As farmed sturgeon thrive, wild populations are in trouble
Two hundred million years ago, sturgeon swam in the waters of the planet’s first continent, Pangaea. But today, these feisty living fossils — bottom-dwellers with sandpapery skin, rows of sharp bony plates and shark-like fins — may be on their way out.
Sturgeon from the Caspian Sea have long been prized for their caviar, made from unfertilized roe whose harvest requires killing the female fish. But overfishing, habitat destruction and pollution have imperiled Caspian sturgeon, and in January, an international trade ban went into effect on wild caviar.
Americans are among the world’s biggest consumers of caviar, and one solution to the plight of the wild sturgeon may actually lie here at home. In California’s San Francisco Bay-Delta, sturgeon farms started in the past two decades may help keep pressure off wild populations in the Caspian. Lauded by famous chefs like Wolfgang Puck and Traci Des Jardins, California’s homegrown white sturgeon caviar is finding favor among connoisseurs.
But even as sturgeon farming takes off, the Delta’s own wild sturgeon are in trouble. In April, green sturgeon, which can reach over 7 feet in length and weigh 350 pounds, were listed as "threatened" under the Endangered Species Act. Hulking white sturgeon, which can grow to 20 feet long and 1,500 pounds and are a favorite for sport fishing, have declined to just 7 percent of their 1998 population.
Both species range in rivers, estuaries and the Pacific Ocean from Mexico to Alaska. Today, there are only two major runs of wild white sturgeon reproducing on the Pacific Coast, in the Sacramento-San Joaquin system, which feeds the Bay-Delta, and the Columbia River along the Oregon and Washington border. In the threatened southern population of green sturgeon, only the Sacramento River fish are still reproducing.
Marty Gingras, senior biologist for the California Department of Fish and Game, says he’s talking to local fishermen in hopes that their observations about the elusive, long-lived fish might help him understand its decline: "If you don’t know anything about a segment of the population, it stands a hair up on the back of your neck."
Entrepreneur Peter Struffenegger, who manages the Sterling Caviar farm near Sacramento, became interested in domestic caviar when Iranian caviar was banned in the mid-1980s. He began breeding white sturgeon in 1986, using a system largely developed by Russian émigré Serge Doroshov, now a researcher at the University of California, Davis.
Sturgeon are raised in closed-system, disease-free tanks, some as large as 90,000 gallons. Today, Sterling caviar is in high demand, and Struffenegger expects to produce 8 to 9 tons of it this year. An ounce of his finest caviar sells for $70, compared to more than $200 for an ounce of Russian beluga caviar.
Outside Struffenegger’s tanks, however, sturgeon are harder to find; last fall’s low white sturgeon count in the Delta — only 10,000 fish — shocked biologists and fishermen alike. "Ten thousand fish could whittle down to a small number of reproducing fish. In any one year there could be (only) 50 to 100 sturgeon reproducing," says Josh Israel, a graduate student studying green sturgeon at UC Davis.
Biologists are eager to study the white sturgeon’s spawning, migration and habitat needs, not just for its own sake: The plight of the fish is likely tied to other threatened species in the Delta. "The Delta isn’t in good shape. The system is collapsing," says Melissa Neuman, recovery coordinator for NOAA Fisheries (HCN, 5/30/05: A massive restoration program may have nothing left to save).
Although commercial sturgeon fishing is illegal in California, sport fishing is extremely popular. In March, the California Department of Fish and Game tightened the size requirements on its one-per-day bag limit for white sturgeon, but some local fishermen, like fishing guide René Villanueva, say it might be time to restrict white sturgeon fishing to catch-and-release only.
A plethora of problems
Gingras says the threats to the fish include "everything you can imagine in a growing urban environment." He points to warmer waters and altered water flows due to dams, powerful pumps that force fresh water out of the Delta, development around the sturgeon nurseries in the estuaries, pollutants, and even boats that run over surfacing sturgeon.
But the daunting tasks of restoring water flow, cooler temperatures and spawning habitat in the sprawling Delta have yet to be discussed, let alone tackled. If NOAA Fisheries designates "critical habitat" for the green sturgeon, that could provide leverage to force change — but the process for such designation is notoriously arduous (HCN, 4/15/02: Habitat protection takes a critical hit).
Poaching is a growing problem, too — a 6-foot female sturgeon during spawning season can hold about $3,000 in roe for black market caviar. On June 29, California Department of Fish and Game wardens made their biggest bust ever as part of the ongoing Operation Delta Beluga sting operation, arresting nine fishermen and brokers.
To top it off, sturgeon mature late and grow slowly. It takes fish up to a decade to reach maturity, and then they only spawn every four to 11 years.
Some sport fishermen have called for a hatchery program. "The technique is available," says Doroshov, whose lab at UC Davis is still the leading authority on sturgeon reproduction. But he says that improving the fish’s habitat would be better: "Minor changes can improve things. They should look at habitat and spawning grounds first."