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Secondary production of the green mussel (Perna Viridis L. 1758) in the Araya Peninsula, Venezuela

Abstract:

It was examined the growth, density, biomass, and secondary production of a population of the green mussel Perna viridis from morro de Guarapo, Araya Peninsula, Sucre state, Venezuela, during february 2000 to January 2001. The size structure of the population was polymodal. The strongest recruitment event occurred in february-april and december-january and a less important event, in september. A total of five cohorts were identified. The dry weight showed monthly oscillations related to nutrient cycles and recruitment events. The total length of the shell was the parameter that best fit an allometric growth model (Lt= -5.26 + 2.28Al; r = 0.98). The parameters of von Bertalanffy model were: L∞= 104.54 mm, K= 1.13/year, and a monthly growth rate = 5.91 mm/mo. Mussels reach a length of 71 mm during their first year of life, with a maximum longevity of 3 years. The population density was significantly different between months and oscillated between 1100 ind.m-2 in march 2000 and 66 ind.m-2 in december 2000. The average density was 283.88 ind.m-2. The biomass and monthly secondary production were the highest in the most abundant cohorts, showing a population renewal of less than a 1-year. These results suggest that this bank can be exploited for commercial purposes.