White-Beaked Dolphin (Lagenorhynchus albirostris)

Did You Know?

· Lagenorhynchus, the scientific name for the genus of white-beaked dolphins, is derived from the Latin word lagenos for "bottle" or "flask" and rhynchos for "beak."

· White-beaked dolphins are the largest members of the genus Lagenorhynchus.

Status
MMPA - White-beaked dolphins, like all marine mammals, are protected under the MMPA.

Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Delphinidae
Genus: Lagenorhynchus
Species: albirostris

Species Description
White-beaked dolphins, sometimes called "squidhounds" by fishermen in Canada, are relatively small delphinids (Reeves et al. 2002). They are about 8-10.5 ft (2.4-3.2 m) in length and weigh 395-770 lbs (180-350 kg). Males are generally slightly larger than females. This species has a robust, streamlined body with a very small beak with white "lips." They have a prominent "dorsal" fin located in the middle of the back that is relatively large, lobed, and sickle-shaped. Their body is generally dark gray or black with white patches on the beak, sides, ventral area, and back behind the dorsal fin. This coloration can be variable.

White-beaked dolphins are usually found in social groups that range from 5-50 (usually less than 30) individuals, but have been occasionally seen in larger groups of up to 1,500 animals. There is little information on the social structure of this species, but separation by age and sex may occur. They are sometimes seen in mixed schools associated with large rorqual species such as fin whales, and humpback whales, and other small cetaceans, especially in feeding areas (Reeves et al.2002). These gregarious dolphins often engage in acrobatic activity, breaching and jumping at the surface. They will often approach vessels to "bowride".

White-beaked dolphins dive to feed on small "mesopelagic" and schooling fish (e.g., capelin, cod, haddock, hake, herring, and whiting), crustaceans, and cephalopods (e.g., squid and octopus). This species has been observed cooperatively feeding on schools of fish at the water's surface and may forage along the ocean bottom for benthic organisms. They have 22-28 pairs of small conical teeth in each jaw that are useful for grasping prey.

White-beaked dolphins become sexually mature and begin breeding between 7-12 years of age when they reach about 8 ft (2.4-2.5 m) in length. After a gestation period of about 11-12 months, females give birth to a single calf that is about 4 ft (1.1-1.2 m) long and weighs 90 lbs (41 kg). Calving generally takes place during the summer (May-September). The estimated lifespan of this species is unknown.

Habitat
White-beaked dolphins are "endemic" to the colder temperate and subpolar oceanic waters of the North Atlantic Ocean. They generally prefer shallow waters less than 200 m (656 ft) deep (Jefferson et al. 2008). In the 1970s and 1980s, white-beaked dolphins off the northeastern U.S. Atlantic coast may have shifted habitats with Atlantic white-sided dolphins. During this time, white-beaked dolphins, which were normally found in inshore waters, moved offshore due to an increase in sand lance on the continental shelf and a decline in herring.

Distribution
White-beaked dolphins have a broad distribution throughout the temperate waters of the North Atlantic Ocean, from about 40-80° North. Their range includes the Barents Sea, Scandinavia, Svalbard, Greenland, Iceland, Ireland, northern Europe, Canada (Gulf of St. Lawerence and Newfoundland) and the U.S. Atlantic coast (north of Cape Cod, Massachusetts). These dolphins have a limited distribution in U.S. waters. This species moves seasonally offshore and south away from the formation of ice in winter, and closer inshore and north in summer when ice recedes. In some areas of their range, these dolphins may reside all year (Shirihai and Jarrett 2006).

Population Trends
For management purposes, white-beaked dolphins inhabiting U.S. waters have been placed into the Western North Atlantic stock. There are no current population estimates for this stock. This species commonly occurs in the Barents, Norwegian, and North Sea 's, and scientists estimate tens to hundreds of thousands of animals throughout its entire range (Jefferson et al. 2008). There are insufficient data for this species to determine the population trends.

Threats
White-beaked dolphins have been incidentally taken in fisheries such as gillnets, cod traps, and trawl nets. They have been directly hunted and killed for food and oil in waters off of Canada (Labrador and Newfoundland) as well as in Greenland, Iceland, the Faroe Islands, and Norway (Jefferson et al. 2008). This species is also commonly entrapped in ice off the coast of Newfoundland.

Conservation Efforts
The International Union for Conservation of Nature and Natural Resources (IUCN's) Red List of Threatened Species considers this species "Lower Risk Least Concern."

Regulatory Overview
This species is protected under the Marine Mammal Protection Act of 1972, as amended.

Key Documents
(All documents are in PDF format.)

Title	Federal Register	Date
Stock Assessment Reports	n/a	various

More Information

References:

Reeves, R. R., P. A. Folkens, et al. (2002). Guide to Marine Mammals of the World. New York, Alfred A. Knopf. p. 395-397.
Jefferson, T. A, M. A. Webber, and R. L. Pitman. (2008). Marine Mammals of the World, A Comprehensive Guide to their Identification. Amsterdam, Elsevier. p.201-203.
Shirihai, H. and B. Jarrett (2006). Whales, Dolphins and Other Marine Mammals of the World. Princeton, Princeton University Press. p. 199-200.