Pacific White-Sided Dolphin
Lagenorhynchus obliquidens

Physical Description

• Smallish marine mammal with a thick, streamlined body and short snout
• Large curved, or hooked, dorsal (back) fin
• Their back, lips, and tail are black; their sides, dorsal fin, and flippers are gray; their belly is white. They have a white stripe that extends from their eye to their tail
• Adults can reach a weight of 300-400 pounds and a length of 5-8 feet
• Males are generally larger than females

Range

• North Pacific Ocean
• Yellow and East China Sea to the south of Japan, Sea of Japan, Sea of Okhotsk, southern Bering Sea, Aleutian Islands, coasts of Canada, Alaska, Washington, Oregon, California

Habitat

• Found in the open ocean and in nearshore waters
• Rarely found close to shore

Reproduction

• Males reach maturity at 10, females at 8-11 years old
• They mate and give birth from late spring to fall
• Gestation is 9-12 months
• Calves are generally about 30 pounds at birth, and 3-4 feet long
• Calves are nursed for about 18 months
• Females give birth every 3 years

Diet

• Squid, small schooling fish (like capelin, herring, and sardines), salmon, hake, rockfish, pollock

Predators

• Orcas and sharks

Interesting Facts

• Pod sizes are usually between 10-100 animals, but they can be seen in schools of thousands.
• These very playful dolphins are often seen riding the bow of ships, jumping, somersaulting, or spinning in the air.
• A primary threat to Pacific white-sided dolphins is entanglement in fishing gear, so reporting any lost fishing gear you see is very important for their safety!
• They use their teeth to hold on to their food before they swallow it whole, and they eat 20 pounds of food a day!

Sources: NOAA Fisheries; Nature Mapping Foundation; Voices in the Sea

Photo: Howard Hall

To hear a Pacific white-sided dolphin’s call, visit Voices in the Sea, a collaboration between the Pacific Life Foundation and Scripps Institution of Oceanography.