May 24, 2005 A red tide has prompted environmental officials from central Maine to Cape Cod, Massachussetts, to close shellfish beds from all commercial and recreational harvesting along the Atlantic coastline, choking the region’s supply of mussels, oysters, scallops, and clams.
The tide is considered to be the worst in Massachusetts Bay in 12 years and could adversely impact the shellfish industry, the public’s health, and natural ecosystems, said Dr. Don Anderson, a Senior Scientist with the Woods Hole Oceanographic Institution.
Red tide is a common name for the phenomenon that occurs when certain algae, in this case Alexandrium fundyense, bloom with a red-hued pigment.
People who consume shellfish exposed to high levels of toxins swept in with the tide could develop paralytic shellfish poisoning, or PSP, which in severe cases can cause respiratory paralysis and even death.
According to Dr. Anderson, the phrase “red tide” can be a misnomer as the phenomenon is not actually associated with a tide, and the water during a red tide is sometimes brown, green, or, in the case of Florida’s red tides, legitimately red. Sometimes the species of algae never reach the densities required to discolor the water. “The water up here right now is not red,” Anderson said. “It doesn’t look like anything more up here in Massachusetts than blue ocean water.”
A combination of toxic algae cells moving south from Maine and New Hampshire into the entrance of Massachusetts Bay and a “big, nasty nor’easter that blew in on May 7th” made the ocean conditions ripe for a red tide, Dr. Anderson said.
Depending on weather, ocean currents, and other variables, the tide is expected to last from two to four weeks, J. Michael Hickey, Massachusetts’ chief shellfish biologist, told The Boston Globe.
“Some years you have little blooms that don’t amount to a whole lot,” Hickey told the Globe. “This year it looks like we’re going to have a big one.”
The Woods Hole Oceanographic Institution has been tracking this particular bloom since May 9, the day after the nor’easter ended. A ten-day scientific cruise that left Massachusetts Bay for Canada’s Bay of Fundy at the same time has sampled the water on the way in and out of the bay and found that the number of algae cells had doubled in ten days.
“We were able to get samples right from the beginning of the outbreak and notify state officials,” Anderson said. “Even before then we were alert because we knew there were toxins starting to appear in Maine and New Hampshire.”
Anderson and his colleagues are waiting for a current storm to pass over Massachusetts before they head into the waters to do additional sampling to better characterize the event. He says the state can basically monitor the shellfish but that the institution is responsible for monitoring the water. Although the algae can have serious health repercussions, the programs set in place should help in keeping people safe.
“Nobody in New England has died in recent times from this particular toxin,” Anderson said. “People should trust the monitoring programs. They shouldn’t suddenly avoid eating seafood at all times. There’s a good safety net out there.”
