Teaching The Hudson Valley

In Search of the Symbol of the Estuary

Posted by Steve Stanne
on July 06, 2010

Steve is the Hudson River Estuary Program’s education coordinator. Part of New York State’s Department of Environmental Conservation (DEC), the Estuary Program aims to ensure clean water; protect and restore fish, wildlife and their habitats; provide water recreation and river access; adapt to climate change; and conserve the watershed’s world famous scenery.

Steve's monthly blog entries will explore the natural history and ecology of the Hudson, and the intersections between this estuarine ecosystem and the human communities along its shores.

Left to right: Steve with Estuary Program biologist Kris McShane, Pace Academy for Applied Environmental Studies senior fellow Andy Revkin, and a 120 pound Atlantic sturgeon.

It’s not often that one has the opportunity to see the Hudson’s
totemic Atlantic sturgeon alive and up close, so I didn’t hesitate
when offered the chance to accompany DEC’s Hudson River
Fisheries Unit biologists on a sturgeon fishing trip recently.

On a hot, clear June day I hopped aboard a research boat at
Norrie Point and headed out onto the Hudson with high hopes.
It’s spawning time for these fish; mature adults are journeying
from the Atlantic Ocean into fresh water reaches of the river
as they have for thousands of years.

DEC is trying to determine whether the population has been increasing since the 1990s, when commercial fishing to satisfy demand for caviar drove down the numbers of large female sturgeon. With the eggs being served up to gourmets, baby sturgeon nearly disappeared from the Hudson. To head off disaster, DEC put a moratorium on sturgeon fishing in 1996.

The Atlantic sturgeon population would not recover quickly. Males don’t reach maturity until they are 12-15 years old; females not until at least age 15 and often not until age 18-20. Thus males born in 1996 were not likely to appear on the spawning grounds till 2008, while females would not be expected to return until at least 2011.

The DEC’s Hudson fisheries team began a study of spawning Atlantic sturgeon in 2006, hoping to find evidence that the fishing closure had had the desired effect. Our trip was part of that effort.

As we headed south towards Crum Elbow, team leader Amanda Higgs described the plan of action. We would lower gill nets 300 feet long to the river bottom, using floats to lift the top of a mesh curtain 8 to 14 feet above bottom.

The force of the river current through the mesh is strong, so the nets are set an hour or so before slack tide, when the water comes to a standstill before reversing direction. At slack, the crew hauls the nets back to the surface.

On this trip we set three nets, and then drifted on the river, waiting for the flood current to ease. The biologists prepared to work up any fish we caught – setting out gear for measuring, tagging, and taking tissue samples.

Preparing to hoist an Atlantic sturgeon into boat.

Mixed in with the practicalities were tales of catches from the past few years – of fish eight feet long weighing some 250 pounds. But there were also stories of empty nets; even the most skilled fishers have unlucky days.

As the current slowed the biologists started pulling the first net – hard work, lifting it 40 feet up to the surface and into the boat. Camera ready, I watched the point where the meshes came into view, only a few feet below the surface in the turbid river water. They held dead leaves and sticks from the river bottom, and lots of tiny amphipods (shrimp-like crustaceans also called scuds), but that was all. On to the second net. Another three hundred feet of dripping mesh came up and over the side without a fish.

Reassuring us, Amanda pointed out that the third and last net had been set in a particularly productive spot, where seven sturgeon had come up in a single haul not long ago. As mesh began to slide into the boat, I was thinking that even one would be enough. Fifty feet in, 100 feet in, 150, 200 – and there it was, a huge shape, upside down in the net with white belly shining ghostlike up at us.

The crew quickly untangled the sturgeon from the net, looped nooses around its body, and hoisted it into a water filled trough in the boat. In the process, we noted milt coming from its vent; this fish was a male. Oxygen was pumped into the water to help the fish recover before Amanda and her crew began the data-collecting protocols.

DEC biologists collecting data on an Atlantic sturgeon.

Lifted into a sling bathed in water, the Atlantic sturgeon was measured: a bit over 80 inches – six feet, eight inches – in length.

A slender plastic tag was attached to its body near the tail. A bit of dorsal fin tissue was snipped off for genetic analysis. Then the sturgeon was moved to a smaller sling and hung from a scale – it weighed 120 pounds.

Finally, and less formally, before being released back into river, the fish posed with us for photographs.

The general picture from this research is positive. While fisheries biologists don’t have enough data to declare with scientific certainty that the Hudson’s Atlantic sturgeon population is increasing, there are encouraging signs.

In 2008, the year that the first males born under protection in 1996 were expected to return, over 105 fish were netted. So many were the same size - these fish were all five and a half to six feet long, as would be expected for a given year class (a group of fish born in the same year), that the researchers took to calling them cookie-cutter fish.

I’m looking forward to going sturgeon fishing again a few years from now, when the even larger females from that 1996 year class find their way back to the river.

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