Blue-Green Algae in East Hampton's Hook Pond

A month after the East Hampton Town Trustees closed Georgica Pond in East Hampton to crabbing due to a dense bloom of cyanobacteria, or blue-green algae, the harmful algal bloom has appeared in Hook Pond, also in East Hampton.

Christopher Gobler of Stony Brook University, who has led a water-quality monitoring program in conjunction with the trustees for the past three years, informed Diane McNally, the trustees' clerk, of the new bloom in an email on Friday. The discovery is the first in Hook Pond since Dr. Gobler began the monitoring program.

The latest sample of Hook Pond’s water, Dr. Gobler said in an email to The Star on Monday, is the first to be above the state Department of Environmental Conservation’s threshold for blue-green algae. Toxin levels, he said, are above Word Health Organization standards for drinking water but below the recreational risk standard.

Officials of East Hampton Village have posted signs around the pond warning against exposure to cyanobacteria, according to Becky Molinaro, the village administrator. Exposure to blue-green algae can cause vomiting or diarrhea, skin, eye, or throat irritation, nausea, or allergic reactions or breathing difficulties.

The freshwater Hook Pond, Ms. McNally said on Monday, has no shellfish and is less accessible to the public than Georgica Pond, the latter a popular site for crabbing, kayaking, and other activities, so a formal resolution by the trustees to close it was unnecessary.

Pio Lombardo, a consultant who has conducted water-quality studies for the town and village, will present the findings of a study of Hook Pond's water quality to the East Hampton Village Board at its regular meeting on Friday.

At their meeting on Tuesday, the trustees, who manage many of the town's beaches, waterways, and bottomlands on behalf of the public, voted to extend the closure of Georgica Pond to crabbing through Sept. 22. They are likely to revisit that prohibition at their next meeting that evening. Last year, owing to an earlier bloom of cyanobacteria, the trustees closed Georgica Pond to crabbing from July into the autumn.

While blue-green algae are naturally present in lakes and streams, an abundance, caused by warm water temperatures and a lack of tidal flushing, can lead to harmful algal blooms. Cyanobacteria has also been detected this year in Fort Pond in Montauk, Wainscott Pond in Wainscott, and Agawam Lake and Mill Pond in Southampton.