Most Threatened Species Of Dolphin

All around the world dolphins, like many other aquatic mammals are threatened by anthropogenic activities. But just which ones are in the gravest of danger?

7. Unique Species, Unique Threats

Dolphins in today’s world face a large number of threats which are decimating their population at an alarmingly quick rate. Thousands of dolphins are caught each year as bycatch in commercial fishing gear. Entangled dolphins are unable to reach the surface of waters for breathing and thus drown in the sea. People in some parts of the world also poach dolphins for their meat and oil. Habitat loss of dolphins due to dam constructions, increased load of waterway traffic in dolphin inhabited rivers and seas and other forms of waterfront developmental activities, also wipes out large numbers of dolphins. Finally, climate change, resulting in massive waves of change over land and water, also threatens the future survival of dolphins.

6. Irrawady Dolphin

Irrawaddy dolphins are distinguished from other species of dolphins by virtue of their bulging foreheads and short beaks. Their body size ranges between 180 to 275 centimeters, and they have a slaty blue to slaty grey color. These dolphins inhabit the estuarine, mangrove, and freshwater ecosystems in the countries of South Asia like India, Bangladesh and Myanmar and in South East Asian countries like Thailand, Indonesia, Cambodia, Vietnam, and the Philippines. These dolphins are classified by the International Union for the Conservation of Nature as "vulnerable", with highly reduced populations in most parts of their range. The Mekong River Irrawady dolphin population is estimated to be only around 78 to 91 individuals. Their numbers are also extremely low in Markham River (87) and Malampaya Sound (77). Slightly better figures are exhibited in terms of their population in the Sundarbans mangrove forests of India and Bangladesh (451). In the coastal waters of Bangladesh, 5,383 individuals are estimated to survive. These data are presented based on a report by World Wide Fund for Nature. Habitat destruction, irresponsible fishing practices (such as Australian gill nets), the use of explosives in Malampaya, capture for display in Indonesia and Myanmar, are some of the threats to the survival of Irrawaddy dolphins.

5. Indus River Dolphin

Indus River dolphins are endemic to Pakistan, inhabiting the waters of the Indus River system. They are also the official Pakistani National Marine Mammal. The species grow to a maximum size of about 2.5 m and posses long beaks and stocky body. Their short dorsal fins are also their primary distinguishing feature. The species actively migrate upstream during the monsoon season and downstream during the drier months of the year. The large scale construction of dams and irrigation networks resulting in habitat fragmentation, is one of the primary reasons for decimation of population of this species. Irresponsible fishing practices, poaching of the dolphins for meat and oil as well as high rates of pollution of the Indus River, are the other major threats to the survival of the Indus River dolphins. The International Union for the Conservation of Nature has classified the dolphins as "endangered", and only around 1,100 dolphins of this species survive as per World Wide Fund for Nature estimates.

4. Hector's Dolphin

Hector’s dolphins, represented by 4 subspecies of genetically distinct populations, are endemic to New Zealand, found in the coastal waters around this country. Hector’s dolphins are classified as "endangered" by the International Union for the Conservation of Nature, and one subspecies of these dolphins, the Maui’s dolphin is critically endangered. As per World Wide Fund for Nature estimates, 7,400 individuals of this species survive with the number of Maui’s subspecies being only around 55. Hector’s dolphins are the smallest marine dolphins with a short, stocky body and easily distinguished by their dorsal fin which is claimed to appear like a “Mickey Mouse ear”. The dolphins grow up to a length of around 4 feet. Though previously poached in large numbers, present threats to the survival of these dolphins include chemical pollution of marine waters, entanglement in gill nets as bycatch in fisheries, high volumes of marine traffic, and habitat loss due to coastal developmental activities.

3. Ganges River Dolphin

Ganges River dolphins posses a grayish brown-colored body with females being larger in size (maximum of 2.67 meters) than males (2.12 meters). Their long, narrow snout is one of their primary distinguishing features. The Ganges River dolphins are exclusively freshwater species inhabiting the Ganga-Brahmaputra River system in India, Nepal, and Bangladesh. The International Union for the Conservation of Nature has classified the Ganges River dolphins as "critically endangered", and World Wide Fund for Nature estimates their current numbers to be around only 1,200 to 1,800 individuals. The large-scale construction of dams and barrages along the rivers, high rates of river pollution, fisheries bycatch, poaching, are some other factors are threatening to render the species extinct.

2. Baiji (Yangtze River) Dolphin

The Baiji, a freshwater dwelling dolphin, endemic to the Yangtze River of China, was declared "extinct" in 2006 after a scientific expedition failed to detect any surviving baiji in the waters of the Yangtze. However, in the following years, scarce reports of Baiji sightings by local fishermen has sparked a new hope that a few individuals might still exist in the Yangtze River which also led World Wide Fund for Nature to favor the protection of Baiji habitats in China. Currently, the species is categorized as "critically endangered" by the International Union for the Conservation of Nature, though there is a high possibility that it might also be extinct. Habitat loss, extensive poaching episodes, high levels of pollution and bycatch fishing is believed to have led to the doom of this dolphin species.

1. Conservation Efforts

Dolphins conservation is highly significant to save the freshwater and marine ecosystems they inhabit. Loss of dolphins in such great numbers rings a warning bell about the alarming rate of loss of other aquatic life forms from the rivers and oceans of the world. The threats that decimate dolphin populations are also equally threatening for many other species of aquatic life including whales, porpoises, turtles, and fishes. The loss of each species disturbs the ecological balance and disrupts the food chain. Dolphin conservation efforts focus on accurate estimation of dolphin population sizes, research on the threats leading to their declining numbers, and a cooperative involvement of the public, governments and environmental organizations to save the dolphin habitats, protect them against both poaching and live capture.

More in Environment