Fidelity of American Shad, Alosa sapidissima (Gupeidae), to its River of Previous Spawning

Abstract

Of 5074 adult American shad, Alosa spidissima, tagged in the Annapolis River, Nova Scotia, during the 1981 and 1982 spawning runs, 292 (5.8%) were recaptured, 180 in the river during the same year, 56 in the river in subsequent years, 53 at distant marine sites, and 1 in another Nova Scotia river. Recovery from 6124 adult shad tagged in a marine environment (Cumberland Basin, Bay of Fundy) was similar (395 recaptures, 6.5%) but distribution was markedly different. Thirty-five were taken in the Basin during the same year, but only 7 in subsequent years. Conversely, 139 were recaptured at distant marine sites, and 214 in rivers from the St. Lawrence River, Quebec, to the St. John's River, Florida. Assuming equal probabilities for recapture within this species' geographical range, Annapolis River freshwater recaptures were specific for the Annapolis River but Cumberland freshwater recaptures were nonspecific. Except for two returns, possible strays, fidelity to the Annapolis was 97%.