STUDIES ON THE AGE AND GROWTH OF PELTEOBAGRUS VACHELLI (RICHARDSON)

From October 1996 to September 1997, 1024 specimens were collected in the middle reaches of the Yangtze River for the studies on age and growth of Pelteobagrus vachelli (Richardson).Vertebra was used for age determining.Relationships between vertebra radius and body lenth for female and male were respectively expressed as L = 6.95 + 131.46R - 10.12R2 and L = 18.06 + 113.64R - 1.70R2 .Those between body weight and body length for female and male were respectively expressed as W = 1.85 ?10-5L2.98 and W = 1.69 ?10-5l2.55.Back-calculated body length represented the Lee's phenomenon at the age of 1 to 2 for female and at the age of 1 to 3 for male.The growth of male was fast than that of female.Significant differences between female and male were observed on the growth after 2 years old.Gompertz' s equations were used for fitting the growth of length (Lt) at variousages (t) as L, = 300.88e-1.67e-0.42t for female and Lt= 415.15e-1.96e-0.33t for male, and the growth of weight (Wt) at various ages (t) as Wt = 511.77e-4.98e-0.38t for female and Wt =777.53e-4.92e-0.32t for male.According to the growth equations, the inflexion points of length growth were 1.22 for female and 2.04 for male, and those of weight growth were 4.22 for female and 4.98 for male.