Abstract
The growth, maturation and feeding habits of Acanthogobius hasta were studied in Ariake Sound. In June, a new cohort ranging from 16 to 64mm S L appeared. They were thought tohave hatched in the spring of the same year. The cohorts grew slowly throughout summer and autumn. Their growth rate became faster thereafter, with most of them attaining over 200mm SL between January and February. Males grew faster than females and attained sizes as large as 400mm SL. After April, they declined rapidly in number, and disappeared by July. A. hasta is an annual fish. Its bodyform changed with growth and differed between males and females at SL≥ca. 100mm. GSI started toincrease in December, reached a peak in mid-February, and then decreased. Females having postovulatory follicles were first observed in mid-February and accounted for all the catch in mid-April. Females that had spawned did not seem able to spawn again. They spawn only once in life from mid-Februaryto early April. Stomach contents revealed that feeding habits changed with growth and differed between virgins and primiparas.
