Utilization of Natural Fish Food Item, Periphyton for Replacement of Commercial Feed in Milkfish (Chanos chanos) Culture

Abstract

Feed is the costliest input that accounts 50-60% of operational expenditure in aquaculture. To reduce the feed quantity and minimize related environmental impacts arising from feed wastage in aquaculture, natural fish food item, periphyton can be utilized as an alternate option. Milkfish (Chanos chanos), being a herbivore fish, can be cultured by developing periphyton biomass as natural diet and thereby to reduce use of commercial feed. Monoculture of milkfish (15000 no./ha) for 180 days was undertaken in 50 m2 pond enclosures with four different feeding systems: (P0) control with total feeding and no periphyton; P75, P100 and P125 were with periphyton grown on 75, 100 and 125% pond surface area, respectively along with partial feeding. White nylon net (40 mesh) as substrate for periphyton growth was fixed vertically in the epilimnion of pond water. Fish growth (242.29±5.22 g), productivity (3146±60 kg/ha) and benefit-cost ratio (1.81) were significantly highest (P<0.05) with lowest FCR of 1.17±0.02 in P125. FCR could be reduced maximum by 46% compared to P0 in P125 based on the dry matter of periphyton grown in negative control enclosures containing no fish. Therefore, this method is appropriate for monoculture of milkfish to reduce feed cost and ensure environmental sustainability