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Paralytic Shellfish Poisoning (PSP), Cochlodinium, & Red Tide Information

Related Pages:   Beach Information  |   Nuisance Algae  |   Seafood Safety

Current Status

As of September 2009, there were no closures in Buzzards Bay for 2009 due to Red Tide and paralytic shellfish poisoning (PSP). However, elsewhere in Massachusetts, some areas are closed. Go to the DMF PSP website for the latest information. You should also consult with your local shellfish constable for the status of your community.

In September 2009, however, we did receive reports of "rusty brown" tides caused by the non-toxic dinoflagellate Cochlodinium polykrikoides. Go to the bottom part of this page to learn more about that species of microalgae.

Although large areas of Massachusetts were closed to Red Tide in 2009, larger areas were closed in the summer of 2005 and 2006. Coincidentally, because of exceptionally heavy rains in early June that year (6 to 10 inches of rain), on June 7, 2006 the state also closed all of state waters to shellfishing, including Buzzards Bay. This occurred in addition to the PSP closures. The first closure of any part of Buzzards Bay due to PSP occurred in 2005, when the northernmost end of the bay was closed, near the canal. That year other parts of the state suffered prolonged Red Tide closures that had a disastrous impact to the incomes of commercial shellfishermen.

Information about the Massachusetts 2005 Red Tide and impacts in Buzzards Bay

Beginning on April 27, 2005 the Massachusetts Division of Marine Fisheries initiated a prohibition on the taking of shellfish in Nauset Harbor, in Orleans because of elevated levels of paralytic shellfish poison (PSP) toxin in shellfish. A wider scale closure was initiated at Cape Ann to New Hampshire on May 19. This closure expanded southward, until on May 27, the Division of Marine Fisheries announced a widespread prohibition on the taking of shellfish in Massachusetts Bay, Cape Cod Bay, and upper Buzzards Bay. On the outer Cape, the closure continued to extend south to Monomoy Island on June 2, and further south to Nantucket Island on June 3. By June 6, the PSP closure extended southwest to Edgartown on Marthas Vineyard.

On June 9, 2005, Governor Mitt Romney declared an economic disaster in Massachusetts, allowing the state to seek federal disaster aid. On June 10, DMF closed Federal Waters adjacent to Massachusetts to the taking and landing of shellfish (read the DMF notice). On June 16, closures extended to the entire south coast of Marthas Vineyard closed. In response to the Governor's declaration, the Small Business Administration announced it would issue low-interest loans to qualified individuals on June 21. However, on June 24, the federal government decided the red tide outbreak did not qualify for federal disaster relief. The closures were enacted because of a bloom of a type of a type of planktonic algae, a dinoflagellate of the genus Alexandrium. Blooms of Alexandrium are often called "Red Tide" because the water can have a pinkish tinge from the density of algae in the water. Red Tides are a threat to human health because the algae produce PSP toxins, specifically one called saxitoxin, that can accumulate in shellfish during blooms. PSP toxin is a threat to human health, and can even cause death.

While PSP closures occur from time to time in the cold waters north of Cape Cod, for the first time ever, the PSP closure extended through the Cape Cod Canal and south into Buzzards Bay to Wings Neck in Bourne and Stony Point Dike in Wareham. This area includes Buttermilk Bay, Onset Bay, and Phinneys Harbor. The inclusion of the north end of Buzzards Bay reflects the historically high levels of PSP toxin observed at the end of May in Cape Cod Bay, that were transported southward, through the canal. The exceptionally high levels of Alexandrium in Cape Cod Bay are believed to be the result of heavy spring rains and unusual May Nor'easters that drove in the offshore phytoplankton bloom.

Click to read the May 27, 2005 New Hampshire to Buzzards Bay PSP closure notice.

On July 1, 2005 DMF reopened the closed areas of Buzzards Bay and few selected areas of Cape Cod. Openings continued gradually through July and August, but a few areas remained closed as shown in the map above. Concerns remain about the possible long term implications of future outbreaks of red tide south of Cape Cod, and in Buzzards Bay, and whether the dinoflagellate cysts that remain in the bottom sediments from this outbreak, will make these areas more prone to future red tides. It is presumed that cysts deposited in one season provided the innoculum for new outbreaks in future years. Some studies have shown that Alexandrium cysts may survive in sediments under natural conditions for at least several years.

Newspaper and Magazine Articles, and information pages

Woods Hole Oceanographic Institution Northeast PSP page
May 26, 2005 Woods Hole Oceanographic Institution Press Release
June 1, 2005 Oceanus Magazine Article
June 2, 2005 New Bedford Standard Times article: Red tide closes shellfish areas
June 4, 2005 New Bedford Standard Times article: Red tide cells may multiply
June 4, 2005 New Bedford Standard Times article: Red tide closures extended
June 16, 2005 New Bedford Standard Times article: Red tide menace spreads
June 16, 2005 New Bedford Standard Times article: Mass. shuts more coast as red tide multiplies
June 18, 2005 New Bedford Standard Times article: Seafood sellers feel pinch of red tide
June 24, 2005 Boston Globe article: US denies disaster aid for red tide in Massachusetts

Massachusetts DMF PSP Biology Page.
Massachusetts Department of Public Health Page on Red Tide poisoning.
Woods Hole Oceanographic Institution Harmful Algal Bloom page
NOAA New England Red Tide Information.

September 2005 Cochlodinium Bloom in Buzzards Bay

A bloom of a different species of dinoflagellate was reported along the northeast shores of Buzzards Bay in Bourne and Falmouth during September 2005. The dinoflagellate is called Cochlodinium polykrikoides (synonym= C. heterolobatum). An algal bloom is a population explosion of microalgae algae where cell densities may exceed millions of cells per liter water. The bloom in Buzzards Bay has exceeded 7.6 million cells per liter, and red patches of water were observed off Falmouth and Bourne. The bloom subsided a few weeks later after waters cooled. A Cochlodinium bloom has never been reported for Buzzards Bay before.

Unlike the Alexandrium dinoflagellate, Cochlodinium does not contain neurotoxins that affect people, but like Alexandrium, it contains reddish pigments, so that in large enough concentrations, Cochlodinium can also discolor coastal waters with a reddish hue if it appears in great enough concentration Cochlodinium had been considered a Harmful Algal Bloom (HAB) species simply because in high concentrations in contained systems, it caused the death of fish by consuming all the oxygen in the water (plants generally produce excess oxygen in the day, but like animals, they are always consuming oxygen too). However, more recent studies have concluded that Cochlodinium polykrikoides infact exhibit a pronounced chemical toxicity (Gobler et. al, 2008; Harmful Algae 7(3):293-307). Tanga and Gobler (2008, Harmful Algae, 8(3):454-462) documented that juvenile bay scallops experienced "100% mortality during 3 days exposure to cultures at cell densities an order of magnitude lower than raw bloom water." These authors proposed that the algae releases reactive oxygen compounds as the mechanism of mortality, but a subsequent study by Kim et. al (2009; Biosci Biotechnol Biochem. 73(3):613-8.) suggested that other compounds might be the cause of observed mortality, which cause the observed neurotoxic, hemolytic, and hemagglutinative effects. Large concentrations of Cochlodinium may also affect the growth, survival, and development of some zooplankton larvae of more desirable species, like oysters.

Warm waters and high nutrients are thought to contribute to blooms of Cochlodinium. In Peconic Bay on Long Island, fertilizer runoff and surface and groundwater discharges of wastewater is believed to have contributed to some recent "Brown Tides" and Cochlodinium blooms observed in that estuary. The Peconic Bay National Estuary Program has prepared and easy-to-understand Cochlodinium Fact Sheet that contains much useful information about the species.

What are Dinoflagellates?

Dinoflagellates are a broad group of single celled organisms generally classified as a Class (Dinoflagellata) in the phylum Protista. Protists are a catchall group that includes plant-like organisms and animal-like organisms. Dinoflagellates are typically found floating in the water, and are thus known as plankton. Some dinoflagellates have chlorophyll (and make their own food), and are thus considered "algae" or phytoplankton. Other dinoflagellates eat small plants or animals, and are therefore considered zooplankton. Some dinoflagellates are mixotrophic; that is they both have chlorophyll, and they eat other organisms. Cochlodinium is mixotrophic. Some dinoflagellates are even parasitic on other animals

The distinguishing features of dinoflagellates that separate them from other protists include the fact that they have armored plates made of cellulose, they may contain chlorophylls a and c and fucoxanthin (along with other pigments that give them a reddish color), and they have two flagella for swimming through the water, one of which is contained in a spiral groove on the body.

Besides the notoriety of the red tide dinoflagellates, many beach goers are familiar with another dinoflagellate know as "sea sparkles." These are in fact a large (at least for a single-cell organism - 1mm) plankton-eating species of dinoflagellate called Noctiluca that can be seen scintillating in the water as bright sparkles of light at night. [Ctenophore jellies are also bioluminescent, and also cause flashes during nighttime swimming in Buzzards Bay, but they are another story.].

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