Integrated Watershed Development (IWD) has immense potential to enhance aquaculture production as the approach promotes soil and water conservation and creates water resources for various purposes including life-saving irrigation, animal watering, household uses and groundwater recharge, which eventually gives opportunity for the accommodation of aquaculture and integrated fish farming in particular. A projection analysis was carried out on water harvesting and fish production potential based on the water yield (runoff potential) and experimental fish production in Doon valley. Considering the existing Water Harvesting Structures (WHSs) and local constraints for fish farming due to higher altitude, cold temperature, limited inputs availability etc., only 10% of the total area and 10-50% of the production potential observed in the experimental farming are accounted for projection on fish farming potential in WHSs. About 52662 ha-m of rainwater can be harvested if 10% of the total catchment area and the tentative rate of 1 ha-m water yield from every 10 ha of catchment in Uttarakhand are considered, which would produce a total of 118490, 59245 and 23698 t additional fish per annum at 50%, 25% and 10% of the observed fish production rate (4.5 t ha-m-1), respectively. Considering the existing limited assured irrigation and land constraints, paddy-fish culture can be integrated in at least 5% (14,411 ha) of the total paddy fields (2,88,225 ha) in Uttarakhand, which would produce about 4,300 t of additional fish at 50% (300 kg ha-1) of the production achieved in the experiment (600 kg ha-1).
The present highest annual production level of 6422 t in Uttarakhand (NABARD, undated) is over 6 times lower than the demand of 50% of fish consumers in the State. Accounting all the fish production potential (23,698 t at 10% of observed yield, 4.5 t ha-1 yr-1 from 10% of total harvested water area) and potential 4300 t fish from paddy-fish culture besides the present fish production of 2534-6422 t year-1 amounts to 30,532-34420 t annually. This total quantum would not meet the tentatively estimated annual demand, 39684 t for 50% of fish consumers (90% of the population), based on average recommended consumption rate of 200 gm per individual per week and leave a deficit, 5264-9152 t annually.
The existing or projected demand can be met by either increasing the area of production from 10% to 20% or by increasing the production potential to 20% of the observed production. Fish demand of 50% consumers (39,684 t) may also be achieved if the ultimate potential of the State contemplated (44,000 t) in NABARD (undated) is achieved mainly by harnessing running water area for trout production and low-lying area in plains for carp production in Uttarakhand. Fish production (1,29,212 t) at the 50% production level of the observed potential (4.5 t ha-m-1) in harvested water from 10% of the area would meet the demand of fish consumers of the State (79,369 t) and produce a surplus (52,843 t) for export to other regions. Thus, the importance of fisheries in IWD requires no emphasis for its positive impact on food security, resource conservation and rural development. Approaches and strategies to scale up aquaculture production by integration of fisheries interventions into Integrated Watershed Development Programs (IWDP) are discussed.