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Mesoplodon densirostrisBlainville's beaked whale

By Michael Quinones

Geographic Range

Blainville's beaked whales are thought to have the widest range of all species in their genus Mesoplodon. This cosmopolitan species occurs in every ocean with exception of the Arctic. Blainville's beaked whales prefer tropical and warm temperate waters, and their distribution may vary with the movements of warm-water currents. In the Western Atlantic, their range stretches from the Gulf of Mexico and the Caribbean Sea to Nova Scotia. A number of strandings have been reported from Florida to Nova Scotia, and also in Puerto Rico. In the eastern Atlantic, they have been recorded off the coasts of Spain, the Netherlands, Portugal, the United Kingdom, and the Canary Islands. The farthest north they have been recorded in the eastern Atlantic is Aberaeron, Wales. In the Pacific, Blainville's beaked whales range from California to Taiwan. Records of strandings and sightings in the Pacific include the Line Islands, the Philipines, the mainland coast of China, Japan, the Ryukyu Islands, Midway, the Cook Islands, the Solomon Islands, New Caledonia, and the Hawaiian Islands. There are few records of Blainville's beaked whales in the Indian Ocean, likely due to a low observation effort. They have been recorded in Seychelles, Nicobar Islands, and the Maldives. Strandings have also been reported on the island of Mauritius in the southwest Indian Ocean. (Baird, et al., 2009; Ballance, et al., 2001; Borsa and Robineau, 2005; Claridge, 2006; Herman, et al., 1994; Hevia, et al., 2011; Mead, 1989; Pastene, et al., 2006; Reeves, et al., 2002; Rosario-Delestre, et al., 1999; Schorr, et al., 2009; Waring, et al., 2009)

Habitat

Blainville's beaked whales seem to prefer warm temperates and tropical waters, avoiding the Arctic and Antarctic Oceans. They prefer water temperatures from 10°C to 32°C. Preferred depths range from 700 to 1000 meters, often alongside much deeper waters. They seem to favor areas that are topographically diverse. Along with temperature, depth, and topography, their habitat is dependent on the level of productivity in the water. Blainville's beaked whales were once thought to avoid coastal regions and shallow waters, however, recent studies suggest that they seem to be more pelagic than other species of beaked whales and are the most frequently spotted of all beaked whales near tropical islands. (Baird, et al., 2006; Baird, et al., 2009; Claridge, 2006; Mead, 1989; Reeves, et al., 2002)

  • Average depth
    700-1000 m
    ft

Physical Description

Blainville's beaked whales have long and narrow bodies, similar to the other species in the genus Mesoplodon. Their fusiform bodies are widest near the middle and taper at each end. They weigh 820 to 1,030 kg and have an estimated lengths of 4.5 to 4.6 m. The longest recorded length was a female with a length of 4.7 meters. At birth, they are roughly 2 m long and weigh around 60 kg. (Besharse, 1971; Jefferson, 1993; Mead, 1989; Raven, 1942; Reeves, et al., 2002)

Blainsville's beaked whales have a moderately flat melon, somewhat long beak, thick rostrum, a small falcate dorsal fin located roughly two-thirds down the back, and a pair of throat grooves found under the lower jaw. Their blowhole tends to be semi-circular with the open side aimed toward its head. Blainville's beaked whales are dark bluish gray color on the dorsal and lateral regions and lighter gray on the ventral side. They are very difficult to distinguish from other members of their genus because they are so similar in appearance. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011; Besharse, 1971; Jefferson, 1993; Mead, 1989; Raven, 1942; Reeves, et al., 2002)

Males have a heavily arched rear half of their lower jaw, unlike juveniles and females. Males also have large teeth that project out from the lower jaw and rise above the upper jaw. Single-stalked barnacles often bind to these exposed teeth in small clusters. Females and juveniles also have teeth, but they are not easily seen because they are beneath the tissue of the gum within the mouth. Males often have scars present on their bodies, which studies suggest result from competing with each other for access to females. (Besharse, 1971; Jefferson, 1993; Mead, 1989; Raven, 1942; Reeves, et al., 2002)

  • Average mass
    820-1,030 kg
    lb
  • Average mass
    1.088e+06 g
    38343.61 oz
    AnAge
  • Average length
    4.5-4.6 m
    ft

Reproduction

Fighting among males for access to females is believed to be common, as numerous long narrow scars are found on males. These are likely caused by the large, tusk-like teeth of males. Studies suggest they form harems, which consist of several females and a single dominant male. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011)

Knowledge about reproduction habits of Blainville's beaked whales is very scarce. The estimated age of sexual maturity is 9 years. Mature females give birth to a single calf. Newborn calves are estimated to weigh around 60 kg and measure 1.9 to 2.6 m in length. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011)

  • Key Reproductive Features
  • iteroparous
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    1
  • Average age at sexual or reproductive maturity (female)
    9 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    3287 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    9 years

Little is known about parental investment in this species, but female whales typically nurse calves. There is little parental investment in this species.

Lifespan/Longevity

The lifespan of Blainville's beaked whales is unknown. (Jefferson, 1993)

Behavior

Little is known about the Blainville's beaked whales' social behavior. They are difficult to research because they flee from humans and their blow at the surface of the water is not very noticeable. They are typically found individually or in social groups averaging 3 to 7 individuals, but on occasion as many as 12. Due to the lack of research, it is unclear whether these groups are composed of different ages and sexes or if they are segregated. Some research suggests that adult populations are possibly grouped into harems. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011; Baird, et al., 2006; Claridge, 2006)

Like other beaked whales, Blainville's beaked whales are deep divers that feed on prey in deep water. They typically dive down 500 to 1000 m, and stay underwater for 20 to 45 minutes. Dives lasting longer than 50 minutes and reaching depths around 1400 m have been recorded. In dives deeper than 800 m, descent rates are faster than ascent rates. In dives that are 100 to 600 m deep, descent and ascent rates are similar. Dives are performed during both the day and at night. Migration habits are unknown. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011; Baird, et al., 2006; Claridge, 2006)

Home Range

Size of home ranges of Blainsville's beaked whales is unknown.

Communication and Perception

Blainville's beaked whales use echolocation to locate prey on deep dives. They produce two types of clicking sounds, each associated with a specific foraging phase. Search clicks, between 0.2 and 0.4 seconds, are sent during their diving phase in search of prey. Short burst clicks are buzz clicks emitted while capturing prey. (Johnson, et al., 2006)

Food Habits

Most of the information on the food habits of Blainville's beaked whales is collected from the stomach contents of stranded individuals. The primary prey is thought to be cephalopods (Cephalapoda), as they eat armhook squid (Gonatidae), glass squid (Cranchiidae), and cock-eyed squid (Histioteuthidae). However, they most likely consume a significant quantity of other fish and invertebrates. (MaCleod, et al., 2003; Reeves, et al., 2002)

  • Primary Diet
  • carnivore
    • eats other marine invertebrates
  • Animal Foods
  • fish
  • mollusks
  • other marine invertebrates

Predation

There are no records of any predation of Blainville's beaked whales. (Mead, 1989)

Ecosystem Roles

Blainsville's beaked whales prey on cephalopods, but are not known to be eaten by any other animals. Barnacles (Cirripedia) attach themselves to the tusk-like teeth of males.

Commensal/Parasitic Species
  • barnacles (Cirripedia)

Economic Importance for Humans: Positive

Blainville's beaked whales are sometimes hunted by small cetacean hunters in various locations. Occasionally, they are also taken accidentally by Japanese tuna boats. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011)

Economic Importance for Humans: Negative

There are no known negative impacts of Blainsville's beaked whales on humans.

Conservation Status

The IUCN Red List classifies Blainsville's beaked whales as "Data Deficient," meaning that there is insufficient information to determine the stability of their population or its trend. However, they appear to be fairly common in most warm waters, and are the most common of all the whales in their genus (Mesoplodon). Current threats include accidental and intentional hunting and ingesting pollution. Confusion by military sonar has caused them to wash up on beaches in large numbers. They may also be affected by climate change, but the potential impacts are not yet certain. ("Blainville's Beaked Whale (Mesoplodon densirostris)", 2011; Mead, 1989)

Contributors

Michael Quinones (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Alecia Stewart-Malone (editor), University of Wisconsin-Stevens Point, Catherine Kent (editor), Special Projects.

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

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

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

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

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

cosmopolitan

having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.

echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

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.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

sexual

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

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

2011. "Blainville's Beaked Whale (Mesoplodon densirostris)" (On-line). NOAA Office of Protected Resources. Accessed August 11, 2011 at http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/beakedwhale_blainvilles.htm.

2011. "CITES-Listed Species" (On-line). UNEP-WCMC Species Database. Accessed August 11, 2011 at http://www.cites.org/eng/resources/species.html.

Baird, R., D. Webster, D. McSweeney, A. Ligon, G. Schorr, J. Barlow. 2006. Diving behavior of Cuviers (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales in Hawai’i. Canadian Journal of Zoology, 84: 1120-1128.

Baird, R., G. Schorr, D. Webster, S. Mahaffy, D. McSweeney, M. Hanson, R. Andrews. 2009. "Movements of satellite-tagged Cuvier’s and Blainville’s beaked whales in Hawai’i: evidence for an offshore population of Blainville’s beaked whales" (On-line pdf). Cascadia Research. Accessed August 11, 2011 at http://www.cascadiaresearch.org/hawaii/Bairdetal2009beakedwhales.pdf.

Ballance, L., R. Anderson, R. Pitman, K. Stafford, A. Shaan, Z. Waheed, R. Brownell. 2001. Cetacean sightings around the Republic of Maldives, April 1998. Journal of Cetacean Research and Management, 3(2): 213-218. Accessed August 11, 2011 at http://www.mrc.gov.mv/files/publications/Ballance_etal_2001.pdf.

Besharse, J. 1971. Maturity and sexual dimorphism in the skull, mandible, and teeth of the beaked whale, Mesoplodon densirostris. Journal of Mammalogy, 52: 297-315.

Borsa, P., D. Robineau. 2005. Blainville’s beaked whale in New Caledonia. Pacific Science, 59: 467-472. Accessed August 11, 2011 at http://muse.jhu.edu/journals/pacific_science/v059/59.3borsa.pdf.

Claridge, D. 2006. "Fine-scale distribution and habitat selection of beaked whales" (On-line pdf). Accessed August 11, 2011 at http://www.bahamaswhales.org/resources/D_Claridge_MSc_Thesis.pdf.

Herman, J., A. Kitchener, J. Baker, C. Lockyer. 1994. The most northerly record of Blainville's beaked whale Mesoplodon densirostris, from the eastern Atlantic. Mammalia, 58(4): 657-661.

Hevia, M., D. Arcucci, J. Belgrano, F. Cipriano, C. Gasparrou. 2011. "Reports of the International Whaling Commission" (On-line pdf). Accessed August 11, 2011 at http://iwcoffice.org/_documents/sci_com/SC63docs/SC-63-SM3.pdf.

Jefferson, T. 1993. Marine Mammals of the World. Rome: Food & Agriculture Org.

Johnson, M., P. Madsen, W. Zimmer, N. Aguilar De Soto, P. Tyack. 2006. Foraging Blainville's beaked whales (Mesoplodon densirostris) produce distinct click types matched to different phases of echolocation. The Journal of Experimental Biology, 209: 5038-5050. Accessed August 11, 2011 at http://jeb.biologists.org/content/209/24/5038.long.

MaCleod, C., M. Santos, G. Pierce. 2003. Review of data on diets of beaked whales: evidence of niche separation and geographic segregation. Journal of the Marine Biological Association of the UK, 83: 651-665. Accessed August 11, 2011 at http://www.abdn.ac.uk/marfish/pdfs/MacLeod2003.pdf.

Mead, J. 1989. Beaked whales of the Genus Mesoplodon. Handbook of Marine Mammals, 4: 349-430.

Pastene, L., K. Numachi, M. Jofre, M. Acevedo, G. Joyce. 2006. First record of the Blainville's beaked whale, Mesoplodon densirostris Blainville 1817 (Cetacea, Ziphiidae) in the eastern South Pacific. Marine Mammal Science, 6(1): 82-84.

Raven, H. 1942. On the structure of Mesoplodon densirostris, a rare beaked whale. Bulletin of the AMNH, 80(2): 23-50. Accessed August 11, 2011 at http://digitallibrary.amnh.org/dspace/handle/2246/1201.

Reeves, R., B. Stewart, P. Clapham, J. Powell. 2002. Guide to Marine Mammals of the World. New York: Alfred A. Knopf, Inc..

Rosario-Delestre, R., M. Rodriguez-Lopez, A. Mignucci-Giannoni, J. Mead. 1999. New records of beaked whales (Mesoplodon spp.) for the Caribbean. Caribbean Journal of Science, 35(1-2): 144-148. Accessed August 11, 2011 at http://www.suagm.edu/umet/pdf/Rosario99CJS.pdf.

Schorr, G., R. Baird, M. Hanson, D. Webster, D. McSweeney, R. Andrews. 2009. Movements of satellite-tagged Blainville’s beaked. Endangered Species Research, 10: 203-213. Accessed August 11, 2011 at http://www.int-res.com/articles/esr2010/10/n010p203.pdf.

Taylor, B., R. Baird, J. Barlow, S. Dawson, J. Ford, J. Mead, G. Notarbartolo di Sciara, P. Wade, R. Pitman. 2008. "Mesoplodon densirostris In: IUCN 2012" (On-line). IUCN Red List of Threatened Species. Version 2012.2. Accessed November 15, 2012 at http://www.iucnredlist.org/details/13244/0.

Waring, G., E. Josephson, K. Maze-Foley. 2009. "Blainsville's beaked whale (Mesoplodon densirostris): Northern Gulf Of Mexico Stock" (On-line pdf). Accessed August 11, 2011 at http://www.nefsc.noaa.gov/publications/tm/tm213/pdfs/F2009GMexBlainvilles.pdf.

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