Peruvian beaked whale
| Peruvian beaked whale | ||||||||||||
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| Mesoplodon peruvianus | ||||||||||||
| Reyes , Mead & van Waerebeek , 1991 |
The Peruvian beaked whale ( Mesoplodon peruvianus ), also known as the dwarf beaked whale or the dwarf beaked whale , is a species of whale from the family of the beaked whales (Ziphiidae). The species was not scientifically described until 1991 and is considered the smallest member of its family.
features
With a length of 3.70 to 3.90 meters and a weight of about 500 kilograms, the Peruvian beaked whale is the smallest species of the beaked whale, with males becoming slightly larger than females. The whale has a spindle-shaped shape, the largest diameter being approximately in the area of the middle of the body. It is dark gray on the top and whitish-light gray on the underside. The males have a chessboard-like pattern on the back, adult males can also have some white lines on the body, which are healed scars from rivalry fights. The fluke is comparatively wide in relation to body length and the base of the tail is flattened on the sides. Like all species of the genus two-toothed whales , it has only two teeth in the lower jaw and the fin is small and sits noticeably far back. The muzzle region and the lower jaw form a blunt, beak-like muzzle, and there are two pits on the throat. The lower jaw of the males is arched and the two teeth protrude as short tusks in the middle of the lower jaw.
distribution
The distribution area of the Peruvian beaked whale is in the Pacific Ocean off the coasts of Central and South America. The actual distribution area is unknown, as the species has only been proven by a very limited number of individuals and sightings. The evidence is located in an area near the South American coast from about 30 ° south to 28 ° north latitude . There is also a single find of a stranded animal in New Zealand , which, however, was probably a stray individual animal . Alternatively, the distribution area is larger than previously assumed.
Way of life
These whales are likely to live together in small groups of three to five animals and are mainly located in the deeper sea area. Like most beaked whales, they are good and persistent divers and feed primarily on octopus and fish from the deeper sea areas. Like other beaked whales, it probably hunts its prey at depths of around 500 meters.
There is no information about reproduction. During a sighting of a whale school of 5 individuals off the coast of Chile , a single young animal was also observed for the first time.
Systematics
The Peruvian beaked whale is classified as an independent species within the two- toothed whale (genus Mesoplon ). It was scientifically described in 1991 by Julio C. Reyes , James G. Mead and Koen van Waerebeek . The description was based on the skull and skeleton of a male whale that was stranded at Playa Paraiso in Peru in 1988. Before the species was officially described, it was named "Mesoplodon species A" based on sightings.
Beaked whales have been documented earlier in the southeastern Pacific, for example when an animal was caught by fishermen in Chile in 1949, which Philip Hershkovitz assigned to the camperdown whale ( Mesoplodon grayi von Haast , 1876 ). There was a beaked whale stranding in Paracas in 1855, which was likely an Andrew's beaked whale ( Mesoplodon bowdoini Roy Chapman Andrews, 1908 ) and there were several other sightings of unidentified beaked whales in Peruvian waters in the 1980s, as well as a stranding of one in 1989 female camperdown whale. Since the first few more Peruvian beaked whales on the coast of South, Central and North America are stranded or have been observed, including on the coast between Bahía de la Paz and Juan de la Costa in the Mexican state of Baja California Sur and the coast of Oaxaca up to a sighting of five individuals off the Chilean coast.
No subspecies are distinguished within the species .
Hazard and protection
Targeted whaling poses no threat to the Peruvian beaked whale, but the fact that specimens get caught in fishing nets and in shark protection nets off the South American coast and drown. However, there is too little data to give a precise indication of the total population or the degree of risk, so that the IUCN classifies the species as “data deficient”. The main threat to the species comes from intensive fishing, especially the tuna fishery .
In the last few years in particular, the influence of underwater noises, especially from sonar used underwater and explosions on various whales, including beaked whales, has been examined and discussed. There is clear evidence that these noise emissions have an impact on whales and lead to stranding of dolphins and beaked whales, among others. The extent to which these emissions affect the Peruvian beaked whale is not known, but it can be assumed that it is also affected. In addition, plastic residues were found in stranded animals, which were also discussed as a specific cause of death in individual cases.
The Peruvian beaked whale is included in Appendix II of the Washington Convention on the Protection of Species (CITES).
supporting documents
- ↑ a b c d "Pigmy Beaked Whale." In: CD MacLeod: Family Ziphiidae (Beaked Whales) In: Don E. Wilson, Russell A. Mittermeier: Handbook of the Mammals of the World. 4. Sea Mammals. Lynx Edicions, Barcelona 2014; P. 352. ISBN 978-84-96553-93-4 .
- ↑ a b c d e Mesoplodon peruvianus in the endangered Red List species the IUCN 2006. Posted by: Cetacean Specialist Group, 1996. Retrieved on 12 May, 2006.
- ↑ a b G. Paolo Sanino, José L. Yáñez, Koen van Waerebeek: A first confirmed Specimen record in Chile, and sightings attributed to the Lesser Beaked Whale Mesoplodon Peruvians Reyes, Mead and Van Waerebeek, 1991. Boletín del Museo Nacional de History Natural, Chile, 56, 2009; Pp. 89-96. ( Full text ).
- ↑ a b Mesoplodon peruvianus . In: Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
- ↑ Julio C. Reyes, James G. Mead, Koen van Waerebeek: A new species of Beaked Whale Mesoplodon peruvians sp. n. (Cetacea: Ziphiidae) from Peru. Marine Mammals Science 7 (1) January 1991; Pp. 1-24. doi : 10.1111 / j.1748-7692.1991.tb00546.x
- ↑ Jórge Urbán-Ramírez, David Aurioles-Gamboa: First Record of the Pygmy Beaked Whale Mesoplodon Peruvians in the North Pacific. Marine Mammals Science 8 (4) October 1992; Pp. 420-425. doi : 10.1111 / j.1748-7692.1992.tb00058.x
- ↑ Jesús García-Grajales, Alejandra Buenrostro Silva, Eunice Rodríguez-Rafael, Juan Meraz: Biological observations and first stranding record of Mesoplodon peruvianus from the central Pacific coast of Oaxaca, Mexico. Therya 8 (2), May 2017. doi : 10.12933 / therya-17-451
Web links
- Further information with picture and distribution map
- Mesoplodon peruvianus in the endangered Red List species the IUCN 2006. Posted by: Cetacean Specialist Group, 1996. Retrieved on 12 May, 2006.