HYDE PARK, N.Y. - The Atlantic sturgeon, a giant fish long prized as a source of delicate smoked flesh and caviar, is rapidly dwindling in the Hudson River, its last refuge.
The population decline in the Hudson is probably linked to a sharp rise in the netting of Atlantic sturgeon along the New Jersey and New York coasts in the early 1990s, when the states' fishermen turned to sturgeon after fishing for other declining species was curbed by government officials.
The pressure on the Hudson's largest denizen, which can reach 12 feet and weigh 800 pounds, has also risen as other species of the ancient family of armor-plated sturgeon, particularly those in the Caspian Sea, have been decimated by poachers seeking their valuable roe for caviar.
The lack of Atlantic sturgeon has not affected supplies or prices of smoked sturgeon or caviar because the species accounts for only a small percentage of the caviar market and has been increasingly supplanted in smokehouses by farm-raised sturgeon from the West Coast. But biologists worry that any reduction in the diversity of life in the river could disrupt its overall ecology.
The sturgeon shortage here has also sparked a dispute between fisheries officials and fishermen from New York and New Jersey, who together have dominated sturgeon fishing in recent years.
Last winter, when a commission that regulates shared fisheries for 15 East Coast states called for a ban on harvesting the sturgeon, New York quickly complied, but New Jersey, which has long had the biggest annual haul, continued to allow a limited sturgeon catch.
Any harvest now would put too much pressure on the species, many sturgeon experts say. The slow-growing fish only reach sexual maturity after 15 or 20 years and at lengths of five feet or more, said Dr. David Secor, a fisheries biologist at the University of Maryland. The continued netting will inevitably remove many fish before they can reproduce, he said, adding that, "at these numbers, every fish counts."
Other species rebounding
The condition of the Hudson's Atlantic sturgeon stock contrasts sharply with that of almost all other Hudson River fish species, whose populations are generally rebounding. Even a once-rare cousin of the Atlantic sturgeon, the smaller short-nose sturgeon that was placed on the federal Endangered Species List in 1967, is relatively common today. The only other fish in decline, the American shad, is also suffering from heavy harvesting outside the river.
On a recent morning in Hyde Park, it was hard to tell that the Atlantic sturgeon, Acipenser oxyrhyncus, was in trouble. A team of biologists, aided by a few of the river's dwindling population of commercial fishermen, stacked a half-ton haul of a dozen adult ++ fish in the bilge of a research boat.
The sturgeon's plight only became evident a day later when the scientists switched from nets aimed at adult fish - with mesh big enough to let a volleyball pass - to nets with a weave fine enough to snare foot-long yearlings.
In 600 yards of gill nets, not a single baby Atlantic sturgeon was found. That is typical these days, said Dr. Mark B. Bain, a biologist from Cornell University who is in the third year of a study of the river's sturgeon. "At first, we thought we weren't seeing any because our technique was bad," Bain said. "Now we know they're just not there."
Bain recently calculated that the Hudson probably contained only 3,000 year-old fish. "You don't need to use a mathematical model to figure out if that's sustainable," Bain said. "It's not."
Along with the lack of juveniles, adult fish over 7 feet long - particularly females - are "extremely scarce," said John Field, who monitors sturgeon and shad for the Atlantic States Marine Fisheries Commission, the interstate body that recommended the total ban on sturgeon fishing.
With the New York ban likely to be in effect for at least 15 years, according to state fisheries officials, the Hudson River's commercial fishermen have lost one of their last mainstays. And Long Island coastal fishermen cannot get permits to fish for sturgeon in New Jersey waters.
The New York ban leaves New Jersey - which has had by far the largest catch of the fish since 1989 - as the last Atlantic Coast state allowing a significant harvest. In the meantime, New Jersey's Department of Environmental Protection still maintains that its harvest, with 164 fish caught last year and 117 permits issued this year, is small enough so as not to harm the species.
Much of the state's sturgeon catch is unavoidable, involving fish caught in gill nets meant for monkfish and other species, said James F. Hall, an assistant environmental commissioner in charge of resource management.
Second major crash