Dispersal and growth of yearling Atlantic sturgeon, Acipenser oxyrinchus released into Chesapeake Bay

Significant fisheries for Chesapeake Bay Atlantic sturgeon, Acipenser oxyrinchus, have been absent for nearly a century, and there has been no evidence of recovery in the intervening years. Endangerment of Atlantic sturgeon in the Chesapeake Bay has stimulated interest in aquaculture-based restoration programs. A critical and unknown issue is whether hatchery released fish would encounter habitats that support growth and survival. In July 1996, approximately three thousand Atlantic sturgeon yearlings were released into Nanticoke River (Maryland) and subsequently tracked to evaluate their growth and dispersal. Biotelemetry of 32 individuals showed down-estuary emigration into the Chesapeake mainstem habitat during summer and fall at average ground speeds below 0.5 km/d. During the first year after release, 262 yearlings were captured by commercial fishermen. All yearlings and two-year-old fish were determined to be of hatchery origin (8% capture rate). Yearlings were captured throughout the Chesapeake Bay mainstem and tributaries. Two released sturgeon were captured in the Albemarle Sound System (Chowan River, NC). Juveniles captured during summer and fall experienced ca. 1.5% daily specific growth rate. Diets comprised annelid worms, isopods, amphipods, and mysids. Wide dispersal, high incidence of feeding, and positive growth rates suggested that hatchery-produced juveniles dispersed to areas that supported consumption, growth, and survival. Because the Chesapeake Bay continues to support juvenile habitats, we propose that curtailed or absent spawning stock or spawning habitat, or both, are principal factors that have contributed to lack of Atlantic sturgeon recovery during the twentieth century.