Fishermen's knowledge as background information in tropical fish ecology: a quantitative comparison with fish sampling results

Abstract

An investigation of fishermen's knowledge of fish occurrence patterns on various spatio-temporal scales has been realized in the Fatala Estuary (Guinea, West Africa), accompanied by a one-year survey with standardized gill-net sets. Seventy one fishermen distributed in four zones corresponding to gill-net sampling sites were questioned about seasonal variations of species' relative abundances. Longitudinal and seasonal patterns of fish relative abundances were described with correspondence analysis and ANOVA for both approaches. Comparison of results showed a good coherence between fishermen's answers and gill-net sampling results. Thus, it is proposed that investigation of fishermen's ecological knowledge should be used as a preliminary study to help defining fish sampling designs in tropical rivers and estuaries.