Age, Growth and Maturation of Largehead Hairtail(Trichiurus japonicus) in the East China Sea

Largehead hairtail(Trichiurus japonicus) is a commercially important fish species in China Seas, characterized by wide distribution, seasonal migration, spawning all year round. Under long-term high fishing pressure, the biological traits of largehead hairtail have changed, such as miniaturization, smaller size-at-age and earlier age-at-maturation. To explore its current biological characters, we analyzed age, growth and maturation of largehead hairtail in the East China Sea by analyzing the otolith microstructure and gonads. The results showed that largehead hairtail is mainly composed of 1 year and 2 years old individuals. The estimated von Bertalanffy growth function(VBGF) showed significant differences between sexes, and asymptotic pre-anal length of male is longer than that of female. Two spawning seasons were observed in spring and autumn by monthly gonadosomatic index(GSI). Compared to historic survey data, the average pre-anal length at age decreased and size-at-maturation became smaller in the East China Sea. This study updates life history parameters of largehead hairtail, and provides a reference for the present status of largehead hairtail, which can contribute to largehead haritail stock assessment and sustainable utilization in the China Seas.