European flat oyster (Ostrea edulis)
Native to the European Atlantic coast but introduced to the United States for aquaculture. Shells are typically round or oval-shaped and 1.5-4 inches across. The top shell is more rounded while the bottom is almost completely flat. Shells can be white, cream, or brown in color and typically have tight concentric bands. European flat oysters originally came to Maine for aquaculture, but has since escaped captivity. The species is now considered invasive throughout New England.
Fun fact: European flat oysters can produce up to a million eggs at a time!
Eastern oyster (Crassostrea virginica)
Native to the North American Atlantic coast. Shells are tear-shaped, elongated, and usually ridged, growing 3-5 inches long. They can be white, gray, or tan in color. They are filter feeders and form large reefs, filtering plankton and food particles out of the water. These hard-shelled reefs can also form the basis for many other forms of life. Disease, pollution, overharvesting, and spread of European flat oysters have caused eastern oyster populations to decline significantly.
Fun fact: A single eastern oyster can filter up to 50 gallons of water per day!
Soft-shell clam (Mya arenaria)
Native to the North American Atlantic coast, but has since spread to Europe and the North American Pacific coast. They prefer to burrow in soft mud in tidal mudflats and can grow up to 4 inches long. Their shells are thin and easily broken, and they are often preyed upon by crabs, gulls, and moon snails. Soft-shelled clams are also known as "longnecks" or "steamers" and are an integral part of New England cuisine.
Fun fact: 90% of the soft-shelled clam harvest from Chesapeake Bay is exported to New England!
Atlantic surf clam (Spisula solidissima)
Native to the North American Atlantic coast, primarily harvested off the coast of New Jersey and the Delmarva Peninsula. Largest bivalves found in the western North Atlantic, reaching a maximum of 8.9 inches. Shells are thick, triangular, and yellow-whitish with rounded edges and concentric ridges. Shells do not close fully. Prefer coarse or fine sand. They are planktivorous filter feeders, filtering plankton and small plant matter from the water. They are preyed upon by snails, crabs, shrimp, and fish. Thanks to good management practices, surf clams are considered to have a healthy population.
Fun fact: West Atlantic surf clams can live up to 35 years!
Hard clam/Northern Quahog (Mercenaria mercenaria)
Native to the North American Atlantic coast, grown and harvested under U.S. state and federal regulations. Can grow from 3-5 inches, but typically are on the lower end of the range when full grown. Shell is thick, gray to white in color, with outer concentric growth rings. Inside of the shell is white with violet markings. Some hatchery raised clams have dark, zigzag stripes across the shell. Slow growth rates, live from 12-20 years on average, but can live up to 40 years. Inhabit intertidal and subtidal areas and prefer a higher salt content in the water. Prefer a mixture of sand and mud with some coarse material (but can realistically live in any substrate type).
Fun fact: Hard clams are not considered a sustainable type of seafood unless they come from one of the growing number of aquaculture farms.
Atlantic jackknife clam (Ensis leei)
Native to the North American Atlantic coast. Thin and elongated, reaching approximately 8 inches in length. Length is about six times the width with both ends equally as wide. Pink to purple-brown bands on a yellow to red-brown background, with many growth bands evident. The species prefers sand or muddy sand in lower tidal and shallow subtidal zones in bays or estuaries.
Fun fact: Harvested in coastal Massachusetts for homemade clam strips; towns have regulations for how many can be harvested at once!
Blue mussel (Mytilus edulis)
Native to both the East and West coasts of the United States, and a common species farmed worldwide. Have teardrop-shaped shells that are typically 2-4 inches long, and are blue, black, or dark brown in color. Typically live in the intertidal zone, attaching themselves to rocks or other hard surfaces using byssal threads. Can grow in massive groups called mussel beds.
Fun fact: Blue mussels are able to defend themselves from predatory snails by tying them down with byssal threads, trapping them.
Northern horsemussel (Modiolus modiolus)
Native to both coasts of North American, preferring colder waters along the northern coastlines. Large solid, swollen and oblong or triangular shaped shell. Hinged end is bluntly angled with the rest of shell being more gently curved. When younger, the outer shell is dark blue or purple-ish color. Once the mussels get older, they tend to be a glossy yellow or dark brown. No ribbing but growth lines may be noticeable. Inside of the shell is white except for areas where the muscles were attached. Typically 4 inches long, but can grow up to 8.6 inches. Often found living among gravel and rock, from just below low-tide line to 600 feet deep. Can form dense mats of live individuals, similar to blue mussels.
Fun fact: Found in many waterways around the world!
Atlantic ribbed mussel (Geukensia demissa)
Native to the North American Atlantic coast. The ribbed mussel is relatively large, on average growing to be 2-4 inches. The shell is thin and fan shaped. The outer layer of the shell is glossy and black/brown with some yellow or white in color. The ribbed mussel on average can live to be 15 years old and can be found in subtidal oyster reefs, salt marshes, and man made structures. Ribbed mussels are filter feeders, consuming microscopic zooplankton.
Fun fact: Ribbed mussels live in aggregations with a density of 2,000-3,000 per square meter in New England!
Atlantic bay scallop (Argopectan irradians)
Native to the Atlantic coast, from the Gulf of Mexico to Cape Cod. The Atlantic bay scallop is rounded with distinctive ridges along the shell edges and can grow up to 3 inches in diameter. The color of this species varies from gray, purple, brown, and red. The interior of the shell is white. The shells hinge has two pronounced points. Bay scallops have small tentacles and 30-40 blue eyes visible on the shell edges. The species is a filter feeder, found in shallow waters and eelgrass beds. They can live for up to 2 years.
Fun fact: Scallops are able to swim by clapping their shells together!
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