Age and Growth by Scale Analysis of Pomacanthus imperator (Teleostei: Pomacanthidae) from Dongsha Islands, Southern China

A total of 200 specimens of Pomacanthus imperator from Dongsha Islands (South China Sea), were examined for age and growth. Scale radial length (R) is linearly proportional to standard length (L) and their relationship can be expressed by the formula L=3.6+43.8R. Relationship between standard length and body weight (W) can be expressed by the formula W=1.63×10^–4L^2.77. Mean standard lengths of each age group were back-calculated from scale annuli readings and were found to be 66.4, 94.2, 120.7, 133.9, 145.6, 157.9, 170.7, 188.0, 200.9, 217.6, 222.0, 242.8, 253.0, 268.1, 277.0 and 293.0mm for age classes 1 through 16, respectively. The von Bertalanffy parameters L, K, and t_o fitted to back-calculated standard lengths were, respectively, 411.9mm, 2852.1g, 0.067years^–1, and –0.91 years. Marginal increment analysis indicated that annulus formation takes place between January and March.