Aquaculture production in Malawi is low and hinges on very few tilapia species, which have poor fingerling quality, poor growth and low fingerling supply. Oreochromis karongae has shown potential for fast growth, but is constrained by low fecundity, hence low fingerling supply. O. karongae hatchability has been improved with the introduction of a portable hatchery. The demand to produce uniform size fish for commercial farming has posed a challenge for natural incubation. The research was vital to the finalization of the development of a technology that has high potential to increase fingerling availability and improve fish production in Malawi. The research is in line with Malawi Government’s efforts to increase fish production using simple technologies.
A portable hatchery technology was developed to help combat low O. karongae fingerling availability in Malawi. O. karongae fry was bred in the two hatching units (portable hatchery and earthen ponds) and nursed in concrete tanks and hapas. Treatments were replicated thrice. One-way analysis of variance (ANOVA) was used to determine the significant difference in growth and survival rates of fish in all treatments at 5% significance level. The nursing technology had a significant effect on growth (P<0.05) but not survival of fry (P>0.05). Survival rate was significantly higher for fry hatched from portable hatchery than from earthen ponds (P<0.05).
The study has shown that earthen ponds hatching followed by tank fry nursing promoted better fry growth while portable hatchery prepares the fry for better survival to fingerling stage in both pond hapas and concrete tanks. Farmers intending to promote higher fry survival and maximize returns from selling large quantities should consider adopting portable hatchery.