Atlantic Spotted Dolphin
Atlantic spotted dolphins are found in the tropical waters of the Atlantic Ocean. They usually form groups of five to 50 individuals but sometimes travel in groups of up to 200. They are fast swimmers and often “surf” in the waves created by vessels.
Young Atlantic spotted dolphins do not have spots. As a result, they can look like slender bottlenose dolphins. Their distinctive spotted pattern starts to appear all over their bodies as they get older.
Atlantic spotted dolphins, like all marine mammals, are protected under the Marine Mammal Protection Act.
NOAA Fisheries and its partners are working to conserve Atlantic spotted dolphins and further our understanding of this species through research and conservation activities.
NOAA Fisheries estimates population size in our stock assessment reports.
The worldwide population of Atlantic spotted dolphins is unknown. Scientists estimate that there are at least 81,000 Atlantic spotted dolphins in U.S. waters.
To manage Atlantic spotted dolphins in U.S. waters, we have divided them into three stocks: the northern Gulf of Mexico stock, the Puerto Rico and U.S. Virgin Islands stock, and the western North Atlantic stock. Based on the most recent surveys, our scientists estimate that there are about 37,000 dolphins in the northern Gulf of Mexico stock and about 44,000 dolphins in the western North Atlantic stock. The number of dolphins in the Puerto Rico and U.S. Virgin Islands stock is unknown.
Atlantic spotted dolphins are about 5 to 7.5 feet long and weigh about 220 to 315 pounds. They have a robust body with a tall, curved dorsal fin located midway down their back. Their beaks are moderately long. Like other cetaceans, their head has a distinctive melon, a rounded forehead that collects sounds from the environment. They have 30 to 42 pairs of small, cone-shaped teeth in each jaw.
Atlantic spotted dolphins’ color patterns vary with age and location. Young dolphins do not have any spots. Instead, they have a dark gray back with a pale white underside. This lack of spots can make young Atlantic spotted dolphins look like slender bottlenose dolphins. An Atlantic spotted dolphin starts to develop spots after its first birthday. As the dolphin matures, the spots become darker and more widespread, especially on its back.
Atlantic spotted dolphins are usually found in groups of less than 50 individuals but sometimes travel in groups of up to 200. In coastal waters, groups usually consist of five to 15 individuals. Within these groups, the dolphins are sometimes organized by age or sex. Atlantic spotted dolphins blow bubbles through their blowholes as one way to communicate with members of their group. They also communicate with sound.
Atlantic spotted dolphins are often described as “acrobatic” swimmers, frequently leaping out of the water or jumping at the water’s surface. They can also swim very quickly and often “surf” in the waves created by vessels. They sometimes interact with other cetacean species, such as bottlenose dolphins.
Atlantic spotted dolphins can dive up to 200 feet and have been recorded holding their breath for up to 10 minutes. Most of their dives are less than 30 feet and last for 2 to 6 minutes. These dolphins eat small fish, invertebrates, and cephalopods (such as squid and octopi). They have 30 to 42 pairs of small, cone-shaped teeth in each jaw. Groups of dolphins often coordinate their movements to catch prey together. Individuals sometimes use their beaks to dig into the sand on the ocean bottom to catch hidden fish.
Atlantic spotted dolphins are found in warm temperate, subtropical, and tropical waters throughout the Atlantic Ocean. Their range includes the waters of the U.S. East Coast (Gulf of Mexico to Massachusetts), the Bahamas, Brazil, the Azores and Canary Islands, and Gabon. Warm currents such as the Gulf Stream may affect their distribution.
Atlantic spotted dolphins prefer the waters along the continental shelf (the edge of a continent below the ocean’s surface). They usually live in coastal or continental shelf waters that are 65 to 820 feet deep, but are sometimes found in deeper oceanic waters.
NOAA Fisheries is committed to the protection of Atlantic spotted dolphins. Targeted management actions taken to secure protections for these dolphins include:
- Overseeing marine mammal health and stranding response.
- Addressing ocean noise.
- Educating the public about Atlantic spotted dolphins and the threats they face.
Our research projects have discovered new aspects of Atlantic spotted dolphin biology, behavior, and ecology and helped us better understand the challenges that all Atlantic spotted dolphins face. Our work includes:
- Stock assessments.
- Monitoring population abundance and distribution.
Keep Your Distance
Be responsible when viewing marine life in the wild.
Observe all dolphins and porpoises from a safe distance of at least 50 yards and limit your time spent observing to 30 minutes or less.
Report Marine Life in Distress
Report a sick, injured, entangled, stranded, or dead animal to make sure professional responders and scientists know about it and can take appropriate action. Numerous organizations around the country are trained and ready to respond.
Learn who you should contact when you encounter a stranded or injured marine animal >
Report a Violation
Call the NOAA Fisheries Enforcement Hotline at (800) 853-1964 to report a federal marine resource violation. This hotline is available 24 hours a day, 7 days week for anyone in the United States.
You may also contact your closest NOAA Office of Law Enforcement field office during regular business hours.
All marine mammals, including Atlantic spotted dolphins, are protected in the United States under the MMPA.
Atlantic spotted dolphins, like all marine mammals, are protected under the Marine Mammal Protection Act. In the United States, NOAA Fisheries works to protect all stocks of Atlantic spotted dolphins.
Atlantic spotted dolphin. Photo: NOAA Fisheries.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings, including dolphins. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health. When stranded animals are found dead, our scientists work to understand and investigate the cause of death. Although the cause often remains unknown, scientists can sometimes identify strandings due to disease, harmful algal blooms, vessel strikes, fishing gear entanglements, pollution exposure, and ocean noise. Some strandings can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.
Learn more about the Marine Mammal Health and Stranding Response Program
Addressing Ocean Noise
Underwater noise threatens dolphin populations, interrupting their normal behavior and driving them away from areas important to their survival. Increasing evidence suggests that exposure to intense underwater sound in some settings may cause some dolphins to strand and ultimately die. NOAA Fisheries is investigating all aspects of acoustic communication and hearing in marine animals, as well as the effects of sound on whale behavior and hearing. In 2016, we issued technical guidance for assessing the effects of anthropogenic (human-caused) sound on marine mammals’ hearing.
Educating the Public
NOAA Fisheries aims to increase public awareness and support for Atlantic spotted dolphin conservation through education, outreach, and public participation. We share information with the public about the status of Atlantic spotted dolphins, as well as our research and efforts to promote their recovery.
NOAA Fisheries conducts various research activities on the biology, behavior, and ecology of Atlantic spotted dolphins. The results of this research are used to inform management decisions for this species.
Stock Assessments
Determining the size of Atlantic spotted dolphin populations helps resource managers determine the success of conservation measures. Our scientists collect population information and present the data in annual stock assessment reports.
Monitoring Population Abundance and Distribution
Scientists observe Atlantic spotted dolphins to record their numbers and distribution. By comparing numbers collected over multiple years, scientists can look for trends—i.e., whether the population is increasing, decreasing, or remaining stable during a given period.
The estimated lifespan of Atlantic spotted dolphins is unknown. They reach sexual maturity when they are 8 to 15 years old. Females give birth to a single calf every 1 to 5 years. Mothers nurse their calves for 1 to 5 years.
Entanglement
One of the main threats to Atlantic spotted dolphins is getting caught in fishing gear. Dolphins can become entangled or captured in commercial fishing gear such as gillnets and purse seines. These interactions can cause dolphins to be injured or killed by entanglement in the gear.
Ocean noise
Underwater noise pollution interrupts the normal behavior of Atlantic spotted dolphins that rely on sound to communicate and echolocate. If loud enough, noise can cause permanent or temporary hearing loss. Noise interference from vessels, as well as industrial and military activities, disturbs Atlantic spotted dolphins’ feeding, communication, and orientation.
Illegal feeding and harassment
Atlantic spotted dolphins sometimes interact with different types of fishing vessels, often following them and eating discarded catch. A few Atlantic spotted dolphins have been hunted and killed in the Caribbean, South America, West Africa, and other offshore islands for food and bait.
CITES Appendix II
- Throughout Its Range
MMPA Protected
- Throughout Its Range