Context

As per reports published by the IUCN Red List in November 2018, it was found that, freshwater dolphins found in the Amazon River Basin were “dying off fast” and could face extinction unless they were more vigorously protected against fishing.

About

Amazon River dolphin

There are two types of Amazon River dolphins namely, the “boto” (Inia geoffrensis) and the “tucuxi” (Sotalia fluviatilis), which were once considered abundant in the Amazon.

The Amazon River dolphin is the largest river dolphin. Adult males reach average 2.32 metres and 154 kilograms, while females reach average 2 metres and 100 kilograms. It has very evident sexual dimorphism, with males measuring and weighing between 16% and 55% more than females, making it unique among cetaceans ('Cetaceans' is the collective name for all whales, dolphins and porpoises who between them form a single group, known as an order), where females are generally larger than males.

Besides the Amazon dolphins, freshwater dolphins in other parts of the world are also facing extreme pressures. In the Indian Subcontinent, the Gangetic or Indus River Dolphin (Platanista gangetica) found in the Ganga and Indus River Basins is considered “Endangered” by the IUCN. In China, the Yangtze River dolphin was declared functionally extinct in 2006 due to human activities like overfishing, dam building, pollution and boat traffic.

What is the threat?

The primary reason for the decrease in numbers is use of the dolphins’ flesh and blubber as bait for catfish, which have become widely available commercially. Killing the dolphins endangered their survival, particularly since the females bear a single calf on average every four to five years.

Increasing pollution and gradual destruction of the Amazon rainforest add to the vulnerability of the species. Captive breeding is not considered a conservation option for this species due to intra-species aggression and low longevity.