Seasonal movements of river dolphins (Inia geoffrensis) in a protected Amazonian floodplain

摘要

Deliberate killing for use as bait in a regional catfish (Calophysus macropterus) fishery is the primary threat affecting the survival of the Amazon river dolphin, or boto (Inia geoffrensis). Establishing and improving freshwater protected areas has been suggested as a possible course of action to protect the species. However, the ecology of the boto is poorly understood and more information is needed on the species' habitat use and movement patterns to ensure that spatial protection initiatives meet conservation needs. In this study, mark-recapture/resight data collected in and near the Mamiraua Sustainable Development Reserve, a varzea in the Brazilian Amazon, was used to examine transition probabilities of botos between various habitat types. Our findings suggest that it is imperative that spatial protection initiatives focused on the boto take into account the importance of varzea habitat and bay systems for individuals in early life stages. Moreover, because botos frequently occupy the main rivers, particularly during the low water period, protecting areas of the main river waters adjacent to varzeas could aid in the protection of hunted populations.