Performance of diets composed of Artemia biomass and fish meal fed to juvenile marine Tilapia in cages

Abstract

Mariculture development in Kenya has previously relied on culture of fish in intertidal earthen fish ponds that are fertilized to enhance primary production and use of limited supplementary feeds. Most of the supplementary feeds used have previously been obtained from those of freshwater fish due to lack of marine fish feeds in the country. Cage culture is being introduced to utilize the open space in the sea and hence introduction of more species for farming, that require new feeding strategies that are feasible. Therefore the need to develop marine based fish feed formulations. Taking this into consideration, Kenya Marine and Fisheries Research Institute is developing a feed formula that brings ingredients from the coastal environment that are unique: i.e. seaweeds, coconut husks and Artemia for development of a marine feed. Initial assessments of the developed feed indicate that marine Tilapia grows at 1.2 g day-1, Rabbitfish at 1.9 g day-1 and Milkfish at 1.4 g day-1. The formula is being refined and validated over time before being given out for commercial use in the feed industry to enhance production from mariculture. The treatments were carried out in replicate during a culture period of 138 days. Locally formulated and prepared diets containing 30% crude protein were applied. Treatment 2, a fish meal omena (Rastrineobola argentea) based feed showed better growth outcome as compared to treatment 1 (Artemia based feed) in terms of weight gain, specific growth rate (0.93), survival rate (70%) and feed conversion ratio (2.2). Frequent data collection for both water quality and growth parameters is recommended to enable visualize better growth trends and culture conditions. Further research at different stocking densities with larger juveniles (50g weight) that can withstand the cage environment is recommended.