The New York State Department of Environmental Conservation (NYSDEC) maintains a website of bodies of water that have had Harmful Algal Blooms. The link to this website is: http://www.dec.ny.gov/chemical/83310.html
***Please note: not all blooms are reported to the NYSDEC. If a body of water is not listed, it does not mean that it currently does not have a bloom or did not have a bloom in the past. It is best to avoid swimming, boating, fishing or other recreating if the body of water you are interested in has discolored water or has scum or floating mats present.