Age, growth and reproductive characteristics of gold striped amberjack 1 Seriola lalandi in the waters off western Kyushu, Japan

Growth and reproductive characteristics of gold striped amberjack Seriola lalandi collected in the waters off western Kyushu from April 2003 to March 2008 were determined based on vertebral centrum readings and gonad histology, respectively. Translucent and opaque zones on vertebral centrum were identified, and the number of opaque rings counted. Von Bertalanffy growth parameters did not significantly differ between males and females (F=0.28, P>0.05), and transformed value for the von Bertalanffy growth parameter FL ∞ and K were 1108 and 0.3091, respectively. The spawning period was evaluated to be from April to June for S. lalandi, based on the results from monthly changes in the gonadosomatic index and histological observations. Based on the relationships between the fork length and the developmental stage of testes and ovaries, the smallest fork length of male and female with mature gonads was 624 and 662 mm, respectively. The first maturation age was estimated to be 2 years old for both sexes.