Age and Growth of Big Eye Priacanthus macracanthus in the East China Sea

Abstract

A total of 2, 863 specimens of big eye Priacanthus macracanthus caught by bull 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 structure and growth rate. Ages were determined using mesopterygoid readings. Mesopterygoid 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 mesopterygoid length relationship was significantly different between males and females. Based on evidence from monthly changes of marginal increments, marks on the mesopterygoids were formed twice a year in June and January. From the monthly changes of GSI, a spawning peak is estimated to occur in May and June. Growth equations are given for each sex. Females are larger than males, and differences in mean fork length between males and females increased 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 northeast and southwest of Taiwan and smaller than for the Indian Ocean.