Effect of Supplementary Feed Fertilizer and Physico-Chemical Parameters on Pond Productivity Stocked With Indian Major Carps in Monoculture System

A study was conducted to evaluate the effect of supplementary feed fertilizers and physico-chemical parameters on the primary and secondary productivity of earthen ponds stocked with Indian major carps (Catla catla Labeo rohita and Cirrhinus mrigala) under monoculture system. Three fish species (35015 g) were stocked at 70fish/pond for 90 days. Each species had three treated and one control pond. The control ponds received only organic and inorganic fertilizers while treated ponds of all the fish species received organic and inorganic fertilizers along with supplementary feed. Pond productivity in terms of chlorophyll-a estimation phytoplankton and zooplankton abundance were studied on daily as well as on weekly basis. Results of the study revealed that chlorophyll-a concentration significantly varied in fish ponds (Cirrhinus mrigala F = 52.91 Labeo rohita F = 20.00 and Catla catla F = 11.73) and higher in treated than control ponds on daily basis. Whereas chlorophyll-a concentration on weekly basis was found significantly higher in ponds containing Cirrhinus mrigala (F = 40.14) and non-significant in Labeo rohita (F = 2.98) and Catla catla (F = 0.75). The diversity indices (diversity equitability and Simpson index) of phytoplankton and zooplankton were significantly higher in treated versus control ponds. The order of abundance among 23 species of phytoplankton recorded during the study period were; Cyanophyceae greater than Englenophyceae greater than Bacillariophyceae. In conclusion supplementary feed along with fertilizers and higher temperature significantly enhanced natural productivity of ponds compared to fertilizers alone.