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| Ecology and Behavior |
Often seen in large herds of hundreds or even thousands, these highly gregarious dolphins are also commonly seen with other species, especially northern right whale dolphins and Risso's dolphins. They are highly acrobatic and playful, commonly bowriding, and often leaping, flipping, or somersaulting. Large herds are often observed feeding in an apparently cooperative manner on large schools of fish.
Reproduction:
Males reach sexual maturity at about 10 years, and females at 8-11 years of age. Calving in some areas apparently occurs during a protracted summer breeding season, which extends into fall. In the central Pacific, calving takes place in late winter to spring. Length at birth is estimated to be 92-100 cm in the central Pacific. |
| Feeding and Prey |
| Pacific white-sided dolphins feed mostly on small schooling fish and squid. There is evidence that these dolphins feed mostly on deep scattering layer (DSL) organisms, possibly using cooperative foraging techniques. |
| Threats and Status |
Main threats include:
Harpooning
Gillnet and drift net firsheries
Conservation status:
Pacific white-sided dolphins have never been primary targets of Japanese drive fisheries, but they have been harpooned in Japanese waters. They are taken in a number of fisheries (mainly gillnet and driftnet fisheries) in the eastern North Pacific, and in the 1980s and early 1990s, several thousand per year were killed in the now-defunct squid driftnet fisheries that were operated in the offshore central Pacific by Japan, Taiwan, and Korea.
Not Listed (IUCN); Not Listed (ESA). |
| References |
BLACK, N. A. 1994. Behavior and ecology of Pacific white-sided dolphins (Lagenorhynchus obliquidens) in Monterey Bay, California. M.Sc. thesis, San Francisco State University.
BROWNELL JR., R. L., W. A. WALKER, AND K. A. FORNEY. 1999. Pacific white-sided dolphin Lagenorhynchus obliquidens Gill, 1865. Pp. 57-84 in S. H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 6 The second book of dolphins and the porpoises. Academic Press.
FERRERO, R. C., AND W. A. WALKER. 1996. Age, growth, and reproductive patterns of the Pacific white-sided dolphin (Lagenorhynchus obliquidens) taken in high seas drift nets in the central North Pacific Ocean. Canadian Journal of Zoology 74:1673-1687.
MIYAZAKI, N., T. KURAMOCHI, AND M. AMANO. 1991. Pacific white-sided dolphins (Lagenorhynchus obliquidens) off northern Hokkaido. Memoirs of the National Science Museum 24:131-139.
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.
VAN WAEREBEEK, K. AND B. WÃRSIG . 2002. Pacific white-sided dolphin and dusky dolphin Lagenorhynchus obliquidens and L. obscurus. Pp. 859-861 in W. F. Perrin, B. Würsig and J. G. M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
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| Species Illustrations |
Photo credit: Sharon Chester (captive-Cal Acad of Sciences) |
| Relevant OBIS-SEAMAP Datasets (# sets:
37) |
| Aerial Surveys of Marine Birds and Mammals in Support of Oil Spill Response and Injury Assessment |
| Mingan Island Cetacean Study 84-07 |
| MMS Aerial Surveys for Seabirds and Mammals, Oregon and Washington |
| MMS Central/Northern California High-altitude mammals |
| MMS Central/Northern California Low-altitude birds and mammals |
| MMS High Altitude Survey for Mammals, Southern California |
| MMS Low Altitude Survey for Mammals, Southern California |
| MMS Oregon/Washington Marine Mammal Surveys |
| MMS Oregon/Washington Miller Freeman Cruise (Birds) |
| MMS Seabird Ecology Study |
| MMS Ship Transect Survey for Mammals and Seabirds, Southern California Bight |
| MMS Surveys in the Southern California Bight |
| NMML 2000 Bering Sea Shelf Cetacean Survey |
| NMML Harbor Porpoise Aerial Survey, Bristol Bay, Replicate 1, 1991 |
| NMML Harbor Porpoise Aerial Survey, Bristol Bay, Replicate 3, 1991 |
| NMML Harbor Porpoise Vessel Survey, SE Alaska, Spring 1991 |
| NMML Harbor Porpoise Vessel Survey, SE Alaska, Spring 1992 |
| NMML Harbor Porpoise Vessel Survey, SE Alaska, Spring 1993 |
| NMML Harbor Porpoise Vessel Survey, SE Alaska, Summer 1992 |
| NMML Harbor Porpoise Vessel Survey, SE Alaska, Summer 1993 |
| NMML Small Cetacean (coastal) Aerial Survey 1997, Gulf of Alaska |
| NMML Small Cetacean (coastal) Aerial Survey 1999, Gulf of Alaska |
| SWFSC Cetacean Acoustic Detection and Dive Interval Studies (1601) |
| SWFSC Cetacean Sightings during a Marine Mammal Survey in the Eastern Tropical Pacific (1468) |
| SWFSC Cetacean Sightings during a Marine Mammal Survey in the Eastern Tropical Pacific (1508) |
| SWFSC Cetacean Sightings during a Marine Mammal Survey in the Eastern Tropical Pacific (1509) |
| SWFSC Marine Mammal Survey in the Eastern Tropical Pacific (1467) |
| SWFSC Marine Mammal Survey of the California Coast (1426) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (1081) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (1164) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (1165) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (1267) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (1268) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (1369) |
| SWFSC Marine Mammal Survey of the Eastern Tropical Pacific (989) |
| SWFSC Oregon, California and Washington Line-Transect Experiment (Orcawale) (1604) |
| SWFSC Oregon, California and Washington Line-Transect Experiment (Orcawale) (1605) |
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