Growth and Spawning Period of Ridged-eye Flounder Pleuronichthys lighti Wu 1929 in the Central Seto Inland Sea,Japan

Ridged-eye flounder Pleuronichthys lighti Wu 1929 is a commercially important flatfish in East Asia. Its growth and spawning period in the central Seto Inland Sea, western Japan were examined. The gonadosomatic index increased from September to November, with a peak in November, and decreased from December. Females ≥1 year had mature eggs in November. The results suggest that the main spawning period was November. Using otolith sectioning and etching methods, the opaque zone in sectioned sagittal otoliths was found to be formed annually,during the spawning period. The maximum ages were 5 years old for both sexes. The parameters for the von Bertalanffy growth equation of both sexes were TL∞= 262 mm, k = 1.18.year^-1, t0 =0.10 year, indicating that ridged-eye flounder grows rapidly until they are 1 year old.