CA says drought killed endangered salmon in Sacramento River
Amid a brutal heat wave and worsening drought, the California Wildlife Agency made a dire prediction in July: “Almost all” of the juvenile population of an endangered salmon species. disappearance was likely to be cooked to death on the Sacramento River in 2021.
This turned out to be true. It is estimated that only 2.6% of the juvenile chinook salmon population returning in the winter survived the hot, dry summer, the State Department of Fisheries and Wildlife said.
The plight of the salmon recovering in winter has profound implications for California’s chronically overexploited water supplies, although recent levels of rain and snow suggest the drought may abate. Environmental restrictions aimed at supporting fish populations could deprive cities and farmers of water deliveries this year.
At the same time, fishermen and conservationists say the pitiful salmon survival rate, among the lowest on record, is a disaster that should have been avoided – and raises questions about the commitment of California and the administration towards the environment.
Regulators, however, said the survival figures reflect the severity of one of the worst droughts on record, as well as other factors.
The massive fish deaths, exposed in a New Years letter to the federal government, came despite warnings that disaster was imminent.
Last spring, the National Marine Fisheries Service said the survival rate could be as low as 12%. Then the Ministry of Fisheries and Wildlife said it could be worse, predicting that “almost all” of the juveniles were at risk.
Environmentalists argue that the mass fish kills were caused by mismanagement of the river by the state and the federal government last spring.
Salmon are disappearing from the wild
Winter-rewind salmon – which actually spawn in the heat of summer in a small part of the Sacramento River in Redding – has been listed as endangered since 1994 by the federal government. Because they only have a three-year reproductive cycle, environmentalists and regulators fear that a single disastrous season could put salmon on the brink of extinction in the wild.
At this point, the winter run is now almost entirely kept alive by workers from the US Fish and Wildlife Service, who collect eggs and sperm from some of the adults who come up the base of Shasta Dam to spawn.
Once hatched, the young fish are reared in refrigerated pens at the Livingston Stone National Fish Hatchery, at the base of the dam.
The other two main Chinook salmon runs in the Central Valley – the fall and spring run – haven’t done much better, and they too are largely supported by hatcheries, said Peter Moyle, fishery scientist. ‘UC Davis.
“It’s a tough time to be a fish native to central California,” Moyle said.
The winter run is the most critically endangered of California salmon populations.
Taxpayers have spent millions of dollars to upgrade the Shasta Dam to free up more cold water for fish, and millions more are spent each year to monitor the water temperature of the Sacramento River and the plight of the Pisces.
Young salmon generally cannot survive when temperatures in the river exceed 56 degrees, and the United States Bureau of Reclamation is supposed to preserve a pool of cool water in Lake Shasta, California’s largest reservoir, to be dumped into the river in summer and early fall.
But last spring, the office shipped hundreds of thousands of acre-feet of water from Shasta 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 release of water.
“This is the inevitable consequence of emptying reservoirs mainly for agro-industry,” he said. “When things are going well, the state does not respect its legal requirements or its principles.”
John McManus, president of the Golden State Salmon Association, also argued that the disaster was due to insufficient protection of the fish.
“They knew they were going to cook the eggs,” said McManus, whose group represents commercial fishermen. “It has everything to do with the management and allocation of water. “
But state and federal officials have said fish kills aren’t just about rising temperatures on the river. Many fish apparently perished because of a thiamine deficiency, or vitamin B1.
The deficiency was caused, ironically, by an abundance of anchovies in the Pacific, said Michael Milstein, spokesperson for the National Oceanic and Atmospheric Administration, a federal agency that tracks salmon struggles in California waters.
Adult salmon have feasted on anchovies, which cause thiamine levels to drop. This was passed on to the miners. Deficiency affects the chances of survival of the young salmon.
“They can’t swim properly,” he said. “They are swimming in circles.
One of the weakest fish survival on record
Even in good times, winter racing struggles 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 rate for 2021 is the lowest recorded since 2005, and is even worse than the 4% depth figure from the last drought in 2015, according to federal figures.
This cold-water fish has developed a unique life cycle that has allowed it to thrive even during the brutally hot summers of the Central Valley. The adults evolved to spawn in the summer in the perennially cold, spring-fed streams 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 the river in Redding, where temperatures regularly rise above 105 degrees in the summer.
Only cold water released from the bottom of California’s largest reservoir keeps eggs and young fish alive.
For much of the past decade, state and federal officials have discussed plans to catch, transport and release fish in the McCloud River, then recapture juveniles as they attempt to descend before entering the reservoir.
The McCloud, one of the tributaries of Lake Shasta, 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 young fish before entering the lake, but it was never deployed in the McCloud.
The Trump administration has delayed the project that the Obama administration originally proposed. At one point in 2019, the Trump administration ordered the state to remove equipment from federal property, facing the threat of jail time.
Instead, the Trump administration focused on a plan that would raise the Shasta Dam. The administration argued that an additional 18½ feet of space would increase the amount of cold water in the lake, which would help fish trying to spawn under the dam.
Raising the dam to increase the capacity by an additional 634,000 acre-feet of storage space – about two-thirds of the capacity of Folsom Lake – would also increase the water supply for irrigation and urban use.
The project to raise the dam was fiercely opposed by the California authorities. While the project is still technically alive, water policy experts say the Biden administration did drop it.