CONSERVATION OF THE RIVER DOLPHIN (INIA BOLIVIENSIS) IN BOLIVIA - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 56

gangetica ) and the critically endangered baiji ( Lipotes vexillifer ), which it is doubtful will
survive as a species (IUCN, 2009; Reeves et al., 2003; Zhanga et al., 2003). Multiple and
potentially adverse anthropogenic pressures occur in the major river basins of South America
including mining, logging, dam construction, oil and gas exploration, and use of toxic
contaminants.
The River Dolphin is distributed widely throughout the Orinoco River basins of
Colombia and Venezuela as well as the Amazon basin in Brazil, Colombia, Ecuador, Peru,
Guyana and Bolivia (Best & Da Silva, 1993). Little is known about the status of the Inia
population, and published studies that refer to their ecology, behavior, social structure and
biology are scarce. Our knowledge of the basic ecology of the Inia comes from research
conducted in Brazil (Magnusson et al . , 1980; Best & da Silva, 1984; 1989; 1993; da Silva,
1994; da Silva & Martin, 2000; Martin & da Silva 2004), Colombia (Layne, 1958; Trujillo,
1992; Hurtado-Clavijo, 1996; Vidal et al., 1997), Ecuador (Utreras, 1995; Herman et al.,
1996; Deniker, 1999), Peru (Leatherwood, 1996; Reeves et al., 1999; Zúñiga, 1999;
Leatherwood, S. et al., 2000; McGuire, 2002; McGuire & Henningsen, 2007), Venezuela
(Trebbau & Van Bree, 1974; Trebbau, 1978; Meade & Koehnken, 1991; Schnapp &
Howroyd, 1992; McGuire, 1995; McGuire & Wienemiller, 1998;McGuire & Aliaga-Rossel,
2007), and Bolivia (Aliaga-Rossel, 2000, 2002; Aliaga-Rossel et al., 2006). However,
information from Ecuador and Venezuela generally comes from short term studies, using
different methods, which makes comparisons among studies difficult. Long term studies in
South America are currently being carried out in Brazil by Vera Da Silva and by the Omacha
Foundation in Colombia (McGuire, pers. com., 2008; Trujillo, pers. com., 2008) but no long
term studies have been initiated for the bufeo in Bolivia. The Faunagua Foundation does have
a program that studies aquatic mammals and water quality in Northern Bolivian Amazonian
Rivers. Data garnered from this program might prove to be useful and be incorporated into
future dolphin studies. This chapter reviews the current information on the taxonomic
situation, ecology, distribution, threats and conservation status of the River Dolphin in
Bolivia, and identifies research and conservation priorities.
T AXONOMY AND M ORPHOLOGY
The Pink River Dolphin belongs to the Order Cetacea, Suborder Odontoceti; superfamily
Platanistoidea; Family Iniidae, with a single Genus Inia , located only in South America
(Reeves et al., 2003).
The Bolivian River Dolphin is geographically isolated from Inia populations in the
Amazon's main stem, by a series of waterfalls and rapids between Guayaramerin, Bolivia and
Porto Velho, Brazil (ca. 400 km). This isolation formed during the late Pliocene (5- 6 millions
ago), which might be the cause of the allopatric separation from the other Inia populations in
the Amazon basin. Comparative mitochondrial DNA sequence analysis has been used to
investigate and clarify the taxonomic relationships within Inia (Hamilton et al., 2001;
Banguera-Hinestroza et al . , 2002). These studies found substantial sequence divergence
between Bolivian Inia and Inia geoffrensis in the Amazon and Orinoco Rivers. Banguera et
al., (2002) provided additional and stronger evidence from an Inia population in Bolivia that
warranted its status as a separate species ( Inia boliviensis) . Their results indicated that two