Burmeister's Porpoise (Phocoena spinipinnis) is a species of porpoise endemic to the coast of South America. It was first described by Hermann Burmeister, for whom the species is named, in 1865.

Population and distribution

Whilst Burmeister's Porpoise seems to be relatively common in its range, little work has been done to survey the species. Its range appears to be continuous in coastal waters from northern Peru in the Pacific round Tierra del Fuego and upto southern Brazil in the Atlantic. The total population is at least in the tens of thousands. Whilst usually described as staying very close to the sure, individuals have been spotted as far as 50km from the shore and in the freshwater Valivia River in southern Chile.

Physical description

Most photographs of Burmeister's Porpoises are taken of dead specimens and show the animal to be coloured black. This phenomenon gave rise to the earlier common name, the Black Porpoise. However live individuals are typically a dark grey colour. They turn black in just a few minutes after death. The underside varies in colour but is usually a lighter grey. Burmeister's are about 150cm long when fully mature and weigh 50-75kg. The maximum recorded weight is that of a female at 105kg. They have a shallow indentation at their blowhole set just in front of the eyes. The shape and placement of the dorsal fin is unusual for a cetacean - it is triangular rather than curved and points backwards more than upwards. It is located about three-quarters of the way along the back - further back than any other dolphin or porpoise. These features are sufficient to distinguish the porpoise from the similar-sized Chilean Dolphin which is found in the porpoise's Pacific range.

Behaviour

Burmeister's Porpoise is difficult to observe. It appears to be shy, shows little of its body when surfacing and will move quickly away from approaching boats. They are typically seen alone or in pairs with occasional larger groups. One report from Chile saw a group of 70 in number. The porpoise feeds on various pelagic fish such as anchovies, hake and mackerel.

Conservation

Like all porpoises, Burmeister's is vulnerable to accidental capture in fishing nets. This is common in Uruguay, Peru and Chile. The annual estimated catch is largest in Peru, at 2000 individuals [5]. Burmeister's are also harpooned deliberately for food and for use as shark bait. The IUCN lists the animal as data deficient in its Red List of Threatened Species and the long-term of these actions is unknown.

References

1. Burmeister's Porpoise in the Encyclopedia of Marine Mammals, J.C. Reyes, 1998. pages 177-179. ISBN 0125513402
2. National Audubon Society Guide to Marine Mammals Reeves et al, 2002. ISBN 0375411410
3. Whales, Dolphins and Porpoises, Carwardine, 1995. ISBN 0751327816
4. Phocoena spinipinnis, Brownell and Praderi Mammal Species vol 217 pages 1-4, 1984.
5. Aspects of the biology of Burmeister's Porpoise from Peru Reyes and Can Waerebeek, 1995. Report of the International Whaling Commission. Special Issue 16.
6. A description and image of Burmeister's Porpoise from phocoena.org