Age, growth and mortality of white grunt (<i>Haemulon plumierii</i>) from the central coast of Brazil

Abstract

White grunt ( Haemulon plumierii ) otoliths were collected from 1997 to 1999 off the central coast of Brazil. Analysis of the edges of otolith sections suggests that one translucent and one opaque zone are formed once a year. Observed size and age class ranges for H. plumierii were 218–378 mm total length (TL) and 2–28 years, respectively. The von Bertalanffy growth models estimated were significantly different between sexes. The growth models for females, males and all fish were L t = 298.0[1 – e – 0.59(t–0.08) ], L t = 331.8[1 – e – 0.35(t+1.08) ] and L t = 312.2[1 – e – 0.48(t+0.32) ], respectively. Growth is fast during the first 4 years of life, when the average fish size is already in excess of 80% of the asymptotic size. The maximum age observed in this study is greater than those previously reported for H. plumierii . The natural mortality rate (M) estimate based on the oldest observed fish was 0.15 year -1 , while total mortality (Z) from the age-based catch curve was 0.21 year -1 (95% confidence interval: 0.18–0.24 year -1 ). These estimates show that the stock was under low to moderate levels of exploitation in the late 1990s.