Age and growth of the yellowtail snapper, Lutjanus chrysurus (Bloch, 1791), off Northeast Brazil

Abstract

The yellowtail snapper, Lutjanus chrysurus, is a coastal reef species which is frequently caught in the bottom line fisheries along the continental shelf and slope of Northeast Brazil, with a strong tendency of decrease in its landings over the years 1995-1999. The fork length frequency distributions were significantly different between states, with the exception of Pernambuco and Ceará. The age ond growth rate were determined from otolith readings and observations of opaque and translucent bands, indicating the existence of 0 to 17 years old individuals. Readings of whole and sectioned otoliths were identical in 25.24% of the observations while in 43.81% more rings were read in sectioned otoliths and 30.95% more rings were read in whole otoliths. For individuals older than 10 years more rings were always observed in sectioned otoliths, for individuals with ages between 5 and 10 years the ages were similar, while for individuals younger than 5 yeras more rings were observed in sectioned otoliths. The parameters of the growth equation presented the following values: L∞= 62.0 cm; K= 0.05 year^-1; t₀=-8,1 year^-1. A great variability of sizes at a given age was observed, what seriously hampers attempts of age determination from length frequency distributions.