How was the Bolivian Amazon River dolphin discovered and recognized as a species?
What does the Bolivian Amazon River dolphin look like?
Unlike marine dolphins, the river dolphin has a long, thin snout, poor eyesight and is less active. It does not jump out of the water.
- The Bolivian bufeo has a smaller skull, more teeth and a longer body compared to the Amazon River dolphin (3). The two species are very similar, but became evolutionarily distinct being separated by the Teotônio rapids in the middle of the Madeira (Brazil). (Note: actually, below these rapids there is a zone where hybrids between the two species occur) (4)
- The Bolivian bufeo is well adapted to fishing in rivers, lakes and inundated floodplains.
Where can the Bolivian Amazon River dolphin be found?
There are more or less 5,000 bufeos residing within the Mamore and Iténez river basins within the Bolivian Amazon. There are no bufeos in the Beni river basin, because the species has never passed the Cachuela Esperanza rapids in the lower Beni!
As for the Bolivian bufeo, it has a smaller population size. This makes it extra vulnerable to a number of threats, with a potential to drive the species to extinction in the long run. Recently, the species has been recognised internationally as Endangered under the IUCN Red book (3). At the national level, the species is still listed as Vulnerable under “The Red Book of Threatened Vertebrate Fauna of Bolivia” (4) published by the Ministry of Environment and Water (MMAyA) of the Plurinational State of Bolivia.
Hydroelectric dams create a physical barrier between upstream and downstream dolphins, leading to population fragmentation (5) (6) (7). This can aggravate the decline in the Bolivian bufeo numbers as smaller groups of isolated dolphins can quickly crash. In Brazil, a group of dolphins are trapped between the Jirau and Santo Antonio dams.
The dolphins could also be affected by changes in their floodplain habitat as a consequence of upstream sediment trapped by dams. The dolphins may also suffer from a lack of food as a result of dam construction as they primarily feed on migrating fish species.
Mercury accumulation in the river
Mercury released from artisanal and industrial gold mining is introduced into the ecosystem of the river. In Bolivia, gold mining is most common in the upper Madre de Dios basin (upstream of the distribution range of dolphins) and in the upper Iténez. Methylmercury accumulates and biomagnifies substantially in the Bolivian River dolphins as they are top predators in Amazon freshwater ecosystems (8).
Current laws and conservation efforts on these species
Dolphin Conservation Our mission to conserve the Bolivian Amazon River Dolphin
Cooperatively conduct scientific research: (see the SARDI cooperation with Colombia, Peru, Ecuador, Brasil)
- To close information gaps about the Bolivian River Dolphin. See for example how we use satellite tags to know more about dolphin movements along the river.
- To understand anthropogenic impacts on the Bolivian Amazon River Dolphins and the river ecosystem. Freshwater dolphins are useful bioindicators for the assessment of the health of river ecosystems as they are sensitive to habitat changes
- To make better decisions and recommendations on river dolphin conservation and management measures (for example aiming at reducing fisheries impact)
- To achieve sustainable development by giving better advice to social and economic projects on the consideration of minimizing environmental impacts on the Bolivian Amazon River Dolphin and riverine ecosystem
We have used satellite transmitter tags for the first time in partnership with institutions in Colombia and Brazil to track movements of Inia boliviensis in areas considered critical for their conservation (see Mosquera-Guerra et al. 2019). We have recorded the health conditions and mercury bioacumulation in these dolphins.
Promote interest and awareness in the public on the Bolivian river dolphin and their Amazonian river habitat and protect the species
- Facilitate fluid communication to the media and press to inform the general public on our work and on the conservation status of the Bolivian Bufeo
Work with the government, local communities, farmers and fisheries
Educating and advising the government, local communities, farmers and fisheries on dolphin-friendly measures
How can you give support?
Raise awareness: Talk with your family and friends, share information on Social Media
Fundraise and donate to ongoing conservation projects on the Amazon river and dolphins
Use your hands: Volunteer your time to conservation projects and participate in environmental clean-ups around the Amazons
- Join us on our Dolphin expeditions
Empower the dolphins: Support policies and sign petitions that urges the government to protect Bolivian Amazon River Dolphins and their habitats
Reduce, reuse, and recycle: Avoid using disposables such as plastic bags, prefer reusable items or paper bags.
Stop river pollution: Be aware of the chemicals used in house detergents, cleaners and cosmetics. The same goes for fertilizers and pesticides in your garden or at farms.
Meet the dolphins: As a tourist in the Amazon, be responsible – keep distance, remain quiet and do not throw waste into the river. Do not feed the dolphins!
Bibliography All the references used in this webpage (Please write us if you want a copy!)
(1) d’ORBIGNY, A. Viaje a la América Meridional. Tomo II. Nueva edición [en línea]. Lima: Institut français d’études andines, 2002 (generado el 19 juin 2019). Disponible en Internet: http://books.openedition.org/ifea/6781. ISBN: 9782821845251. DOI: 10.4000/books.ifea.6781.
(2) Taxonomic Committee American Society for Mammology (2020). Inia boliviensis fact sheet. https://marinemammalscience.org/facts/inia-boliviensis/
(3) Ruiz-García M. et al. (2006) Morphological analysis of three Inia (Cetacea: Iniidae) populations from Colombia and Bolivia. Acta Theriológica, 51
(4) Gravena W. et al. (2015) Living between rapids: genetic structure and hybridization in botos (Cetacea: Iniidae: Inia spp.) of the Madeira River, Brazil. Biological Journal of the Linnean Society, 114: 764-777.
(5) Guizada L. et al. (2016) Abundance of the Bolivian River Dolphin (Inia boliviensis) in Mamoré River, Upper Madeira Basin. Aquatic Mammals, 42 (3): 330-338.
(6) Salinas Mendoza A. et al. (2013) Population status of the Bolivian river dolphin (Inia boliviensis) in tributaries of the Iténez River (Bolivian Amazon). Book chapter.
(1) Huang S.L. et al. (2012). Common pattern of population decline for freshwater cetacean species in deteriorating habitats. Freshwater Biology, doi:10.1111/j.1365-2427.2012.02772.x
(2) Da Silva V. et al. (2016) Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades. PlosONE, 13(5): e0191304
(3) Da Silva V. et al. (2018). Inia geoffrensis. The IUCN Red List of Threatened species 2018: e.T10831A50358152. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T10831A50358152.en
(4) Aliaga Rossel E. (2009) Inia boliviensis. Pp. . En:MMAyA (Ed.). Libro Rojo de la fauna silvestre de vertebrados de Bolivia. La Paz, Bolivia.
(5) Pavanato H.J. (2016). Risks of dam construction for South American river dolphins: a case study of the Tapajós River. Endangered Species Research, 31:47-60.
(6) Araujo C.C. et al. (2015). The dammed river dolphins of Brazil: impacts and conservation. Oryx, 49 (1): 17-24.
(7) Forsberg B.R. et al. (2017). The potential impact of new Andean dams on Amazon fluvial ecosystems. PlosONE, 12(8): e0182254.
(8) Mosquera-Guerra et al. (2019). Mercury in populations of river dolphins of the Amazon and Orinoco Basins. EcoHealth, https://doi.org/10.1007/s10393-019-01451-1
(9) Loch C. et al. (2009). Conﬂicts with ﬁsheries and intentional killing of freshwater dolphins (Cetacea: Odontoceti) in the Western Brazilian Amazon. Biodiversity and Conservation, 18: 3979-3988.
(10) Iriarte V. et al. (2013). Insights on the use of dolphins (boto, Inia geoffrensis and tucuxi, Sotalia fluviatilis) for bait in the piracatinga (Calophysus macropterus) fishery in the western Brazilian Amazon. Journal for Cetacean Research and Management, 12(2): 163-173.
(11) Mintzer V.J. (2013). Effect of illegal harvest on apparent survival of Amazon River dolphins (Inia geoffrensis). Biological Conservation, 158: 280-286.
(12) Da Silva V. et al. (2018). The use of Amazonian dolphins (Inia and Sotalia) as bait for the piracatinga fishery. IWC. 17 pp.
(1) The National Plan for the Conservation of the Bolivian River Dolphin has marked the following milestones:
- 20 expeditions for counting Bolivian dolphins were done in the Mamoré and Iténez river basins
- Elaboration of the national distribution map of the species
- Recognition of the potential impact of blanquillo (Calophyusus macropterus) fisheries on dolphins used as bait (see infograph)
- Increasing use of the Bolivian dolphin as banner species for aquatic conservation and sustainable tourism
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