Freshwater Tucuxi

This small dolphin, similar in appearance to the bottlenose dolphin but much smaller, is found along the river and lake systems of the Amazon basin, the lower Orinoco River and coastal marine waters from the Florianopolis region of Brazil to Nicaragua. There are two morphologically distinct forms, the freshwater tucuxi and the marine tucuxi, the former being distinctly smaller in size.

Subspecies: Freshwater tucuxi (S. fluviatilis)

Population size: The current size of the population is data deficient although they are in many places locally abundant. However, there is concern over the tucuxi, particularly due to the high numbers caught and killed by gillnets in the lower reaches of the Amazon.

Distribution: The freshwater tucuxi is found as far as 2,500km upstream in the Amazon River system and 250km upstream in the Orinoco River. The freshwater tucuxi are exclusively a freshwater species that inhabit rivers and lakes but not in flooded forest and avoids rapids.

Threats: It is regularly caught and killed as incidental catch in gillnet fisheries and is threatened by the proposal of a number of potential hydroelectric damming projects that will cause the freshwater population to fragment and become isolated. These projects are also likely lead to the extinction of a number of migratory fish species that constitute important parts of their diet. In addition, development of riverside industrial and agricultural projects will cause disturbance and pollution as well as destroying natural habitats.

Interesting Facts: Tucuxi is pronounced “too-koo-shee�. The freshwater tucuxi is a communal animal often travelling in groups of as many as 20 individuals. They calve during the low water season in October and November after an 11 to 12 month gestation period, entering lakes as the water levels rise and leaving as the water levels begin to drop to avoid entrapment.