The blueback herring or blueback shad (Alosa aestivalis) is an anadromous species of herring from the east coast of North America, with a range from Nova Scotia to Florida. Blueback herring form schools and are believed to migrate offshore to overwinter near the bottom.These fish are silvery in color, have a series of scutes (modified, spiny and keeled scales) along their bellies, and are characterized by deep bluish-green backs.