They are hard to find in the winter, as they tend to go deeper before spawning season in the range 13–18 °C (55–64 °F);[9] they have been pulled up in nets as deep as 120 metres (65 fathoms).

Like other herrings, the American shad is primarily a plankton feeder but eats small shrimp and fish eggs.

Consequently, the shad run correspondingly later in the year passing from south to north along the coast, commencing in Georgia in January; in March in the waters tributary to Pamlico and Albemarle Sounds; in April in the Potomac; and in May and June in northern streams generally from Delaware to Canada.

[2] The spawning fish select sandy or pebbly shallows and deposit their eggs primarily between sundown and midnight.

The eggs are transparent, pale pink, or amber, and being semibuoyant and not sticky like those of other herrings, they roll about on the bottom with the current.

Juvenile shad remain in the rivers until fall when they move down to salt water; they are now 40 to 115 mm (1+1⁄2 to 4+1⁄2 in) long, resembling their parents in appearance.

Like most herring species, American shad are very high in omega 3 fatty acids and, in particular, contain nearly twice as much per unit weight as wild salmon.

Traditionally, shad were caught along with salmon in set nets, which were suspended from poles driven into the river bed reasonably close to shore in tidal water.

For example, the number of shad harvested in the Merrimack River declined from almost 900,000 in 1789 to none in 1888, likely due to the inability to reach their spawning ground following a period of heavy dam construction.

[citation needed] Fish passage efforts, including the Chesapeake Bay program, have begun to remedy this situation.

The Atlantic States Marine Fish Commission is a crucial forum for coordinating the collective effort to conserve American shad.

On the year of every gubernatorial election, would-be candidates, lobbyists, campaign workers, and reporters gather in the town of Wakefield, Virginia, for Shad Planking.

Each spring, the town of Lambertville, New Jersey, on the Delaware River across from New Hope, Pennsylvania, also hosts an annual Shad Festival.