Pacific
White-sided Dolphin Lagenorhynchus obliquidens
The Pacific
white-sided dolphin occurs throughout the north Pacific Ocean
as far south as the South China Sea and Baja California and
in the ocean north of about 38oN to the Aleutians
(Wilson and Ruff 1999). The Pacific white-sided dolphin was
largely absent form the coastal waters of British Columbia in
the 1970s until the mid 1980s when they suddenly became fairly
numerous (Stacey and Baird 1991). The species has been
regularly seen there and in Alaska since 1992.
Whether in
large or small groups, this active and acrobatic dolphin is
very noticeable. It often rides bow waves of moving boats. It
makes high leaps out of the water returning to the water from
aback flip or forward arching dive.
A favourite of
public aquaria because of its activity, ease of training and
feeding, the Pacific white-sided dolphin remains poorly known
in the wild. Details about its movements, reproduction, and
ecology are sketchy.
Dolphins and
porpoises can be distinguished by the shapes of their rostrums
(beak) and teeth. Dolphins
belong to the family Delphinidae that are characterized by a
distinct rostrum and conical-shaped teeth whereas Porpoises
belong to the family Phocoenidae that have a rounded rostrum
and spade-shaped teeth.
References
Brownell, R.
L. Jr., W. A. Walker and K. A. Forney. 1999. Pacific
white-sided dolphin Lagenorhynchus obliquidens, Gill
1965. Pp. 57-84 in S. H. Ridgway and R. Harrison (eds.).
Handbook of marine mammals: the second book of dolphins and
the porpoises. Academic Press, London.
Costa, D. P.
and T. M. Williams. 1999. Marine mammals energetics. Pp.
176-217 in J. E. Reynolds and S. A. Rommel. Biology of marine
mammals. Smithsonian Institution Press, Washington, D.C.
Dalheim, M.E.
Towell, R.G. 1994. Occurrence and distribution of Pacific
white-sided dolphins (Lagenorhynchus obliquidens) in
southeastern Alaska, with notes on an attack by killer whales
(Orcinus orca). Marine Mammal Science 10: 458-464.
Lang, T. G.
and K. S. Norris. 1966. Swimming speed of a Pacific bottlenose
dolphin. Science 151: 588-590.
Stacey, P. J.
and R. W. Baird. 1991. Status of the Pacific white-sided
dolphin Lagenorhynchus obliquidens, in Canada. Canadian
Field-Naturalist 105: 219-232.
Wilson, D. E.
and S. Ruff 1999. The Smithsonian book of North American
mammals. University of British Columbia Press, Vancouver, BC
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