Bay remains closed to shellfishing; DEM monitors for harmful algae bloom

Angelo Liberti, chief of water protection for the Rhode Island Department of Environmental Management, had more questions than answers yesterday as the department announced the closure of Narragansett Bay, Mt. Hope Bay, the Kickemuit and Sakonnet rivers, and their tributaries to shellfishing remains in effect until further notice.

The unprecedented closure for harmful algae blooms was implemented last Friday. While DEM regularly monitors local waters for the presence of phytoplankton that can produce harmful algae blooms, Liberti said phytoplankton counts were so high the department, in concert with the Department of Health, issued the closure.

The toxin, known as domoic acid, produced by these phytoplankton is responsible for causing amnesiac shellfish poisoning (ASP) in humans. Symptoms of ASP include short- and long-term memory loss along with other serious health effects.

Liberti said a significant bloom has been reported in the Gulf of Maine, and DEM is working with authorities there to test meats from Rhode Island shellfish as well as assess causes for the bloom. He said there are nine species of phytoplankton that are remarkably similar and three of them are capable of producing toxins.

Liberti didn’t have an explanation for the sudden bloom, adding that there have been numerous theories but no consensus. Also, he could not say what would be considered a safe period to wait before reopening waters to shellfishing should toxins be found in shellfish meats.

Water samples have been taken from different parts of the bay, including both the east and west passages.

According to the DEM release issued Tuesday, “Until Bay samples indicate the bloom is declining, efforts to collect local shellfish for analysis to determine if the toxins are present in shellfish meats at levels of concern will be suspended.”

It goes on to say, given the high concentrations of phytoplankton in several areas of Narragansett Bay and the confirmed presence of toxins in the phytoplankton, “and out of an abundance of caution,” all portions of the bay where these elevated levels were found were closed to shellfish harvesting until further notice. There is no evidence that southern Rhode Island coastal ponds have been affected by the harmful algae bloom.

For updates on shellfish closure areas, contact the DEM 24-hour shellfishing hotline at 401-222-2900. For more information on DEM divisions and programs, visit dem.ri.gov. Follow DEM on Facebook at facebook.com/RhodeIslandDEM or on Twitter (

@RhodeIslandDEM) for timely updates.