Taxonomy
Halichoerus grypus | Grey Seal | Rón glas
Distribution
Status
Conservation status
| Range | Favourable |
| Population | Favourable |
| Habitat | Favourable |
| Future Prospects | Favourable |
| Overall Assessment of Conservation Status | Favourable |
| Overall Trend in Conservation Status | N/A |
IUCN Conservation Status |
| Ireland | Not evaluated* |
| Europe (1) | Least concern |
| 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 V
- Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Appendix III
- Wildlife Act (1976)
- Wildlife (Amendment) Act (2000)
- Wildlife (N.I.) Order of 1985.
Native status
Native as a species.
Population sometimes described as a metapopulation which includes British, French and possibly other populations.
Source: NPWS 2013.
Species Biology
Identification
In the Grey Seal (Halichoerus grypus) there is quite a degree of variation in colouration between individuals and sexes as well as between age groups and when individuals are moulting.
Many sexually mature females are a mid-grey dorsally fading to a paler grey of off white ventrally.
Spots may or may not be present and overall colour varies between much paler or darker than described.
Sexually mature males are generally dark grey or brown dorsally with paler patches and also paler ventrally.
New born pups are white until first moult after about 2-3 weeks old.
The species is sexually dimorphic with males to c. 2ms in length and averaging about 230kgs in weight and females to c. 1.7ms in length and averaging 190kgs in weight.
The shape of the head and the shape and position of nostrils are perhaps best for distinguishing between the Grey Seal (Halichoerus grypus) and the Common Seal (Phoca vitulina).
The Grey Seal has no major differentiation between a muzzle and forehead whereas in the Common Seal there is a noticable bridge between forehead and muzzle.
In the Grey Seal the nostrils are well separated and sub-parallel whereas in the Common Seal the nostrils form a distinct vee shape, almost touching each other above the mouth.
Source: Harris S., Yalden D.W. 2008.
Habitat
This species forages at sea, within the continental shelf boundary.
Particularly in the breeding season, but also at other times individuals of the species 'haul-out' onto land.
Haul-out sites in the breeding season will most often be onto shores of islands or onto remote mainland shores. In Britain and Ireland breeding sites are above high water mark.
Depending on the location the 'haul-out' sites may be on rocky, shingle or sandy shores and even on grassland if it is within c. 300ms of the sea. For breeding the site will be above high water mark.
Source: Harris S., Yalden D.W. 2008.
The species may be expected to be encountered in a variety of coastal habitats both terrestrial and aquatic.
Habitats may include but are not necessarily limited to;
- Marine water body (M)
- Littoral (L)
- Salt marshes (CM)
- Brackish waters (CW)
- Shingle and gravel banks (CB)
Sources: Harris S.,Yalden D.W., 2008; Fossitt, J.A., 2001.
Reproduction
In Ireland, duing the breeding season, the highest numbers of pups are born between October and November.
Source: Lyons D. O. 2004
Typically, once a pup has been born, the mother will mate within the two weeks following the birth. Individuals of thhis species display a level of breeding site fidelity.
Implantation may be delayed for up two and a half months, and gestation lasts between eight and a half, and nine and a half months.
Pups are weaned at about two and a half weeks.
Males reach sexual maturity anywhere between four and six years, females between three and five years.
Females may live to 35 years or, rarely, older. Males may live to 20 years or, rarely, older.
A sexually dimorphic species, with males larger than females.
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 |
| Illegal taking / removal of marine fauna | F05 | Low |
| Marine water pollution | H03 | Low |
| Noise nuisance, noise pollution | H06.01 | Low |
| Changes in abiotic conditions | M01 | Low |
*This would include the threat to this species of becoming by-catch / accidental catch.
These threats accord well with the threats, relevant to the Irish / U.K. metapopulation of this species, outlined in the 2007 European level Regional IUCN Red List assessment for the species.
Source: European Mammal Assessment team 2007.
Conservation actions
In the Article 17 Habitats Directive reporting for the period 2007-2012 Conservation Measures implemented or being implemented during the period were;
- Establishment of protected areas / sites (6.1)
- Legal protection of habitats and species (6.3)
- Regulation / Managment of fishery in marine and brackish systems (7.3)
- Regulating managing exploitation of natural resources on sea (9.2)
- Regulation / Management of hunting and taking (7.1)
There are no Conservation Actions in the 2007 European Regional, or 2008 Global, IUCN Red List assessment for this species that are not covered by the Habitats Directive Conservation Measures listed above.
Sources: European Mammal Assessment team 2007; Thompson, D. & Härkönen, T. (IUCN SSC Pinniped Specialist Group) 2008.
Distribution
World distribution(GBIF)
A North Atlantic species. There are populations on east coast of North America and the east coast of Europe (including Iceland and the Faroes). These two populations are reproductively isolated. The eastern North Atlantic population is concentrated around Ireland and Britain. The Baltic Sea population is regarded as a sub-population of the eastern North Atlantic population.
Sources; Harris S.,Yalden D.W. 2008; Thompson, D. & Härkönen, T. (IUCN SSC Pinniped Specialist Group) 2008.
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
There currently appears to be a wide, relatively even distribution around Irish coastlines.
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 Grey Seal 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
European Mammal Assessment team 2007. Halichoerus grypus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 08 October 2014.
Fossitt, J.A. (2001) A Guide to Habitats in Ireland. The Heritage Council.
Harris S., Yalden D.W. (2008). Mammals of the British Isles :Handbook, 4th Edition. The Mammal Society.
Lyons, D. O. (2004) Summary of National Parks & Wildlife Service surveys for Common (Harbour) seals (Phoca vitulina) and Grey seals (Halichoerus grypus),1978 to 2003.Irish Wildlife Manuals, No. 13. National Parks & Wildlife Service,Department of Environment, Heritage and Local Governement. Dublin, Ireland
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.
Thompson, D. & Härkönen, T. (IUCN SSC Pinniped Specialist Group) 2008. Halichoerus grypus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 08 October 2014.