Spectacled porpoise

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The spectacled porpoise (Phocoena dioptrica) is a small to mid-sized porpoise that lives in the cold waters of the Southern Ocean. It has no beak, small rounded front fins, and a triangular dorsal fin. Adults show a distinctive color pattern: a dark back and a white belly, with a noticeable dark eye patch. Some individuals have a pale saddle patch near the dorsal fin and a dark line around the blowhole.

Size and appearance
- Females grow up to about 2.04 meters; males up to about 2.24 meters.
- Weights can reach around 85 kg for females and 110 kg for males.
- Males have larger, more rounded dorsal fins. Females are generally lighter in color. Young animals may look more grey than black.

Range and habitat
- The spectacled porpoise is thought to be circumpolar, living in cool temperate, sub-Antarctic, and Antarctic waters (0.9–10.3 °C).
- It is mostly oceanic, but sightings and carcasses are also found in coastal areas.
- Records come from the Atlantic, Pacific, and Indian Oceans, including around Patagonia, South Georgia, the Falkland Islands, New Zealand, Heard Island, and Kerguelen.

Diet
- Little is known about feeding, but it is believed to eat fish and squid.
- Stomachs from some strandings have contained anchovy, crustaceans, cephalopod beaks, and other small prey.

Reproduction
- Very little is known about their reproduction.
- In Tierra del Fuego, young porpoises are estimated to be about 1 meter long at birth, in late spring to summer. Details on pregnancy and lactation are not well documented.

Taxonomy and related species
- The name “dioptrica” means spectacled, referring to the eye patches.
- Genetic studies show high diversity, suggesting a large or widespread population and a recent expansion.
- They are most closely related to Burmeister’s porpoise; vaquitas diverged from them earlier.

Population and threats
- The population size and how animals move across the Southern Ocean are not well known.
- Bycatch in fishing gear and entanglement are considered major threats.
- Stranding data from Tierra del Fuego suggest the population could be stressed in some areas, but overall status is still not fully clear.

Conservation status
- The spectacled porpoise is listed as Least Concern (IUCN 3.1) since 2018, reflecting limited data but a relatively wide distribution. More research is needed to understand its population trends and threats.

Captivity events
- There have been two documented cases of living spectacled porpoises taken for medical treatment. Both eventually died during rehabilitation (a calf in 1997 and an adult male in 2019).