I wrote this article in December 2014. Unfortunately, the Nimbus Fish Hatchery saw its lowest ever return of adult steelhead, 143 fish, this season after I wrote the article. This is undoubtedly the result of low, warm conditions on the American and Sacramento rivers, the consequence of poor management of Folsom, Oroville and Shasta rivers over the past three drought years by the U.S. Bureau of Reclamation and the California Department of Water Resources. Reclamation also cut flows from 1500 cfs to 800 cfs last, imperiling the returning fall Chinook salmon as they return to spawn. This is a great tragedy, since the American is such a precious urban fishery.
The American River, Sacramento’s unique urban fishery, is located in a beautiful parkway that provides a refuge from the insanity of city life. It is my “home river” and first stream I ever fished as a kid and teenager in the 1960s.
In its clear waters I caught my first-ever steelhead, king salmon and legal-sized striped bass anywhere. I have spent thousands of hours since my first trip to the river nearly 50 years ago. Species I have caught, besides steelhead, salmon and stripers, include largemouth bass, bluegill, green sunfish, carp, yellow suckers, pike minnows and one lone smallmouth bass.
I have experienced my best-ever steelhead fishing on this river, even though I’ve fished the Trinity, Smith, Chetco, Eel, San Lorenzo, Klamath, Feather, Sacramento and other renowned steelhead streams.
In addition to fishing on the lower river, I have spent many hours in meetings fighting to restore steelhead and salmon populations to the lower river. However, it is only in recent years that scientists, including as Dr. Robert Titus, CDFW Senior Environmental Scientist, and others have begun solving some of the mysteries of the fish, including the water temperatures and flows that they prefer.
Titus and William Cox, CDFW State Hatchery Program Manager, spoke at the Save the American River Association annual meeting at Ancil Hoffman Park in Sacramento on “The Importance of Water Temperature and the Management of Steelhead Trout and Chinook Salmon” on December 7, 2014.
Before Folsom Dam, salmon and steelhead ascended into North, Middle and South Forks of the American to spawn. As late as 1944, 1945 and 1946, the Department documented spring run Chinook salmon ascending the fish ladder at the old Folsom Powerhouse.
According to studies done on the projected impacts of the dan, the officials determined that an annual production of 430,000 steelhead yearlings and 4 million fall Chinook salmon smolts would be needed to mitigate for the dam.
After just hundreds of the river’s steelhead returned to Nimbus Fish Hatchery in the first few years after Folsom Lake was completed, the DFW introduced Eel River steelhead to the hatchery, boosting annual steelhead returns to the hatchery in the thousands every year. Genetic analyses conducted since then indicate steelhead from both the hatchery and the river are genetically more similar to Eel River steelhead than other Central Valley steelhead stocks.
From the 1950s until the 1990’s the SWRCB Water Rights Decision D-893 provided for only 500 cfs from mid September through December and 250 cfs from January through September 15. There were no temperature requirements.
However, from the 1990s after the Judge Hodge decision, the management of the river entered a new era. The American River operations group was formed, court decisions mandated studies of the river’s salmon and steelhead and the Central Valley steelhead was listed as “threatened” under the Endangered Species Act (ESA) according to Titus.
After studies on juvenile steelhead oversummering begin in 2001, a flow management standard was adopted by state and federal authorities in 2007 and the federal government released the OCAP “biological” opinion for the Central Valley and State Water Project in 2009.
Titus said the basic habitat needs of salmon and steelhead in fresh water are the same – a sufficient flow of cool, oxygenated water and clean gravels for redds. However, flow and water temperatures limit salmon and steelhead production on the American.
There are competing temperature demands between Chinook salmon and steelhead. Juvenile steelhead, while living in the river over the summer, need a daily mean water temperature of 65 degrees F or lower. Titus emphasized that 65 degrees is the limit, not a preferred temperature, with 76 degrees being the lethal temperature for steelhead.
Chinook salmon spawning in the fall need water temperatures below 60 degrees for spawning and 58 degrees for egg incubation.
However, there is limited coldwater pool in Folsom Lake, since Folsom is a relatively small reservoir for the size of the American River drainage.
“The salmon are now spawning a little later, in response to the cold water pool,” said Titus. “It is remarkable that when the water temperature hits 60 degrees, the salmon start spawning in the river, just like a switch was turned on.”
He also documented how steelhead in the lower American River, the ones that anglers like myself love to catch, may be the “fastest growing trout” in the world.
“There is a lot of food in the American – the fish average a growth rate of.82 mm per day. They grow really well,” he said.
He contrasted a slide of steelhead from the American River with one from Secret Ravine Creek, a tributary of Dry Creek. Whereas the American River fish is plump and healthy looking, the fish from Secret Ravine looks skinny and undernourished.
However, the same relatively warm conditions American River steelies encounter every summer have spurred the outbreak, first documented in 2004, of an anal vent disease called “rosy anus”associated with water temperatures of 65 degrees and above.
“We first began to observe these in 2004 at Arden Bar,” said Cox. “We have never seen them in a natural population, although they have cropped up in hatcheries. By October’s end approximately 50 percent of the fish had rosy anus.”
Titus also revealed that about two thirds of the adult population of Chinook salmon, 150,000 salmon died before spawning in 2001.
Cox said, “The same thing happened in 2002 on the Klamath. The fish got crowded in poor conditions and the ich and columnaris parasites proliferated.”
Titus has determined that the American River needs 2500 cfs to accommodate 70,000 spawning adults in the river system. The massive pre-spawning mortality documented in 2004 was a combination of too many fish and not enough habitat.
Titus said 70,000 spawners are forecasted for this fall –and that the optimum flows are at least 2,500 cfs to prevent superimposition of fish on the redds.
The bottom line? We need temperatures of 65 degrees or less at Watt Avenue to protect steelhead,” said Titus. “We also need to enhance the coldwater pool in Folsom Lake to maintain biodiversity of Chinook salmon on the American River. Finally, we need to balance temperature needs of Chinooks and steelhead.”
Since Folsom is a small lake, it will require heightening the dam or changing the operations, said Titus.
Felix Smith, Save the American River Association board member and retired wildlife biologist, said water temperature criteria protective of the various salmonid life stages is missing in the current Folsom/Nimbus Dams and Reservoir operations and permit conditions.
“This is because Westlands Water District wants the water and if they hold back the water in Folsom, it will impact Westlands,” said Smith. “To restore salmon and steelhead on the American, we need to put more pressure on the Bureau of Reclamation to maintain the cold water pool during the summer. Then we need adaptive management during October, November and December to benefit Chinook salmon and steelhead.”