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MV CYANO has detected a cyanobacteria bloom in Middle Chilmark Pond. The Chilmark Board of Health has issued a red bloom “ADVISORY” for Middle Chilmark Pond. The cyanobacteria bloom in Middle Pond is “benthic”, which means the cells are near the bottom of the pond, rather than on the surface, and the water column looks clear.  This will look different than the “green scum” we normally see on the surface during a bloom.


Island Boards of Health have designated highly conservative risk levels in order to keep the community safe. The red ADVISORY means that, in addition to not letting your dog and/or toddler play in the water and possibly ingest it, (which is generally advised against at any time during the season when blooms are possible), the Chilmark Health Department advises against fishing (crabs, fish, shellfish) and/or eating catch, or wading or swimming in Middle Chilmark Pond until conditions change for the better. 


The other regions of the Pond remain in green status “BLOOM NOT DETECTED”, with no restrictions to activities. Thanks to Chilmark Pond Foundation, weekly cyanobacteria monitoring of all regions of Chilmark Pond will continue into the fall. 


Should you have further questions about risk, please reach out to Chilmark Health Agent, Anna McCaffrey,  Should you have any further questions about the testing procedures, please feel free reach out to GPF:


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