Capturing Ecosystem Services, Stakeholders' Preferences and Trade-Offs in Coastal Aquaculture Decisions : A Bayesian Belief Network Application

Aquaculture activities are embedded in complex social-ecological systems. However, aquaculture development decisions have tended to be driven by revenue generation, failing to account for interactions with the environment and the full value of the benefits derived from services provided by local ecosystems. Trade-offs resulting from changes in ecosystem services provision and associated impacts on livelihoods are also often overlooked. This paper proposes an innovative application of Bayesian belief networks - influence diagrams - as a decision support system for mediating trade-offs arising from the development of shrimp aquaculture in Thailand. Senior experts were consulted (n = 12) and primary farm data on the economics of shrimp farming (n = 20) were collected alongside secondary information on ecosystem services, in order to construct and populate the network. Trade-offs were quantitatively assessed through the generation of a probabilistic impact matrix. This matrix captures nonlinearity and uncertainty and describes the relative performance and impacts of shrimp farming management scenarios on local livelihoods. It also incorporates export revenues and provision and value of ecosystem services such as coastal protection and biodiversity. This research shows that Bayesian belief modeling can support complex decision-making on pathways for sustainable coastal aquaculture development and thus contributes to the debate on the role of aquaculture in social-ecological resilience and economic development

Social-ecological analysis of integrated agriculture-aquaculture in Dedza, Malawi

Through the case of integrated agriculture-aquaculture in rural Malawi, this paper argues that hybrid research can reveal new interactions in social-ecological systems not evident when studies by social or natural methods independently. While recent research acknowledges the social and natural dimensions of aquaculture systems, studies often create an artificial divide by attempting to address each aspect in isolation. Social science research has overlooked the biophysical aspects of aquaculture, while scientific research has uncritically accepted orthodox explanations of environmental outcomes without addressing the social contexts of such systems. The social component of this research reveals that fish farmers in Malawi are rejecting practices which do not work in the local context (fertilization with pond mud) and adopting strategies that do work (irrigation with pond water). The physical component of this research compliments the social by elucidating that irrigation with pond water resulted in higher soil nutrient and moisture content. The paper concludes that small-scale aquaculture can make significant contributions to rural household food and income security in Africa and that hybrid research methods can improve our abilities to investigate the complex, connected nature of social-ecological systems