Re-examination of age and growth of daggertooth pike conger Muraenesox cinereus in the western Seto Inland Sea, Japan

摘要

Age determination and growth using otolith rings in Muraenesox cinereus was re-examined in the western Seto Inland Sea, Japan. Previous study in this area indicated that new rings were formed annually from March to May, and then from September to October once individuals had achieved four or five rings. In this study, monthly changes in marginal growth rate indicated that the first ring was formed before November in the year following hatching, and from then on another ring was formed annually in July or August. The birth month was determined to be August based on a peak in monthly change in the gonad somatic index. Estimated von Bertalanffy growth functions were L = 806.6{1 − exp[− 0.33(t + 0.06)]} and L = 1264.0{1 − exp[− 0.19(t + 0.15)]} for males and females, respectively. Lengths after 3 years of age in this study were 100 mm longer than those in a previous study for both sexes.