Stilt fisher knowledge in southern Sri Lanka as an expert system: A strategy towards co-management

Most small-scale fisheries throughout the world are based primarily on fisher knowledge, which is essentially experiential knowledge consisting of a replicable, verbally transmitted set of skills. Even though fisher knowledge is well documented for some fisheries, there are only a few studies that explain how it actually works as a management system. Stilt fishing is a unique method confined to the southern coast of Sri Lanka. We studied traditional stilt fisher knowledge as an expert system that helps make decisions for successful fishing. Study shows that traditional fisher knowledge base and the decision-making process can be explained as an expert system. Fisher knowledge on biological and physical indicators that gives cues on commencement date of fishing season, arrival of fish schools and its composition and ecology and behaviour of target fish were distilled and empirically confirmed. Traditional stilt fishers were found to hold detailed knowledge about weather, fishing season, feeding and migratory behaviour of target fishes, mainly the bluestripe herring (Herklotsichthys quadrimaculatus). Empirical studies on feeding behaviour, movement and migratory path of bluestripe herring indicate the reliability of fisher knowledge. Fishers' expectations before starting fishing (ex-ante) on species composition arriving at fishing territory were 100% accurate at the actual harvest in conclusion of fishing (ex-post). Success in fishing depends mainly on technical skills, and there exists considerable variation in the level of expertise among fishers. Traditional fishers are more successful in fishing than non-traditional fishers. Traditional stilt fishers provide inexpensive information that can complement scientific information to produce better management outcomes. Fisher knowledge can therefore be effectively utilized in formulating policies for co-management of coastal fisheries in Sri Lanka. Opportunities exist to set up proper baseline for the management of artisanal coastal fisheries with the ultimate aim of incorporating traditional fisher knowledge into management decision making.