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Plum Island Sound

Plum Island Sound begins about one mile east of the Rt. 1a bridge over the Parker River. The river turns south and broadens out into a large estuary behind the barrier beach island called Plum Island. The Sound runs for about 4 and 1/2 miles until it joins up with the Ipswich River and empties into the Atlantic Ocean between Plum Island and Castle Neck. Most of the Sound is surrounded by the Parker River National Wildlife Refuge and is also part of the Parker River/Essex Bay Area of Critical Environmental Concern.


Plum Island Sound has long been recognized as one of the most pristine estuarine habitats in the northeast and is an area of regional and statewide significance. Plum Island Sound is in the center of the 20,000 acres of salt marsh that lie between Cape Ann and the New Hampshire border. This marsh is the largest continuous stretch of salt marsh north of Long Island. This area is known as an important migratory stop for birds of the Atlantic Flyway as well as for its bird habitat, its historic anadromous fish runs, and as a spawning ground for finfish and other organisms that serve as food for offshore fish.

Plum Island Sound supports an important shellfish industry. The major product is softshell clams also known as steamers. Plum Island Sound clams are widely known for their high quality and command a high price nation wide. The Massachusetts Division of Marine Fisheries maintains records of shellfish landings reported by town shellfish constables. These reports most likely significantly underestimate the actual landings so the value of the Plum Island Sound shellfish harvest is difficult to measure. The estimated value of the harvest is approximately $1 million per year.

Parker River/Essex Bay Area of Critical Environmental Concern
Plum Island Sound Long-Term Ecological Research Site  conducted by the Ecosystems Center, Woods Hole, MA.


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