Chilean dolphin

The Chilean dolphin (Cephalorhynchus eutropia), also known as the Black dolphin, is one of six dolphins in the genus Cephalorhynchus. The dolphin is found only off the coast of Chile; it is commonly referred to in the country as tonina.

Characteristics

Physical description

The Chilean dolphin is small at around 1.7 metres (5 ft 7 in) in length, with a blunt head. Adults reach up to 60 kg, with females slightly larger than the male bulls. This dolphin is thickly shaped with its girth up to two-thirds its length. Their small and thick shape is often mistaken for other types of porpoises. The dorsal fin and flippers are small in proportion to body size in comparison with other dolphins. The throat, underside, and the closest part of the flippers to the body are white. The remainder of the body is a mix of greys. A black line connects their blowhole, eyes, and dorsal fin. It has 28–34 pairs of teeth in the upper jaw and 29–33 in the lower. The two eyes are positioned at the ends of the mouth lines, giving the appearance of a smile. The tail has a characteristic notch in the middle. The most distinct features of the Chilean dolphin are its short beak, round dorsal fin, and rounded flippers.

Behavior

Unlike other types of dolphins that commonly exhibit social behavior, the Chilean dolphin often remains distant during possible encounters with humans.

Communication

Communication between individuals is performed with a series of clicks, whistles, and cries at varying frequencies. and green algae.

Population and distribution

The population of the Chilean dolphin, perhaps one of the least studied of all cetaceans, is not known with certainty. It is estimated that less than 5,000 Chilean dolphins remain in the wild. However, the majority of the Chilean dolphins population is found in the southern regions. The species prefers shallow water regions, specifically areas near rivers and high tides. The close association with riverine and estuarine ecosystems makes Chilean dolphins extremely vulnerable to habitat loss both from coastal and upstream river basin degradation. Their relatively limited distribution and need for specific environmental conditions makes the Chilean dolphin particularly susceptible to population loss, even in the most remote areas.thumb|Chilean dolphin jumping

Habitat

The Chilean dolphin is seen over a wider interval of latitudes than other Cephalorhynchus species — from Valparaíso at 33°S to Cape Horn at 55°S. In the northern areas, they are found in bays and estuaries with more exposed coastlines, while they prefer fjords and channels in the southern regions. They are commonly seen in bays and channels as well as near rivers and areas with greater changes in tide. Most Chilean dolphins reside in salt water, however they have been spotted in freshwater rivers. Additionally, Chilean dolphins prefer shallow waters, usually less than 20 meters, and tend to stay within 500 meters of shore. Research has found that pods are highly localized, and environmental factors often serve as barriers between pods.

Threats

Humans pose the largest threat to the Chilean dolphin population. In addition to being caught for human consumption, the dolphins are also used as bait for long-line sword fishing and crab fisheries. It is reported that between 1,300 and 1,500 Chilean dolphins are harpooned in the Strait of Magellan each year. Use as bait was particularly popular until the 1990s, and hunting of Chilean dolphins is now illegal. Since 2023, at least 14 Chilean dolphins have died as a result of widespread bird flu in Chile. Reports indicate that Chilean dolphins are preyed upon by killer whales and sharks.

Conservation

The Chilean dolphin is listed on Appendix II Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II Initiatives established by Catholic University of the Maule (UCM) and the Environmental Protection Fund FPA of the National Environment Commission (Chile) aim to protect the natural habitat of the Chilean dolphin and provide safe tourism opportunities to view the dolphin.

Name

In the early part of the 20th century, the Chilean dolphin was commonly known as the black dolphin. This was later agreed to be a poor choice of name. Most of the few individual specimens studied by scientists were either washed-up individuals whose skin had darkened due to exposure to air or live specimens seen at sea but only at a distance (and so appeared darker than they were). As more specimens were studied, it became clear that the back of the dolphin was in fact a mixture of grey colors and that its underside was white. The scientific community is now universally agreed in naming the dolphin Chilean on account of its distribution along the coast of the country.

Pictures

References

External links

Whale and Dolphin Conservation Society
yaqu pacha - Organization for the Conservation of South American Aquatic Mammals