Possibly deadly toxin closes more shellfishing areas

A potentially deadly marine toxin that was detected in Town of Huntington waters earlier this month appears to have spread, leading state environmental officials to temporarily close off an additional 7,500 acres of shellfish harvest areas.

The expanded closure covers all shellfish beds in Lloyd Harbor, Coast Guard Cove and Huntington Bay south of a line between Lloyd Neck Point and Eatons Neck Point. Last week the state Department of Environmental Conservation closed 2,200 acres of harvest areas in Northport Bay, Centerport Harbor and Duck Island Harbor - embayments that are home to clams, mussels and oysters. Those areas remain closed.

The two-stage closure follows the pattern set over the past few years since saxitoxin was first found in waters off Northport in 2006, said Chris Gobler, an associate professor at Stony Brook University's School of Marine and Atmospheric Sciences, who studies harmful algae.

"This is the fourth time in five years that there has been a shellfish closure," said Chris Gobler. "We went from never seeing it to getting it year after year."

The poison is produced by a tiny, single-celled marine plant called Alexandrium fundyense. High concentrations of the plankton in water can cause shellfish that filter-feed there to accumulate toxic amounts - something that can lead to paralytic poisoning in humans who consume tainted shellfish.

Smaller amounts of saxitoxin have also been found over the years in Flanders Bay, Mattituck Inlet and Hempstead Bay, and along the South Shore in the Great South Bay and Jamaica Bay, Gobler said. But he said the Northport-Huntington Harbor complex is the only place where concentrations have been high enough to repeatedly shut down shellfishing.

Scientists think nitrogen from sewage and septic waste may feed the growth of the plankton.

Warm weather in March and April may also have given it a boost. Gobler said.

Alexandrium forms cysts that drop like seeds to the bottom of the Northport-Huntington Bay complex in late May or June. Those cysts re-emerge in the spring, when the water reaches between 40 to 50 degrees, and the plankton blooms anew.

"Since 2007, the cyst density has grown in Northport Harbor," Gobler said. "We know that's why they keep coming back."

The DEC will post a map of the closure areas on the agency's website at www.dec.ny.gov/outdoor/7765.html. For updates, call 631-444-0480.