Age, growth parameters and fisheries indices for the lane snapper in the Abrolhos Bank, SW Atlantic

Otolith-based methods combined with catch lengths were used to produce three simple fishing indicators for assessing stock status of the lane snapper Lutjanus synagris in the Abrolhos Bank, central Brazilian coast. Fish were obtained during landings between May 2005 and June 2007. Marginal Increment Analyses combined with edge analysis on sectioned otoliths (n = 303) confirmed annulus formation in an annual basis during June-October. Lane snapper were aged up to 18 years and the largest fish measured 56 cm total length. Growth was not significantly different between sexes, and the von Bertalanffy growth equation was derived as Lt = 56[1-e(−0.22(t−0.0))]. Highest cohort yield was achieved between 33.5-41.4 cm (optimal length) at ages 4-6. Age at first maturity was 2.8 years, and generation length was 10 years. Instantaneous total mortality (Z) was 0.58 year−1 and natural mortality rate (M) ranged from 0.17-0.36 year−1. Overall indicators point out for the need to implement fish management, as 30% of catch are composed of immature individuals and 7-12% by mega-spawners. A slot limit for the lane snapper in Abrolhos Bank is proposed, with restrictions for individuals < 24 and > 50 cm.