Saturday, July 21, will mark the annual MERR Institute Dolphin Count, during which volunteers along Delaware's coastlines will help with the reporting of one of the most popular Delaware residents, the Atlantic Bottlenose Dolphin.
And while the Bottlenose may be the most visible to those along the coastline, they are only one of eight species that can be found swimming about in Delaware waters. Here's a closer look:
Striped Dolphin (Stenella coeruleoalba): Notable for a black patch around each eye, a thin dark streak behind eye, and one or two dark bands between its eyes and flippers, the striped dolphin (also known as the blue-white dolphin) is a highly sociable species that often travels in large groups (known as pods) numbering from 25 to 100. They are the Wilt Chamberlains of the dolphin world, known to jump out of the water more than 20 feet when swimming or playing. They are also quite agile, able to perform back somersaults, tail spins, swim upside-down and ride along a boat's bow in some areas. When searching for food such as fish, squid and shrimp, the Striped Dolphin can submerge for up to 10 minutes and reach depths of 600-plus feet. They are considered conscious breathers, which means they are never completely asleep and always aware of their surroundings.
Atlantic White-sided Dolphin (Lagenorhynchus acutus): Their name taken from their distinguishable white belly and sides, this playful, sociable species also enjoys traveling in large groups offshore (usually in waters over 100 feet deep). They have been observed interacting in the wild with other cetacean species such as the fin whale, humpback whale and long-finned pilot whale.
Common Dolphin (Delphinus delphis): There are actually two versions of the Common Dolphin, the short- and long-beaked, both of which have been documented, with the long-beaked being more noticed in coastal waters. These fast, agile dolphins have much darker backs and can be spotted playfully frolicing in waters offshore, whether it's jumping, flipping, bow-riding boats or wake-riding whales.
Atlantic Bottlenose Dolphin (Tursiops truncatus): Perhaps the most well-known of all dolphin species, they display a high level of intelligence, ability to learn and perform complex tasks. Combined with their outgoing nature, these made them very popular in mainstream culture. They are believed to have excellent eyesight and hearing, but have a poor sense of smell because the blowhole is their nose and it must close during dives to avoid taking water into the lungs. They have been observed numerous times helping others, leading humans back to land, defending them against attacks from sharks and helping other marine mammals find their way back home when lost at sea.
Risso's Dolphin: Risso's are solitary animals (found traveling in small groups of about 5) and are easily distinguished by their near-black to light-gray-colored skin tone and bulbous-shaped head. As they age, their skin goes from a dark near-black coloring to a light-gray color. They also have a blunt bulbous-shaped head and a large dorsal fin which helps them stabilize and navigate through the ocean water. In order to identify one another, each dolphin has a unique frequency that allows the group to know which one is communicating in the group.
Atlantic Spotted Dolphin: Throughout their youth, the spotted dolphins don't have spots at all, and more resemble slender versions of their Bottlenose cousins. They acquire the spots with age. They are known as gregarious dolphins, often found in social groups and close families, with the calves staying with their mothers for their first five years of life. They have also been observed to be strategic group hunters, where they will encircle their prey of small fish.
Rough-toothed dolphin: This dolphin gets its name from its roughly shaped teeth, which make the species easy to identify among other dolphins. They also possess a streamlined body which makes it easy to travel through the water with very little water resistance. They also have a large dorsal fin, long snout and a canonical-shaped head when compared to other dolphins that are known to have smaller snouts and more melon-shaped skulls. Their skin tone is a combination of light and dark gray coloring and many of the older species are known to exhibit white, yellow or pink markings around the mouth and sides of their body.
Harbor Porpoise: As the name suggests these porpoises tend to swim in or around harbors in coastal waters, such as bays, estuaries, harbors, rivers and tidal channels. When it comes to the social lives of harbor porpoises, little is known about them and how they live, and they are considered relatively passive when it comes to others. When approached by boats the harbor porpoise prefers to keep its distance and may shy away from approaching aquatic vehicles.
MERR is a nonprofit organization dedicated to the conservation of marine mammals and sea turtles and their habitat. MERR provides stranding response for marine animals that occur throughout the state of Delaware.