As shellfish harvesting in parts of Southampton Town has been shut down by the eastward spread of the toxic “red tide” algae bloom, East Hampton officials have watched anxiously for signs that the toxin could find its way to East Hampton Town waters next.
The scientists who discovered and have been tracking the emerging health threat in Southampton, however, say that conditions in most stretches of East Hampton waters are very different from those areas that have seen the toxic blooms and are unlikely to see this specific concern pose a threat to human health or shellfishing here.
This Friday, June 1, Stony Brook University School of Marine and Atmospheric Sciences professor Dr. Chris Gobler will discuss the situation in a free talk sponsored by the East Hampton Town Trustees, starting at 5:30 p.m. at Town Hall.
“Most water bodies in East Hampton are really, really well flushed as compared to the water bodies we’re talking about in Southampton,” Dr. Gobler, who leads the team of Stony Brook researchers who have been tracking the red tide that forced the state to prohibit shellfish harvesting from western Shinnecock Bay, Mattituck Harbor and Sag Harbor Cove this month, said. “Anywhere you get that kind of flushing, you are going to have good water quality and we’ve mostly seen this organism in areas where water quality is maybe not as good, that don’t receive that flushing.”
The organism that has spurred such concerns in the last couple months is known as Alexandrium, a form of red algae that has begun to appear in East End waters in recent years. It produces a biotoxin called saxitoxin that can cause paralytic shellfish poisoning, or PSP, in shellfish that live in waters where Alexandrium is blooming. The toxin has been blamed for the deaths of two people and hundreds of acute illnesses in people, primarily from the Pacific Northwest, who ate shellfish tainted with it.
Alexandrium blooms have appeared in Long Island waters beginning in early to mid April and usually wane as waters warm in May and June. It was first detected in Southampton Town in 2009, though in small amounts. But in 2011 Stony Brook scientists detected a dense Alexandrium bloom in western Shinnecock Bay and alerted the state Department of Environmental Conservation, which led to a temporary ban on shellfishing in the 3,600-acre portion of the bay for most of May and June after dangerous levels of saxitoxin were found in shellfish there. This year, after a warm winter, the state detected the Alexandrium bloom and elevated saxitoxin levels in western Shinnecock by early April. On April 26 shellfish samples from Sag Harbor Cove were also found to contain dangerous levels of saxitoxin, and shellfishing was banned there as well. Both areas have since been cleared for shellfish harvesting again after the Alexandrium died off as waters warmed.
It is likely that Alexandrium is present in most if not all of the East End’s water bodies, Dr. Gobler said, but that only presented with the right combination of conditions can it bloom in dense enough numbers to pose a threat.
The primary factors that seem to be feeding the emergence of Alexandrium blooms, according to scientists tracking it, are enclosed water bodies that do not get regular flushing with clean water from the ocean and the close proximity of dense residential development. Dr. Gobler himself noted that East Hampton Town is probably the least densely developed town on Long Island.
East Hampton Town Trustee Lynn Mendelman said that her board asked Dr. Gobler to speak in East Hampton to reassure residents of the safety of East Hampton’s waters and shellfish as well as educate them about the factors and potential threats posed by Alexandrium and other harmful algae blooms in local waters.
“Our situation is not grave at this time,” Ms. Mendelman said. “We can’t say 100 percent it won’t happen here in the future—we have some inner embayments that, if the conditions were right we could see it. So we’re being prudent by trying to make sure people understand what is going on.”
East Hampton has experienced another red tide species, which blooms later in the summer and early fall and has not been found to have human health effects—though it can be deadly to fish and shellfish species. That organism, known as Cochlodinium, tends to range farther and bloom in much greater numbers than Alexandrium. It has been seen in open waters of Gardiners Bay and even Block Island Sound, though the blooms tend to originate in more enclosed water bodies.
East Hampton also experienced the devastating “brown tide” blooms in the 1980s and 1990s. While brown tide outbreaks have continued in some isolated parts of Southampton Town waters, East Hampton has not seen one since at least 1995.