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5 Cage Fish Culture: An Alternative Livelihood Option for Communities87The characteristic feature of the Nepalese cage fish culture is its sustainableproduction through the use of plankton-feeding fish, such as bighead carp,Aristichthys nobilis, and silver carp, Hypophthalmichthys molitrix (Swar and Gurung1988 ; Rai and Mulmi 1992 , Gurung et al. 2005) . In this system, stocking is managedat a level of sustainability at which fish production remains low per unit area comparedto intensive cage fish farming as the fish rely only on natural food withoutexternal feed input (Rai and Mulmi 1992) . Approximately 3–5 g body weight fingerlingsof silver carp and bighead carp are stocked in nursery net cages of 5 × 5 × 2 mof mesh size of 5–10 mm, grown for about 8–12 months, and transferred to productioncages of 25–50 mm mesh cages of 5 × 5 × 2 m, hung on bamboo frames that alsofunction as a float. The stocking density ranges from 10 to 15 fish m −3 depending onthe size of the fish. This method is extensive, and therefore, an environmentalfriendly farming system as it does not introduce nutrients into the water body.5.2.1 Origins of the Idea of Cage Fish Culture and itsExpansion in the ReservoirThe plankton-based cage fish culture in Nepal was initiated in lakes of the PokharaValley for the benefit of the landless and deprived Jalari community for livelihoodenhancement (Gurung and Bista 2003) . As this cage fish farming practice was successful(Swar and Gurung 1988 ; Gurung et al. 2005) , it was thought that cage fishfarming could also provide an alternative livelihood for displaced people inKulekhani Reservoir. A proposal from the Government of Nepal was accepted bythe International Development Research Centre (IDRC), Canada, to research onlimnology and assess the feasibility of developing cage fish farming in KulekhaniReservoir (Rai and Mulmi 1992 ; De Silva 1998 ). Based on the findings that thetechnology was feasible, appropriate cage fish culture was subsequently extendedsuccessfully into Kulekhani reservoir (Rai and Wagle 2007) .5.3 Kulekhani ReservoirKulekhani Reservoir (27°23 ¢ 25″–27°41 ¢ 31″N; 85°2 ¢ 46″–85°16 ¢ 16″E) that waslocated approximately 42 km from the capital Kathmandu in the northeastern partof Makawanpur District with a catchment of 126 km 2 was impounded in 1982.Kulekhani Reservoir is a small 220 ha water body situated in the mid hills ofCentral Nepal at 1,430 m above sea level. The reservoir was designed with ananticipated lifespan of more than 50 years. The reservoir draws down upto 54 mduring the peak season of power generation, reducing the water surface area downto about 65 ha. Earlier, it was assumed that most of the time the water level in the