For decades it was the only freshwater dolphin species in the world not considered threatened by human activity. The tucuxi of the Amazon held out even as similar species in South America and Asia were dammed in, poisoned, or killed as bycatch; one is considered to have gone extinct.
Now, the tucuxi (Sotalia fluviatilis) has finally succumbed: in the latest assessment for the IUCN Red List of Threatened Species, this river dolphin has been declared endangered, with threats arising from entanglement in fishing nets to damming of rivers. Those are the same factors that threaten the pink river dolphin (Inia geoffrensis), with which the tucuxi shares a habitat and which was itself declared endangered in 2018.
The pink river dolphin, famous for its color and a central figure in Amazonian folklore, is more docile and an easier subject for scientists to study. Researchers are now seeking to find out more about each of the two Amazonian dolphin species and understand their peculiarities.
A study published in 2019 estimated an abundance of both species in the Tefé River and Lake Tefé, which lie in the interior of Brazil’s Amazonas state. It found that the tucuxi
— source news.mongabay.com | Sibélia Zanon | 21 Apr 2021
