Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (mid-Atlantic)-American shad. [Alosa sapidissima]

Species profiles are literature summaries on the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The depleted populations of the American shad, Alosa sapidissima, are being restored in many of the rivers along the East Coast that originally supported large runs. The American shad is an anadromous fish that lives several years in the ocean and returns to its natal river to spawn in the spring when temperatures reach 12/sup 0/C. The eggs are carried by currents downstream from spawning sites in large rivers for 8 to 12 days until they hatch. The larvae, which metamorphose to juveniles in 3 to 4 weeks, remain in the river until fall when they migrate to the sea. Shad move offshore and southward during winter at water temperaures of 3 to 15/sup 0/C. American shad feed on zooplankton. They adapt readily to fresh or saltwater, but they prefer salinities exceeding 4 ppt. 50 refs., 3 figs., 8 tabs.