Atlantic White-sided Dolphin Lagenorhynchus acutus
The Atlantic white-sided dolphin gets its name from the distinctive white stripe on its side, which starts just below the dorsal fin and runs into a yellow/ochre blaze continuing onto the tailstock which is easily seen when the animal is bow-riding or porpoising. They are quite stocky little dolphins with short stubby beaks yet a relatively large dorsal fin. Image: Gale/yeimaya (Flickr)
Find out more: Whale and Dolphin Conservation, The Mammal Society, iNaturalist