Fertilization and stocking of unmanaged ponds through temporal plankton community structure map (PCSM): A nascent concept in aquaculture planning

Background: This paper deals with a non-conventional approach called PCSM model. It was developed to aid in horizontal expansion of aquaculture through utilization of unmanaged ponds for modified extensive aquaculture. This model applies to small lentic water bodies like ponds (<10 ha area) where plankton count and limnological parameters are naturally within permissible range for fish culture or survival. It can only help in – ‘ modified extensive aquaculture ’ by increasing the abundance of plankton groups that are most preferred. This is only applicable for culturing planktophagus fishes. Methods: : PCSM incorporates annual plankton community dynamics (data) of some representative ‘ unmanaged ’ ponds of the region. Only the dynamics of top two highly palatable and highly preferable Phytoplankton ( Chlorophyceae and Bacillariophyceae ) and Zooplankton ( Rotifera and Copepoda ) groups for Indian Major Carps were focused upon. The monthly composition of each plankton group in each pond of the region was averaged and plotted into a graphical model called Multiple Spline Curve with 5% padding using SigmaPlot. Results: : The model here has been developed in reference to pond based polyculture of 3 Indian Major Carps ( Catla catla , Labeo rohita and Cirrhinus mrigala ), which is still a dominant practice in the unmanaged freshwater ponds in India. The model can help in deciding two things – Fertilization timing (PCSM: Fertilization Module) and Stocking time (PCSM: Stocking Module). It is region specific and presently developed for Raipur district of Chhattisgarh, India. Discussions: : Through PCSM, effective pond fertilization period is 7 months out of 12 (April, June, August, September, October, December and February). Moreover, year round multiple stocking multiple harvesting based fish culture can be ensured in unmanaged pond through PCSM guided stocking schedule (June, August, November and December).