Pantropical Spotted Dolphin
The Spotted Dolphin is the second most commonly encountered Dolphin species here in Puerto Vallarta. We usually see groups of 10-12 individuals, often they are very social as well, spending time near the boat. Spotted Dolphins are a fairly regular occurrence here in Puerto Vallarta
Pantropical Spotted Dolphin Classification
The Pantropical spotted dolphin is the species of dolphin known for its persecution in the eastern tropical Pacific tuna-fisheries. Millions of dolphins have been killed as a result of the practice of ‘setting nets’ on the dolphins to catch the tuna below. Despite legislation and catch limits having since been set, bycatch is still a major threat to this species. Two subspecies of pantropical spotted dolphin are currently recognised, a coastal form S. a. attenuata, found in coastal waters of the eastern tropical Pacific, and an offshore form, S. a. graffmani found elsewhere in the range.
The pantropical spotted dolphin is a medium sized, streamlined cetacean. Its falcate dorsal fin is pointed and very narrow and the small pointed flippers are dark on both sides. It has a dark grey cape, extending mid-way down the flanks and sweeping up behind the dorsal fin. The sides and belly are a lighter grey colour. As its name suggests, the body is covered with spots to a varying degree according to age and location with individuals in some areas having few to no spots. The coastal subspecies is generally larger, more robust, with a thicker beak and more spots. The lips and tip of the beak are white, and there is a dark stripe from the lower jaw to the flipper on both sides. Calves are born with no spots, and have a dark grey cape and very pale sides and belly. Juveniles develop dark spots on the belly and lighter spots on the dorsal side and spotting continues to increase with age with fusing of the spots in older animals. Confusion may occur with several other long-beaked oceanic dolphins including spinner and bottlenose dolphins, and the Atlantic spotted dolphin in areas where the two species overlap. Identifying characteristics of the pantropical spotted dolphin is the smaller more slender size, the distinct dorsal cape and a smaller, narrower dorsal fin.
Pantropical spotted dolphins are highly active and acrobatic, frequently performing high breaches and side-slaps. They are fast swimmers, and perform long low leaps at high speeds. They are known to bow and wake-ride in most parts of their range, although they generally avoid boats in the eastern tropical Pacific where they were persecuted for many years. The coastal form tend to be found in groups of less than 100 individuals while groups of the offshore form can number in the thousands. Pantropical spotted dolphins can often be seen associating with other species of oceanic dolphins and yellow-fin tuna, a behaviour that has historically been exploited by tuna fishermen.
Pantropical dolphins are, as their name suggests, found in a band around the globe in both tropical and subtropical waters, preferring areas where the surface temperature of the water is higher than 25°C. In addition to being seriously threatened by bycatch, as they are taken incidentally in several fisheries around the world, they are hunted for human consumption in large numbers in Japan and in smaller numbers in other countries around the world. Other threats to the species include habitat degradation and human disturbance. No global population estimate exists for this species although it is thought to be one of the most abundant species of cetacean in the world today. Despite this, some populations, like the offshore northeastern population that was the target of tuna fisheries, are not thought to be recovering from previous exploitation. The IUCN lists this species as of ‘Least Concern’.
- Spotted porpoise
- White-spotted dolphin
- Narrow-snouted dolphin
- Bridled dolphin
- Male: 2.6m
- Female: 2.4m
- Calf: 0.8m
- Male: 120kg
- Female: Unknown
- Calf: Unknown
II (eastern tropical Pacific and Southeast Asian populations)