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Pantropical Spotted Dolphin (Stenella attenuata)

Status | Species Description | Habitat | Distribution | Population Trends | Threats | Conservation Efforts | Regulatory Overview | Taxonomy | Key Documents | More Info

Status

MMPA Depleted - Pacific northeastern offshore stock
CITES Appendix II - throughout its range

Species Description

Weight:
250 pounds (114 kg)
Length:
6-7 feet (2 m)
Appearance:
gray with lighter spots and long, slender snouts/ beaks
Lifespan:
46 years
Diet:
cephalopods and fishes
Behavior:
often occur in groups of several hundred ; they are considered quite gregarious, often schooling with other dolphin species

Like other dolphins of the genus Stenella, these are relatively small dolphins, reaching lengths of 6 to 7 feet (2 m) and weighing approximately 250 pounds (114 kg) at adulthood. They have long, slender snouts or beaks. Like the Atlantic spotted dolphin (Stenella frontalis), pantropical spotted dolphins are without spots when born, accumulating them as they age until they are almost completely covered with overlapping patterns. Pan-tropical spotted dolphins are also distinguished by a dark "cape" or coloration on their backs stretching from their head to almost mid-way between the dorsal fin and the tail flukes and by a white-tipped beak.

Mating and calving occurs year-round, with gestation being like that of most dolphins, around eleven months. Lactation often takes place for two years, but also can last for only one year. At three to six months old, however, calves will begin taking solid food. Calving intervals depend on the population, but range from two and a half to four years. Maturity occurs at around 11 years of age and maximum longevity is 46 years.

Pantropical spotted dolphins often occur in groups of several hundred to one thousand animals. They are considered quite gregarious, often schooling with other dolphin species, such as spinner dolphins. Although specific migratory patterns haven't been clearly described, they seem to move inshore in the fall and winter months and offshore in the spring. They feed primarily on mesopelagic cephalopods and fishes.

Habitat

Spotted dolphins spend the majority of their day in shallower water typically between 300 to 1,000 feet (90 to 300 m) deep. At night, they dive into deeper waters to search for prey.
spotted dolphin
Pantropical Spotted Dolphins
(Stenella attenuata)
Photo: NOAA Southwest Fisheries Science Center

Distribution

Pantropical spotted dolphins can be found in all oceans of tropical and subtropical climate worldwide. Animals of the northeastern stock are found in the eastern tropical Pacific Ocean (ETP), far at sea. Coastal spotted dolphins are found within 100 miles of the coast. In addition, a Hawaiian stock occurs throughout the Hawaiian islands.

Population Trends

The most recent stock assessment reports with population estimates are available on our website.

Threats

Historically:

Currently:

Conservation Efforts

Ongoing research considers how the fishing effort affects the mother-calf bond, life-history information, and stock structure. Two programs run by NMFS' Southwest Fisheries Science Center aim to conserve spotted dolphins.

The Dolphin-Safe Program focuses on reducing fishing-related dolphin mortality by developing alternative fishing methods that do not involve dolphins.

The Dolphin Energetics Program focuses on determining whether energetics limitations associated with the fishing practice may be contributing to the observed lack of recovery of fishery-associated dolphin stocks in the ETP.

Regulatory Overview

In 1980, we listed the coastal stock as depleted under the Marine Mammal Protection Act. The offshore stock was listed as depleted in 1993.

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Delphinidae
Genus: Stenella
Species: attenuata

Atlantic spotted dolphins (Stenella frontalis) are another species of spotted dolphin.

Key Documents

(All documents are in PDF format.)
Title Federal Register Date
Depleted Designation for Northeastern Offshore Stock 50 CFR 216.15 1993
Stock Assessment Reports n/a various

More Information

Updated: January 21, 2015