Because of the drought, millions of baby salmon from Northern California are about to get a truck ride to the Sacramento-San Joaquin Delta.
The fish, juvenile fall-run chinook salmon, would normally ride the Sacramento River for 200 miles from the Coleman National Fish Hatchery to the Delta, then swim to San Francisco Bay and through the Golden Gate. But because of this year’s critical lack of precipitation, the Sacramento is running low, slow and clear — all conditions that threaten the survival of out-migrating salmon.
The conditions have prompted the U.S. Fish and Wildlife Service to follow through on a provisional plan announced earlier this month to start trucking the salmon from Coleman to the Delta. The service announced today that the first load of this year’s production of 12 million fish will leave the hatchery at 4 a.m. Tuesday and be driven to a holding pen at Rio Vista.
Bob Clarke, regional fisheries program supervisor for the Fish and Wildlife Service, says conditions along the Sacramento would likely be fatal to all the juvenile fall-run salmon that Coleman hatchery would usually release directly into the river. “It could literally be lethal to all the fish released, and none of them would make it out to the ocean,” Clarke said in a recent interview. “That would do nobody any good to release fish at Coleman and have them all perish.”
The outmigrating hatchery fish face a range of hazards in this drought year. The river is clearer than normal because of low flows, and that makes it easier for predators to find the fish. The lack of fresh rainfall and snow melt moving downstream has resulted in higher and potentially deadly water temperatures in the lower Sacramento. And in the Delta, fish can get lost because a channel that’s normally blocked at this time of year to keep young salmon on course has been left open to allow fresh water to circulate more freely.
California fishing groups are happy with the decision to truck the fish past all those dangers. John McManus, executive director of the Golden Gate Salmon Association, says giving the baby salmon a fighting chance of getting to the ocean will help the thousands of Californians who rely on salmon for part of their living.
“This means a lot of families whose major wage earner is in the salmon industry might have a decent year in 2016,” when they return to spawn. “There has been fear on the docks about what awaits us out on the horizon as a result of the drought. People are afraid for their livelihoods.”
A combination of circumstances, including poor river conditions and scarce food for salmon in the Pacific, led to a steep decline in the Sacramento River fall-run chinook fishery. So few fish returned to spawn that commercial fishing off California was shut down entirely in 2008 and 2009 and severely curtailed in 2010. McManus says trucking offers hope of avoiding a repeat of that disaster.
“All of a sudden, it looks a little brighter,” McManus said, “because the federal government moving these fish in a truck means survival numbers will go way up and we’ll see more fish in the ocean two years from now.”
California hatcheries have trucked fish before — in fact, it has become nearly routine for state-run hatcheries like those on the Feather, American and Mokelumne rivers. But as Bob Clarke of the Fish and Wildlife Service points out, biologists see a downside to giving the fish a lift.
He says trucking disrupts the juvenile salmon’s ability to “imprint” on its natal stream, part of the process that’s believed to be vital in guiding the fish back to spawn at the end of their lives.
“So when they come back, because their imprinting process was disrupted, they stray to all the different rivers in the Central Valley,” Clarke said. And that’s a problem because of the potential impact of hatchery-raised fish on the valley’s dwindling stocks of wild chinook salmon.
“One of the obligations the Coleman hatchery has is to minimize the impact on wild stocks,” Clarke says. “We have to try to get our hatchery fish to come back to the hatchery and not mix with wild stocks, crowd them out on spawning grounds, spawn with them. When we truck them, they stray at a much, much higher rate than when we don’t truck them.”