At Ken Beer’s fish ranch, thousands of white sturgeon and catfish thrash in round tanks or in long concrete raceways.
Beer’s 320-acre operation, called The Fishery, supplies live fish to markets and restaurants in the Sacramento region. It depends on a supply of cool water. If water temperatures are too warm, cool-water fish such as sturgeon can’t survive.
Luckily for Beer, he can tap groundwater from wells on his property to keep his business going. But some other fish farms can’t. California’s multiyear drought is changing the state’s aquaculture industry. Experts say it eventually could alter the species that wind up being sold in the state’s fish markets, farmers markets and in restaurants that buy fish directly from growers.
Rising atmospheric temperatures and drought may spur the rise of certain fish species – like catfish, said Fred Conte, aquaculture specialist at UC Davis. “Catfish do very well in higher temperature water,” Conte said.
He said new fish species will likely be introduced by farmers as the environment changes. “We already have plans to move toward more native species like Sacramento perch and Sacramento blackfish,” said Conte. “These fish do well in warmer temperatures.”
However, the sight of farmed perch and blackfish at live markets will not happen anytime soon, Conte said. “We still have to perfect the technology to put that fish into production.”
Meanwhile, some existing fish farms have been profoundly affected by the drought. The Calaveras Trout Farm in Snelling, for instance, lost 2 million fish last year because the water in its tanks became too warm, said owner Tim Goodson.
In April, Goodson received word from the Merced Irrigation District that he would receive no water this year. He closed the farm soon after, giving away or burying the 1.7 million trout that had hatched in October and laying off seven employees.
Goodson said the shutdown cost him $1 million.
The Merced Irrigation District draws water from Lake McClure, which is currently only 10 percent full, said Mike Jensen, the district’s government relations manager.
Starved for water, the Merced River is getting warmer. “The water temperatures in July got up to the 80s, and that’s too high to sustain the trout,” Goodson said. Most of the trout he raises are sold to the recreation fish industry. His operation doesn’t have chillers to cool the river water he receives.
California’s high, low and average temperatures have been rising, and extreme heat events are on the increase, according to a recent report by the California Environmental Protection Agency. That report said the rate of warming has accelerated since the mid-1970s, and that nighttime minimum temperatures increased almost twice as fast as maximum daytime temperatures.
Existing fish farmers who can tap groundwater are far better off than those, like Goodson, who depend on rivers. But with overpumping depleting groundwater levels, they are becoming more conscious of the need to husband every drop.
Water is used and reused at the Passmore Ranch fish farm in Sloughhouse, whose fish swim in 80 million gallons of groundwater pumped up from the Cosumnes aquifer.
The water flows first to tanks inhabited by the most sensitive fish, like sturgeon and black bass.
“Our water travels to our tanks first, then onward to our lakes, then finally to our gardens,” said Michael Passmore, co-owner of the farm. “After the fish have utilized the water, we then send it to irrigate our land-based crops to utilize that water yet again.”
In Galt, Beer’s operation supplies 2 million pounds of fish to local outlets. He recycles most of the groundwater he pumps out of the ground – by moving it from pond to circular tank to raceway.
At the moment, Beer is weighing whether to spend $300,000 to install three cooling towers to keep the water on his farm habitable for sturgeon. In order to reach maturity, and especially for caviar production, sturgeon need water in the range of 40 to 45 degrees.
Beer said he thinks the size of his operation gives him some room to maneuver and adjust to the the drought. Others may not be so fortunate, he said.
There are currently 144 freshwater fish farms registered with the state. Commercial aquaculture operators account for less than a quarter of that number, said Beer. The rest grow stock for the recreational fishing industry.
“There will be some attrition if the drought continues,” said Beer. “I don’t worry about competitors; I worry about our industry almost disappearing.”