Burmeister's porpoise
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Burmeister's porpoise (Phocoena spinipinnis) is a species of porpoise endemic to the coast of South America.<ref name=iucn/> It was first described by Hermann Burmeister, for whom the species is named, in 1865.
Population and distribution
While Burmeister's porpoise seems to be relatively common in its range, little work has been done to survey the species. The total population is at least in the tens of thousands. Its range appears to be continuous in coastal waters from northern Peru in the Pacific Ocean round Tierra del Fuego and up to southern Brazil in the Atlantic Ocean.<ref name=iucn/> Burmeister's porpoises frequent inshore bays, channels, and fjords,<ref name="iucn" /> but individuals have been spotted as far as Template:Cvt from the shore and in the freshwater Valdivia River in southern Chile.<ref name=iucn/> Though normally found in continental shelf waters, they have been found as deep as Template:Cvt<ref name=iucn/>
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, black porpoise. However live individuals are typically a dark grey color.<ref name=":1" /> 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 Template:Cvt long when fully mature and weigh Template:Cvt. The maximum recorded weight is that of a female at Template:Cvt. 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.Template:Citation needed
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.Template:Citation needed
Conservation
Like all porpoises, Burmeister's is vulnerable to accidental capture in fishing nets.<ref name=iucn/><ref>Template:Cite journal</ref> This is common in Uruguay, Peru and Chile. The annual estimated catch is largest in Peru, at 2000 individuals.<ref name=":1">Aspects of the biology of Burmeister's Porpoise from Peru Reyes and Can Waerebeek, 1995. Report of the International Whaling Commission. Special Issue 16.</ref> In Peruvian waters, Burmeister's porpoise caught as bycatch are primarily used for human consumption.<ref name=iucn/> Until the late 1990s, Burmeister's were also harpooned deliberately for food and for use as crab bait.<ref name=iucn/>
In severe El Nino events, the ecosystem of the Humboldt current is disrupted. Anchovies either perish or leave the area, and it appears that many porpoises and other marine mammals, including the Burmeister's porpoise, must find other food sources or starve as a result.<ref name=":2">Template:Cite book</ref> In 1997, during an El Nino event, Burmeister's porpoises were found stranded on Peruvian beaches.<ref name=":2" />
The IUCN lists the animal as Near Threatened in its Red List of Threatened Species.<ref name=iucn/> The long-term prognosis for the species is unknown.<ref name=iucn/>
Burmeister's porpoise is listed on Appendix II<ref name="Appendices">"Appendix II Template:Webarchive" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009.</ref> of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II<ref name="Appendices" /> as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.
See also
References
Bibliography
- Burmeister's Porpoise in the Encyclopedia of Marine Mammals, J.C. Reyes, 1998. pages 177–179. Template:ISBN
- National Audubon Society Guide to Marine Mammals Reeves et al., 2002. Template:ISBN
- Whales, Dolphins and Porpoises, Carwardine, 1995. Template:ISBN
- Phocoena spinipinnis, Brownell and Praderi Mammal Species vol 217 pages 1–4, 1984.