Age and growth 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 the Nagasaki Fish Market from May 1995 to February 1998, were examined to obtain information on age struc ture and growth rate. Ages were determined using mesopterygoid readings. Me sopterygoid length was measured from the focus to the outer margin along a line perpendicular to the sagittal plane of the body. The fork length to me sopterygoid length relationship was significantly different between males a nd females. Based on evidence from monthly changes of marginal increments, marks on the mesopterygoids were formed twice a year in June and January. F rom the monthly changes of GSI, a spawning peak is estimated to occur in Ma y and June. Growth equations are given for each sex. Females are larger tha n males, and differences in mean fork length between males and females incr eased with growth. The calculated fork lengths at age in the present study approximate a previous report based on total length frequency distributions from the East China Sea, and were larger than these reported from waters n ortheast and southwest of Taiwan and smaller than for the Indian Ocean.