Red tide, an algae bloom toxic to shellfish and fin fish, is already rampant in the waters off the South Fork of Long Island, having reappeared for the sixth year in a row and over a month earlier than years past, according to Stony Brook Southampton professor Dr. Chris Gobler and Peconic Baykeeper Kevin McAllister.
Already visible in the Shinnecock and Peconic bays, including Noyac Bay off Sag Harbor, according to Dr. Gobler the red tide first appeared around July 20, whereas previously the algae has bloomed in late August and early September.
“The organism has been present for some time, but we do not know why it has become so prominent in recent years,” said Dr. Gobler. “We believe the warmer-than-usual summer has been responsible for its early arrival.”
A harmful algal bloom, red tide is visible, usually presenting itself in rust-colored bands on surface water. While harmless to humans, Dr. Gobler noted the species is highly toxic to fish, shellfish, larvae, zooplankton and other algae.
“These properties prevent it from being consumed by predators and prevent it from needing to compete with other algae for resources such as nutrients,” explained Dr. Gobler. “Higher nitrogen levels lead to more intense blooms. We also know the blooms seem to be isolated to the Peconics and Northeastern Shinnecock Bay.”
The tide will remain until the water cools, reducing the number of available nutrients.
According to Dr. Gobler, quantifying the impacts of red tide is difficult, although he noted the smallest organisms, larvae, are the most vulnerable albeit the most difficult to track.
“Large fish in pound nets and at Stony Brook’s marine station have died during blooms,” said Dr. Gobler. “Fishermen have reported a decline in landings during and following the blooms. The Southampton Town Trustees reported a large scallop die-off in Noyac Bay following last year’s bloom. None of these things are good news for the ecosystem.”
McAllister agreed that areas where aquaculture is occurring are the most vulnerable, particularly if their growth is in cages, but that pound nets are equally vulnerable as when fish trapped in the nest can be exposed to the toxic algae for prolonged periods of time.
“I think the wild stock is also vulnerable if there is a persistent bloom,” he added.
Dr. Gobler, whose lab at Stony Brook Southampton is focused on water quality research and plankton ecology, said the occurrence of red tide is a sign of poor water quality, however while his lab has learned much about the species they are still studying why the blooms start and why they reoccur on such a consistent basis, as opposed to brown tide, which is more sporadic.
McAllister said he has seen literature referencing the occurrence of red tides dating back centuries, but that he believes an increase in nutrients like nitrogen in the water likely is due to human influence, specifically the result of aging wastewater treatment systems leeching into the groundwater and concurrently into streams and bays, as well as the use of some fertilizers in landscaping and lawn maintenance.
“It’s been around for a long time, but with that being said, we are seeing these harmful algae blooms more frequently and certainly along developed coastal communities,” said McAllister. “I don’t have the smoking gun, but I do believe there is a correlation between development and the strain on coastal marine life.”