Baby Chinook salmon from the Central Valley of California often swim far downstream to the ocean to survive into the next stage of life. This year, they will receive a helping hand in the form of a fleet of tanker trucks that will carry nearly 17 million fish to sea.
It is all part of a series of steps in western states to prevent tens of millions of endangered salmon from suffering in a year of historic drought for the region.
This isn’t the first time wildlife managers have transported salmon downstream, but this year drought is drying up rivers earlier than usual and making them too hot for salmon to survive. That means the giant tanker trucks, which travel 50 to 100 miles downstream to the coast around San Francisco, are a lifesaver.
“The California Department of Fish and Wildlife is using the lessons learned from the last 15 years or more of salmon releases and the last drought to maximize the success of the releases,” said Jason Julienne, Central Region Hatchery Supervisor. North. in a sentence. “Transporting young salmon to downstream release sites has proven to be one of the best ways to increase survival in the ocean during dry conditions.”
Other parts of the west coast are also experiencing a severe drought that is affecting salmon populations.
In Oregon, biologists from the Yurok tribe found that 70% of juvenile Chinook salmon caught in a spinning screw trap for evaluation were dead, something they say is extremely abnormal. The cause was a lethal pathogen, C. shasta, linked to low water levels and higher temperatures. By mid-May, 98% of the salmon tested by the tribe were seriously infected with the pathogen.
“We’re seeing a massive fish kill unfold in real time,” said Yurok Fisheries Department Director Barry McCovey, a Yurok citizen who has studied fish diseases in the Klamath for more than two decades. in a sentence.
McCovey added: “The death of juvenile fish will limit salmon production for many years. It will also negatively affect many other native species, from killer whales to ospreys, because salmon plays an essential role in the overall ecosystem. “
In California, the trucking operation means that approximately 20% more salmon from Central Valley rivers will take wheels rather than fins to travel downstream, with a total of 16.8 million fish mounted on 146 temperature-controlled trucks. between April and June. The typical Chinook life cycle takes them from rivers to ocean and back over the course of three years.
Two Chinook salmon populations are considered endangered on the West Coast, and seven are considered threatened under the Endangered Species Act, according to the National Oceanic and Atmospheric Administration. Sustained drought conditions can spell disaster as well, as fish rely on cooler water to keep their eggs viable. During the drought of 2014 and 2015, because the levels were so low, the water was released from Lake Shasta rose to a temperature which killed almost all juvenile Chinooks.
California is in the middle of its fourth-third hydrological year in state history, with most reservoirs at less than 50% of full capacity, and some rivers flowing at only 30% of their average rate this spring. Higher temperatures also mean that rain is more likely to evaporate before hitting the ground.
Commercially and recreationally caught salmon generates more than $ 900 million in economic impact annually for California, according to the state Department of Fish and Wildlife. The cost of bringing salmon to fish transport can exceed $ 800,000, but the effort could save many of the 23,000 jobs related to the fishing industry.