The pantropical spotted dolphin is an open ocean dolphin that is, in fact, spotted and gets its name from the fact that it lives throughout the tropical latitudes of all the world’s oceans. It often associates with other species of dolphins (especially the spinner dolphin) and with large bony fishes in some places. It is an active species and is known to leap repeatedly from the water when traveling at high speeds, either tracking prey or simply playing. There are several recognized subspecies, which exhibit significant physical variation, in shape and size.
This species feeds on schooling, epipelagic and mesopelagic fishes and squids in the open ocean. Like their prey, pantropical spotted dolphins form large groups – typically composed of hundreds or even thousands of individuals – for hunting and socializing. They reach sexual maturity at approximately 10 to 12 years of age and live for at least 40 years.
As the spinner dolphin is a wide ranging, open ocean species, its conservation status is not well known. It is, however, at the center of a major conservation controversy. In the 1980s, fisheries that targeted the yellowfin tuna were responsible for accidentally catching and killing pantropical spotted and spinner dolphins, sparking the famous and successful dolphin-safe tuna campaign. The tendency of adult yellowfin tuna in the eastern Pacific Ocean to school with similarly sized adult dolphins led to the unfortunate habit of fishermen setting their nets around dolphin pods with the hope of catching the nearby tuna. That activity is now illegal in most places around the world, but scientists believe that several million spinner and spotted dolphins have been killed in tuna nets. Curiously, throughout this species’ range outside of the eastern Pacific Ocean, it does not associate with large tunas and is not threatened by tuna fishing. The pantropical spotted dolphin now has legal protection throughout much of its range and is the focus of several international conservation efforts. Today, it is the second most numerous species of dolphin behind the common bottlenose dolphin, but its numbers are only about half of what they once were, and more research is needed to determine whether or not tuna fishing still has an impact on this species. Continued study is needed to determine the direction of population trends, but scientists generally consider the pantropical spotted dolphin to be a species of least concern.