POPULATION CHARACTERISTICS OF THE BLACK-SEA BASS CENTROPRISTIS-STRIATA FROM THE SOUTHEASTERN US

We examined the age structure and status of the southeastern U.S. stoc k of black sea bass, using recorded and estimated landings and size fr equencies of fish from commercial, recreational, and headboat fisherie s from 1979-1990. Annual landings in numbers at age were estimated by application of separable virtual population analysis (VPA), which was used to estimate annual, age-specific fishing mortality for different levels of natural mortality (M = 0.2, 0.3, 0.4 and 0.5 yr(-1)). Mortal ity levels (F) ranged from 0.54 to 1.59 between 1979 and 1990 for full y recruited ages (4-7) (M = 0.3). Maximum spawning potential ranged fr om 42% to 50% based on mature female biomass, from 49% to 56% based on egg production, and from 22% to 30% based on total mature (male and f emale) biomass. Because black sea bass are protogynous hermaphrodites (transforming from females to males) and the effect of changes in popu lation abundance on sex transformations is unknown, the percent reduct ion in males to females was estimated solely on increased mortality by fishing (ranging from 50% to 60% of the unfished proportion). Thus, t he use of maximum spawning potential based on total mature biomass sho uld also be considered for comparison to a biological reference point used in defining overfishing.