Taxonomy
Tursiops truncatus | Bottle-nosed Dolphin
Distribution
Status
Conservation status
| Range | Favourable |
| Population | Favourable |
| Habitat | Favourable |
| Future Prospects | Favourable |
| Overall Assessment of Conservation Status | Favourable |
| Overall Trend in Conservation Status | Favourable |
IUCN Conservation Status |
| Ireland | Not evaluated* |
| Europe (1) | Data deficient |
| Global (2) | Least concern |
* There is currently no Irish Red List for Marine Mammals.
Legal status
Protected by the following legal instruments:
- Habitats Directive (92/43/EEC), Annex II, Annex IV
- Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Appendix II*
- Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention) Appendix I
- Convention on Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II
- Council Regulation (EC) No. 812/2004
- Wildlife Act (1976)
- Wildlife (Amendment) Act (2000)
- Whale Fisheries Act 1937
Native status
The 2012 IUCN Global Red List for this species lists Ireland as one of the countries where it is native.
Source: Hammond, P.S. et al 2012.
Possible native resident component as well as migrant components to populations in and around Irish waters.
Source: NPWS 2013.
Records have been made in every month of the year although there are insufficient data to allow estimates of seasonal abundance.
Source; Wall, D. et al 2013.
Species Biology
Identification
- Total length: newborn to 1.3ms, adult female to 3.2ms, adult male to 3.4 ms
- Average weight is 200kg.
- Head Shape: Small, stubby, long, wide, and rounded beak well marked off from exaggerated melon, lower jaw protrudes beyond upper. Soft mouth line curves upwards at back to give familiar, faintly amused, facial expression.
- Dorsal Fin & Tail Stock: Tall fin, broad at base and curved backwards. Moderately keeled tailstock.
- Colouration: Medium grey back above, pale or light grey flank and belly. Calves slightly bluish. Animals in the Pacific have distinct pink tinge on underside.
- Additional Body Markings: Pale line drawn from flipper to eye and some spotting occurs on older animals on the belly; adults may have white callus on tip of lower jaw (additional body markings claimed for some geographical forms)
Source: Irish Whale and Dolphin Group.
Habitat
The Bottlenose Dolphin, in Irish waters, occurs to the continental shelf, as well as a resident population occurring in the Shannon estuary.
The species can occur in much deeper waters.
Source: Harris S., Yalden D.W. 2008.
Habitats;
- Marine water body (M)
Sources: Harris S.,Yalden D.W., 2008; Fossitt, J.A., 2001.
Reproduction
- Females sexually mature at 5-10 years.
- Males sexually mature at 10-15 years.
- No fixed breeding season but most births in British waters taking place between May and November inferring that most mating takes place within those months also.
- Gestation approximately 12 months.
- Females may live to 50 years males 5-10 years less.
Source: Harris S., Yalden D.W. 2008
Threats faced
| THREAT | ARTICLE 17 THREAT CODE | RANKING |
| Fishing and harvesting aquatic resources* | F02 | Medium |
| Seismic exploration, explosions | H06.05 | Medium |
| Wildlife watching | G02.09 | Medium |
| Death or injury by collision | G05.11 | Low |
| Noise nuisance, noise pollution | H06.01 | Low |
| Marine water pollution | H03 | Low |
| Changes in abiotic conditions | M01 | Low |
*This would include the threat to this species of becoming by-catch / accidental catch as well as the threat of a reduction in prey availability and also entanglement in fishing gear.
These threats accord well with threats outlined in the 2007 European Regional IUCN Red List assessment for the species which identifies additional threats that may be relevant in Irish waters;
- Marine construction and demolition
- Other forms of habitat destruction and degradation
Source: IUCN SSC Cetacean Specialist Group 2007.
Conservation actions
In the Article 17 Habitats Directive reporting for the period 2007-2012 Conservation Measures listed as in place or in the process of being implemented in Ireland were;
- Establishment of protected areas / sites
- Legal protection of habitats and species
- Regulation / Management of fishery in marine and brackish systems
- Regulating / Managing exploitation of natural resources on sea
- Regulation/ Management of hunting and taking
Apart from the acknowledgement of the existence of legislative protection, suggested Conservation Actions in the 2007 European Regional IUCN Red List assessment for this species included;
- Research on population structure, abundance, and removals.
In a 2009 Cetacean Action Plan a total of 41 Actions were identified as part of the plan. The plan and the 2013 review of the plan are available from the NPWS website.
Source: DEHLG 2009; NPWS 2013a.
Distribution
World distribution(GBIF)
Global marine distribution in tropical and temperate coastal, inshore, shelf and offshore waters.
Accuracy of world distribution shown in the Global Biodiversity Information Facility (GBIF) map below will be constrained by, amongst other factors, data held but not shared by countries and organizations not participating in the GBIF.
Irish distribution
Resident population in the Shannon estuary. Sightings also from coastal and offshore waters. Previously records most often from western areas but records from eastern and northern coastal areas are increasing.
Temporal change
Records submitted to Data Centre in 2024
The following map is interactive. If you would prefer to view it full screen then click here.
How can you help
The National Biodiversity Data Centre is trying to improve our knowledge on the distribution of the Bottle-nosed Dolphin in Ireland. Should you observe this species, please submit sightings to add to the database. Detailed observations will assist us gaining a better insight into where the species is most abundant in Ireland and we might also be able to detect regional variations. Please submit any sightings and photographs at:
http://records.biodiversityireland.ie/index.php
All
records submitted online can be viewed on Google Maps – once checked
and validated these will be added to the database and made available for
conservation and research.
Further information
For further information contact Dr. Liam Lysaght llysaght@biodiversityireland.ie
References
Publications
DEHLG (2009) Conservation Plan for Cetaceans in Irish waters.
Fossitt, J.A. (2001) A Guide to Habitats in Ireland. The Heritage Council
Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K.A., Karkzmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y. , Wells, R.S. & Wilson, B. (2012). Tursiops truncatus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 13 October 2014.
Harris S., Yalden D.W. (2008). Mammals of the British Isles :Handbook, 4th Edition. The Mammal Society.
IUCN SSC Cetacean Specialist Group; regional assessment by European Mammal Assessment team (2007). Tursiops truncatus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 13 October 2014.
NPWS (2013) The Status of EU Protected Habitats and Species in Ireland. Species Assessments Volume 3. Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.
NPWS (2013a) Delivery Schedule for Actions listed in the Conservation Plan for Cetaceans in Irish waters – June 2013
Wall, D., Murray, C., O’Brien, J., Kavanagh, L., Wilson, C., Ryan, C., Glanville, B., Williams, D., Enlander, I., O’Connor, I., McGrath, D., Whooley, P. & Berrow, S. (2013). Atlas of the Distribution and Relative Abundance of Marine Mammals in Irish Offshore Waters: 2005 – 2011. Irish Whale and Dolphin Group, Kilrush, Co. Clare.