In the spring of 2007, a small number of empty valves from the bay scallop, Argopecten irradians irradians (Lamarck), were observed at several locations in Pomquet Harbour, Nova Scotia, Canada. Snorkeling surveys at selected sites in the harbor were carried out in spring 2007, summer 2007, and spring 2008. Scallop densities were very low in all sampling times, ranging between 0.04 and 0.053 scallops/m². The size distributions from 2007 suggested a single cohort of 0 individuals, with one 1 scallop. The 2008 samples were predominantly 1 scallops, with five 0 individuals. Four marked scallops from 2007 were collected alive in 2008, demonstrating their ability to overwinter. These scallops had an average daily growth rate of 0.08 mm/day from July 2007 to May 2008. A thermistor deployed in the same eelgrass beds indicated that the scallops survived extended periods of time with temperatures below 0°C. In 2013, four of the sites were surveyed again, and dramatic increases in density were recorded, averaging 1.713 scallops/m². The bay scallops in Pomquet Harbour probably represent an incidental introduction, as larvae, from aquaculture operations ∼80 km to the north.