Understanding the trade-offs in tropical reservoir fishery in a socio-ecological perspective

A study involving the assessment of ichthyo-diversity, physico-chemical aspects of reservoir, socio-economics of the reservoir fishers and their sustainability issues was conducted in Peechi Reservoir, in Thrissur District, Kerala, India during 2016-2018. The study indicated the need for developing appropriate reservoir based fishery management measures in protected ecosystems considering the intricate trade-offs between conservation strategies leading to ensuring livelihoods for the resource poor fishers. Fish and water samples collected were analysed on various scales. The study indicated that Salmostoma novacula was the major species contributing to the diversity in terms of abundance in the reservoir. The diversity, species evenness (0.92 to 0.95) and species richness index (1.73 to 2.39) were observed to be higher at the sampling site ‘Intermediate 1’. Canonical correspondence analysis (CCA) indicated that diversity was positively associated with dissolved oxygen (0.58), pH (0.62) and hardness (0.66) and negatively correlated with conductivity (-0.60). Socio-economics of the reservoir fishers identified very low monthly relative contribution of the species to the fishers’ income of the reservoir, which calls for better management measures of the reservoir with respect to supporting the livelihood and sustainable management. Based on fishers’ perception on fisheries management, an index called reservoir fisheries management index (RFMI) was introduced, which indicated that management of technical drivers will ensure better fisheries in Peechi Reservoir. The study identified that technological interventions like enclosure-based culture system using indigenous fishes of the reservoir such as Etroplus suratensis , hatchery operations and tourism during the lean period to support the livelihood of the fishers are critically needed. Thus, a participatory mode of culture supported sustainable conservative management may be incorporated in this reservoir. This is the first study of its kind in reservoir based aquatic system.