Spectacled Porpoise (Phocoena dioptrica)

The spectacled porpoise (Phocoena dioptrica) is a fascinating marine mammal indigenous to the Southern Ocean. This enigmatic creature is one of the least studied among the cetaceans, a group that includes whales, dolphins, and other porpoises.

Physical Characteristics

The spectacled porpoise is named for its distinctive markings, which resemble spectacles. It has a robust body, with a length ranging from 1.25 meters in females to 2.24 meters in males. The average weight ranges between 55 and 80 kilograms, though the largest recorded individual weighed 115 kilograms. The dorsal fin is notably large and triangular, while the pectoral fins are smaller and rounded, differentiating it from other species within the Phocoena genus. Another distinctive feature is its spade-shaped teeth, which contrasts with the cone-shaped teeth found in dolphins.

Habitat and Distribution

This species inhabits the cold waters of the southern hemisphere, particularly around the southern east coast of South America from Uruguay to Cape Horn, as well as near the Falkland Islands and South Georgia. Sightings have also been reported near New Zealand, Macquarie Island, the Auckland Islands, Heard Island, and the Kerguelen Islands. The spectacled porpoise tends to prefer cold ocean currents, such as the Falkland Current.

Behavior and Ecology

Relatively little is known about the behavior of the spectacled porpoise due to its elusive nature. It is generally found near offshore islands but occasionally ventures into the open ocean. Its preference for subantarctic regions suggests an adaptation to cold water environments, similar to other porpoises like the harbour porpoise and Dall's porpoise.

Related Species

The spectacled porpoise is one of several species within the Phocoenidae family, which includes the vaquita, an endangered species found in the Sea of Cortez. Other related species include the finless porpoise, the Yangtze finless porpoise, and the Indo-Pacific finless porpoise.

Conservation Status

Due to the scarcity of sightings and data, the conservation status of the spectacled porpoise remains unclear. However, like many marine mammals, it may face threats from human activities such as fishing, pollution, and climate change.