Nursing of hybrid catfish (Clarias macrocephalus x C. gariepinus) in flow through water systems

Abstract

     The study on the nursery method of hybrid catfish (Clarias macrocephalus x C. gariepinus) was divided into 2 periods: Phase 1 nursery in the flowing water system, using a round oval-shaped plastic bucket at stocking densities of 500, 2,500, 5,000, 7,500 and 10,000 fish larvae per square meter. A completely randomized design (CRD) trial was planned for 5 replications. Moina was given as feed to satiation. Water flowing at the rate of 30 liters per hour at 1-10 days of age, and Phase 2, bringing the fish larvae from the first phase of the experiment to nurse in cages in earthen ponds by taking the fry from the first phase of the experiment. They were combined at each density level before being nursed in cages in earthen ponds at the density of 500 individuals per square meter. These were arranged in 3 replicates. The small catfish were fed with 32% protein as food at the rate of 5-10% of body weight per day. The diet was adjusted accordingly to the feeding amount of the fish fry at 11-30 days of age.

     The results showed that in the first phase, the fish were nursed for 1-10 days at a density of 500 fish/m² had statistically significant (p<0.05) higher in average weight, length, and daily weight gained and growth   performance than all other experimental groups. When comparing survival rates, it was also found that fish groups at a density of 5,000 fish/m² had the best survival rate but not statistically different (p>0.05) from fish fed at other densities.The results of Phase 2 fish growth from day 11 to day 30. It was found that the fish at the density of 500 fish/m² had the statistically (p<0.05) highest in average weights and daily weight among all experimental groups. However, its mean length and survival rate were not statistically significantly different (p>0.05) from other fish in the experimental density groups.These results indicated that nursery for hybrid catfish in the flowing water system up to 7,500 fish/m² can be reared at 1-10 days of age and when further cultured in ponds until 30 days of age, there is no effect on growth and survival rates.