Spawning and mortality of eggs and larvae produced by different brood sizes of Walking Catfish (Clarias batrachus L.)

Abstract

An experiment was carried out on the spawning and mortality of eggs and larvae of Magur, Clarias batrachus collected from brood-stock pond during the study period.The lowest spawn production (3774 eggs) was recorded in the fish having 23 cm total length and 115 g total body weight and the highest spawn production (10102 eggs) was recorded in the fish having 26.4 cm total length and 230 g total body weight. The spawn production was found to increase with the increase of total length,standard length and total body weight following the equations, Y= –13921+833.7X, r= 0.685, Y= 13965+909.8X, r= 0.667 and Y= 1326+33.02X, r= 0.810, respectively. The relationships between spawn production with total length, standard length and total body weight of the fish were found to be linear and significant (p<0.01). The lowest mortality rate (30.41%) was recorded in the fish having 26.4 cm total length and 224 g total body weight and the highest mortality rate (42.76%) was recorded in the fish having 23 cm total length and 125 g total body weight. The mortality rate of eggs and larvae was found to decrease with the increase of total length, standard length and total body weight of female brood following the equations, Y= 108.6–2.878X, r= –0.865, Y= 110.4–3.214X, r= –0.862 and Y= 54.99–0.108X, r= –0.970, respectively.The relationships between mortality rate of eggs and larvae with total length, standard length and total body weight of the fish were found to be linear and significant (p<0.01).