Sengekontacket Pond will reopen for shellfishing Friday morning following state tests that came back clean, Edgartown shellfish constable Paul Bagnall confirmed.
The pond was closed to shellfishing on July 31 after more than two inches of rain fell, and remained closed this week.
Water testing in the pond was done on Wednesday by the state Division of Marine Fisheries.
Bacteria levels in the pond spike following heavy rainfall events, said Oak Bluffs shellfish constable David Grunden, because pollution from the roads and shorelines to enter the pond.
“Droppings from birds, rats, squirrels, raccoons and so forth . . . all that fecal material can get washed into the ponds off the surfaces, which increases the bacterial count in the pond,” he said.
When the pond is closed, red flags are posted at the Big and Little Bridges. The closure does not affect boaters or swimmers. Sengekontacket spans the towns of Oak Bluffs and Edgartown.
This year marks the first time since 2007 that most of the pond was opened for shellfishing during the summer months. A memorandum of understanding was signed among Edgartown, Oak Bluffs and the state Division of Marine Fisheries to open parts of the pond for the summer with certain restrictions, including rainfall closures.
Until October, if there is more than one inch of rain in a 24-hour period, the pond will be closed to shellfishing for a minimum of five days.
“Anytime it is over two inches of rain, the state has to collect water samples before we can reopen it,” Mr. Grunden said.