Researchers say several East End ponds and bays are among reported hot spots.
RIVERHEAD, N.Y. — Stony Brook University researchers said they have found Vibrio vulnificus in several Long Island water bodies, adding a sharp public health note to broader warnings about algal blooms, shellfish closures and poor water quality before summer.
The findings drew attention after Christopher Gobler, a Stony Brook coastal ecologist, previewed water-quality concerns April 21 on the Peconic River boardwalk in Riverhead. The bacteria, often described in public reports as flesh-eating, can cause rare but severe infections when it enters wounds or is linked to contaminated shellfish. The latest discussion comes as Suffolk County, state regulators, researchers and coastal communities prepare for the warm-weather season.
Gobler said Stony Brook researchers had detected the bacteria in several waters, including Sagaponack Pond, Mecox Bay and Georgica Pond on the South Fork. Other concern areas were described on parts of the South Fork and North Shore, though a full islandwide sample count was not released in the initial public summaries. “People who are infected with this bacteria have a 20% chance of dying within just 48 hours following infection,” Gobler said. His remarks came before the annual State of the Bays symposium, held April 24 at Stony Brook Southampton’s Avram Theater, where researchers presented a wider picture of Long Island’s water troubles.
The bacteria warning was not announced as a blanket beach closure. It was part of a broader report on coastal stress that included harmful algal blooms, low-oxygen zones and shellfish closures tied to toxins. RiverheadLOCAL reported that Gobler displayed a map showing “dozens and dozens” of impaired locations in Long Island’s estuaries, harbors, bays, lakes and ponds during 2025. He also said three Southold water bodies were closed to shellfishing because of paralytic shellfish poisoning and that the western half of Shinnecock Bay was closed. Nearly three dozen locations were experiencing hypoxia, with dissolved oxygen below state standards, he said.
Vibrio bacteria occur naturally in coastal waters and rise in warmer months. The Centers for Disease Control and Prevention says Vibrio can cause vibriosis after a person swallows the bacteria or gets it in a wound. Vibrio vulnificus is one of the most serious species, and many infected people require intensive care or limb amputation. About one in five people with the infection die, sometimes within one or two days of becoming ill, according to federal health guidance. In 2023, New York officials said Vibrio vulnificus had been identified in a deceased Suffolk County resident, while fatal vibriosis cases were also identified in Connecticut.
Gobler and county officials tied much of Long Island’s worsening water quality to nitrogen pollution moving from land into bays and harbors. He said onsite septic systems are a major source because much of Suffolk County is not connected to sewers. Deputy Suffolk County Executive Jennifer Juengst said the county is pursuing a 35-year effort to replace 360,000 cesspools and failing septic systems. She said the county’s septic improvement program can provide up to $20,000 for an eligible upgrade, with state funding adding as much as $25,000 more. Suffolk County’s beach monitoring program runs from May through September and covers more than 190 beaches.
Researchers also pointed to shellfish and seaweed aquaculture as part of the response. Michael Doall, Stony Brook’s associate director for aquaculture and restoration, said shellfish and seaweed farming can remove nitrogen from the water while supporting the coastal economy. Doall described them as “zero input crops” because they need no fertilizer, feed, fresh water or pesticides. Gobler said one recent study found aquaculture could address about 20% of the nitrogen reduction needed in Northport Bay while using about 1% of surface waters. Researchers described that work as one tool, not a stand-alone fix for aging wastewater infrastructure.
The public reaction grew quickly after local reports focused on the phrase flesh-eating bacteria and the 20% fatality figure. The East End Beacon reported that Gobler addressed the backlash at the April 24 symposium and described the infection risk as a “high consequence, low probability event.” The outlet also reported that oyster growers at the meeting said sales had fallen after the coverage, with some customers believing local shellfish were unsafe. Gobler said he had been trying to explain both the risks and the progress being made on Long Island water quality, including septic upgrades, shellfish restoration and new water technologies.
Residents near affected waterways said the changes are visible. Richard Dietz, who lives along the shoreline in East Quogue, told News 12 that the water near his home is “not as usable as it used to be.” Southampton Town Trustees said the bacteria’s presence is not uncommon in warm salt or brackish water and said they would keep coordinating with health authorities and monitoring conditions. Stony Brook’s symposium framed the issue as part of a wider system under pressure from warming waters, wastewater, fertilizer runoff, harmful blooms and low oxygen.
No new local deaths were announced in the reports reviewed after the April 21 briefing, and officials did not announce a broad closure tied only to the latest Vibrio findings. The next major phase is the summer monitoring season, when county testing, state shellfish decisions and Stony Brook research are expected to shape the public picture of conditions in Long Island waters.