The har clam (Mercenaria mercenaria) or quahog, is a bivalve mollusc native to the eastern shores of North America, from Prince Edward Island to the Yucatán Peninsula. Older sources may give it the systematic name Venus mercenaria. It is one of many unrelated bivalves referred to as clams. Confusingly, the ocean quahog is a different species, Arctica islandica.