Abstract
Artificial breeding, embryonic development, larval rearing and pond culture of freshwater eel Guchibaim, (Mastacembelus pancalus) were studied at the Field Laboratory Complex of Bangladesh Agricultural University, Mymensingh during April, 2007 to December, 2009. The fecundity of M. pancalus was found to have significant (P<0.01) linear relationship with the gonadal weight. The equation was represented by, Y=72.36x+799.77. Four sources of hormonal substances were tested to examine that effectiveness on ovulation, fertility and hatching rate of M. pancalus eggs under controlled conditions. Double doses of PG (1st 60 mg/kg body wt.; 2nd 110 mg/kg body wt.) and HCG (1st 1000 IU/kg body wt.; 2nd 1650 IU/kg body wt.) were found to be better than single dose of ovaprim (6 ml/kg body wt.) in egg maturation and ovulation. Profasi and ovaprim were found comparatively less effective to ovulation. Embryonic and larval developments of M. pancalus were studied under laboratory conditions. At fertilization, the eggs were 0.7 mm in diameter. First cleavage took place within 0.30 hrs after fertilization and the embryonic rudiments of developing eggs appeared at 34-35 hrs at 27.0-31.0°C. The yolk sac was completely absorbed at 72 hrs during embryonic development on attainment of 5.5 mm total length. At the same time, digestive system became fully developed and the larvae were started to search for food. Nursery rearing of M. pancalus was studied in relation to different supplementary feed with varying stocking densities for a period of six weeks in earthen ponds. The growth performances of Guchibaim (ADG, SGR and survivality rate) were found to be better at a stocking density of 0.7 million individual/ha when fed with a mixture of mustard oil cake, rice bran, fish meal, vitamin premix and dicalcium phosphate than other diets. Stocking density had significant effect on the growth, survival and production of fish fry. The physico-chemical and biological characteristics of water were found to be in optimum ranges for the fish culture. Mastacembelus pancalus when stocked (initial at0.002g) at 24800/ha in monoculture yielded 987.50 kg/ha/6 months, with net return of Tk. 63697 having food conversion ratio of 1.84. Production potentials of M. pancalus in monoculture were examined, which indicated that the cultivation of this species is economically viable and the growth rate of M. pancalus is higher in open water system than that in closed system.