Growth performance and mortality of different life stages of carp fish seed in freshwater fish culture system

Due to the non-availability of good quality fish seed of Indian Major Carps (IMCs), majority of fish farmers of district Saran, Bihar are bound to stock their ponds with either fry or poor quality fingerlings at higher densities procured from local or interstate vendors. Consequently, this results in poor growth, increased mortality rate and reduced fish production. An on-farm trial was conducted to assess the growth performance, total yield and economic analysis of carp fish culture/ seed rearing of different life stages in fresh water fish culture system in Saran district during September, 2019 to March, 2020 in 9 earthen ponds of area 0.1 ha and depth 1.5 m each at three farmers’ ponds at similar location. Treatments were designated as T₁ - farmer’s practice (stocking of IMCs fry at the rate of 15000 no/ha), T₂ - stocking of IMCs fingerling at the rate of 8000 no./ha) and the recommended practice T₃ - stocking of IMCs yearlings at the rate of 4000 no./ha). All the treatments groups were fed @ 3% body weight with rice bran (RB) and mustard oil cake (MOC) in 1:1 ratio twice daily. Physicochemical parameters of water such as temperature, pH and dissolved oxygen were found to be within optimum range for carps. The average fish production recorded in T₃ treatment was higher, thus indicating a faster and better growth performance of fish yearlings compared to fry (T₁ group) and fingerling stage (T₂ group) of fish. Gross profit to the tune of Rs. 2.31, 5.31 and 5.93 lakh per hectare were recorded from rearing IMCs fry, fingerlings and yearlings stages, generating a net profit of Rs. 1.06, 3.06 and 3.98 lakh and a benefit-cost ratio of 1.85, 2.36 and 3.04, respectively.