Compared to most marine odontocetes, river dolphins live in an environment that is less-stable and more spatially complex than the ocean. Yearly seasonal fluctuations in river levels may be as great as 20 meters, and lead to seasonal extremes in quality and quantity of aquatic habitat available to river dolphins. Seasonal changes in water levels also affect the availability of dolphin prey due to seasonal patterns of fish reproduction and fish migrations. Human-induced threats to river dolphins, such as incidental net entanglement, vessel strikes, and deliberate killing appear to vary seasonally as well. In this chapter, we present our investigations of the seasonal ecology of Inia spp from three river basins of South America (Inia geoffrensis humboldtiana in Venezuela's Orinoco River Basin, Inia geoffrensis geoffrensis in Peru's Amazon Basin, and Inia boliviensis in Bolivia's Mamoré Basin). We provide results from our observational studies (which included boat- based surveys of groups and photo-identification of individuals) and we discuss these results in the context of other information about the seasonal ecology of Inia, including distribution, movement patterns, group size, age-class composition, and seasonality of reproduction. We conclude with a discussion of how seasonal ecology should be considered in the conservation of river dolphins and of the management of human activities that affect them.
|Título de la publicación alojada||Biology, Evolution and Conservation of River Dolphins within South America and Asia|
|Editorial||Nova Science Publishers, Inc.|
|Número de páginas||26|
|ISBN (versión impresa)||9781608766338|
|Estado||Publicada - 2010|