Deep dive...into Atlantic spotted dolphins

Fast swimmers who are often active at the ocean’s surface, Atlantic spotted dolphins are found across most of the warm Atlantic.  

Unsurprisingly, they get their name from their distinctive spots! When they’re born, they start out grey, like other dolphins. But after a year or two, they develop speckles which later turn into mottled spots.  

By the time Atlantic spotted dolphins mature into adults, they appear with light spots on their dark backs and darker spots on their pale bellies. Interestingly, the Atlantic spotted dolphins who live in the Gulf Stream, far offshore, often lack spots.  

The species (Stenella frontalis) weighs in between 220 – 320 pounds and are around five to seven feet long. The dolphins have bulky heads and bodies, and long, narrow beaks. Their dorsal fin is long and curved.  

The cetaceans usually form groups of between 5 and 50 individuals but they are sometimes spotted travelling in large pods of up to 200. They’re extremely social and are also very playful. Atlantic spotted dolphins can be seen performing acrobatics, riding the bow waves of boats and/or surfing the waves behind them.  

As well as being a fast swimmer, the Atlantic spotted dolphin is a great diver. It can dive for up to 60 metres and has been recorded holding its breath for up to 10 minutes.  

Atlantic spotted dolphins have been extensively studied by the Wild Dolphin Project in the Bahamas since 1985. They use surface and underwater photography to identify individual dolphins.

Every field season, known dolphins are re-identified, new dolphins including calves and immigrants are identified, and the losses of animals are documented too.  

The research project also monitors reproductive and health status, and social associations. Find out more on the Wild Dolphin Project website. 

The species is listed as ‘Least Concern’ on the IUCN Redlist of Threatened Species. 

The species is found across most of the warm Atlantic (warm, temperate and tropical waters) and usually keeps within 360 kilometres of the shore. Sometimes, it can be seen in deeper oceanic waters.  

Atlantic spotted dolphins are often seen in the waters off the Bahamas, the Azores, the Canary Islands, Brazil and off the U.S. East Coast (from the Gulf of Mexico to Massachusetts). In the Bahamas, the Atlantic spotted dolphins spend a lot of time in shallow water on sandbanks which makes them very accessible to research.  

Check out this underwater video of Atlantic spotted dolphins in Tenerife taken on the WeWhale vessel ‘Esiel’.  

Atlantic spotted dolphins often work as a team to catch prey together. They eat small fish, invertebrates (molluscs, crustaceans etc.) and cephalopods (squid, octopus, cuttlefish etc.). The species has been observed using their beaks to dig into the sand on the ocean floor to catch hidden fish.  

One of the main threats to Atlantic spotted dolphins is entanglement in fishing gear. This can go on to cause injury, fatigue, comprised feeding and sometimes even death. 

The species is at risk of vessel strikes throughout their range but the threat is higher in areas with busy ship traffic. 

Climate change and pollution are a threat to all whales and dolphins because of the loss of habitat as waters become warmer.  
 
Plastics and micro plastics, along with chemical pollutants, entering into the water system are a serious threat to all creatures in our ocean.  
Atlantic spotted dolphins, like other cetaceans, use noise to communicate and to locate prey. Increased noise pollution from vessels and other human activity interferes with this ability. 

There is no commercial hunting of Atlantic spotted dolphins but there have been recorded instances of the species being hunted and killed in the Caribbean, South America, West Africa, and other offshore islands, for food and bait. .

As with other dolphin species, Atlantic spotted dolphins are sometimes the prey of orcas and large sharks.