Overwintering Morone saxatilis (Striped Bass) often aggregate in waters heated by the warm-water discharge of power plants. In these areas, fishes are susceptible to cold shock during winter disruptions of power generation when the water quickly drops in temperature. We collected 98 Striped Bass from a suspected cold-shock mortality event at a power plant in Pictou Harbour, NS, Canada, in January 2013 and herein describe their size, age structure, and diet. The specimens ranged from 11.8 to 60.2 cm TL and were 1–5 years of age. Fifteen percent of their stomachs contained food, and Striped Bass and Apeltes quadracus (Fourspine Stickleback) were the only prey species identified. The goal of this study was to report on the mortality event as a likely recurring source of overwintering mortality for Striped Bass in the southern Gulf of St. Lawrence, a population designated by the Committee on the Status of Endangered Wildlife in Canada to be of special concern.