Cochlodinium, or rust tide, has been discovered in Three Mile Harbor, Northwest Harbor, and Accabonac Harbor.
At the meeting of the East Hampton Town Trustees on Tuesday night, Stephanie Forsberg, in the aquaculture report she delivered to her colleagues, reported the recent discovery. Cochlodinium, she said, is algae that can be fatal to shellfish and finfish, but is not harmful to humans when ingested.
Two weeks ago, as reported in The Star, rust tide had not been seen in waters overseen by the trustees, despite its existence to the west, in Peconic Bay and Shinnecock Bay. “It shows you how quickly things can change in a week,” Ms. Forsberg said. Densities of the rust tide are lower than were found in westerly waters, she said, “but these are higher than we’ve seen in the past.”
A difficulty in addressing the algal bloom, she said, is that “it can change, from day to day, where it is. It’s not necessarily isolated to one part of a harbor. We can be hopeful for our ecosystem and shellfish that it doesn’t stay in any one place long enough, that tidal flushing will move it.” Tides, wind, and cooler temperatures will eventually resolve the situation, she said.
The trustees, in cooperation with Dr. Christopher Gobler of Stony Brook University, have funded a comprehensive monitoring of the waters they oversee. Ms. Forsberg told her colleagues that water sampling has been increased to at least once per week. “We’re going to continue to do that now because that’s all we can do,” she said.
“What’s the leading cause?” Nat Miller, a trustee and bayman, asked.
“Nitrogen,” Ms. Forsberg answered, “but we don’t know exactly from which source. It can be very site-specific. At least now we have quantification of it.”
Ms. Forsberg also reported that no blue-green algae, or cyanobacteria, had been discovered in Georgica Pond. Last September, a dog died after apparently drinking water containing a toxin that, she said, may have come from a pond adjacent to Georgica Pond.