Longevity and resilience of Chesapeake Bay striped bass

Since the early 1960s, the Chesapeake Bay striped bass population has undergone a large cycle of abundance, recovering to record levels during the 1990s. Changes in age structure over this period were examined to determine contributions of old females (>13 yr) to the recovery. In 1992, in a sample of large female striped bass, 10 yr of absent year classes (1972-1981) were observed corresponding to a period of recruitment overfishing. Fishery-independent stock assessments conducted 1985-1990 by Maryland Department of Natural Resources indicated that old females, while present in small numbers, made relatively small contributions to annual egg production during the period of recovery. Abundances, weighted for age-specific fecundity, indicated that older fish were probably the most important contributors to recruitment throughout the 1970s and early 1980s. Egg production after 1986 was principally contributed by young females, those produced after 1981. Demographic analysis also supports the view that a Maryland fishing moratorium designed to protect year classes after 1981 stimulated recovery. Longevities of >30 yr documented in this study suggest that striped bass populations can persist during long periods of poor recruitment due to a long reproductive lifespan. Longevity may have also conferred resiliency against an extended period of recruitment overfishing in the Chesapeake Bay. (C) 2000 International Council for the Exploration of the Sea.