Evaluation of three substrate bound periphyton systems for the farming of oreochromis niloticus in South India

Abstract

A cost-effective fish culture technology for Oreochromis niloticus was developed, whilst growing periphyton on three different substrates. The main objective of the study was to provide additional nourishment to the fish through supplementary feeding of periphyton as well as to reduce the accumulation of nitrogenous compounds in the water column through effective recycling of organic waste. Likewise, the suitability of the substrates (bamboo poles, PVC pipes and nylon nets) in cement cisterns were evaluated and compared based on the production characteristics and water quality parameters. Results indicated that the newly developed PVC supported artificial fibre system had greater aggregation of periphyton and thereby these treatments (TP-4) recorded high survival rates (66.6%), mean weight of fish (53.9±2.02 g) and net production (1928.9 kg haG1) compared to other two treatments and control. Similarly, the Food Conversion Ratio (FCR) and Specific Growth Rate (SGR) too were undoubtedly better in TP-4 (2.9 and 1.56, respectively), signifying the importance of adequate levels of supplementary feeding in these treatments. The levels of nitrite and ammonia in treatments with substrate bound periphyton were within permissible level indicating that the system effectively recycled the nitrogenous waste to valuable protein. With red tilapia culture gaining popularity in India, this is first such study from Kerala, South India, signifying the scope for wider acceptability among fish farmers in the region.