Wildlife officials on Tuesday formally launched a massive trucking operation to move 30 million Sacramento River salmon toward the sea to help the fish avoid harmful river conditions caused by drought.
Tuesday’s operation transported about 400,000 juvenile salmon, each about 3 inches long, in three climate-controlled tanker trucks from Coleman National hatchery near Red Bluff to floating pens in the Sacramento River near Rio Vista.
About 240 such truck trips are expected over the next 10 weeks from five state and federal salmon hatcheries in the Central Valley. Officials said the operation is unprecedented: They could not recall another time when so many juvenile salmon were transported by truck in such a short period of time.
“This is a real unusual situation, and it requires us to take immediate and unusual action,” said Howard Brown, Sacramento River branch chief of the National Marine Fisheries Service. “If we don’t take immediate action, we run the risk of perhaps losing an entire year-class of salmon.”
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The goal is to save the salmon from low river flows, warm water and greater exposure to predators – all induced by the worst drought to strike California in 40 years. Although rain is forecast for this week, officials said it would not be nearly enough to avoid harm to salmon if they were released at the hatcheries, which is the usual practice.
These hatchery salmon are the foundation of a $1.4 billion commercial and recreational fishing industry in California that supports about 23,000 jobs.
“If we didn’t truck these salmon, under these drought conditions we believe we would likely lose them all,” said John McManus, executive director of the Golden Gate Salmon Association, which represents commercial and recreational fishermen and has been urging officials since December to prepare a trucking plan.
Every fall-run Chinook salmon produced at the five hatcheries in the Central Valley will be moved. In addition to Coleman hatchery on Battle Creek, which is operated by the U.S. Fish and Wildlife Service, the trucking operation involves four hatcheries operated by the California Department of Fish and Wildlife: Feather River Hatchery, Nimbus Hatchery on the American River, Mokelumne River Hatchery and Merced River Hatchery.
The fish travel by tanker truck more than four hours, avoiding about 200 miles of challenging river habitat, before reaching the Rio Vista waterfront. The trucks stop several times along the way to ensure the enclosed tanks – which resemble a small milk transport truck – are operating properly and to check on the welfare of the fish. On Monday, one of the first tankers had to turn back to Coleman Hatchery because its onboard aerator was operating intermittently.
“This is a herculean effort between state and federal agencies to try to stave off a fisheries disaster,” said Stafford Lehr, fisheries branch chief at the California Department of Fish and Wildlife. “Our fish right now are undergoing extreme duress due to the drought.”
Fishery experts normally release salmon into rivers at the hatcheries so the fish can imprint on that location and find their way back from the ocean as adults, in three to four years, to spawn another generation of salmon. They acknowledged many of the salmon might not find their way back due to the trucking operation, but that trucking gives the population better odds this year.
The fish normally take about three weeks to travel 270 miles downriver on their own from Coleman hatchery. In comparison, the truck trip exposes them to dramatic changes in water temperature and chemistry in just a few hours – a disorienting experience that can make them vulnerable to predators. That’s where the net pens come in.
At the Rio Vista site, a former Army installation along the Sacramento River, the tanker trucks back down a slope to a pier. The truck connects to a 10-inch diameter aluminum tube, which shoots the salmon across the pier into one of three white net pens suspended in an aluminum pontoon barge. The nets hang down into the river itself, so the fish can adjust to the new water environment while safely protected from predators.
Boats tow the barge slowly downriver for two to four hours. Then the pens are opened on an outgoing tide, allowing the salmon to continue their downstream migration to the sea on their own. The net pens and barging operation is handled by the Fishery Foundation of California, a nonprofit organization.
Officials chose the Rio Vista location because the young salmon, called smolts, aren’t big enough yet to maneuver in the strong currents of San Francisco Bay. It is also hoped that this location in the Delta will help them imprint on the Sacramento River.
The rest of this year’s salmon crop is still at the hatcheries waiting for a truck ride. As some of these fish wait, they will continue growing larger. When they reach a minimum of 4 inches long, they will be trucked a little farther, to Mare Island in Vallejo, and then released into net pens in San Pablo Bay.
Plans are also in the works to assist winter- and spring-run Chinook salmon, which are protected by the Endangered Species Act. The National Marine Fisheries Service and U.S. Bureau of Reclamation plan to expand holding capacity at Livingston-Stone Hatchery, located at Shasta Dam, and bring in water chillers. Winter-run salmon will be trapped from the Sacramento River and transported to the hatchery to help them survive as temperatures warm up in the weeks ahead, Brown said.
The fisheries service is also looking for places to transport the fish where in-stream temperatures will remain cool. And it is working with the State Water Resources Control Board, which regulates water rights, to prioritize streams where water diversion curtailments might be ordered to ensure enough water flow for fish.
“We are looking at the potential for a full year-class failure of winter-run salmon,” Brown said. “We’re trying to plan for a worst-case scenario.”