People working on a clam farming project leaves footprints in the mud on a mud flat on the Kennebec River in Arrowsic, Maine in this May 28, 2018 file photo. Most of of Maine’s coast and tidal waterways were closed Tuesday to shellfish harvesting due to heavy rains. Credit: Robert F. Bukaty | AP

Nearly the entire Maine coast is closed to shellfish harvesting due to Tuesday’s heavy rain, and it is expected to remain that way for at least several days, according to a state fisheries official.

The coast from Timber Point in Biddeford to Moose Neck in Addison was closed Tuesday by the state Department of Marine Resources from 2 inches of rain falling in a 24-hour period. Heavy rainfall can contaminate clams, quahogs, mussels, periwinkles and other shellfish that are harvested along the coast as food by washing pollution from land into tidal waters.

Kohl Kanwit, director of DMR’s bureau of public health, said that the department tests waters in areas that have been closed due to such flooding to determine whether they are safe to reopen. The earliest that the department reopens such areas is three or four days after they are closed, so contaminants have enough time to drain away, but this time of year it often takes longer because rainfall tends to be heavier.

[See all Hancock County coverage here]

She said there is no typical time for how long a coastal flood closure might last.

“Every storm is different,” she said.

Some smaller areas within the closed section of coast have a different closure trigger of 1 inch of rain in 24 hours but also have set times for when the closure will expire. Tidal harvesting areas in the Back and Sasanoa rivers between Westport and Georgetown, in the Medomak and St. George rivers, and around North Haven island will reopen Thursday, Sept. 20. Other areas in Scarborough, Cumberland, Freeport, Brunswick, Harpswell and along the lower Sheepscot River will reopen Tuesday, Sept. 25.

In addition to the broad flood closure, a biotoxin closure is in effect from Grindstone Neck in Winter Harbor to Machiasport due to concerns about domoic acid, a naturally occurring biotoxin that can cause amnesic shellfish poisoning, which can make people ill and cause permanent short-term memory loss.

Kanwit said how long that closure lasts also will depend on test results. The department has to get two “clean” test results — which come up negative for harmful concentrations of domoic acid — at least seven days apart before the area will be reopened to shellfish harvesting.

More information about the closures can be found online at, or by calling 800-232-4733 or 207-624-7727.

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Bill Trotter

A news reporter in coastal Maine for more than 20 years, Bill Trotter writes about how the Atlantic Ocean and the state's iconic coastline help to shape the lives of coastal Maine residents and visitors....