Black-chinned Dolphin, Lagenorhynchus australis
Image Caption: Peale’s Dolphin, Near Ventisquero Pio XI, Feb 2006 en:Lagenorhynchus australis (taken at Ventisquero Pio XI, Chilean Patagonia). Credit: FDrummondH/Wikipedia (CC BY-SA 3.0)
The black-chinned dolphin (Lagenorhynchus australis), also known as Peale’s Dolphin or Peale’s Black-chinned Dolphin, can be found near Tierra del Fuego at the southern tip of South America. Within these waters, it prefers to reside in faster currents near channels or narrows, but can also be found in shallow waters near the shore, like bays, where it can be protected.
The black-chinned dolphin is currently classified in the Lagenorhynchus genus, although some experts assert that it should be placed in Cephalorhynchus, because it so closely resembles species in that genus. If this were found to be true, the black-chinned dolphin would have to be classified within that genus or placed in a new one. This species, along with the dusky dolphin and the Pacific White-sided Dolphin, is also under review to be placed under a new genus known as Sagmatias. However, there is information that supports the classification of this species into the Cephalorhynchus genus, including the white markings under its pectoral fins.
The black-chinned dolphin can reach an average body length of 6.9 feet with a weight of about 253 pounds. Its back is typically black in color, while the face and chin are dark grey in color. The back also holds an off-white stripe that extends down each side and widens as it reaches the underbelly, which is white in color. White also occurs under the pectoral fins and along the flanks above the fins. Its dorsal fin is large compared to the rest of its body and all of its flippers and fins are pointed.
Like other species of dolphin, the black-chinned dolphin is social, but it gathers in small groups of about five to twenty individuals. Larger groups of up to one hundred individuals have been seen in the summer and fall seasons, although this is rare. These groups can be seen swimming in a line along the shore, typically moving slowly, although it is capable of short bursts of movement.
The total population number of the black-chinned is not known, but it is thought to be locally common. Its tendency to remain in smaller areas near the shore makes it vulnerable to human action. Major hunting of this species occurred between 1970’s and 1980’s, when fishermen would kill it in order to use its meat as fish bait. Although this hunting does not often occur in more recent years, it has not been made illegal. The black-chinned dolphin can become trapped in gillnets in Argentinian waters, but the damage this has or can cause to its population numbers has not been confirmed. Many conservation groups, including the Whale and Dolphin Conservation Society, strongly support initiating more research projects regarding this species. It appears in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), which describes it as having an unfavorable status that requires more research and possible conservation efforts. Currently, the black-chinned dolphin appears on the IUCN Red List with a conservation status of “Data Deficient.”