Reproductive characteristics of big eye Priacanthus macracanthus in the East China Sea

A total of 2,863 specimens of big eye Priacanthus macracanthus caught by bu ll trawl in the East China Sea and landed at Nagasaki Fish Market from May 1995 to February 1998, were examined to obtain information about their repr oductive characteristics. From monthly changes in the gonadosomatic index, the spawning peak was estimated to be in May and June. From the distributio n of oocyte diameters and histological observations of ovaries, the develop ment process of oocytes was concluded to be of the group-synchronous oocyte development type. Maturation size was estimated to occur at 190 mm FL from the relationship between the fork length and the frequency of mature speci mens. Batch fecundity was calculated to be about 7 x 10(4) at 190 mm FL and 23 x 10(4) at 250 mm FL from the relationship between fork length and numb er of mature eggs.