Burmeister, 1865 - Burmeister's porpoise
Distinctive Characteristics
The unique dorsal fin of Burmeister's porpoise rises at a very shallow angle from behind the midpoint of the back, and the trailing edge is straight to convex. Additionally, there are tubercles along the leading edge of the fin (this characteristic gave the species its scientific name). Other than this, the species has a rather typical phocoenid body form, with a blunt, nearly beakless head and broad-based flippers with rounded tips.
Coloration is dark charcoal to grey, with lighter grey streaks on the chin and belly. Burmeister's porpoises have dark eye patches, dark lips, and dark chin-to-flipper stripes (well-defined by lighter areas above and below). These flipper stripes are asymmetrical; they are more narrow and extend further forward on the right side.
Teeth number 10 to 23 in each upper tooth row and 14 to 23 in each lower row. As in other phocoenids, the teeth are spatulate.
Can be confused with
Burmeister's porpoises can be confused with South American fur seals and South American sea lions, which often stick their flippers in the air (these can look like Burmeister's porpoise dorsal fins). Differences in coloration, dorsal-fin shape, and swimming style should allow Burmeister's porpoises to be distinguished easily from Commerson's dolphins and spectacled porpoises, and head shape will be the best characteristic to allow distinction from franciscana.
Size
Most adults are up to 1.85 m in length, although animals from Uruguay up to 2 m have been recorded. Maximum weight is about 85 kg. Newborns are 0.8 to 0.9 m.
Geographical Distribution
Burmeister's porpoises are distributed in coastal waters of South America, from southern Brazil, south to Tierra del Fuego, and north to northern Peru.
Biology and Behaviour
Very little is known about the natural history of this species. Most sightings are of less than 6 individuals, but aggregations of up to 70 have been reported. Behaviour of this species is inconspicuous; they breath with little surface disturbance.
There appears to be a protracted summer birth peak; most births in Peru apparently occur in late summer to autumn.
Feeding is on fish, such as anchovies and hake, as well as squid.
Exploitation
Burmeister's porpoises are caught mostly in gillnets. They are taken, apparently in small numbers, in shark gillnets in Uruguay, fish (and until recently, king crab) gillnets around Tierra del Fuego, and gillnets for a variety of fish off Chile and Peru (by far, the largest kills). Additionally, they may be caught in direct fisheries for dolphins, using mostly gillnets, which have prospered in recent years in Peru, and to a lesser extent, Chile.
IUCN Status
Insufficiently known.