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.
|250 pounds (114 kg)|
|6-7 feet (2 m)|
|gray with lighter spots and long, slender snouts/ beaks|
|cephalopods and fishes|
|often occur in groups of several hundred ; they are considered quite gregarious, often schooling with other dolphin species|
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.
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.
The most recent stock assessment reports with population estimates are available on our website.
- targeted in tuna purse-seine fishery: in the Eastern Tropical Pacific
- Due to the as yet unexplained association between large yellowfin tuna and some dolphins in the ETP, spotted dolphins have been the targets of the tuna purse-seine fishery that uses the dolphins’ locations to find tuna.
- Many dolphins used to be caught in the nets and suffocated.
- Current fishing methods for tuna imported into the U.S. under the Dolphin-Safe program do not allow such destructive fishing practices.
- Interactions with tourists are a growing issue for the Hawaiian stock
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.
In 1980, we listed the coastal stock as depleted under the Marine Mammal Protection Act. The offshore stock was listed as depleted in 1993.
- Pantropical spotted dolphins are hunted for food in Asia, Indonesia, the Phillippines, and parts of the Pacific.