Two trials were conducted in mud-bottomed concrete tanks to assess the potential of using artificial substrates to enhance fish production in ponds. Three substrate types were tested: bamboo poles, PVC pipes and sugarcane bagasse bundles. In one trial, periphyton was grown on the substrates in the absence of fish. In the second trial, masheer (Tor khudree Sykes) fingerlings were stocked at three densities. Results showed a significant effect of substrate type on fish growth (P 0.001) and on net fish production (P 0.05), with best growth in the tanks using the bamboo substrate. In the bagasse treatment, 100 percent fish mortality occurred. Highest extrapolated periphyton-based gross fish yield (i.e. without feed inputs) was 450 kg ha1 90 d1 with PVC and 491 kg ha1 90 d1 with bamboo substrate. The best periphyton growth occurred on bamboo, followed by bagasse and PVC. Without fish, mean periphyton biomass during the culture period was 0.56-1.20 mg cm2 on bamboo [ash-free dry matter (DM)], against 0.09-0.36 mg cm2 on PVC and 0.20-0.59 mg cm2 on bagasse. No clear effect of fish density or water depth on periphyton biomass could be seen. Only on bamboo, fish density seemed to have a negative effect on periphyton ash-free dry matter and a positive effect on pigment content (chlorophyll-a and phaeophytin). Periphyton from bamboo had a lower ash content (38-47 percent of DM) than from PVC (54-55 percent of DM) or bagasse (51-58 percent of DM). It is concluded that substrate type has a strong effect on periphyton productivity and composition, and on fish productivity. Good fish production was achieved without feed inputs. More research is needed to study the economic viability of periphyton-based systems in the context of Indian aquaculture.
Keshavanath, P., Gangadhar, B., Ramesh, T. J., van Rooij, J. M., Beveridge, M. C. M., Baird, D., & Verdegem, M. C. J. (2001). Use of artificial substrates to enhance production of fresh water herbivorous fish in pond culture. Aquaculture Research, 32, 189-197. https://doi.org/10.1046/j.1365-2109.2001.00544.x