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

Rockabill to Dalkey Island 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:2011-09
Date site confirmed as SCI: No information provided
Date site designated as SAC:2019-03
National legal reference of SAC designation:94/2019


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2.1 Site-centre location [decimal degrees]:


2.2 Area [ha]


2.3 Marine area [%]


2.4 Sitelength [km] (optional):

No information provided

2.5 Administrative region code and name

No information provided

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      181.835  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          DD       
M1365Phoca vitulina    32  32         
M1351Phocoena phocoena    138  349   
M1349Tursiops truncatus          DD       
  • 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)

No information provided


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4.1 General site character

Habitat class % Cover

Total Habitat Cover


Other Site Characteristics

The selected site forms a strip of dynamic inshore and coastal waters in the western Irish Sea, extending approximately 40 km in length and encompassing a range of comparatively shallow marine habitats, including diverse seabed structures, reefs, islets and islands. It borders existing designated sites for Annexed species and habitats and is adjacent to a wide array of coastal features, e.g., mudflats, lagoons, estuaries, coastal cliffs, sea caves, several of which are also designated. Extending east from Dublin Bay towards the offshore Kish Bank, the site contains the entire Burford Bank, a sedimentary seabed structure (i.e. fine sand) at the mouth of Dublin Bay, that on its north side is flanked by gravel and coarse sand deposits. The site also contains the northern segment of the Frazer Bank (i.e. fine sand) off Dalkey Island and Killiney Bay. Reef habitats within the site occur at Dalkey Island, Maiden Rock and Muglins in the southern portion, off Howth Head, Ireland's Eye and Lambay Island in the central portion, and Rockabill in North Dublin.

4.2 Quality and importance

The area selected for designation represents a key habitat for the Annex II species - harbour porpoise, within the Irish Sea. Population survey data show that porpoise occurrence within the site boundary meets suitable reference values for other designated sites in Ireland. The species occurs year-round within the site and comparatively high group sizes have been recorded. Porpoises with young (i.e. calves) are observed at favourable, typical reference values for the species. Casual and effort-related sighting rates from coastal observation stations are significant for the east coast of Ireland and the latter appear to be relatively stable across all seasons. The selected site contains a wide array of habitats believed to be important for harbour porpoise including inshore shallow sand and mud-banks and rocky reefs scoured by strong current flow. The site also contains two Annex II seal species – Harbour seal (Phoca vitulina vitulina), Grey seal (Halichoerus grypus) for which terrestrial haul-out sites occur in immediate proximity to the site. Bottlenose dolphin (Tursiops truncatus) has also occasionally been recorded in the area. Along the eastern seaboard the habitat type Reef is uncommon due to prevailing geology and hydrographical conditions. Expansive surveys of the Irish coast have indicated that the greatest resource of this habitat within the Irish Sea is found fringing offshore islands which are concentrated along the Dublin coast. A detailed survey of selected suitable islands has shown areas with typical biodiversity for this habitat both intertidally and subtidally. These Reefs are subject to strong tidal currents with an abundant supply of suspended matter resulting in good representation of filter feeding fauna such as sponges, anemones and echinoderms.

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

4.4 Ownership (optional)

No information provided

4.5 Documentation (optional)

Andersen, L.W., Ruzzante, D.E., Walton, M., Berggren, P., Bjrge, A. & Lockyer, C. (2001). Conservation genetics of harbour porpoises, Phocoena phocoena, in eastern and central North Atlantic. Conserv.Gen. 2: 309–324. Anon. (2006). Small Cetaceans in the European Atlantic and North Sea (SCANS-II). Final Report covering the project activities from 01.04.2004 to 31.12.2006 under Life Project Number LIFE04NAT/GB/000245. Sea Mammal Research Unit, University of St. Andrews, UK. 54 pp. Baines, M.E. & Evans, P.G.H. (2009). Atlas of the marine mammals of Wales. CCW Marine Monitoring Report No. 68. Countryside Council for Wales. 89pp. 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., O'Brien, J., O'Connor, I. & McGrath, D. (2007). Abundance estimate and acoustic monitoring of harbour porpoise Phocoena phocoena in the Blasket Islands candidate Special Area of Conservation. Report to the National Parks & Wildlife Service, November. 23pp. Berrow, S., Hickey, R., O'Brien, J., O'Connor, I. & McGrath, D. (2008a). Harbour porpoise survey 2008. Report to the National Parks & Wildlife Service, October. 33pp. Berrow, S., Hickey, R., O'Connor, I. & McGrath, D. (2008b). Small cetacean site survey investigations 2008. Report to the National Parks & Wildlife Service, October. 24pp. Berrow, S., O'Brien, J., O'Connor, I. & McGrath, D. (2009). Abundance estimate and acoustic monitoring of harbour porpoises (Phocoena phocoena (L.)) in the Blasket Islands' candidate Special Area of Conservation. Biology and Environment: Proc. Royal. Ir. Acad. 109B: 35-46. Berrow, S. (2009). Abundance estimates of harbour porpoises in Irish waters. In Berrow, S.D. & Deegan, B. (eds.) Muc Mhara – Ireland's smallest whale. Proceedings of the 2nd Irish Whale and Dolphin Group International Whale Conference, 19-21 Sept 2008, Killiney, Co. Dublin. p19-22. Hammond, P.S., Benke, H., Berggren, P., Borchers, D.L., Buckland, S.T., Collet, A., Heide-Jrgensen, M.P., Heimlich-Boran, S., Hiby, A.R., Leopold, M.F. & ien, N. (1995). Distribution & abundance of the harbour porpoise and other small cetaceans in the North Sea and adjacent waters. Final Report for Life Project Number LIFE 92-2/UK/027. Sea Mammal Research Unit, University of St. Andrews, UK. 239 pp. Hammond, P.S., Berggren, P., Benke, H., Borchers, D.L., Collet, A., Heide-Jrgensen, M.P., Heimlich, S., Hiby, A.R., Leopold, M.F. & ien, N. (2002). Abundance of harbour porpoise and other cetaceans in the North Sea and adjacent waters. J. Appl. Ecol. 39: 361.376. Hammond, P.S. & MacLeod, K. (2006a). Quarterly newsletter for project SCANS-II: Small Cetaceans in the European Atlantic and North Sea (SCANS-II). Issue 7: June 2006. 3pp. Hammond, P.S. & MacLeod, K. (2006b). Quarterly newsletter for project SCANS-II: Small Cetaceans in the European Atlantic and North Sea (SCANS-II). Issue 8: September 2006. 2pp. I.W.D.G. (2009). Published and online Irish Whale and Dolphin Group sources were included in the review of available harbour porpoise data. These included all Survey Reports delivered via the PReCast & ShOPS ship survey programmes, in addition to information gathered to date in the ISCOPE (2003-2005) and ISCOPE II (2006-2009) projects. Leopold, M.F., Wolf, P.A. & Van der Meer, J. (1992). The elusive harbour porpoise exposed: Strip transect counts off southwestern Ireland. Neth. J. Sea Res. 29(4): 395-402. MERC Consultants Ltd. (2010). Project Report: Irish Sea Reef Survey. Unpublished report to the National Parks & Wildlife Service of the Department of the Environment, Heritage & Local Government. 36pp NPWS (2009). Conservation Plan for Irish Cetaceans – Public consultation draft. National Parks & Wildlife Service, Department of the Environment, Heritage and Local Government, Dublin. 99pp. Northridge, S.P., Tasker, M.L., Webb, A. & Williams, J.M. (1995). Distribution and relative abundance of harbour porpoises (Phocoena phocoena L.), white-beaked dolphins (Lagenorhyncus albirostris Gray), and minke whales (Balaenoptera acutorostrata Lacepde) around the British Isles. ICES J. Mar. Sci. 52: 55-66. Pollock, C.M., Reid, J.B., Webb, A. & Tasker, M.L. (1997). The distribution of seabirds and cetaceans in the waters around Ireland. JNCC Report No. 267. Joint Nature Conservation Committee, Peterborough. 167pp. Reid, J.B., Evans, P.G.H. & Northridge, S.P. (2003). Atlas of cetacean distribution in north-west European waters. Joint Nature Conservation Committee, Peterborough. 76pp. Walton, M. (1997). Population structure of harbour porpoises Phocoena phocoena in the seas around the UK and adjacent waters. Proc. R. Soc. Lond. B. 264: 89-94.


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6.1 Body(ies) responsible for the site management:

No information provided

6.2 Management Plan(s):

An actual management plan does exist:

No, but in preparation

6.3 Conservation measures (optional)

No information provided



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