs and sperm from a few of the adults that make their way up the base of Shasta Dam to spawn.
After they’re hatched, the young fish are reared in refrigerated holding pens at the Livingston Stone National Fish Hatchery at the base of the dam.
The other two main Central Valley chinook salmon runs — the fall and spring run — haven’t been faring much better, and they, too, are largely propped up by hatcheries, said Peter Moyle, a fisheries scientist at UC Davis.
“It’s a difficult time to be a native fish in central California,” Moyle said.
The winter-run is the most critically endangered of California’s salmon populations.
Taxpayers have spent millions of dollars retrofitting Shasta Dam to release more cold water for the fish, and millions more are spent annually monitoring the temperature of the Sacramento River’s waters and the plight of the fish.
The young salmon generally can’t survive when temperatures in the river exceed 56 degrees, and the U.S. Bureau of Reclamation is supposed to preserve a pool of cool water in Shasta Lake, the largest reservoir in California, for release into the river in summer and early fall.
But last spring the bureau shipped hundreds of thousands of acre-feet of Shasta’s water to farmers with special water rights, said Doug Obegi, an attorney with the Natural Resources Defense Council. Obegi said the State Water Resources Control Board, which oversees water rights, should have prevented this early water release.
“This is the inevitable consequence of draining the reservoirs primarily for agribusiness,” he said. “When push comes to shove the state does not live up to its legal requirements or its principles.”
John McManus, president of the Golden State Salmon Association, also argued that the disaster was caused by insufficient protection for the fish.
“They knew they were going to cook the eggs,” said McManus, whose group represents commercial fishermen. “It has everything to do with water management and allocation.”
But state and federal officials said the fish kill wasn’t simply a matter of temperatures rising on the river. Many of the fish apparently perished because of a deficiency in thiamine, or vitamin B1.
The deficiency was caused, ironically, by an abundance of anchovies in the Pacific, said Michael Milstein, a spokesman for the National Oceanic and Atmospheric Administration, a federal agency that tracks the salmon’s struggles in California’s waters.
Adult salmon have been feasting on anchovies, which cause a breakdown in thiamine levels. That was passed along to the juveniles. The deficiency hurts the young salmon’s survival chances.
“They can’t swim right,” he said. “They swim in circles.”
Fish survival among the lowest on record
Even in good times, the winter-run struggle to survive. Since 2005, the highest recorded survival rates were 49% in 2011 and 44% in 2017 – two extremely wet years.
The 2.6% survival for 2021 is the lowest recorded since 2005, and is even worse than the 4% figure from the depths of the last drought in 2015, according to federal figures.
This cold-water fish evolved a unique life cycle that allowed them to thrive even in the Central Valley’s brutally hot summers. Adults evolved to spawn in the summer in the perpetually cold spring-fed creeks above what is now Shasta Dam.
When the dam was completed in 1945, it effectively forced the population to spawn in a short stretch of river in Redding, where temperatures regularly top out at over 105 degrees in the summer.
Only the cold water released from the bottom of California’s largest reservoir keeps the eggs and young fish alive.
For much of the last decade, state and federal officials have discussed plans to capture, truck and release fish into the McCloud River and then re-capture the juveniles when they attempt to swim back down before they enter the reservoir.
The McCloud, one of Shasta Lake’s tributaries, is a river fed by frigid natural springs.
Similar “trap and haul” programs have been used in the Pacific Northwest.
California water officials began building a floating device that would capture the young fish before entering the lake, but it’s never been deployed in the McCloud.
The Trump administration delayed the project the Obama administration had originally proposed. At one point in 2019, the Trump administration ordered the state to remove the equipment from federal property, under the threat of jail time.
Instead, the Trump administration focused on a plan that would raise Shasta Dam. The administration argued that an extra 18½ feet of space would increase the amount of cold water in the lake, and that would help the fish trying to spawn below the dam.
Raising the dam to increase capacity by an extra 634,000 acre-feet of storage space — about two-thirds the capacity of Folsom Lake — would also increase the water supply for irrigation and urban use.
The plan to raise the dam was fiercely opposed by California officials. While the project is still technically alive, water policy experts say the Biden administration has effectively tabled it.