Age and growth of the Japanese silver-biddy, Gerres equulus, in western Kyushu, Japan

To reveal the age and growth of Japanese silver-biddy, Gerres equulus, specimens collected from the waters around Kagoshima Prefecture, western Kyushu, Japan, during September 2000–December 2002 were studied. Ages were derived from 1106 sectioned otoliths. Monthly changes in the marginal increment ratio of the otoliths indicated that annulus formed once a year, during June–September, when the spawning occurred. The Japanese silver-biddy grew rapidly until the second year and showed a slower growth rate thereafter. Ages ranged from 1 to 10 years for both sexes, most of which were 2–4 years old for males and 2–5 years old for females. Using standard lengths (SL, mm) at each age, the growth curves were expressed as Lt = 206.30[1 − exp{−0.425(t + 0.038)}] for males and Lt = 213.22[1 − exp{−0.452(t + 0.001)}] for females.