Tursiops truncatus

Description: 

Bottlenose dolphins are arguably the best known of all cetaceans; familiar to everyone thanks to the TV star "Flipper".

 

Bottlenose dolphin © M. Camm

Physical Description & Behaviour

The species has a robust appearance with a stocky snout distinctly set off from its forehead by a crease, which gives the animal its common name. It is usually slate grey or charcoal in colour, with a paler underbelly. Males can reach up to 3.8 m in length and 600 kg in weight. The dorsal fin is tall and curved.

They usually live in small groups in inshore habitats but may also be encountered offshore in groups of hundreds of individuals. Some bottlenose dolphins have been known to live solitary lives and to approach humans from time to time, such as “Fungie” in Western Ireland.

Bottlenose dolphins are very active swimmers. Tail slapping, leaping and aerial performances are often part of their natural behaviour. They prefer feeding on fish and molluscs, but their diet can be highly varied. They use echolocation for foraging like all toothed whale species.

 

Distribution & Abundance

Bottlenose dolphins are regarded as the most cosmopolitan of all dolphins. They are found in all temperate a nd tropical marine waters of the world. A few resident populations exist around the British Isles and used to be indigenous off the Dutch coast. A group of more than 100 individuals, which is permanently resident in the Moray Firth near Inverness and Cromarty in Scotland, is the northernmost bottlenose dolphin population worldwide. According to SCANS II about 2000 individuals inhabit the ASCOBANS area.

IUCN Red List of Threatened Species™ Assessment

  • ASCOBANS Area: LC (least concern)

 

Threats

As an often coastal and very popular and intelligent species, bottlenose dolphins face a number of human-induced threats. These include direct catches and kills, live captures, bycatch in gillnets, driftnets, purse seines, trawls, long-lines, and on hook-and-line gear used in commercial and recreational fisheries, overfishing and the resulting prey depletion, marine pollution, underwater noise and tourism.

 

More information on the bottlenose dolphin can be found at
http://www.cms.int/reports/small_cetaceans/data/t_truncatus/t_truncatus.htm.

 

 

Assessment information
CMS InstrumentsASCOBANS, CMS, ACCOBAMS, Western African Aquatic Mammals, Pacific Islands Cetaceans
IUCN StatusVulnerable
Geographic range
Countries France (Status: Increase), Ireland (Status: No apparent change), Portugal (Status: Unknown), Spain (Status: Increase), United Kingdom (Status: No apparent change)
Common names
EnglishBottlenose Dolphin
Taxonomy
ClassMammalia
OrderCetacea
FamilyDelphinidae
Scientific name Tursiops truncatus
Population size and trend
Population Size interval Size quality Estimated population size Size reference Size notes
Trend interval Trend quality Trend Trend reference Trend notes
Northern East AtlanticFair19,295 (CODA), 12,645 (SCANS)* Project Report: Review of Trend Analyses in the AS [more] The population size estimate is based on data collected during SCANS-II (2005) and CODA (2007) surveys. See the previous Trend Analysis document for more details. SCAN-II and CODA reports can be found in the additional notes section. *Note: the estimated population sizes are for the entire CODA and SCAN-II survey areas and not just for the Northern East Atlantic. The separate estimate for this region is not available.
FairUnkown Project Report: Review of Trend Analyses in the AS [more]
Central Eastern AtlanticFair19,295 (CODA), 12,645 (SCANS)* Project Report: Review of Trend Analyses in the AS [more] The population size estimate is based on data collected during SCANS-II (2005) and CODA (2007) surveys. See the previous Trend Analysis document for more details. SCAN-II and CODA reports can be found in the additional notes section. *Note: the estimated population sizes are for the entire CODA and SCAN-II survey areas and not just for the Central East Atlantic. The separate estimate for this region is not available.
FairUnkown Project Report: Review of Trend Analyses in the AS [more]
Bay of BiscayFair19,295 (CODA), 12,645 (SCANS)* Project Report: Review of Trend Analyses in the AS [more] The population size estimate is based on data collected during SCANS-II (2005) and CODA (2007) surveys. See the previous Trend Analysis document for more details. SCAN-II and CODA reports can be found in the additional notes section. *Note: the estimated population sizes are for the entire CODA and SCAN-II survey areas and not just for the Bay of Biscay. The separate estimate for this region is not available.
FairIncrease Project Report: Review of Trend Analyses in the AS [more]
Northern North SeaFair19,295 (CODA), 12,645 (SCANS)* Project Report: Review of Trend Analyses in the AS [more] The population size estimate is based on data collected during SCANS-II (2005) and CODA (2007) surveys. See the previous Trend Analysis document for more details. SCAN-II and CODA reports can be found in the additional notes section. *Note: the estimated population sizes are for the entire CODA and SCAN-II survey areas and not just for the Bay of Biscay. The separate estimate for this region is not available.
FairNo apparent change Project Report: Review of Trend Analyses in the AS [more]
English ChannelFair19,295 (CODA), 12,645 (SCANS)* Project Report: Review of Trend Analyses in the AS [more] The population size estimate is based on data collected during SCANS-II (2005) and CODA (2007) surveys. See the previous Trend Analysis document for more details. SCAN-II and CODA reports can be found in the additional notes section. *Note: the estimated population sizes are for the entire CODA and SCAN-II survey areas and not just for the English Channel. The separate estimate for this region is not available.
FairNo apparent change Project Report: Review of Trend Analyses in the AS [more]
Irish SeaFair19,295 (CODA), 12,645 (SCANS)* Project Report: Review of Trend Analyses in the AS [more] The population size estimate is based on data collected during SCANS-II (2005) and CODA (2007) surveys. See the previous Trend Analysis document for more details. SCAN-II and CODA reports can be found in the additional notes section. *Note: the estimated population sizes are for the entire CODA and SCAN-II survey areas and not just for the Irish Sea. The separate estimate for this region is not available.
FairNo apparent change Project Report: Review of Trend Analyses in the AS [more]
Other details
Additional notesA SCANS-II report can be found here: http://biology.st-andrews.ac.uk/scans2/inner-furtherInfo.html and here http://biology.st-andrews.ac.uk/scans2/documents/final/SCANS-II_final_report.pdf. A CODA report can be found here: ttp://biology.st-andrews.ac.uk/coda/documents/CODA_Final_Report_11-2-09.pdf. The notes in the Threat section (Related Content) refer to the level of importance needed to address causes of mortality (identified from post-mortem examinations) of cetaceans in the ASCOBANS Agreement Area. This information also comes from this report: Project Report: Review of Trend Analyses in the ASCOBANS Area (AC18_6-05_ProjectReportTrendAnalysis_Corr.pdf).

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