Accabonac Harbor in Springs has been spared, at least for the time being, from Suffolk County’s annual aerial application of methoprene, a mosquito larvicide. A survey on Monday of mosquito breeding in the harbor, conducted by two East Hampton Town trustees and three volunteers, showed few areas of significant mosquito breeding, said John Aldred, a trustee.
County vector control officials were informed of the finding, and decided not to spray at Accabonac this week.
The trustees celebrated the decision at their meeting that night, taking it as a sign that their new larval sampling program is succeeding in reducing the controversial use of methoprene. Environmentalists, scientists, and many elected officials believe the larvicide is harmful to nontarget species, including lobsters, crabs, and fish.
The county routinely applies methoprene via low-flying helicopters over marshes at Napeague and Beach Hampton in Amagansett, and at Accabonac Harbor. Last year, Suffolk Legislator Bridget Fleming, along with the Nature Conservancy, which owns land around the harbor, the trustees, and vector control officials agreed on a trial program to map mosquito breeding through weekly water sampling there.
Surveying began last week and is to continue weekly until August. Mr. Aldred and Susan McGraw Keber, a trustee, with the volunteers, are conducting the sampling and sending their findings to vector control. County officials use the data to fine-tune their protocol, reducing overall application of methoprene. (In conjunction with methoprene, the county also applies Bacillus thuringiensis israelensis, or Bti, a naturally occurring bacterium that contains toxin-producing spores that affect mosquito, blackfly, and fungus gnat larvae.)
Mr. Aldred told his colleagues at Monday’s meeting that “vector control sent an email out in the afternoon saying they won’t have to do any spraying this week as a result of our sampling.”
“That’s real, serious progress,” said Bill Taylor. “They weren’t willing to listen to us two years ago.”
The discussion, however, followed a long exchange with Kevin McAllister, a marine scientist and activist who has long urged the trustees to take a stronger stand against the county’s use of methoprene over waterways under their jurisdiction.
“We’ve collectively enlisted the Nature Conservancy to oversee larval monitoring,” Mr. McAllister said. “All well and good, but I would like to know where we’re going with this. From my perspective, the science is very settled. Methoprene has impacts, no question.”
The goal, he insisted, should be an absolute end to its use. “I hope you don’t lose your voice on this and continue to stand firm in your opposition to methoprene,” he said, suggesting that by participating in the trial, “opposition to the use of methoprene is essentially silenced, for the time being. It shouldn’t be. This should be very clear-cut to all of us now.”
The goal, answered Jim Grimes, is to identify and monitor breeding activity, and to “see if you could hit these hotspots you know existed with Bti and hopefully avoid spraying of those areas, and if this worked out, it would be expanded to other areas. . . . At the same time, I’m sympathetic to the health department. Its role is the public’s well-being.”
The South Fork has not been immune to West Nile virus or Eastern equine encephalitis, Mr. Grimes added. Last September, a mosquito collected in Bridgehampton tested positive for West Nile, one of more than 100 samples to test positive in the county.
Mr. Grimes described the monitoring as a baby step. “Changing a program has got to start somewhere. It was made very plain in 2016 that they were not necessarily going to take methoprene out of their toolbox. . . . You’ve got to start someplace. You can rail against the machine, but more good can be done working toward something, as opposed to coming and saying the same thing over and over.”
“I’m reserved in my anticipation that we may eliminate methoprene,” said Ms. Keber. Progress will be slow, she said, “but it’s a process we’re going to have to go through in order for us to make headway.” Rick Drew acknowledged that Mr. McAllister presents a persuasive case, but asked that he “follow it up with recommendations of best practices that might be incorporated in a level-two program going forward.”
Mr. McAllister maintained that the county is motivated more by nuisance control than disease prevention. “As a scientist,” he said, “I have full conviction that methoprene needs to fully stop.”
On Tuesday, he acknowledged that the Accabonac Harbor program does represent progress toward that goal, but “I just hope this isn’t a delay tactic” or “a charade to ultimately drag out a process where everybody goes silent after a while.”
Mosquitoes can carry West Nile virus, Eastern equine encephalitis, and other diseases. Although methoprene is registered by the federal Environmental Protection Agency and the State Department of Environmental Conservation, its use has long been controversial on the South Fork.
Also at the meeting, the trustees approved the Cornell Cooperative Extension’s Long Island Shellfish Restoration Project, a state grant-funded effort to seed waterways with 115 million hard clams and 40 million oyster spat. C.C.E. has identified four nursery sites in the town, three of them under trustee jurisdiction, at which two floating upweller system nurseries, known as FLUPSYs, will be placed.
Kim Barbour, the cooperative extension’s marine program outreach manager, said she hoped that eight FLUPSYs could be in East Hampton waters by next month, at Sunset Cove Marina and Three Mile Harbor Marina, both at Three Mile Harbor; the Lion Head Beach Association marina, at Hog Creek in Springs, and at Gurney’s Yacht Club in Lake Montauk, where the trustees do not assert jurisdiction. “Our clams are getting big,” she said. “We need to try to move on this if possible, or find alternative locations outside of town waters. We wanted to bring this project here.”
The trustees also approved another proposal, the Accabonac Macroalgae Bio-extraction Project, a study to determine the feasibility of removing excess nitrogen from water by placing, and then removing, macroalgae that absorbs it.
Thirty metal frames will be installed in Accabonac Harbor near Pussy’s Pond, onto which two types of seaweed will be affixed. The vegetation — gracilaria, a genus of red algae, and ulva, a green alga also called sea lettuce — will be analyzed every two to four weeks, and upon its removal, after three months, to see if it is a viable way of removing excess nitrogen from the water.
The frames will be in a shallow area that is closed to shellfishing, so conflict with other user groups is unlikely, the trustees determined.