The latest environmental scourge to beset the East End’s bays—a “red tide” algae bloom that gives off a toxin that is potentially lethal to humans—reared its head in Sag Harbor waters last week, forcing New York State to ban the harvesting of shellfish and conch from the area indefinitely.
Approximately 490 acres of Sag Harbor Cove were closed to shellfishing, starting last Thursday afternoon, April 26, following the detection of the toxin in shellfish taken from the cove. The closure impacts all of Sag Harbor Cove west of the Haerter Veterans Memorial Bridge, including all of Upper Sag Harbor Cove and its tributaries. All harvesting of shellfish and conch, or whelk, in those areas is prohibited until further notice. State Department of Environmental Conservation officials said monitoring in the cove uncovered saxitoxin, a neurotoxin blamed for the deaths of at least two humans in the U.S. since 2010.
Earlier in April, the DEC closed areas in western Shinnecock Bay and parts of the North Fork and Nassau County for the same reason. It is the second straight year that western Shinnecock Bay was closed because of the presence of the algae, a swimming species known as Alexandrium that is among several species that are dubbed “red tides” for the color they stain the water when they bloom.
The discovery of the toxin by the DEC came after a warning by marine biologists from Stony Brook University School of Marine and Atmospheric Sciences who had found increasingly dense levels of Alexandrium in water samples in the cove.
“This was a site that just visually looked like it had elevated levels of algal biomass, so it’s one of the spots we were keeping tabs on,” said Dr. Chris Gobler, a marine biologist and Stony Brook professor who leads the team of scientists who discovered the red tide bloom in Sag Harbor Cove. “It was still a surprise. We didn’t know before even a week ago that this was a place that would have any Alexandrium. We keep on having all these firsts—not the good kind.”
Dr. Gobler said that Alexandrium have always been present in local waters and are only blooming now because conditions in local waters have become favorable to their development. A study he co-authored last year highlighted rising levels of nitrogen in Long Island waterways because of residential development along their shores and the steep rise in harmful algal blooms that has followed.
“The commonality between Sag Harbor Cove and other places we’ve seen these bloom is an enclosed area, high nitrogen levels, being surrounded by a fairly well developed area,” he said. “These cells are probably all over the place and in the places that the conditions set up right, they hit high enough cell densities to be a problem. There may be other sites that turn up, we are checking dozens of sites on the East End, hundreds of samples a week.”
Shellfish ingest the Alexandrium cells and accumulate the toxin in their flesh. If the algae bloom subsides, the shellfish will gradually expel the toxin and be safe to eat again.
Alexandrium is a cold-water species and has typically bloomed in Long Island waters only in April, May and June, fading away as waters warm into summer.
Another species of red tide algae seen in Sag Harbor Cove, as well as most of the Peconic and Shinnecock Bay systems, in recent years can be lethal to fish and shellfish but does not appear to be harmful to humans. Alexandrium is the only algae bloom that has been seen on the East End that carries a toxin that can make humans sick, though another species has been found in Nassau County that carries a similar neurotoxin.
Prior to last week’s closure, portions of Sag Harbor Cove were on the list of small creeks open to shellfish harvesting in the summertime because of low bacteria levels in the water. Baymen harvest hard clams, oysters and soft clams, or steamers there.
“Anytime there is any kind of closure, it hurts,” said Southampton Town Trustee Ed Warner Jr., a commercial shellfish harvester. “It might only be temporary, but it is a loss and it is not something I see getting better over time.”
For updates on the DEC closure of shellfishing in Sag Harbor Cove and other waterways, call 444-0480 or visit the DEC website at dec.ny.gov.
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