LAUSR

The giant arapaima (Arapaima sp.) has been described as a fish of change in Amazonia due to its important role on conservation of floodplains, food security and income generation for rural communities. However, despite the cultural, ecological and economic importance of arapaima, data on diet are scarce. Aiming to expand knowledge about arapaima diet in western Amazonia, we integrate scientific knowledge with the knowledge of local dwellers. During the low-water period (September 2018) and the falling-water period (June 2019) we collected arapaima stomachs from 11 floodplain lakes in the middle Juruá River. All fishes were measured (TL - total length) and sexed. Food items from each stomach were categorized as fishes, invertebrates, plants and bone remains, and weighed. Also, in the latter period we interviewed experienced local fishers about arapaima feeding. Our integrated approach revealed that young arapaima eat fish and invertebrates, but adult arapaima eat fish of a wide range of species, which were mainly of low and intermediate trophic positions. We report the first case of cannibalism for arapaima, and we also show that during the low-water period, many individuals had empty stomachs or with only some small fish bone remains and/or plant material. Arapaima sex and total length had no influence on the absence of prey in stomach contents. Overall, we conclude that local people had consistent ethnobiological knowledge of arapaima feeding ecology that could be useful within management projects in the region.