Clam Bed Regulations Aim to Cut Pollution - Bird droppings found to cause most of the problem for contamination
BRUNSWICK, Maine (AP) - The Department of Marine Resources and town officials are looking for a way to protect shellfish eaters from an unexpected and unsavory source of pollution - bird droppings.
Starting this year, Maquoit Bay will only be open to shellfish harvesters until Aug. 31, when the flats close for the season. Previously, the flats had been open year-round, except after periods of heavy rain.
The change comes as shellfish monitors, who have traditionally looked at potential pollution from land, learned that the highest pollution levels occurred during periods absent the rain that washes pollutants from inland septic systems and sewage plants.
"Most of the time, the higher scores were in the fall and winter months. So we said 'Maybe it wasn't the rain,'" said Laura Livingston, a water quality specialist at the Department of Marine Resources.
In order to prevent harvesters from gathering contaminated shellfish, the department was requiring Maquoit Bay flats to close for 14 days after rains of more than an inch.
But after being closed for two weeks for rains, officials tested the water's bacteria level and found evidence that there may be little correlation between bacteria concentration and rain.
The state, along with Brunswick Marine Warden Dan Devereaux and Natural Resources Planner Steve Walker, then began scrutinizing data from the last 15 years.
They noticed that in the spring and summer months, bacteria levels typically fell below the threshold for what is considered unsafe. But in some locations, that number spiked during autumn.
Devereaux and Livingston said the higher bacteria counts in the fall come from waste dropped in the bay by migratory birds, including black ducks, geese and gulls.
"We've always known the birds have been an issue," Devereaux said.
Without DNA testing, it's impossible to link the fall spikes to bird droppings, Livingston said, adding that the correlation is a logical one.
"We want to be confident that when we have the area open for shellfish harvesting, it's safe," Livingston said.
Brunswick and the surrounding area is home to about 75 commercial shellfish harvesters.
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