ACS Monterey Bay Program for August 2003
River dolphins of the Peruvian Amazon
Since 1993 the Oceanic Society has
conducted research on the river dolphins of the Peruvian Amazon. Twenty
five hundred kilometers from the mouth of the Amazon two species of
river dolphins, Buto (Inia geofrensis) and Tucuxi (Sotalia
fluviatilis) inhabit the Peruvian Pacaya-Samiria National Reserve.
Fortunately for the dolphins they are protected by both mythology
and Peru's enlightened protection program. In other areas of their
range, especially in Brazil where habitat degradation due to gold
mining is a greater problem for the dolphins than in Pacaya Samiria,
populations of both Bufeo and Tucuxi are threatened. Although Peru
has few financial resources to protect these dolphins, the Pacaya
Samiria river dolphins may represent the healthiest river dolphin
populations in the world today. This situation may not continue as
other factors, especially the value of mahogany, now threaten these
Buto inhabit more diverse habitat than Tucuxi and genetic evidence indicates that they have inhabited the Amazonian basin for much longer. Tucuxi and Buto both are common in the large and smaller rivers of the area, but only Buto appear to enter the flooded forest during high water. Group size for both species is small and does not show large seasonal variations. Photo-id of these species is possible, but because of the highly turbid environment successful individual identification is much more difficult than for most other species.
This is the first program that we have had at ACS on these unique animals.
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