Sturgeon make comeback on the Hudson

BUCHANAN — Year over year for more than a decade, scientists trawling the Hudson River have watched as the numbers of young Atlantic sturgeon remained low after adult populations dwindled to near collapse due to overfishing, habitat disruption and other causes.

But 2012 was an exceptional year for sanctioned fishing of sturgeon by scientists, in part because 2011 may have been an exceptional year for the Atlantic sturgeon.

Surprised by a nearly six-fold increase in the catch rate, scientists with the Hudson River Biological Monitoring Program have applied to increase the numbers of shortnose sturgeon and Atlantic Sturgeon they capture and later release. s

“It’s probably one of the most encouraging things I’ve seen in six or seven years,” said Malcolm Mohead, an analyst with the National Oceanic and Atmospheric Administration.

Taking their time
The prehistoric species of fish are especially susceptible to sudden declines because of the long stretch of time it takes for young sturgeon to mature into sexually active adults. It can take the fish 6 to 25 years to be able to reproduce, according to the World Wildlife Fund.

The population of Atlantic sturgeon in the Hudson has taken 16 years to make a comeback, Mohead said.

“It’s been 16 years since the moratorium (on fishing for sturgeon),” Mohead said. “It looks like they are coming home and they are having babies.”

A more comprehensive report about the rise in sturgeon population is due out this year, he said.

Request to increase sample size

The yearly limit on capturing sturgeon has been capped at 82, but in 2012, the scientists met their quota early as they made randomized trawls for the fish along the Hudson, from the Troy Dam in Albany to Battery Park in lower Manhattan.

Researchers with the environmental consulting firm, Normadeau, captured 78 sturgeon in the first six months of their year, Mohead said. Not only were there greater numbers of sturgeon over all, but the number of young fish shot up dramatically.

“Over 80 percent of the catch were 'young of year,'” Mohead said.

The health and size of the catch has prompted the researchers and Entergy, operator of the Indian Point Nuclear Power Plant in Westchester County, to increase the size of the sample to 200 fish per year, but no more than 600 in a five-year period. Entergy, a regulated utility, is required to fund the study under the terms of its operating permit.

NOAA is currently reviewing that application, Mohead said.

Under pressure
Human populations place unusual pressures on the fish, notably from worldwide demand for caviar— the unfertilised eggs of sturgeon. Supplies of the delicacy currently come largely from Russia and Eastern Europe, not the U.S. On the Hudson, human contamination, alterations of habitat and ocean harvesting of adult fish have impacted their ability to thrive.

They are peculiar fish – spiny, slimy, slow-growing and long-lived. When fully mature, Atlantic sturgeon can measure 14 feet long and weigh 800 pounds.

Among their many quirks, sturgeon have a transitional lifecycle that begins with fish developing in the calm nursery waters of rivers before graduating to ocean-dwelling as adults. Like salmon, the fish then return to river areas to spawn.

Shortnose sturgeon were among the first animals listed as endangered in 1973 with the adoption of the Endangered Species Act. Their numbers have already significantly improved. Atlantic sturgeon were not placed on the endangered list until 2009, but, before then, a 40 year moratorium on hunting the fish instituted in 1998 covered both species, according to NOAA.

John Waldman, a professor of biology at Queens College, said that the sudden spike in the numbers of young fish is a good sign that the natural condition of Hudson River ecosystem is improving, after years of protection under regulations like the Clean Water Act, the Clean Air Act, and laws like the moratorium.

"Maybe this is indicative of a major improvement and maybe it's just a one-year blip," Waldman said. "Even if it's a one-year blip, it means there is a higher proportion of fish in the system that are young, and they are going to come back someday as breeders."

With new sturgeon hatched in 2011, scientists plan to document the population as accurately as they can before this new generation makes the move to the Atlantic.