Blueback herring Blueback herring 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. They reach a maximum size of approximately and are believed to live up to 8 years. The most distinguishing characteristic of this species is the black to dusky
Herring similar features. These silvery-coloured fish have a single dorsal fin, which is soft, without spines. They have no lateral line and have a protruding lower jaw. Their size varies between subspecies: the Baltic herring ("Clupea harengus membras") is small, 14 to 18 cm; the proper Atlantic herring ("C. h. harengus") can grow to about 46 cm (18 in) and weigh up 700 g (1.5 lb); and Pacific herring grow to about 38 cm (15 in). At least one stock of Atlantic herring spawns in every month of the year. Each spawns at a different time and place (spring, summer, autumn,