Database release:

For Special Protection Areas (SPA),
Proposed Sites for Community Importance (pSCI),
Sites of Community Importance (SCI) and
for Special Areas of Conservation (SAC)



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1.1 Type


1.2 Site code


1.3 Site name

Slyne Head Islands SAC

1.4 First Compilation date


1.5 Update date


1.6 Respondent:

Name/Organisation:National Parks and Wildlife Service, Department of Culture, Heritage and the Gaeltacht

1.7 Site indication and designation / classification dates

Date site proposed as SCI:2002-01
Date site confirmed as SCI: No data
Date site designated as SAC:2019-06
National legal reference of SAC designation:295/2019


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2.1 Site-centre location [decimal degrees]:


2.2 Area [ha]


2.3 Marine area [%]


2.4 Sitelength [km]:


2.5 Administrative region code and name

NUTS level 2 code Region Name
IE01Border, Midland and Western

2.6 Biogeographical Region(s)

Atlantic (0.00 %)


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3.1 Habitat types present on the site and assessment for them

Annex I Habitat types Site assessment
Code PF NP Cover [ha] Cave [number] Data quality A|B|C|D A|B|C
      RepresentativityRelative SurfaceConservationGlobal
1170  info      1417.56  0.00 
  • PF: for the habitat types that can have a non-priority as well as a priority form (6210, 7130, 9430) enter "X" in the column PF to indicate the priority form.
  • NP: in case that a habitat type no longer exists in the site enter: x (optional)
  • Cover: decimal values can be entered
  • Caves: for habitat types 8310, 8330 (caves) enter the number of caves if estimated surface is not available.
  • Data quality: G = 'Good' (e.g. based on surveys); M = 'Moderate' (e.g. based on partial data with some extrapolation); P = 'Poor' (e.g. rough estimation)

3.2 Species referred to in Article 4 of Directive 2009/147/EC and listed in Annex II of Directive 92/43/EEC and site evaluation for them

Species Population in the site Site assessment
G Code Scientific Name S NP T Size Unit Cat. D.qual. A|B|C|D A|B|C
      MinMax  Pop.Con.Iso.Glo.
M1364Halichoerus grypus    32  41   
BA014Hydrobates pelagicus    50  50   
BA013Puffinus puffinus    70  90   
BA194Sterna paradisaea    329  329   
M1349Tursiops truncatus    12  12 
  • Group: A = Amphibians, B = Birds, F = Fish, I = Invertebrates, M = Mammals, P = Plants, R = Reptiles
  • S: in case that the data on species are sensitive and therefore have to be blocked for any public access enter: yes
  • NP: in case that a species is no longer present in the site enter: x (optional)
  • Type: p = permanent, r = reproducing, c = concentration, w = wintering (for plant and non-migratory species use permanent)
  • Unit: i = individuals, p = pairs or other units according to the Standard list of population units and codes in accordance with Article 12 and 17 reporting (see reference portal)
  • Abundance categories (Cat.): C = common, R = rare, V = very rare, P = present - to fill if data are deficient (DD) or in addition to population size information
  • Data quality: G = 'Good' (e.g. based on surveys); M = 'Moderate' (e.g. based on partial data with some extrapolation); P = 'Poor' (e.g. rough estimation); VP = 'Very poor' (use this category only, if not even a rough estimation of the population size can be made, in this case the fields for population size can remain empty, but the field "Abundance categories" has to be filled in)

3.3 Other important species of flora and fauna (optional)


Population in the site


Group CODE Scientific Name S NP Size Unit Cat. Species Annex Other categories
     MinMax C|R|V|PIVVABCD
Aldisa zetlandica                   
Alyconium glomeratum                   
Axinella damicornis                   
Axinella dissimilis                   
Cepphus grylle    60  60               
Larus argentatus    50  50               
Larus marinus    30  30               
Lissondendoryx sp.                   
Pentapora foliacea                   
Phakellia ventilabrum                   
Phalacrocorax aristotelis                 
Tamarisca tamarisca                   
Terebratulina retusa                   
  • Group: A = Amphibians, B = Birds, F = Fish, Fu = Fungi, I = Invertebrates, L = Lichens, M = Mammals, P = Plants, R = Reptiles
  • CODE: for Birds, Annex IV and V species the code as provided in the reference portal should be used in addition to the scientific name
  • S: in case that the data on species are sensitive and therefore have to be blocked for any public access enter: yes
  • NP: in case that a species is no longer present in the site enter: x (optional)
  • Unit: i = individuals, p = pairs or other units according to the standard list of population units and codes in accordance with Article 12 and 17 reporting, (see reference portal)
  • Cat.: Abundance categories: C = common, R = rare, V = very rare, P = present
  • Motivation categories: IV, V: Annex Species (Habitats Directive), A: National Red List data; B: Endemics; C: International Conventions; D: other reasons


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4.1 General site character

Habitat class % Cover

Total Habitat Cover


Other Site Characteristics

The site extends along the western shore of the Slyne Head peninsula and comprises an archipelago of islands, islets, rocks and reefs, and the surrounding seas. The site is exposed to the full force of Atlantic storms and swells. Strong tidal streams are present along the coast. The shore is complex with a number of islets adjacent or very close to the shore which give rise to a complex set of intertidal reefs which range from being sheltered from wave action to moderately exposed to wave action. The sublittoral reefs range from being moderately sloping to steeply sloping to rugged rock and vertical bedrock and this in turn reflects the communities present. The islands are mostly low-lying and some have a grassy maritime turf. Sandy coves and areas of shingle occur in places. The islands are uninhabited apart from an automated lighthouse on Illaunamid. Some of the islands are used for sheep grazing.

4.2 Quality and importance

This is a largely undisturbed site of good quality. It supports good examples of communities of both littoral and sublittoral reefs that are very exposed to moderately exposed to wave action. In addition the complexity of the coastline adds considerably to habitat diversity. The rocky shore has an excellent example of community zonation. Sublittorally the reefs vary in physical structure and extend to depths greater than 40 m giving rise to a diversity of communities. The presence of the red alga Drachiella spectabilis is a good indicator of clear water. Excellent examples of the Axinellid cup sponge community occur. Rare or uncommon species recorded are the red soft coral Alcyonium glomeratum, the sea fan Eunicella verrucosa, the rose 'coral' Pentapora foliacea, the sea squirt Diazona violacea, the rare sponge Phakellia vermiculata, the sponge Lissodendoryx sp. that has not been recorded in Ireland in recent years, the hydroid Tamarisca tamarisca, Terebratulina retusa and the rare sea slug Aldisa zetlandica. The site also supports part of a significant breeding population of Halichoerus grypus which occurs in the waters off Slyne Head Peninsula. One of the largest colonies of Sterna paradisaea in Ireland (11.3% of national total), as well as c. 0.2% of the national population of Cepphus grylle are found here. Small numbers of other breeding seabirds, including Hydrobates pelagicus are also found. The site also provides habitat for the Annex II cetacean species Tursiops truncatus and this includes use by groups of dolphins during the breeding season. Bottlenose Dolphins may be potentially vulnerable to intensification of regional fishing activity via the removal of key biological resources and entanglement in fishing gear. Recreational boat use or marine tourism activity by the human population may cause disturbance to natural behaviours and impact negatively on the species within the site.

4.3 Threats, pressures and activities with impacts on the site

The most important impacts and activities with high effect on the site

Negative Impacts
RankThreats and pressures [code]Pollution (optional) [code]inside/outside [i|o|b]
Positive Impacts
RankActivities, management [code]Pollution (optional) [code]inside/outside [i|o|b]

Rank: H = high, M = medium, L = low
Pollution: N = Nitrogen input, P = Phosphor/Phosphate input, A = Acid input/acidification,
T = toxic inorganic chemicals, O = toxic organic chemicals, X = Mixed pollutions
i = inside, o = outside, b = both

4.5 Documentation

Berrow, S.D., Whooley, P. & Ferriss, S. (2002). Irish Whale and Dolphin Group cetacean sighting review (1991-2001). Irish Whale and Dolphin Group. 34pp. Berrow, S.D., Whooley, P., O’Connell, M. & Wall, D. (2010). Irish cetacean review (2000-2009). Irish Whale and Dolphin Group. 60pp. Costelloe, J., and Keegan, B.F. (1984). Littoral and benthic investigations on the west coast of Ireland - XIX. Synonomy, diagnostic morphology, distribution and life-style of Aslia lefevrei (Barrois 1882) (Holothurioidea: Echinodermata). Proceedings of the Royal Irish Academy, 84B: 29-35. Hannon, C., Berrow, S.D. and Coveney, J. (in prep.). The All-Ireland 1995 Breeding Tern Survey. Report being prepared for the National Parks & Wildlife Service and the Irish Wildbird Conservancy. Ingram, S., Kavanagh, A., Englund, A. & Rogan, E. (2009). Site assessment of the waters of northwest Connemara. A survey of bottlenose dolphins (Tursiops truncatus). Report for the National Parks & Wildlife Service of Ireland. University College Cork, Cork. 33pp. I.W.D.G. (1990-2011). Various published and online Irish Whale and Dolphin Group sources. These included all Survey Reports delivered via the PReCast & ShOPS ship survey programmes, in addition to information gathered in the ISCOPE (2003-2005) and ISCOPE II (2006-2009) projects. Lloyd, C. (1982). Inventory of Seabird Breeding Colonies in Republic of Ireland. Unpublished report to Forest & Wildlife Service, Dublin. Lockley, R.M. (1966). The distribution of grey and and common seals on the coasts of Ireland. Irish Naturalists' Journal 15: 136-143. Summers, C.F. (1983). The Grey Seal, Halichoerus grypus, in Ireland. Unpublished report to the Minister for Fisheries, Forestry and Wildlife, Dublin


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6.2 Management Plan(s):

An actual management plan does exist:

No, but in preparation



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