Drivers of the upper River Amazon giant catfish fishery

Artisanal fishers of the upper reaches of the Amazon River use a variety of tactics to catch giant Brachyplatystoma catfish species: Brachyplatystoma vaillantii Valenciennes, Brachyplatystoma rouseauxii (Castelnau) and Brachyplatystoma filamentosum (Lichtenstein). These catfish are migratory, caught with different gears, by different communities, and influenced by temporal and spatial changes in river conditions. Facing these factors, it was hypothesised that the catfish fishery yields in the headwaters of the Amazon are determined by fishing tactics efficiency, riverscape features and governance basis. Data on catfish yields were collected from two contrasting riverscapes (rapids and floodplains) in the most important Amazonian affluent in Colombiathe Caqueta River. Results indicated that: (1) catfish yield was strongly associated with fishing effort in both riverscapes, (2) seasonal drivers play an essential influence in the high rapids reach, and river level in the low floodplain reach, (3) community strategies affected yield, although the effect is different depending on the gear used as the environment profile affects enforcement. Based on the results, it was concluded that efficient upstream management of these species should combine specific measures for each riverscape with an integrated approach to the river production system that considers catfishes longitudinal migrations and the growth overfishing occurring in the Amazon estuary.