also: Amazon River dolphin, bufeo colorado)
Photo by Greg Ochocki
Just under 3 meters (9.8 ft.) in length, the boto, or Amazon River dolphin, is the largest member of the river dolphin family (Platanistidae). It inhabits most of the Amazon and Orinoco River basins: the largest river system in the world. The first part of its scientific name, Inia, is what the Guarayo Indians of Bolivia call this species. The species name, geoffrensis comes from Geoffrey St. Hilaire (1772-1850), a prominent French professor of natural history who was instrumental in procuring the first specimens of the boto.
Most populations of this dolphin are believed to be in good condition. However they are especially vulnerable to habitat degradation. A number of factors may affect these dolphins.
Hydroelectric development currently poses the biggest threat to the boto. To meet Brazil's increasing need for electric power, dam construction in the Amazon River basin is expected to increase significantly by the year 2000. Damming activities separate dolphin populations from many fish species that they prey upon.
Agriculture is another major threat to the boto. Clearing flood-plain forests to make way for crops and pastures affects these dolphins by eliminating part of their food chain: some fish species rely heavily on fruits and seeds that fall from native forest trees into the water. These fish in turn compirse a part of the boto's diet.
Toxic chemical polutants from agricultural pesticides, mining, and paper milling are potentially harmful to the dolphins and the entire river ecosystem. Very little research has been conducted to determine concentration levels of these chemicals or their impact on the environment.
Commerical fishing in the Amazon basin is on the rise, and with it, a probable increase in dolphin mortality due to incidental entanglement in fishing nets. Although data is hard to obtain, in 1984, 35 of these dolphins were found dead as a result of commercial fishing operations.
In 1986, the Cetacean Specialist Group of the International Union for the Conservation of Nature and Natural Resources (IUCN) Species Survival Commission decided to concentrate its efforts on all river dolphins, which are disappearing around the world. A workshop held in Wuhan, China, sponsored by Sea World, produced a number of recommendations for perserving river dolphins.
The boto is classified as "vulnerable" in the ICUN Red Data Book and is listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This Convention regulates trade in certain wildlife species. Several additional international and regional agencies have also identified themselves as potential defenders of these dolphins. Local laws protecting the boto have recently been established but are difficult to enforce.
Only by obtaining improved scientific information on boto biology, ecology, and population dynamics can we develop comprehnsive management and conservation strategies. The fate of the boto is closely linked to that of its environment.
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