CONSERVATION OF THE RIVER DOLPHIN (INIA BOLIVIENSIS) IN BOLIVIA - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 57

mitochondrial genes (control region and Cyt-b) in the Bolivian form did not share any
haplotype in comparison to the other two populations. Furthermore, Ruiz-García et al.,
(2008b), analyzing autosomal and Y-chromosome intron sequences, presented additional
molecular evidence that favored an independent evolutionary history of the Bolivian
population. This reinforces the results of Banguera et al., (2002) which subdivided Inia into
two evolutionary units (Moritz, 1994), although the divergence may not be as temporally
distant as was previously claimed.
Similar to molecular genetics studies, morphological studies, have indicated that the
Bolivian population is a separate species because of its greater number of teeth, smaller body
size but more robust, smaller skull size, larger flipper size and greater tail length (relative to
body length) (Pilleri & Gihr, 1977; da Silva, 1994; Ruiz-García et al., 2006). These
morphologic and molecular data clearly indicate the uniqueness of the Bolivian Inia ,
highlighting the importance of obtaining further knowledge of its biology, distribution,
abundance and ecology.
Distribution and Abundance
In Bolivia, the bufeo is located in rivers of the Amazon basin, within the Cochabamba,
Santa Cruz, Beni, and Pando areas (Figure 1).
Their population and distribution within these Rivers is determined by the availability of
food rather than by the type of water (white waters, black, clear or mixed), pH or
physicochemical characteristics (Aliaga-Rossel, 2003; da Silva, 1994; McGuire, 2002). The
bufeo has a preference for river confluences, lagoons, river bends/curves. During high water
season (November to April), they expand their area of search for food by swimming inside
flooded areas (forests) and small or ephemeral tributary rivers (Best & Da Silva, 1993;
Aliaga-Rossel, 2002; Aliaga-Rossel and Quevedo, in prep). They can stay in the same area up
to a year upon which they move to other habitats. A paucity of seasonal movement
information makes it impossible to completely describe their movement patterns. McGuire &
Henningsen (2007) indicated that Inia frequently move 40 to 60 km within a 24-h period.
Although some individuals can remain in the same location for several days, there are
anecdotal reports of Inia traveling in excess of 1,000 km (McGuire & Henningsen, 2007). In
contrast, Aliaga-Rossel (2000) suggested that Inia boliviensis had a more conservative
maximum range of 60 km which they can potentially travel in less than a week.
The bufeo is located in the sub-basin of the Madeira River (Fig 1), in the department of
Pando, in the Negro and Abuná rivers, which flow into the Madeira River. However, there are
no published registers of these occurrences (Anderson, 1997).
They also inhabit the Itenez's sub-basin (Guapore in Brazil) in the Iténez, and its
respective tributaries including the Baures, Paraguá, Pauserna, Verde, Blanco, San Luis
(Yañez, 1999), San Martín (Salinas 2007, Tapia 1995), Santa Rosa, Machupo (Anderson,
1997) and Irupururu .