PLANNING OF MODIFIED EXTENSIVE AQUACULTURE IN UNMANAGED PONDS THROUGH PCSM (PLANKTON COMMUNITY STRUCTURE MAP): A NEW CONCEPT  

This abstract hints an innovative approach called PCSM model, which is the first of its kind. 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). It can only help in - 'modified extensive aquaculture'. This is only applicable for culturing planktophagus fishes. 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 decide on 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. PCSM incorporates annual plankton community dynamics (data) of a few representative 'unmanaged' ponds of the region. Only the dynamics of top two highly palatable and highly preferable Phytoplankton (Chlorophyceae & Bacillariophyceae) and Zooplankton (Rotifera & 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. In PCSM: Fertilization Module, Only four plankton groups were focused. The pits made in each of their life-line due to dips in population are our areas of interest. These pits must be provided support through reinforcement in the form of pillars aka fertilization. Through PCSM: Fertilization Module, effective pond fertilization period is 7 months (April, June, August, September, October, December and February) out of 12 for unmanaged ponds in Raipur, Chhattisgarh. It will be big saving, less risky (to invest) and presents minimal environmental impact/ alteration. Similarly in PCSM: Stocking Module, only four plankton groups were focused. The peaks made in each of their life-line due to rise in population are our areas of interest. These peaks are perceived as opportunities for stocking. Minimum two peaks are necessary (one from phytoplankton and one from zooplankton) for validating a stocking schedule in a month. Year round MSMH (Multiple Stocking Multiple Harvesting) based fish culture can be ensured in unmanaged pond through PCSM: Stocking Module guided stocking schedule (June, August, November and December) for unmanaged ponds in Raipur, Chhattisgarh. The model needs to be implemented in field. Presently, this model is applicable for unmanaged ponds of Raipur, Chhattisgarh. Such models can also be generated for any region. Reliable data from published reports on plankton dynamics in the unmanaged ponds of a particular area need also be averaged and plotted into this model using SigmaPlot to generate a new region specific PCSM Model, comprising of Fertilization and Stocking modules, for aquaculture planning therein. The model must be updated every 6-10 years with a fresh plankton community survey from some representative unmanaged ponds of the region. This is to counteract any adverse impacts of climate change and changes in plankton succession due to selective promotion of only a few preferable plankton groups. This model will also promote climate change resilient aquaculture planning in unmanaged ponds. If IPCC (2014) AR5 predictions for South-East Asia are taken into account, plankton dominance and succession will most likely get altered. In such a situation, this model in its updated form will give a 'climate change ready' aquaculture planning because the model will change as well with time.

Disclaimer

This is an extended and innovated part emanated from the author's M.F.Sc. (Aquaculture) Thesis work submitted at Dept. of Fisheries, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh and is not related with any project work of ICAR-CIFRI, Barrackpore in any form whatsoever.