Understanding fishers' spatial behaviour to estimate social costs in local conservation planning

Abstract

Artisanal fisheries are a key source of food and income for millions of people worldwide. However, unmanaged or excessive fishing activity can lead to declining returns for fishing effort and livelihood insecurity, and adversely impact wetland ecosystems. Management interventions such as protected areas and temporal closures may improve fishery sustainability and reduce environmental degradation, but often carry costs for fishers. Understanding predictors of fishing behaviour would allow conservation planning to minimise the adverse impacts of interventions, increasing the likelihood of fisher support of change. However, factors influencing fishers’ behaviour are rarely identified or taken into account when implementing conservation actions. Madagascar’s Lake Alaotra wetland supports the nation’s largest and most productive artisanal freshwater fishery, and provides critical habitat for endemic wildlife. Local fishers depend on the fishery for livelihood throughout the year. Catch-monitoring interviews, semi-structured interviews, focus groups, and follows were conducted over 16 months with 784 fishers at Lake Alaotra to understand the socioeconomic dynamics of the fishery. Although information from the fishers was sometimes imprecise, participatory monitoring methods engaged fishers and improved understanding of system dynamics. Linear mixed models confirmed that proposed restricted areas and temporal closures would generate direct short-term costs through reduced catch sizes, which vary between gear types. Socioeconomic data, spatial distribution of fishing effort, and fishers’ evaluations of management scenarios were used to explore alternative strategies. The conservation planning tool Marxan was used to identify reserve networks capable of achieving conservation goals while minimising adverse impacts for fishers. The research demonstrates that: interventions can have unequal impacts on local people: information about costs and benefits of interventions can produce more realistic and implementable conservation plans: and actively engaging fishers and understanding their spatial behaviour at relevant scales is critical for managing fisheries sustainability and promoting effective long-term conservation of freshwater ecosystems.