Bottlenose Dolphin (Tursiops truncatus)
Photo: NMFS Southwest
Fisheries Science Center
Did You Know?
· Results from 2011 Barataria Bay Dolphin Health Study, detailing dolphin injuries, published in Environmental Science and Technology
Winter, the tailless dolphin [pdf]
Credit: Clearwater Marine Aquarium
Scientists assess the health of dolphins in Barataria Bay, LA, part of NOAA's ongoing efforts following the Deepwater BP oil spill
NBC Nightly News video
Bottlenose Dolphin Range Map
(click for larger view PDF)
|Weight:||300-1400 lbs (135-635 kg)|
|Length:||6.0-12.5 ft (~2-4 m)|
|Appearance:||light gray to black|
|Lifespan:||40-50 years; sexual maturity varies by population but ranges from 5-14 years of age|
|Diet:||invertebrates, squids, fishes|
|Behavior:||use high frequency echolocation to locate and capture prey; use multiple feeding strategies, including "fish whacking," where they strike a fish with their flukes and knock it out of the water|
The bottlenose dolphin is one of the most well known species of marine mammals. They have a robust body and a short, thick beak. Their coloration ranges from light gray to black with lighter coloration on the belly. Inshore and offshore individuals vary in color and size. Inshore animals are smaller and lighter in color, while offshore animals are larger, darker in coloration and have smaller flippers. Bottlenose dolphins can sometimes be confused with the rough-toothed dolphins, Risso's dolphins, and Atlantic spotted dolphins in regions of overlapping distributions.
Bottlenose dolphins range in lengths from 6.0 to 12.5 ft (1.8 to 3.8 m) with males slightly larger than females. Adults weight from 300-1400 lbs (136-635 kg). This is a long-lived dolphin species with a lifespan of 40-45 years for males and more than 50 years for females.
Bottlenose dolphins are commonly found in groups of 2 to 15 individuals. Offshore herds sometimes have several hundred individuals. This species is often associated with pilot whales and other cetacean species.
Bottlenose dolphins are generalists and feed on a variety of prey items "endemic" to their habitat, foraging individually and cooperatively. Like other dolphins, bottlenose dolphins use high frequency echolocation to locate and capture prey. Coastal animals prey on "benthic" invertebrates and fish, and offshore animals feed on pelagic squid and fish. Bottlenose dolphins employ multiple feeding strategies, including "fish whacking," where they strike a fish with their flukes and knock it out of the water.
Sexual maturity varies by population and ranges from 5-13 years for females and 9-14 years for males. Calves are born after a 12 month gestation period and are weaned at 18 to 20 months. On average, calving occurs every 3 to 6 years. Females as old as 45 years have given birth.
Bottlenose dolphins are found in temperate and tropical waters around the world. There are coastal populations that migrate into bays, estuaries and river mouths as well as offshore populations that inhabit pelagic waters along the continental shelf.
NMFS Stock Assessment Reports (SARs) for bottlenose dolphins include estimated population sizes for U.S. stocks, though population trends for all of the U.S. stocks are currently unknown.
Rio, a Chronically Entangled Dolphin in the Indian River Lagoon [pdf]
- incidental injury and mortality from fishing gear, such as gillnet, seine, trawl, and longline commercial and recreational operations
- exposure to pollutants and biotoxins
- viral outbreaks
- direct harvest, in Japan and Taiwan
NOAA and its local, state and federal partners started the Barataria Bay dolphin study in 2011 as part of the Natural Resource Damage Assessment (NRDA), the process for studying the effects of the Deepwater Horizon oil spill.
In 2006, NMFS implemented the Bottlenose Dolphin Take Reduction Plan (BDTRP) to reduce the serious injury and mortality of Western North Atlantic coastal bottlenose dolphins incidental to nine U.S. commercial fisheries. In addition to multiple non-regulatory provisions for research and education, the BDTRP requires modifications of fishing practices for small, medium, and large-mesh gillnet fisheries from New York to Florida. The BDTRP also established seasonal closures for certain commercial fisheries in state waters.
Bottlenose dolphins are classified as Data Deficient on the IUCN Red List .
This species is protected under the Marine Mammal Protection Act (MMPA) of 1972, as amended. The Western North Atlantic Coastal stock of bottlenose dolphins is listed as "depleted" under the MMPA. In addition, NMFS has classified five U.S. stocks of bottlenose dolphins as "strategic" stocks: Eastern Gulf of Mexico Coastal; Western Gulf of Mexico Coastal; Northern Gulf of Mexico Coastal; Gulf of Mexico Bay, Sound and Estuarine; and Western North Atlantic Coastal.
90-Day Finding on a Petition to List Multiple Species and Subpopulations of Marine Mammals under the ESA
|79 FR 9880||02/21/2014|
|Bottlenose Dolphin Take Reduction Plan (BDTRP)||71 FR 24776||04/26/2006|
|Depleted Designation for Western North Atlantic Coastal Migratory Stock||58 FR 17789||04/06/1993|
||56 FR 40594||08/15/1991|
||54 FR 41654||10/11/1989|
|Stock Assessment Reports||n/a||various|
- NMFS National Marine Mammal Laboratory Bottlenose Dolphin Information
- NMFS Southwest Fisheries Science Center Bottlenose Dolphin Information
- NOAA's National Marine Sanctuaries
- Bottlenose Dolphin Take Reduction Plan (BDTRP)
- Unusual Mortality Event Along the Florida Panhandle in 2004
- Marine Mammal Commission Bottlenose Dolphin Information
- Ocean Biogeographic Information System (OBIS-SEAMAP) Bottlenose Dolphin Species Profile
Updated: March 17, 2014