PRODUCTION OF MICROALGAE FOR SHRIMP LARVICULTURE

Shrimp culture in Nigeria is not yet well developed despite the abundance of the species in the marine waters. This has been attributed to lack of sustainable production of microalgae both in quality and quantity for shrimp larviculture. A study was conducted at the microalgae laboratory of Nigerian Institute for Oceanography and Marine Research, Lagos, Nigeria to determine the culture possibility of four local microalgae, Chaetoceros, Skeletonema, Isochrysis and Chlorella species. Chaetoceros, Skeletonema, and Isochrysis were cultured in modified Guillard F medium while Chlorella was cultured in Conwy medium. The growth pattern of the four microalgae showed very short lag phases indicating that they adapted well to the culture conditions. The exponential phases of all the microalgae were similar occurring in the third day of culture. Chaetoceros, Skeletonema, Isochrysis, and Chlorella species reached their stationary phases from the sixth to the ninth day with the highest densities of 7,750,000; 1,105,000; 6,091,000 and 6,510,000 cells/ ml respectively. Chaetoceros specie had the highest cell density of 7,750,000cells/ ml at the 7^th day while Skeletonema had the lowest density of 101,500 cells/ml at the 13^th day. The study showed that the microalgae species can grow well and be maintained in the laboratory through continuous sub-culturing. Successful mass cultures of these species indicate that hatchery production of shrimp and prawn larvae is feasible in Nigeria.