Report Surveys of sensitive subtidal benthic communities in • Kilkieran Bay & Islands SAC • Kingstown Bay SAC Report prepared by: MERC Consultants Ltd, Galway. On behalf of: National Parks and Wildlife, Department of the Environment, Heritage and Local Government, Plaza Offices, Headford Road. Galway November 2005 1.INTRODUCTION.......................................................................................................... 3 2. STUDY AREAS ............................................................................................................ 5 2.1 KILKIERAN BAY AND ISLANDS SAC.......................................................................... 5 2.2 KINGSTOWN BAY SAC .............................................................................................. 6 2.3 EXISTING INFORMATION ON THE SITES....................................................................... 8 2.3.1 Kilkieran Bay ..................................................................................................... 8 2.3.2 Kingstown Bay ................................................................................................... 8 3. MATERIALS AND METHODS ............................................................................... 10 3.1 MAERL AND ZOSTERA MARINA SURVEYS................................................................. 10 3.2 GROUND TRUTHING OF BROAD SCALE DATA ............................................................ 12 3.3 FIELD ASSESSMENT FOR ZOSTERA MARINA AND MAERL .......................................... 12 3.3.1 Shallow field assessment for Zostera marina and maerl................................. 12 3.3.2 Deep field/poor water clarity assessment for Zostera marina and maerl ....... 13 3.4 SELECTION OF TRANSECTS FOR FIELD ASSESSMENT FOR ZOSTERA MARINA AND MAERL ........................................................................................................................... 13 3.5 AFOR SCALE .......................................................................................................... 14 3.6 MAPPING OF MEGA FAUNAL COMMUNITIES.............................................................. 14 3.7 DATA RECORDING ................................................................................................... 15 4. RESULTS .................................................................................................................... 16 4.1 GENERAL ................................................................................................................. 16 4.2 SURVEY OF SENSITIVE SUBTIDAL COMMUNITIES ...................................................... 16 5. SUMMARY AND CONCLUSION ........................................................................... 37 6. REFERENCES............................................................................................................ 38 6.1 KILKIERAN BAY AND ISLANDS SAC........................................................................ 38 Map References: ....................................................................................................... 38 Data Bases :.............................................................................................................. 38 6.2 KINGSTOWN BAY SAC ............................................................................................ 38 Map References: ....................................................................................................... 38 Data Bases :.............................................................................................................. 38 6.3 BIBLIOGRAPHY: ....................................................................................................... 39 APPENDIX I SITE SYNOPSES.................................................................................... 40 KILKIERAN BAY & ISLANDS (SITE CODE 002111) ......................................................... 40 KINGSTOWN BAY (002265) ........................................................................................... 43 APPENDIX II SUMMARY DATA FOR SURVEY TRANSECTS ........................... 45 APPENDIX III SPECIES LISTS ................................................................................ 110 2 1.Introduction In furtherance of its policy of developing enhanced tools for managing Irelands marine Special Areas of Conservation (SACs), in 2005 the National Parks and Wildlife Service, Department of the Environment, Heritage and Local Government – commissioned a survey of sensitive subtidal communities in Kilkieran Bay and Islands and Kingstown Bay SACs. The over-riding purpose of the project was to enhance the conservation of marine wildlife and associated habitats in selected SACs through the investigation of ecological quality indicators. Within the scope of the project, the following were considered as sensitive subtidal communities: • beds of seagrass Zostera marina • beds of maerl forming calcareous algae including Lithothamnion corallioides, Phymatolithon calcareum1 • communities of the polychaetes Lanice conchilega (Sand Mason) , Sabella pavonina (Peacock Worm) and the reef forming Serpula vermicularis (Tube Worm), • reefs of the Native Oyster Ostrea edulis (excluding licensed fisheries/aquaculture sites), • reefs of the bivalve mollusc Limaria hians (Gaping File Shell), • communities of Scolanthus callimorphus ( Burrowing Worm Anemone) • beds of the tubicolous anemone Pachycerianthus multiplicatus (Fireworks Anemone), • communities of Virgularia mirabilis and other Sea Pen species, • beds of Neopentadactyla mixta and other burrowing sea cucumbers • communities of the anemone Edwardsia delapiae The well-documented ecological sensitivity of the selected communities means that they are commonly used in programmes designed to monitor environmental change, as the distribution and abundance of these communities are useful as indicators of habitat quality. A detailed baseline assessment of the distribution, extent and condition of these habitats/communities can facilitate the future management and long-term monitoring of the conservation status of designated conservation sites, as is required under the EU Habitats Directive. Only known significant subtidal stands/populations of these communities constituted the primary target of the survey. However, while the survey was not a search operation per se, where additional occurrences of the aforementioned communities were identified as a result of survey effort, these were also surveyed. 1 Both these species of maërl are listed in Annex V of the EU Habitats Directive (Council Directive 92/43/EEC) 3 The specific objectives of the 2005 study were to: • ground-truth data on the distribution of maerl, Zostera marina and burrowing mega fauna within Kilkieran Bay and Isalnds SAC that was collected during the broadscale mapping projects conducted during 2001 • map the distribution of seagrass Zostera marina beds • provide estimates of the density of Zostera marina beds and of specified megafaunal communities • map the distribution of maerl communities • map the distribution of other specific megafaunal communities (see above) Two SACs were selected for survey during 2005: • Kilkieran Bay and Islands SAC, Site Code 002111 • Kingstown Bay SAC Site Code 002265 The present report presents the main findings of the study, which was carried out by Marine Environmental and Resource Conservation Consultants Ltd. The textual report compliments the outputs of a more detailed and comprehensive Geographical Information Systems (GIS) project. The entire GIS project is presented electronically however the main outputs in the form of a series of maps are summarised herein. 4 2. Study Areas 2.1 Kilkieran Bay and Islands SAC Kilkieran Bay and Islands Special Area of Conservation (SAC) is situated on the west coast of Ireland to the north of Galway Bay. The site is one of the largest and most important marine SAC’s in Ireland. Taking in some 21,300 ha, the site encompasses all of the area below MHW mark of Greatmans Bay, Kilkieran Bay and Kiggaul Bay as well as a large area of more open water between Golam Head, Namacken Rocks and Mason Island. Kilkieran Bay itself forms the largest component of the site and is the most significant in terms of conservation value. Kilkieran Bay measures approximately 20km along its northeast-southwest main body. At its widest point it is approximately 8km wide (at the mouth of the bay from Golam Head to Inis Muskerry, however much of the bay is considerably narrower (less than 3km). The entrance to Kilkieran Bay faces the prevailing southwesterly winds, the direction from which the dominant ocean wave patterns also originate. Kilkieran Bay is a fjard, that is a glacially formed drowned embayment with shallow sloping sides. The numerous islands and islets within the bay lead to a complex hydrography with strong tidal currents forming as the tidal flows are funneled around islands and through the many narrow channels. The mean depth of the area is 12 m Below Chart Datum (BCD) although depths within the bay are as great as 42m BCD. The bay encompasses a very wide range of sublittoral marine sediments. These range from mud and fine sand to duned maerl, gravels, broken shell cobbles and boulders. Exposed granite bedrock is to be seen at numerous locations within the site. The area surrounding the site is comprised of lowland blanket bog with many hilly rocky outcrops. The SAC designation extends to a number of terrestrial areas, mostly islands. The site has been designated a SAC