The Blueback Herring (Alosa aestivalis) is a valuable source of food most often caught when migrating upstream to spawn. It is also called summer shad or blue-black shad, endemic to the east coast of North America. It forms schools and is easily identified by its silvery color and a series of modified scales called scutes along the belly. The back is deep bluish-green and distinguished from other similar-looking fish it co-exists with by its black or dusky peritoneum. This anadromous fish is slender, has smaller eyes, and has a dark spot on the shoulder.