Pantropical Spotted Dolphin - Stenella attenuata

Pantropical Spotted Dolphin
Stenella attenuata

Other Names: Spotted Dolphin, White-spotted Dolphin, Bridled Dolphin, Spotter, Spotted Porpoise, Slender-beaked Dolphin

Habitat: Offshore and Inshore

Status: Common

Population: Unknown

Threats: Entanglement in fishing nets and hunting/whaling

Group Size: 50-1,000, coastal form usually in groups of under 100

Fin Position: Center

Newborns: 32-35 in (80-90 cm), unknown weight

Adults: 5 ž-8 ft (1.7-2.4 m), 200-255 lb. (90-115 kg)

Diet: Fish, squid or octopus, and occasionally krill or other crustaceans

Teeth: 70-96 on top row, 68-94 on bottom row

Description

Dorsal fin:

- dark gray dorsal fin same color as cape
- deeply concave trailing edges
- leading edge may be convex
- some tips slightly pointed
- some fins extremely falcate, with exaggerated concave trailing edge
- tip may be slighlty rounded
- leading edge may be nearly straight

Flukes:

- slight notch in middle
- slightly concave trailing edges
- pointed tips

Flippers:

- pointed tips
- small flippers dark on both sides
- strongly convex leading edges

Other characteristics:

- long, narrow beak
- dark upper jaw; band extends to dark patch around eye (variable)
- dark gray cape on upper side
- medium gray tail stock
- distinct keel below (and sometimes above) tail stock, except on large males
- slender, elongated body (coastal form more robust)
- band of medium gray along each side (may be absent)
- pale gray underside
- dark spots cover light areas of body
- light spots cover dark areas of body
- dark band between lower jaw and flippers
- white "lips"
- tip of beak white

Behavior

- very active: schools may be sighted from afar by froth caused by their leaping
- it is a fast, energetic swimmer, using long, shallow leaps
- frequently breaches, sometimes hurling itself high into the air, where it seems to hang before falling back with a splash
- often associates with Long-snouted Spinner Dolphins and Yellowfin Tuna, and often seen with feeding seabirds
- lobtailing and bow-riding common, but in tuna fishing areas some individuals flee from boats

Distribution

- tropical and some warm temperate waters of the Atlantic, Pacific, and Indian Oceans
- widely distributed, mainly in tropical seas but also in the subtropics and some warm temperate waters
- distribution probably not continuous within the range, though it appears to be abundant in many areas
- found mainly where surface water temperature higher than 77° F (25° C)
- commonly occurs around islands
- well-studied in the eastern tropical Pacific but poorly known elsewhere
- overlaps with the Atlantic Spotted Dolphin, mainly in the western North Atlantic, where it occurs mainly offshore
- no known migrations, though offshore form may make seasonal movements, usually summering inshore and wintering offshore

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu

Internet Coordinator: Candice Orca Mottet

e-mail questions, comments, and/or suggestions to wcrc@sci.tamucc.edu

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu