The boto or Amazon River dolphin (Inia geoffrensis) is endemic to South America and is the most studied species of river dolphin in the world. It is unique in that it is the only toothed dolphin to possess different types of teeth in their jaws, ranging from conical styles to the front and crushing, molar types towards the back. They feed mainly on fish and shellfish but have been known to occasionally forage on turtles. There are currently three recognized sub-species of boto: those located in the Amazonia river systems of Brazil, Peru and Ecuador; those within the Orinco basin of Venezuela and Colombia; and finally, individuals located within the Bolivian waterways. However this taxonomy is highly controversial as genetic studies argue that the Bolivian sub-species are in fact a completely separate species in their own right and scientists have yet to agree on a formally recognized classification.

Current status

The status of Amazon River dolphins has only recently been considered to be at risk, showing sharp declines since 2000. It is estimated that they are declining between 7 percent to 10 percent a year. However despite the declining population they are currently listed only as Data Deficient on the IUCN Red List despite previously having a status of Vulnerable. This listing was reversed due to a lack of reliable data concerning their ecology, population numbers and distribution despite the species being the most studied river dolphin in the world.

What are the threats?

All river dolphin species are under threat globally and this has only recently begun to be taken seriously following confirmation that the Yangtze River or Baiji dolphin is now functionally extinct. This was the first large vertebrate in half a century to be driven to extinction as a result of anthropogenic activities (unsustainable shipping, illegal fishing, habitat encroachment, polluted waterways).

The main threat to the Amazon River dolphin is from commercial fishing where they are either killed by fishermen as a perceived competitive threat or used as bait for the lucrative catfish industry which feed on their carcasses. Roughly 1,500 botos are killed each year as bait, with a single dolphin carcass helping to produce 550 kilograms (approx. 1,212 pounds) of catfish worth £30 per kilogram. This equates to roughly £300 (approx. $464) in two nights which is more than double the national minimum wage in the region, highlighting the huge demand for these river dolphins.

Unfortunately fishing pressures are not the only threat currently impacting the dolphins. Many are injured or killed by boat strikes of from propellers as they are naturally inquisitive and attracted to noise; this also makes them very easy to hunt by fishermen. Rising mercury levels in the local rivers have led to contamination of prey and the construction of dams is reducing the food available as fish are unable to swim upstream.

What is being done?

The most pressing issue for the conservation of the Amazon River dolphin is to address the data deficiency regarding their current population size and distribution. Without this the species can't be recognized as endangered which makes implementing government protection difficult. They are currently listed in Appendix II in the CITES list of restricted animal trade, however this is ineffective in the home range of these animals as the areas are remote and not well enforced. In Brazil, for example, the punishment for killing river dolphins leads to 18 months in prison however with just five agents monitoring an area twice the size of Texas, enforcement is an impossible task and people are rarely punished. Therefore non-governmental organizations (NGOs) working in the region have switched their attention to trying to address the need for greater job opportunities and better pay to prevent locals turning to the lucrative catfish industry.