Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). Atlantic and Shortnosed Sturgeons

摘要

Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal species. The Atlantic and shortnose sturgeons (especially the former) were commercially important fishes between 1880 and 1900, but stocks have since decreased markedly and the shortnose sturgeon is now classified as federally endangered. Although the two species are anadromous, the shortnose sturgeon tends to spawn farther upstream, and spawning in both species usually occurs over a clean, hard substrate washed by a moderate to strong current. The shortnose sturgeon usually spawns earlier at the same latitude, with spawning of the species in the St. John River, New Brunswick, being completed by mid-May, as opposed to late June or even July for the Atlantic sturgeon. During non-spawning periods, the shortnose is largely confined to estuaries and apparently does not undergo the extensive coastal migrations that are characteristic of the Atlantic sturgeon. Both species are usually indiscriminate feeders and feed by sucking materials off the bottom with their protrusible mouths. Feeding apparently occurs mostly at night in the shortnose sturgeon.