Scottish MPA Project Data confidence assessment SOUTH ARRAN POSSIBLE NATURE CONSERVATION MPA

Transcription

1 Scottish MPA Project Data confidence assessment SOUTH ARRAN POSSIBLE NATURE CONSERVATION MPA

2 Document version control Version Date Author Reason / Comments Version 1 02/10/2012 Ben James and Laura Clark Revised protected features / MPA proposal format, updating search location version (ver. 5). Version 2 02/10/2012 Siobhan Mannion Update of commentary based on previous comments. Version 3 17/10/2012 Laura Clark and Lisa Kamphausen Version 4 17/10/2012 John Baxter QA review. Version 5 19/10/2012 Laura Clark and Lisa Kamphausen Version 6 30/11/2012 Ben James Review. Production and insertion of revised mapping. Update and edits. Refinements in response to QA review comments. Version 7 14/12/2012 Ian Bainbridge QA review and sign-off. Version 8 15/07/2013 Laura Clark Updated into possible MPA format. Version 9 31/07/2013 Lisa Kamphausen Updated maps and text with 2013 data Version 10 16/08/2013 Ben James Review. Version 11 22/08/2013 John Baxter QA review and sign-off. Distribution list Format Version Issue date Issued to Electronic 7 17/12/2012 SNH web publication. Electronic 11 22/08/2013 SNH web publication [A / 5(#10)].

3 Figure 1 The South Arran possible MPA 1

4 Name of possible MPA South Arran Assessor(s) BJ; LC; SM; LK The South Arran possible MPA (Figure 1) stretches around the southern half of the Isle of Arran in the Clyde Sea from just north of Drumadoon Point on the west coast to Corriegills Point on the east. The outer extent of the possible MPA follows a boundary line three nautical miles from the coast, incorporating Holy Isle, Pladda Island and an existing No Take Zone (NTZ) in Lamlash Bay. The range of seabed habitats and species proposed as protected features are broadly distributed throughout the possible MPA. Maerl beds are scattered across the area, often in association with coarse shell gravels and shallow tide-swept sands with rich associated communities of animals living within the sediments and kelp and other seaweeds above. These features often occur as mosaics. Seagrass stretches along Whiting Bay to form the most extensive known bed in the Clyde Sea (the area north of the Clyde Sea Sill between the Mull of Kintyre and Corsewall Point on the Rhinns of Galloway), with smaller but regular beds distributed along the south coast of Arran at Kildonan and Kilmory. Burrowed mud is widespread around the deeper margins of the possible MPA. Herring have historically spawned in the spring time on gravelly mixed substrates in shallow waters (~10-25 m depth) off the south-west coast of Arran (Morrison et al., 1991). These functionally significant grounds coincide with records of maerl beds and maerl gravel. The possible MPA has developed from a third-party proposal submitted by the Community of Arran Seabed Trust (COAST). Proposed protected features Biodiversity Burrowed mud (BM) Herring spawning grounds (HSG) Kelp and seaweed communities on sublittoral sediments (KS) Maerl beds (MB) Maerl or coarse shell gravel with burrowing sea cucumbers (MC) Ocean quahog (OQ) Seagrass beds (SG) Shallow tide-swept coarse sands with burrowing bivalves (ST) Geodiversity n/a Data used in assessment Version of GeMS database Ver.2 (i10) Other datasets used in feature map (specify) - Marine Scotland Science Nephrops underwater TV survey database. COAST / Seasearch data MS Clyde survey. Summary of data confidence assessment (see detailed assessment on following pages) Confident in underpinning data Yes Partial No Confident in presence of identified features? Summary Data suitable to define extent of individual proposed protected features 2 Partial SG BM;HSG;KS;MB;MC;OQ;ST We have high confidence in the presence of all protected features within the possible MPA. The majority of records of these features have been collected since 2008 and are suitable for coarsely defining their broad geographic distribution. New survey data collected in 2013 are currently being analysed and the results will improve our understanding of the extent of a number of the individual proposed protected features. Preliminary results have been incorporated into the assessment process. Previous survey efforts have focused on Lamlash Bay in relation to the NTZ in place there. Outwith this area, there has generally been a lower intensity of sampling and less information is available to define the extent of individual seabed features. This applies particularly to the maerl and the shell gravel habitats, the shallow tide-swept coarse sands with burrowing bivalves feature and ocean quahogs. The data underpinning this possible MPA have been collected through SNH and Marine Scotland-commissioned studies as well as by COAST and Seasearch volunteer surveyors (diver and intertidal observations). Seabed habitats in shallow waters off the south-west coast at Sliddery have historically served as herring spawning grounds (Morrison et al., 1991). Further work is required to determine the current and potential future significance of this area for spring-spawning Clyde Sea herring.

5 Figure 2 The known distribution of proposed protected features within the South Arran possible MPA 3

6 Data confidence assessment Our assessment of data confidence is based on consideration of the age and source of the data, sampling methods used and overall coverage across the possible MPA (see also Maps A - C). Existing protected areas are shown on Map D. Age of proposed protected feature data (Map A) Number of records collected within last 6 years Comments Many BM;KS;MB;MC;OQ;SG;ST Number of records collected 6-12 years ago Many MB;MC;SG;ST Number of records >12 years old Few HSG;SG Records of the proposed protected features span all three age classes. The majority of the data are less than 12 years old with most having been collected following the establishment of the NTZ in Lamlash Bay in 2008, and subsequent SNH and Marine Scotland-commissioned surveys. Survey data collected in 2013 are currently undergoing detailed analyses but preliminary results have been incorporated into this assessment. Only one seabed habitat record (of the seagrass beds feature) used within the assessment is greater than 12 years old. Recorded during a 1978 intertidal survey in Kildonan Bay, the continued presence of seagrass within the bay was confirmed in 2005 by Seasearch and again in September 2012 as part of a more comprehensive seagrass mapping study undertaken by COAST (Binnie et al., 2012). Records confirming herring spawning at discrete grounds to the south-west of Arran come from 1990 (Morrison et al., 1991). More contemporary records are not available for this feature. A series of annual Seasearch / COAST surveys undertaken between 2003 and 2006 in support of the NTZ proposal account for records between 6 and 12 years old. Baseline habitat mapping and subsequent monitoring work associated with the NTZ (Axelsson et al., 2008 and 2009; Munro et al., in prep) validated many of the earlier records of protected features within the Lamlash Bay area and have improved our understanding of the extent and distribution of these features in this comparatively small part of the wider possible MPA. Additional protected feature records from outwith Lamlash Bay have been generated in the last six years by SNH and Marine Scotland-commissioned surveys (in 2010, 2012 and Moore and Atkinson, 2012; Allen, 2013; Allen et al., 2013.; SNH, 2013) as well as ongoing COAST / Seasearch recording (records reviewed in Howson and Steel, 2013). Source of proposed protected feature data (Map B) Targeted data collection for nature conservation purposes Data collection associated with development proposals (EIA etc.) Comments Statutory monitoring (marine licensing etc.) Recreational / volunteer data collection Other (specify) - Fisheries survey work Nature conservation-orientated surveys commissioned by SNH and Marine Scotland or undertaken by COAST / Seasearch volunteers have generated most of the protected feature records within the South Arran possible MPA. There are dispersed records of burrowed mud in deeper waters around the perimeter of the area from the Marine Scotland Science Nephrops underwater TV database (fisheries stock assessment survey work). Ongoing monitoring studies of seabed habitats within the Lamlash Nay NTZ are considered a statutory requirement. 4

7 Sampling methods / resolution Feature Modelled Acoustic / remote sensing Remote video / camera Infaunal - grab / core Sediment Diving Fisheries sampling BM HSG KS (Lamlash Bay) MB (Lamlash Bay) MC OQ SG (+ intertidal) ST (Lamlash Bay) Sampling methods / resolution Comments A number of sampling methods have been used to collect information of differing resolution on the proposed protected features. Acoustic / remote sensing (sidescan sonar with single track bathymetry) has only been undertaken within Lamlash Bay (Axelsson et al., 2009 and 2010). Remote video sampling (using drop-down, towed and remotely operated vehicle-based camera systems) has been undertaken across the possible MPA, providing an overview of the composition and distribution of seabed habitats. Infaunal grab sampling and in situ diver observations have been targeted to provide a more detailed understanding of the quality, diversity and structure of the specific habitats. Ocean quahogs were recorded in deep muddy sands towards the south of the possible MPA from grab samples collected in 2012 and 2013 (Allen, 2013; SNH, 2013). Moderately high densities of ocean quahog-like bivalve siphons were also observed at a number of separate video stations sampled during this Marine Scotland survey (video analyses reported in Moore and Atkinson, 2012). Shells of the species were present on the seabed surface at these locations. Additional grab sampling was conducted at these locations in 2013 to confirm infaunal species composition (SNH, 2013). Seagrass beds along the south coast of Arran were mapped by intertidal surveyors sampling at low water in October 2012 (Binnie et al., 2012). The herring spawning ground outlined in Morrison et al. (1991) was also mapped in detail, using a combination of multiple grab, ROV and diver observations of egg masses on the sea bed (see Map C for sampling details). Herring spawn has also been collected historically by dredging off the Iron Rock Ledges (Marshall et al., 1937). However, details of specific sampling positions are not available and this area has not been included within this assessment. Proposed protected feature data coverage (Maps A - C) Across the possible MPA Large numbers of proposed protected feature records distributed across the possible MPA Numerous proposed protected feature records scattered across possible MPA with some clumping Numerous proposed protected feature records possibly with some clumping. Boundary not defined solely by recorded feature distribution Few or isolated proposed protected feature records - possibly clumped 5

8 Proposed protected feature data coverage (Maps A - C) For individual features Multiple records of individual proposed protected features providing an indication of extent and distribution throughout the possible MPA Few or scattered records of specific proposed protected features making extent and broad distribution assessment difficult Are acoustic remote sensing data available to facilitate the development of a full coverage predictive seabed habitat map? Comments Few or isolated records of specific proposed protected features Partial. Sidescan data are available for Lamlash Bay from habitat mapping surveys undertaken in 2008 and 2009 (Axelsson et al., 2009 and 2010). Data on the seabed habitat proposed protected features are scattered across the possible MPA but with a significant clumping of records within Lamlash Bay where recent studies have delineated the extent and shape of the maerl beds and adjacent seabed habitats within the NTZ. Incorporation of the full 2013 dataset following detailed analyses will improve the resolution of data coverage throughout the possible MPA. Sampling by Seasearch / COAST retained a focus on the NTZ following initial studies in support of the NTZ proposal in 2003 (Duncan, 2003), but also covered a wider geographic area between 2004 and 2006, with volunteer divers recording the distribution and extent of the subtidal seagrass beds in Whiting Bay and other seabed habitats present in nearshore waters further down the south-east coast of Arran, around Dippen Head and across to Pladda Island. These data represent a second smaller aggregation of proposed protected feature records. As well as continuing work within Lamlash Bay, more recent COAST / Seasearch recording has also extended the known distribution of protected features around the south and south-west coast of Arran, with lower shore seagrass beds off Kildonan and Kilmory mapped for the first time in 2012 (Binnie et al., 2012). Other records in 2012 include maerl beds at the Iron Rock Ledges (close to the older of the two herring spawning grounds) and maerl gravel with burrowing sea cucumbers in waters to the north of Drumadoon Point (Howson and Steel, 2013). These records have been supplemented by SNH and Marine Scotland studies undertaken in 2010, 2012 and The herring spawning grounds lie in shallow waters off the south-west coast. These grounds and the detail of the 1990 sampling positions are provided in Map C together with seabed substrate data from the British Geological Survey (BGS) and recent records of coarse substrate seabed habitats. Although not discussed in detail, Morrison et al. (1991) describe the substrates upon which the herring eggs were laid as gravel and maerl ridges. Recent additional records of maerl beds adjacent to these herring spawning grounds may also represent suitable spawning habitat. Further work would be required to determine the ongoing role of the confirmed grounds and adjacent habitats for spring-spawning Clyde Sea herring. Outwith Lamlash Bay there are either too few records of most of the individual proposed protected features or the records that are available are too widely dispersed to enable their distribution and extent to be defined with confidence until the 2013 data have been analysed fully. Data sources and bibliography Year Title Survey (Map B) Features covered in prep. Munro, C.D., Baldock, L., Brown, K. and Lindsley-Leake, S. (in prep.). Monitoring of marine habitats and species in Lamlash Bay, Arran: methodological developments and 2010 baseline data. Scottish Natural Heritage Commissioned Report No Allen, J.H. (2013). Infaunal analysis of grab samples collected from the Clyde Sea, in March Scottish Natural Heritage Commissioned Report No Available from < Lamlash Bay monitoring 2012 MS Clyde PMF survey KS; MB; ST MB; OQ 6

9 Data sources and bibliography Year Title Survey (Map B) Features covered 2013 Allen, C., Axelsson, M., Dewey, S. and Clark, L. (2013). Marine biological survey to establish the distribution of Priority Marine Features within the Clyde Sea area. Scottish Natural Heritage Commissioned Report No Howson, C. and Steel, L. (2013). Validation and mining of seabed habitat MPA search feature records relating to the South Arran third-party Nature Conservation MPA proposal. Scottish Natural Heritage Commissioned Report No SNH (2013). Preliminary survey results of the 2013 Marine Scotland / SNH Clyde survey. Unpublished interim survey report Binnie, A., Beecher, P. and Gordon, D. (2012). GIS mapping of Zostera seagrass beds within the proposed South Arran Proposed. Community of Arran Seabed Trust (COAST), Lamlash, Isle of Arran, Scotland Moore, C.G. and Atkinson, R.J.A. (2012). Biological analyses of underwater video from research cruises in the Clyde Sea, Loch Torridon and the Inner Sound, the North Minch, Loch Eriboll and off Orkney. Scottish Natural Heritage Commissioned Report No Available from < Axelsson, M., Dewey, S., Doran, J. and Plastow, L. (2010). Mapping of the marine habitats and species of Lamlash Bay, Arran. Scottish Natural Heritage Commissioned Report No Available from < Axelsson, M., Dewey, S, Plastow, L. and Doran, J. (2009). Mapping of marine habitats and species within the Community Marine Conservation Area at Lamlash Bay. Scottish Natural Heritage Commissioned Report No Available from < Duncan, C. (2003). Lamlash Bay Seasearch report. Report by the Marine Conservation Society to Scottish Natural Heritage. Available from < Morrison, J.A., Napier, I.R. and Gamble, J.C. (1991). Mass mortality of herring eggs associated with sedimenting diatom bloom. ICES Journal of Marine Science 48: Parrish, B.B., Saville, A., Craig, R.E., Baxter, I.G. and Priestley, R. (1959). Observations on herring spawning and larval distribution in the Firth of Clyde in Journal of the Marine Biological Association, U.K. 38: Available from < he_firth_of_clyde_in_1958.pdf> 2010 SNH PMF survey Clyde Sea COAST and Seasearch surveys BM KS; MB; MC; SG; ST 2013 MS Clyde survey BM; KS; MB; MC; OQ; ST 2012 COAST seagrass bed mapping survey 2012 MS Clyde PMF survey 2009 Lamlash habitat mapping 2008 Lamlash Bay habitat mapping survey 1990 MSS and UMBSM herring egg survey SG BM; OQ KS; MB KS; MB MB; SG HSG HSG 7

10 Data sources and bibliography Year Title Survey (Map B) Features covered 1937 Marshall, S.M., Nicholls, A.G. and Orr, A.P. (1937). Growth and feeding of the larval and post-larval stages of the Clyde herring. Journal of the Marine Biological Association, U.K. 22: Available from < UMBSM herring larvae survey HSG 8

11 THE EVIDENCE-BASE A B 9

12 C D 10