Age, growth, and length–weight relationship of the checkered snapper Lutjanus decussatus in an Okinawan coral reef

Abstract

Species in the family Lutjanidae (snappers) are important targets of fisheries around the world. Although the checkered snapper Lutjanus decussatus is distributed across the Indo-Pacific, little is known about the demographic parameters of this species. Thus, the age, growth, and length-weight relationship of the checkered snapper L. decussatus (family Lutjanidae) were investigated in an Okinawan coral reef. Alternate translucent and opaque zones were observed in all sectioned otoliths, with an opaque zone occurring at the edge of the otolith predominantly during the spawning season. The maximum ages of the male and female were 24 and 23 years, respectively. The von Bertalanffy growth parameters for the relationship between age and fork length (FL) were as follows: asymptotic mean FL (L_∞)＝288.3mm, growth coefficient (k)＝0.09 year^－1, and age when mean FL is 0 (t₀)＝－12.0 years in males; L_∞＝316.5mm, k＝0.08 year^－1, and t₀＝－12.1 year in females. In the case that the growth parameters were re-estimated using a fixed t₀ value of 0, L_∞＝256.1mm, and k＝0.54 year^－1 in males; L_∞＝274.4 mm, and k＝0.45 year^－1 in females. L_∞ was significantly greater in females than in males, but there were no significant inter-sexual differences in K or t₀. The length-weight relationships for males and females were whole body weight (g)＝4.95×10^－5 FL^2.83 and 1.44×10^－5 FL^3.05, respectively. The present study is the first to demonstrate the age, growth, and length-weight relationship of L. decussatus, which would be useful biological information for the effective management of this species.