On Cape Cod, a mecca for lovers of locally dug shellfish, the menu board at JT's Seafood Restaurant boasts an unlikely message: "All our clams come from Canada."
Normally, owner Bud Noyes would be hawking only the freshest local products. But not this year. Not with the red tide.
Although it is still early in the season, fewer people seem to be lining up for fried strips and bellies at Noyes' clam shack in Brewster, and those who come ask the same question: "What's going on with the red tide?"
"It has cut into sales. People are concerned," Noyes said. "I can relate it to mad cow disease when people stopped eating steak."
As the vacation season heats up, business owners such as Noyes are doing handsprings to assure travelers that the toxic algae bloom known as red tide that closed shellfish beds off Massachusetts and New Hampshire does not have to dampen summer traditions - even the clam bake.
While the toxic tide so far has little impact on Cape tourism, worried would-be travelers are calling the chamber of commerce with questions. Most want to know if the beaches are safe for swimming, said Wendy Northcross, the chamber's chief executive officer.
The answer is yes.
Red tide occurs when microscopic plankton that lives naturally on the ocean floor blooms wildly, causing an explosion of toxic algae in coastal waters. Blooms in the water off Cape Cod are usually washed out to sea before infecting the shellfish beds. But this year's frequent Nor'easters kept the algae close to shore.
Shellfish such as clams, mussels, oysters and moon snails that eat by filtering microscopic food from the water consume the toxic algae, which pool in their stomachs.
While the algae do not harm the shellfish, they can affect the nervous system of humans who eat the fish, causing illness or even death.
But unlike the southern variety of red tide that has closed beaches in Florida with murky and stinky water, the algae off Cape Cod are invisible, odorless and harmless to swimmers.
In a public health bulletin on its Internet home page, the Massachusetts Department of Public Health says: "There is no risk with regard to swimming in the water."
Tourists, Northcross said, are also worried about their lobster fix. The health department says lobster meat, crab, shrimp and most fin fish are safe to eat from affected waters. Scallops are also safe as long as only the cleaned adductor muscle - the only part generally eaten - is consumed.
Few tourists have canceled Cape Cod reservations and cool cloudy weather has hurt the vacation hot spot more than the tide. But business owners worry that as the toxic tide - and publicity about it - spreads, visitors may look for another seaside destination.
"It's getting worse every day," said Mac Hay, co-owner of Mac's Seafood on the town pier in Wellfleet. "The red tide only affects shellfish, but people are not buying [any] fish."
The bloom, the worst in the waters off Cape Cod in decades, could last six weeks, virtually wiping out the summer season for local diggers who rely on the coastal shellfish beds for their livelihood.
The severity of the outbreak worries oceanographic researchers who fear that, with a long and severe red tide outbreak such as this one, it may take longer than average for shellfish to cleanse the toxins from their systems.
Scientists also worry that if large concentrations of the algae return to their dormant form and sink to the bottom of Massachusetts Bay, instead of being washed out to sea as normally occurs, the Cape may face similar outbreaks in the coming years.
There have been no reports of people becoming ill from eating toxic seafood. And experts say that tight government regulations ensure that anything on a menu or in a fish market case is safe to eat.
The Hartford Courant is a Tribune Publishing newspaper.