Males become sexually mature when they are 3 to 5 years old and the females mature at 4 to 6 years old. Water temperature is the primary factor that triggers spawning. Shad will spawn in tidal or non tidal freshwater over broad flats with sand, silt, muck, gravel substrates. They spawn in water depths about 1 - 10 meters but often less than 3 meters. Shad lives several years in the ocean and them returns to its river of origin to spawn.
Males arrive before females.
Spawning takes place at all hours of the day and night but is more intense from noon to midnight. Larvae remain near the spawning grounds, usually a short distance downstream. A decrease in river water temperature seems to trigger the migration. Shad migrate seaward first in the Northern rivers and progressively later in southern rivers. Once in the ocean, the shad remain there until they mature.