Harmful Algal Blooms Monitoring Program

The HAB Monitoring Program has ended for the season and will resume in June 2022.

The Town of Nantucket, in collaboration with Nantucket Land Council, Nantucket Conservation Foundation, Nantucket Land Bank, Linda Loring Nature Foundation, UMASS Boston, and Mass Audubon monitors the following ponds for harmful algal blooms (HABs) weekly from June through September: Long, North Head of Long, Miacomet, Sesachacha, Capaum, Gibbs, Hummock, Clark’s Cove (West Hummock Pond), Maxcy, Washing, Tom Nevers, Stump, Almanac, Wigwam, Pout, and UMASS Boston’s Nantucket Field Station (NFS) Ponds.

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Want to help expand our capacity to monitor all waterways on Nantucket? By “Adopting a Pond,” you can help us monitor water conditions by visiting https://www.nantucketbiodiversity.org/pondsurvey and downloading the Nantucket Pond Water Guide. Please contact Thaïs M. Fournier at tfournier@nantucket-ma.gov for more information on volunteering to monitor our ponds.


The Nantucket HAB monitoring team performs VISUAL HAB inspections for the above mentioned ponds. HAB sampling is only performed by the TON for Hummock, Long, Miacomet, and Sesachacha Ponds.

The duration of a HAB occurrence is dependent on a number of factors, including physical and biological conditions, and therefore is not possible to predict in advance.

As monitoring is performed weekly and at specific locations and times, blooms may occur and disappear throughout the week.

Not all algal blooms that occur in waterbodies are harmful. If you are unsure whether a bloom is harmful or not, please keep away from the pond.

For more information, please visit the Environmental Protection Agency website at https://www.epa.gov/cyanohabs.

Algal Blooms Partners