STUDY ON THE AGE AND GROWTH OF PSEUDORASBORA PARVA FROM NANWAN LAKE UPSTREAM THE HUAIHE RIVER

Pseudorasbora parva is a native small cyprinid fish widely distributes in Asia with a considerable population. To investigate the growth, age composition and growth characteristics of Pseudorasbora parva, 532 individuals were collected from three different water inlets of Nanwan Lake in March, May, July and December. The results showed that the body length were ranged from 35.82 to 88.28 mm with the mean of (61.61±11.8) mm, and that the body weight were ranged from 3.07 to 59.17 g with the mean of (19.23±10.73) g. The age were ranged from 1 to 3.3 years and the dominant population with the mean of 57.38% were individuals with 3 years. The relationship between body length and body weight were W=9.602E–5L^2.928 (R²=0.883) for female and W=4.487E–5L^3.116 (R²=0.889) for male, which showed a significant difference between male and female (F=5.241, P<0.05). A linear relationship was found between the scale radius and body length, which was significantly affected by gender (F=78.405, P<0.05). Growth parameters were L_∞=107.005, K=0.246 and t₀= –0.76 for female and L_∞=145.254, K=0.181 and t₀= –0.66 for male, respectively. The growth inflexion of female (3.607 years) were 70.46 mm for body length and 24.72 g for body weight, and the growth inflexion of male (5.619 years) were 98.64 mm for body length and 73.53 g for body weight. These re-sults suggest that the female was isauxesis while the male was allometric, and that the male had a faster growth rate than female.