Atlantic white-sided dolphins have a short, dark beak, gray sides, a dark back and white underside. On each side, they have a long white stripe that extends from below their dorsal fin to their tail, and underneath that is a yellowish-tan stripe. These dolphins have a tall, hooked dorsal fin.
Atlantic white-sided dolphins can grow to 9 feet in length. Males are generally larger than females. These dolphins weigh about 400-500 pounds.
Atlantic white-sided dolphins gather in pods that can range in size from a few dolphins to several hundred. The Cetacean and Turtle Assessment Program (CETAP) reported in 1982 that an average of 54 dolphins were seen per pod during their surveys. A 2000 study by the Whale Center of New England reported that dolphin pod size increased suddenly during the summer, and could vary depending upon sighting area, whether calves were present, and if groups were feeding or performing other activities. Dolphin groups were smaller when the animals were feeding or interacting with other species, and larger during travel and social interaction and interaction with boats.
Like other toothed whales, Atlantic white-sided dolphins find their food using echolocation, which involves emitting high frequency pulses of sound from an organ in their head, called the melon. These sounds waves bounce off objects around them and are received back into the dolphin's lower jaw, transmitted to the inner ear and interpreted to determine the size, shape, location and distance of prey.
Habitat and Distribution:
Atlantic white-sided dolphins breed from May-August. The gestation period is 10-12 months, and the 3-foot long calves are most commonly born in June and July. Females become sexually mature at 6-12 years of age and have 1 calf every other year, and males become sexually mature at 7-11 years. Calves nurse for 18 months and then are weaned.
The lifespan for Atlantic white-sided dolphins is estimated at 20-27 years.
Atlantic white-sided dolphins are a species that commonly strand, although causes are not always known. They also may be affected by pollution and entanglement or bycatch in fishing gear.
References and Further Information:
- Culik, B. 2010. Odontocetes. The toothed whales: "Lagenorhynchus acutus". UNEP/CMS Secretariat, Bonn, Germany. Accessed April 29, 2012.
- Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B. 2008. Lagenorhynchus acutus. IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. Accessed April 29, 2012.
- NOAA Fisheries: Office of Protected Resources. Atlantic White-Sided Dolphin (Lagenorhynchus acutus). Accessed April 29, 2012.
- OBIS SEAMAP. Atlantic White-Sided Dolphin (Lagenorhynchus acutus). Accessed April 29, 2012.
- Perrin, W. 2011. Lagenorhynchus acutus (Gray, 1828). In: Perrin, W.F. World Cetacea Database. Accessed through: World Register of Marine Species on April 29, 2012.
- SeaLifeBase. Lagenorhynchus acutus, Atlantic White-Sided Dolphin. Accessed April 30, 2012.
- Weinrich, M.T., Belt, C.R., and D. Morin. 2001. Behavior and Ecology of the Atlantic White-Sided DOlphin (Lagenorhynchus acutus in Coastal New England Waters. Marine Mammal Science, Vol. 17, Issue 2, pages 231-248.