Atlantic White-sided Dolphin
Lagenorhynchus acutus

Other Names: Jumper, Springer, Lag, Atlantic White-sided Porpoise

Habitat: Offshore and inshore

Status: Locally common

Population: Unknown

Threats: Hunting/whaling and entanglement in fishing nets

Group Size: 5-50, schools of up to 1,000 recorded offshore

Fin Position: Slightly forward of center

Newborns: 39 in - 4 ft (1-1.3 m), 65-75 lbs. (30-35 kg)

Adults: 6 -8 ft (1.9-2.5 m), 365-440 lbs. (165-200 kg)

Diet: Squid or octopus, fish, and occasionally krill or other crustaceans

Teeth: 58 to 80 on both top and bottom rows


Dorsal fin:

- tall, falcate dorsal fin (more erect in adult males)
- uniformly black or dark gray


- pointed tips
- concave trailing edges
- distinct notch in middle
- black or dark gray on both sides
- tail stock narrows abruptly close to the flukes


- pointed tips
- black or dark gray sickle-shaped


- beak black or dark gray above, white or pale gray below
- gently sloping forehead
- dark ring around eye
- dark stripe between corner of mouth and flipper

Other characteristics:

- black or dark gray upper side
- yellow or tan band along each side of tail stock
- very thick tail stock with distinct keels
- robust body
- pale gray stripe along length of body
- white underside
- white undersides
- white band below dorsal fin


- acrobatic and a fast swimmer
- frequently breaches (though not as often as White-beaked or Common Dolphins) and lobtails
- surfaces to breathe every 10 to 15 seconds, either leaping clear of the water of barely breaking the surface and creating a wave over its head
- wary of ships in some areas, but will swim alongside slower vessels and may bow-ride in front of faster ones; sometimes rides the bow waves of large whales
- generally found in larger schools offshore and smaller ones inshore
- individual and mass strandings are relatively common


- cool temperate and subarctic waters of the northern North Atlantic
- range very similar to that of the White-beaked Dolphin
- toward the east of the range, may occasionally be found as far north as the southern Barents Sea and rarely seen farther south than the English Channel
- in the west, has been reported from west Greenland to Chesapeake Bay (though usually from Cape Cod, northward); appears to be especially abundant in the Gulf of Maine, and large schools penetrate far up the St. Lawrence estuary, Canada
- may be an inshore-offshore movement with the seasons in some areas
- seems to prefer areas with high sea floor relief and along the edge of the continental shelf

TMMSN Galveston

TMMSN Corpus Christi

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This page was created by:Candice Orca Mottet