|A live Argopecten irradians|
Argopecten irradians, formerly classified as Aequipecten irradians, common names Atlantic bay scallop or bay scallop, is an edible species of saltwater clam, a scallop, a marine bivalve mollusk in the family Pectinidae, the scallops.
Bay scallop fishery
This species of scallop used to support a large fishery on the East Coast of the United States, but since the 1950s, the fishery of the wild scallops has decreased greatly. This decrease is apparently the result of several negative influences, one of which is a reduction in sea grasses (to which bay scallop spat attach) due to increased coastal development and concomitant nutrient runoff. Another possible factor is reduction of sharks from overfishing. A variety of sharks used to feed on rays, which are a main predator of bay scallops. With the shark population reduced, in some places almost eliminated, the rays have been free to feed on scallops to the point of greatly decreasing their numbers.
By contrast, the Atlantic sea scallop (Placopecten magellanicus) is at historically high levels of abundance, after recovery from overfishing.
This species has five different subspecies: 
- A. i. amplicostatus (Dall, 1898) 
- A. i. concentricus (Say, 1822) 
- A. i. irradians (Lamarck, 1819) 
- A. i. sablensis (Clarke, 1965) - a fossil subspecies
- A. i. taylorae Petuch, 1987 - the southern bay scallop