This summer, for the first time in its 55-year history, Iron Gate Fish Hatchery will not release young salmon into the Klamath River.
Hatchery management cited the river’s exceptionally poor water quality and heightened fish disease risk as reasons for keeping hatchery smolts in captivity until conditions improve in the fall.
Over the past two weeks, the California Department of Fish and Wildlife has trucked more than a million smolts to two other hatcheries in the Klamath watershed, where they will continue to be looked after through the remainder of the summer. Once the Klamath River cools and the threat of salmon disease wanes, CDFW will return them to Iron Gate and release them.
The decision comes on the heels of a staggering juvenile fish kill on the mainstem Klamath River that began in May. At one point, as many as 97% of sample salmon captured by fishery biologists from the Yurok Tribe were infected with the parasite C. shasta, and many of them were already dead.
The hatchery normally releases its smolts in the early summer, which in many years has coincided almost perfectly with the parasite outbreak. The fish swim right through the infectious zone below Iron Gate Dam, picking up C. shasta spores released by massive colonies of annelid worms that carpet the riverbed. Salmon disease specialists have long bemoaned the practice, which can actually exacerbate the outbreak by providing the parasite with more fish hosts to infect.
This year, however, the hatchery has responded to the river’s severe drought conditions by waiting to release the fish.
“It really was the best idea to just not release the hatchery fish into the river system, because it would’ve been almost futile,” said Mark Clifford, an environmental scientist with CDFW.
Clifford said a salmon migration model run by the U.S. Fish and Wildlife Service, which takes into account the river’s temperature and the number of C. shasta spores present per liter of water, predicted high mortality for the hatchery fish if they were released according to normal protocol.
“They’re estimating the survivability of some fish, and it wasn’t good,” he said.
But because the smolts will only grow as the summer progresses, Iron Gate Hatchery will soon run out of space to comfortably fit the more than 2 million fish that had been spawned last winter. Water quality would decrease, spelling trouble for fish health. To fix that, CDFW is sending a little over half those fish to summer camp.
On a surprisingly smoke-free morning this Wednesday, a truck pulled up next to one of the hatchery’s ponds. A cloud of tiny, gray salmon swirled around in the water as hatchery staff turned on a pump to draw them into the truck’s insulated tank. The translucent pipe showed outlines of the assumedly confused baby salmon as they rose into a funnel, which dropped them into a separate pipe feeding the tank. After more than 20,000 fish had amassed on the truck, the pump stopped.
Then the fish were taken on a quick road trip along the northern shore of Iron Gate Reservoir, where no salmon have swum for more than half a century.
The truck backed up to a pond at the rustic Fall Creek Hatchery, originally built in 1919. Drawing from a consistently cool, oxygenated tributary to the Klamath, the hatchery was originally built to mitigate the impacts of the Copco No. 1 dam and ceased to be useful in 1965, when Iron Gate Dam blocked salmon from reaching it. Between the 1970s and the early 2000s, CDFW raised additional fish there for fishery enhancement.
Photo Credit Arden Barnes
By Alex Schwartz