Phocoena spinipinnisBurmeister's porpoise

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Geographic Range

Burmeister's porpoises are only found along the coastal waters of South America. They inhabit the Atlantic waters on the coast of Brazil and continue to be found south around the coastlines of Tierra del Fuego and the Falkland Islands and north into the coastal Pacific waters of Peru.

Habitat

Burmeister's porpoises usually inhabit shallow waters of 150 meters or less in depth and can often be seen in rivers and estuaries. Because the Atlantic Ocean has a wider continential shelf than the Pacific, it might provide a more preferred habitat. However, the Pacific coast population is larger. This discrepancy may exist because the Burmeister's porpoises must compete with other more dominant coastal cetaceans on the Atlantic Coast, including Sotalia fluviatilis and Pontoporia blainvillei. In contrast, Burmeister's porpoises are very successful on the eastern Pacific coast, where they are the main cetacean species in this area.

Physical Description

Burmeister's Porpoise was discovered by zoologist Hermann Karl Konrad Burmeister of Cologne when he noticed that the dorsal fin of this porpoise extended into an exceptionally sharp point. The dorsal fin also contains rows of tubercles along its front edge, providing the basis for its scientific name "spinipinnis" (which is derived from the latin words "spina" = thorn and "pina" = fin). The body ranges from 1.4 to 1.8 meters in length, making it one of the smaller species in this family. Males appear to be slightly larger on average than females.

Burmeister's porpoise is a uniform color dorsally varying from dark grey to black while the ventral side is paler in pigmentation. This species's tendency to turn black soon after death has earned it the nickname "the black porpoise." The presence of an eye patch surrounded by a pale grey ring is a useful identifying characteristic. Additionally, a unique characteristic is the presence of asymmetric flipper stripes with a nearly uniform, straight edged shape on the left side and a more curvacious right side patch that gradually narrows anteriorly.

The skull morphology of Phocoena spinipinnis can be described based on other members of the genus, particulary Phocoena phocoena whom it closely resembles, with the following characteristics: (1) a brain case tending to be much more compact lengthwise, (2) a dorsal profile of the supraoccipital bone in line with the dorsal profile of the rostrum instead of at a 20 degree angle, (3) a larger temporal fossa, (4)and a lower tooth count of 14-16 upper teeth and 17-19 lower teeth on each side.

  • Range mass
    40 to 70 kg
    88.11 to 154.19 lb

Reproduction

At an average length of 154.8 and 159.9cm respectively, male and female Burmeister porpoises reach sexual maturity. Reproduction has not been extensively studied in this species; however, a pregnant female with a near term fetus was found off the coast of Uruguay in late February. This observation along with other collected specimens have lead reasearchers to believe that the reproductive season occurs during the same period throughout this family with mating from June to September, calving in May through August, and gestation lasting about 10 months. At birth, calves generally have a length of at least 44cm.

  • Breeding season
    Mating occurs from June to September
  • Average gestation period
    10 months

Behavior

Burmeister's porpoises are one of the most poorly known species of this family. They travel in small groups, and it is rare to find more than eight individuals together at one time. They swim in quick, jerky movements, yet are very inconspicuous swimmers, barely breaking the surface of the water when they come up to breath and seldom seen breaching. During surfacing, they break the surface about seven to eight times. This is followed by an underwater dive lasting up to three minutes and a reappearance as far as fifty feet away. The fastest recorded speed for this species is 4km/h. Burmeister's porpoises are very timid and scatter rapidly when approached by boats. These animals are very difficult to find in rough waters and windy conditions, which may be a reason why there are so few spottings of this species. Vital statistics are not well documented but one calf was found to have a respiration frequency of 7 breaths/min in a stressed situation. No underwater sounds have been recorded for this species, yet they can be identified on the surface by respiration sounds.

Communication and Perception

Food Habits

The Burmeister's porpoise feeds primarily on anchovies and hake, yet squid, euphasiids, mysid shrimp, and up to nine species of fish also have been found to be a part of its diet. Those found off the coast of Chile have been known to eat molluscs as well.

  • Animal Foods
  • fish
  • mollusks
  • aquatic crustaceans

Economic Importance for Humans: Positive

Phocoena spinipinnis is often used for its meat in areas where they are frequently caught in fishing nets. The meat of these individuals is used either as food for humans or for baiting crab.

Conservation Status

Like many other cetaceans, the Burmeister's porpoise is often taken as bycatch in fishing nets. Van Waerebeek et al. studied the number of cetaceans caught by fisheries at Cerro Azul on the central coast of Peru. In 87 days, a total of 91 out of 722 (12.6%)cetaceans caught were Phocoena spinipinnis. Exploitation occurs in Peru and Chile, where the animals are shot or harpooned and subsequently sold for their meat, which is used as both bait in crab fisheries and consumed by humans. Purposeful catches have decreased since 1994 when stricter legislation was implemented, however the bycatches have not. The only known natural predator of Phocoena spinipinnis is the killer whale.

Contributors

Jennifer Ellis (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

piscivore

an animal that mainly eats fish

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

"The Porpoise Page" (On-line). Accessed October 5, 1999 at http://geocities.com/CapeCanaveral/Lab/9336/burmeister.html.

@Phocoena.org, March 12, 1999. "Porpoise Science and Conservation" (On-line). Accessed October 5, 1999 at http://phocoena.org.

Bjorge, A., G. Donovan. 1995. Biology of the Phocoenids. Cambridge: International Whaling Commission.

Brownell, R., R. Praderi. 1978. Status of Burmeister's Porpoise, Phocoena Spinipinnis, In Southern South American Waters. Mammals in the Seas, v. 4: 91-96.

Gaskin, D., G. Smith, A. Watson, W. Yasui, D. Yurick. 1984. Reproduction in the Porpoises (Phocoenidae): Implications for Management. Reproduction in Whales, Dolphins, and Porpoises, no. 6: 135-148.

Nowak, R. 1999. Walker's Mammals of the World, sixth edition,volume 2. Baltimore and London: The Johns Hopkins University Press.

Parker, S. 1988. Grzimek's Encyclopedia of Mammals. McGraw-Hill.

Van Waerebeek, K., M. Van Bressem, F. Felix, J. Alfaro-Shigueto, A. Garcia-Godos. July 8, 1997. Mortality of Dolphins and Porpoises in Coastal Fisheries Off Peru and Southern Ecuador in 1994. Biological Conservation, v. 81, no.1-2: 43-49.