Assessing vulnerability and adopting alternative climate resilient strategies for livelihood security and sustainable management of aquatic biodiversity of Vembanad lake in India

Abstract

The present study was carried out at the Thycattussery area in Vembanad lake and assessed the ichthyo-diversity, variability in climatic variables, the exploited status of predominant small-scale sector fisheries (SSFs) and impact of climatic variables upon an existing SSF. Fish, as well as clam specimens collected from the study area, were identified. Diversity indices and dominance curves helped to identify monsoon (June–September) as the diverse season in the wetland. SIMPER (similarity percentage) analysis indicated that Villorita cyprinoides (clam) was the predominant species in the wetland with a mean relative abundance of 16.1%. Canonical correspondence analysis (CCA) of variables with clam production identified calcium hardness and rainfall with axis loadings of –0.56 and 0.50 respectively as the variables predominantly contributing to clam production. Stepwise regression indicated that temperature and rainfall were the determinants of clam production. A decrease in rainfall and an increase in temperature at an annual rate of 0.02 and 0.8%, respectively, decreased the clam production by 5.37%/year in the study area. Further, the generalized linear model (GLM) indicated stagnancy in clam production until 2035 below 400,000 kg per year. The study introduced diversification of livelihood systems using clam culture in climate resilient pen structures (CRPS) as an adaptation strategy. HIGHLIGHTS The study identified climate change as the major stressor affecting small scale fishers in Thycattussery region of Vembanad lake (wetland).; The study exposed a huge decline in the production of a predominant single species (Villorita cyprinoides) fishery to the tune of 5.37% per year and attributed the decline to climatic variables such as temperature and rainfall.; The study predicted that the clam production will have a stagnant phase till 2035 below 400 tonnes per year in the study area, which in turn will have an unanticipated loss in catch per unit effort of the fishers.; The study proposes suitable fishing technology with lesser investments (Climate Resilient Pen Structures) as the appropriate adaptation strategy for restoring the declining fishery in the region.; This strategy brought about by Central Inland Fisheries Research Institute helps the small-scale fishers through diversification of livelihood systems, wherein farmers switch between farming in CRPS (Climate Resilient pen Structures) and fishing in response to seasonal and inter-annual variation in black clam fisheries.;

Keywords

• adaptation
• clam fisheries
• climate change
• climate resilient pen structures
• livelihood
• vulnerability