About the Species
Clymene dolphins are found in the deep, tropical waters of the Atlantic Ocean. They are the smallest dolphin in the genus Stenella, which also includes spinner dolphins, Atlantic spotted dolphins, pantropical spotted dolphins, and striped dolphins.
Clymene dolphins are also known as "short-snouted spinner dolphins" because they often spin while jumping out of the water. Unlike spinner dolphins, however, they do not complete a full rotation during their spins. Instead, they usually land on their sides or backs.
Clymene dolphins, like all marine mammals, are protected under the Marine Mammal Protection Act. NOAA Fisheries and its partners are working to conserve Clymene dolphins and further our understanding of this species through research and conservation activities.
NOAA Fisheries estimates population size in its stock assessment reports.
The worldwide population of Clymene dolphins is unknown.
To manage Clymene dolphins in U.S. waters, we have divided them into two stocks: the northern Gulf of Mexico stock and the western North Atlantic stock. Based on the most recent surveys, our scientists estimate that there are more than 100 dolphins in the northern Gulf of Mexico stock. Estimates for this stock have varied widely over time. The number of dolphins in the western North Atlantic stock is unknown.
- Throughout Its Range
Clymene dolphins are about 6 to 6.5 feet long and weigh about 165 to 200 pounds. They have a streamlined body with a tall, curved dorsal fin located midway down their back. Their beaks are moderately short. Like other cetaceans, their head has a distinctive "melon," a rounded forehead that collects sounds from the environment.
Clymene dolphins have a three-part color pattern with a dark gray back, light gray sides, and a white or pale gray underside. They have distinct black lips that can look like a mustache, as well as a dark line that extends across the top of their beak. They also have 39 to 52 pairs of small, cone-shaped teeth in each jaw.
Behavior and Diet
Clymene dolphins are usually found in groups of 60 to 80 individuals but sometimes travel in groups of several hundred. These groups are sometimes organized by sex.
Clymene dolphins are often described as “acrobatic” swimmers because they often leap out of the water, spin in the air, and “surf” in the waves created by vessels. They have been reported to spin up to three to four revolutions out of the water. They sometimes interact with other cetacean species, such as common dolphins off West Africa and spinner dolphins in the Caribbean Sea.
Clymene dolphins dive to catch small fish and cephalopods (e.g., squid and octopi). They have 39 to 52 pairs of small, cone-shaped teeth in each jaw. They sometimes feed at night to catch prey that migrate towards the water’s surface after dark.
Where They Live
Clymene dolphins are found in deep tropical, subtropical, and temperate waters throughout the Atlantic Ocean. Their range includes the waters of the northwestern Atlantic (New Jersey), the Gulf of Mexico, the Caribbean Sea, southern Brazil, and West Africa (Mauritania to Angola).
Clymene dolphins prefer deep waters off the continental shelf (the edge of a continent below the ocean’s surface). They are usually found in oceanic waters 820 to 16,400 feet deep.
Lifespan & Reproduction
The estimated lifespan of Clymene dolphins is unknown, and little is known about their reproductive habits. These dolphins reach sexual maturity once they are 6 feet long. Females give birth to a single calf that weighs about 22 pounds.
One of the main threats to Clymene dolphins becoming entangled or captured in commercial fishing gear. Specifically, they have been caught in gillnet operations in Venezuela and tuna purse seine nets off the coast of West Africa. Entanglement during these interactions can injure or kill dolphins.
Underwater noise pollution interrupts the normal behavior of Clymene 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 Clymene dolphins’ feeding, communication, and orientation.
Whalers in the Caribbean Sea sometimes target and hunt Clymene dolphins for meat and oil.
Clymene 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 Clymene dolphins.
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.
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 dolphin behavior and hearing. In 2016, we issued technical guidance (PDF, 189 pages) for assessing the effects of human-caused sound on marine mammal hearing.
Dolphin-Safe/Tuna Tracking and Verification Program
Dolphins, like other marine mammals, may become bycatch in fisheries. Some species of tuna are known to aggregate beneath schools of certain dolphin stocks. In some parts of the world, this close association led to the fishing practice of encircling a dolphin school to capture the tuna concentrated below. The Dolphin Protection Consumer Information Act established a national tuna tracking program to ensure that tuna imported into the United States meets certain requirements to ensure the safety of dolphins during tuna fishing operations.
All marine mammals, including Clymene dolphins, are protected in the United States under the MMPA.
NOAA Fisheries conducts various research activities on the biology, behavior, and ecology of Clymene dolphins. The results of this research are used to inform management decisions for this species.
Determining the size of Clymene 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 Clymene 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.