Some Biological Aspects of Pond Reared Mystus cavasius (Hamilton, 1822) Collected from a Local Fish Farm in Mymensingh, Bangladesh

An investigation was conducted to observe some biological aspects including growth, sex ratio, gonadal maturity, artificial insemination, fecundity, fertilization, hatching and larval development of Mystus cavasius in a private hatchery. With the specific growth rate (SGR) of 1.80±0.53 and average daily gain (ADG) of 0.18±1.0, the total weight of the sampled fish ranged from 1.59±0.44 to 28.30±14.77 g, and the length ranged from 3.39±0.77 to 13.62±3.16 cm. There has been a strong association between fish length and weight (r2=0.95). The ratio of males to females was 1:1.58. The female and male lengths at first maturity were 9.2 and 9.6 cm, respectively. The gonadosomatic index (GSI) of females found in the present study were ranged from 4.35 to 7.44 with the mean of 6.71±0.69 during the study period. The fish is highly fecund and fecundity ranged from 5600 to 25860 with the mean of 17083±6055 for the corresponding length 15.49±1.69 cm, body weight 37.53±7.24 g and gonad weight 2.55±0.63 g. During the experiment, the fertilization, hatching rates, and larval development were observed. The scatter plot developed for the association between length and body weight, fecundity-body length, fecundity-body weight and fecundity- gonad weight implies a significant correlation both arithmetically and logarithmically.