American shad are flat-sided fish with a green- or greenish-blue back, a row of 3 to 23 dark spots along its silvery sides, and a white belly. Sharp saw-like scales, or scutes, along its belly, distinguish it from other fish. The American shad is the largest member of the herring family with an average weight of two to seven pounds and an average length of 10 to 30 inches.
American shad are primarily plankton feeders. Depending upon the geographical region, their diet will vary. Copepods, amphipods, shrimp, zooplankton, and other small fish are common food sources.
Shad are found along the Atlantic seaboard from the Gulf of St. Lawrence in eastern Canada to Florida and along the Pacific coast from California to Alaska.
American shad tend to inhabit areas near the bottom in the main river channels. They are very sensitive to water temperature and any dramatic changes in the temperature of its habitat can have a very negative impact on the fish. The ideal habitats for juvenile shad are large reservoirs. However, fish ladders and dam bypasses are necessary to assist in the migration of the American shad past dams.
- American shad are related to the herring, sardine, menhaden, and alewife. The menhaden has often been mistaken for the American shad because of their close resemblance.