AGE, GROWTH, MORTALITY, AND REPRODUCTIVE-BIOLOGY OF RED DRUMS IN NORTH-CAROLINA WATERS

Red drums Sciaenops ocellatus were sampled in North Carolina waters fr om October 1987 through December 1990. Ages determined from sectioned otoliths were validated by length-frequency and marginal-increment ana lyses, and the recapture of oxytetracycline-marked fish. Fish growth w as rapid during the first 5 years, after which annual growth increment s were much smaller. Growth was best described by a continuous double von Bertalanffy growth curve, with a transition age of 4.4 years; K-1, the growth coefficient for fish younger than the transition age, was 0.30/year and K-2, the growth coefficient for fish older than the tran sition age, was 0.07/year. Maximum observed age and size were 56 years and 1,250 mm fork length (FL) for males and 52 years and 1,346 mm FL for females. Fifty-percent maturity was attained among males by age 2 at 621-640 mm FL and among females by age 3 at 801-820 mm FL. Spawning occurred from August through early October in estuarine waters of Pam lico Sound and nearshore ocean waters close to barrier island inlets. Commercial and recreational landings increased during the 1980s, with most of the harvest composed of immature, age-1 fish caught during the fall. Unadjusted annual return rates (18-25%) for tagged juveniles we re high. Annual survival rates based on tag-recapture data were only 6 -24%, and estimates of instantaneous total mortality rates (Z) from co hort-based catch curves were 1.56-2.88 for the 1985-1988 year-classes. The relative abundance of 20-55-year-old red drums has declined 90% s ince 1968-1972.