Marine Mammal Species Description

Blainville's Beaked Whale

Mesoplodon densirostris

(Blainville, 1817)

Classification

Order: Cetacea
Family: Ziphiidae
Alternate Common Names: Atlantic beaked whale, dense-beaked whale.

Status: protected under MMPA

Description:

   Length: 14.7-19 ft (4.5-5.8 m)
   Weight: around 2,280 lbs (1,033 kg)

Blainville's beaked whales have a long rostrum and a small falcate dorsal fin located on the back half of their body. Their lower jaw has a distinct arch near the back. In males this arch is more defined and reaches above the upper jaw. On males, a tooth is visible on top of either side of this arch. These teeth or tusks are sometimes covered with barnacles. They are dark above and light below. Older individuals generally have some scarring on their body, either lines or round scars.

Habitat:

They occur off shore in deep waters 2,297-3,281 ft (700-1,000 m) in depth. One record was near an area with an ocean depth of 16,404 ft (5,000 m). However, they have also been seen in shallower continental slope waters (mean depth 1,050 ft (320 m) and 2.7 miles (4.4 km) from shore). These ranges in depth are most likely because of differences in prey availability at the different locations where the observations were made. School size for this species is small, likely less than 10 individuals, and some evidence suggests that schools may only have one adult male.

Feeding:

Blainville's beaked whales eat squid and fish. They apparently hunt by echolocation deep in the water. Recorded durations of these deep, feeding dives lasted 48-68 minutes and were typically deeper than 2625 ft (800 m) deep. The maximum recorded dive depth was 4,620 ft (1408 m). After these deep dives, individuals would make a group of shorter duration and shorter depth dives for about 1-2.5 hours before beginning another deep foraging dive.

Reproduction:

Female Blainville's beaked whales reach sexual maturity around 9 years old. Females likely give birth to a single calf at a time.

Other:

Distribution / Range:

These whales occur in warm temperate and tropical waters worldwide. In coastal areas of the United States, this species typically occurs off California southward in the Pacific and all along the east coast including the Gulf of Mexico.

Similar species:

This species is most likely confused with other members of the beaked whale genus Mesoplodon. In the genus Mesoplodon, females of different species are hard to tell apart. Males can be distinguished by their tooth placement and beak and mouth shape.

Notes:

References:

Baird, R.W., D.L. Webster, D.J. McSweeney, A.D. Ligon, G.S. Schorr, and J. Barlow. 2006. Diving behaviour of Cuvier's (Ziphius cavirostris) and Blainville's (Mesoplodon densirostris) beaked whales in Hawai'i. Canadian Journal of Zoolology 84: 1120-1128

Baird, R.W., D.L. Webster, G.S. Schorr, D.J. McSweeney, and J. Barlow. 2008. Diel variation in beaked whale diving behavior. Marine Mammal Science 24: 630-642.

Culik, B. 2010. Odontocetes. The toothed whales: "Mesoplodon densirostris". UNEP/CMS Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm. Accessed January 2012.

Mead, J.G. 1999. Blainville?s beaked whale, Mesoplodon densirostris. In The Smithsonian Book of North American Mammals. Wilson, D.E. and S. Ruff, eds., 310-311. Smithsonian Institution in association with the American Society of Mammologists, Washington DC.

Pitman, R. 2009. Mesoplodont Whales - Mesoplodon spp. In: Encyclopedia of Marine Mammals 2nd Ed. Perrin W.F., B. Würsig, and J.G.M. Thewissen, eds. Academic Press, New York, pp. 721-726.

Ritter, F. and B. Brederlau. 1999. Behavioural observations of dense beaked whales (Mesoplodon densirostris) off La Gomera, Canary Islands (1995-1997). Aquatic Mammals 25: 55-61.

Smithsonian Institution. 2007. Beaked Whale Identification Guide. Mesoplodon densirostris. http://vertebrates.si.edu/mammals/beaked_whales/pages/mde/mde_sp_pg1.htm. Accessed January 2012.

Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. 2008. Mesoplodon densirostris. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. www.iucnredlist.org. Downloaded on 09 January 2012.

Tyack P.L., M. Johnson, N.A. Soto, A. Sturlese, and P.T. Madsen. 2006. Extreme diving of beaked whales. Journal of Experimental Biology 209: 4238-4253.