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CONTRIBUTION TO THE SCOTTISH COMPONENT OF THE UK SPECIAL AREA OF CONSERVATION (SAC) LIST

SELECTION OF SOUND OF TO REPRESENT SANDBANKS, REEFS AND HARBOUR SEALS IN THE WESTERN ISLES

1. Background...... 2 2. General description of area...... 2 3. Evaluation of selection criteria ...... 5 I. Sandbanks which are slightly covered by sea water all the time (H1110) ...... 5 a) Representativity (a measure of ‘how typical’ a habitat type is 1)...... 5 b) Area of habitat type on site compared to other sites...... 6 c) Structure and Function (including richness of biotope/habitat) ...... 7 d) Global assessment ...... 9 II. Reefs (H1170)...... 10 a) Representativity (a measure of ‘how typical’ a habitat type is 1) ...... 10 b) Area of habitat type on site compared to other sites...... 11 c) Structure and Function (including richness of biotope/habitat) ...... 11 d) Global assessment ...... 13 III. Harbour / Common seal ( Phoca vitulina )...... 14 a) Size and density of the population of the species present on the site in relation to the populations present within national territory ...... 14 b) Degree of conservation of the features of the habitat which are important for the species concerned and restoration possibilities...... 15 c) Degree of isolation of the population present on the site in relation to the natural range of the species...... 16 d) Global assessment of the value of the site for conservation of the species ...... 17 4. Summary of marine features within the ...... 18 5. Boundary justification...... 19 6. References ...... 21 7. Glossary ...... 22 Appendix A ...... 24 Appendix B ...... 30

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1. Background In December 2004 the European Commission (EC) endorsed the UK list of proposed Special Areas of Conservation (SACs), and as a consequence all Scottish sites were formally designated as SACs. There were, however, a small number of marine interests for which the EC did not agree that Member States lists were complete. These interests, termed “scientific reserves”, include sandbanks which are slightly covered by sea water all the time (sandbanks), reefs and harbour seals (Phoca vitulina) . Marine areas in the Outer of were identified by SNH as regions where SAC sites should be considered further for these features.

The Sound of Barra was consulted on as a possible SAC (pSAC) for Harbour seals ( Phoca vitulina ) and sandbanks in July 2000. However, in light of recent changes in seal distribution and abundance within the pSAC area, and the reserve list for reefs and sandbanks, Scottish Ministers agreed that further survey work should be conducted. The whole of the Sound of Barra was surveyed in 2006 for Annex I habitats, particularly to locate the most substantial areas of sandbanks and reefs. Following this survey, a wider area than the original pSAC is being proposed for a range of habitats and species in Annexes I and II of the Habitats Directive: Annex I habitat “sandbanks which are slightly covered by sea water all the time”; Annex I habitat “reefs”; and Annex II species “harbour seal”. Much of the text within this document has been edited from the latest report on the Sound of Barra (Harries et.al. 2007).

2. General description of area The Sound of Barra comprises a mixture of islands, extensive rocky reefs, sandbanks and shallow channels in a broad stretch between the southern end of and the north eastern shore of the island of Barra in the (see Figure 1). The complex topography, diversity of habitat types and fast tidal streams has created an area of high biodiversity interest.

The main axis of the Sound is ~3km broad and runs approximately northeast to southwest between Barra and South Uist. Most of this area is >5m in depth but shallower rock reefs and sandbanks occur in a few locations. To the southwest of this axis is the north coast of Barra and associated islands such as Fiaray, and Gighay. To the northeast of the Sound is the south coast of South Uist with associated islands such as and Lingay.

The bathymetry of the area trends from shallower areas in the west to deeper areas in the east. The 10m depth contour runs roughly southwest to northeast, from Inner An Oitir Mhor to the southwest shore of Eriskay. West of this line the majority of the seabed is <10m in depth with the exception of a few relatively small basins of slightly deeper water. To the east of the 10m contour there is a gradual increase in depth and the majority of the eastern part of the survey area lies in depths of 20-30m (see Figure 2).

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Figure 1: Location of the Sound of Barra with proposed boundary and qualifying habitat interests

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Figure 2: GeoSwath bathymetric data grid (2m resolution). NB. Figure shows areas that have been surveyed using this technique but this did not cover all of the Sound of Barra

Lingeigh

Eriskay

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3. Evaluation of selection criteria The information available has been assessed against the Annex III criteria in the Habitats Directive, using the guidance provided by the EC for interpretation of these criteria and compilation of dataforms 1. This is in order to appraise site suitability, taking into consideration those habitats and species that are substantially represented: sandbanks which are slightly covered by sea water all the time; reefs; and harbour seals ( Phoca vitulina ). These criteria are:

Habitats: a. Degree of representativity of the natural habitat type on the site ( does it meet the definition ?) b. Area of the site covered by the natural habitat type ( qualifying interest ) in relation to the total area covered by that natural habitat type within national territory c. Degree of conservation of structure and functions of the natural habitat type concerned and restoration possibilities ( including quality of biotopes ) d. Global assessment of the value of the site for conservation of the natural habitat type concerned (including contribution to range) .

Species: a. Size and density of the population of the species present on the site in relation to the populations present within national territory b. Degree of conservation of the features of the habitat which are important for the species concerned and restoration possibilities c. Degree of isolation of the population present on the site in relation to the natural range of the species d. Global assessment of the value of the site for conservation of the species

I. Sandbanks which are slightly covered by sea water all the time (H1110) a) Representativity (a measure of ‘how typical’ a habitat type is 1) The definition of ‘sandbanks which are slightly covered by sea water all the time’ is provided in the EC Interpretation Manual and refined in “The Habitats Directive: selection of special areas of conservation in the UK" (McLeod et.al. 2005). “Slightly covered by sea water all the time” means that above a sandbank the water depth is seldom more than 20m below chart datum. Sandbanks can, however, extend beneath 20 m below chart datum. It can, therefore, be appropriate to include in designations such areas where they are part of the feature and host its biological assemblages.

Within the UK’s inshore waters Sandbanks which are slightly covered by sea water all the time can be categorised into four main sub-types (McLeod et.al. 2005): i. gravelly and clean sands;

1 Standard data form explanatory notes, Natura 2000. Official Journal of the European Communities – OJEC107/20. 24/04/1997. This report can be found at: http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/standarddataforms/n otes_en.pdf

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ii. muddy sands; iii. eelgrass Zostera marina beds; iv. maerl beds (composed of free-living Corallinaceae).

The latter two sub-types are particularly distinctive and are of high conservation value because of the diversity of species they may support and their general scarcity in UK waters (McLeod et.al. 2005).

The Sound of Barra falls within the definition of sandbanks, with the majority of the area shallower than 20m chart datum (see Appendix C). There are a number of typical species within the sand sediments (e.g. burrowing fauna of worms, crustaceans, bivalve molluscs and echinoderms (e.g. seastars and urchins)) and mobile epifauna at the seabed surface (e.g. shrimps, sea snails, crabs and fish). The Sound of Barra has an extensive Zostera area (~360ha), which generally occurs on the sandy substrates in moderately exposed or sheltered environments but the density of the Zostera is often low. Maerl beds are also present over a wide area (~902ha), located within typically exposed environments of the Sound. Although the abundance of live maerl is often low, this habitat still provides a complex niche for a diverse group of species.

Sandbanks which are slightly covered by sea water all the time occur widely around the UK coast. There are a total of nine designated SACs with sandbanks as their primary reason for selection, and an additional fourteen SACs with this feature as a significant presence within the UK. However, there are only two other SACs within the UK site series with distinctive maerl beds (Fal and Helford and the Sound of Arisaig), and four SACs with distinctive Zostera beds (Fal and Helford, Isles of Scilly Complex, Plymouth Sound and Estuaries, Sound of Arisaig).

With regards to representativity, the Sound of Barra fully meets the definition of sandbanks which are covered by sea water all the time (H1110), and are given a grade of A (excellent representativity 1) for this criterion since, unusually, it contains a good representation of all four sub-types of this habitat. (see Appendix A for summary of gradings) b) Area of habitat type on site compared to other sites The area of sandbank habitat is identified in Section 4, this being based upon the proposed site boundary (shown in Section 5).

The total surveyed area within the Sound of Barra (during 2001 and 2006) is approximately 12,500ha. The H1110 sandbanks cover approximately 65% of this area (7,200ha) (see Appendix and Appendix C). Sandbank extents within SACs with sandbanks as a primary reason for selection range from 1,600ha (Plymouth Sound and Estuaries) to 44,182ha (The Wash and North Norfolk Coast), with an average extent of 12,800ha.

Approx 91% of the Sandbank feature within the Sound of Barra lies in depths less than 20m Below Chart Datum (BCD) (Harries et.al. 2007).

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The total UK extent for sandbanks within both the inshore and offshore areas (out to 200nm) ranges from 1,720,000ha based on only sandy sediments in less than 20m water depth (which is likely to be an under-estimation of the total UK resource) to 8,010,000ha based on both sandy sediments in less than 20m plus adjacent areas of sandy sediment down to a water depth of 50m (which is likely to be an over-estimate of this UK resource).(Johnston et.al. 2008). However, prior to offshore sandbank areas being estimated in 2008, inshore SACs were compared against estimated sandbank habitat cover within 0 – 12nm of the UK coast only. The information database for offshore sandbank areas has been developed rapidly in the last couple of years. Therefore, sites being considered for designation in 2008 / 2009 are working to a different habitat area cover within the national territory compared to those considered years before this. This should be taken into account when comparing the grading for the ‘Area of habitat type’ criterion with previously selected marine SACs within Scottish inshore waters.

Given the estimation of 7,200ha of qualifying sandbanks within the Sound of Barra this site contains between 0.4% and 0.09% of sandbanks relative to the UK areas estimated for <20m water depth and <50m water depth respectively.

The Sound of Barra sandbanks contains 0.4% of the estimated UK resource of H1110 sandbanks in less than 20m of water depth. When taking into account the wider reference of sandbanks extending to a water depth of 50m the Sound of Barra contains 0.09% of the estimated UK resource of H1110 sandbanks. The Sound of Barra would be rated as C grade on the basis of the EC dataform criteria (C = <2%) 1.

c) Structure and Function (including richness of biotope/habitat) ‘Sandbanks which are slightly covered by sea water at all times’ encompass the vast majority of the subtidal sediment habitats within the Sound of Barra. There were 15 sandbank biotopes identified during the 2006 survey within the Sound of Barra, ranging from fine muddy sand with algal cover to gravelly sediment with maerl.

Some of the clean mobile rippled medium to fine sands in the west of the site contains impoverished infaunal communities due to its instability, particularly at exposed sites. Other sites which were otherwise identical in this area had better developed infaunal communities.

Finer siltier sands are predominant in the south and south-west, extending north to the south of Eriskay. These sands are generally much more abundant and species rich than in the mobile sands of the western part of the Sound.

Gravelly coarse sediment predominates over much of the relatively deep (>20m) eastern part of the area and frequently includes live maerl. These sediments predominate much of the area east of Eriskay and extend southwards. These substrates are well developed in the eastern parts of the sound and merge with the fine sand areas both south and north east of

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Eriskay. Maerl is also found amongst the mobile sands further west in the Sound in the tideswept channel between Fuday and Lingay.

Subtidal sandbanks supported dense beds of the seagrass Zostera marina at various locations within the Sound. These cover extensive areas of the shallow sands south east of Fiaray and similar well developed smaller beds occur in the Sound of Fuday. There is a large but more diffuse bed of Zostera to the south east of Fuday and it also occurs in smaller isolated patches at various locations within the Sound. The composition of the infauna from these areas of bare sand is modified by the presence of the Zostera and the sediment itself is slightly more heterogeneous than in corresponding areas devoid of Zostera .

Maerl beds are present in exposed environments within the Sound of Barra. Maerl is present over a wide area (~902ha) although the abundance of live maerl is often low (Harries et.al. 2007). However, this habitat still provides a complex niche for a diverse group of species.

The sandbanks within the Sound of Barra (with 15 biotopes) compare favourably with, and complement, nearby sandbanks such as those in Loch nam Madadh and the Sound of Arisaig, with 8 and 13 sandbank biotopes respectively, although these were classified using the previous 1996 biotopes codes. The biotopes within the Sound of Barra survey area varied from impoverished and muddy sands to gravelly and clean sands, from sheltered eelgrass Zostera marina beds to deeper, exposed maerl beds. This range of biotopes reflects the environmental conditions within the Sound. The survey area is highly exposed in the west (with highly mobile, impoverished sands), tide swept but reduced exposure in the mid-channel (increased diversity of fauna with some maerl) with deeper more sheltered areas to the east (stable fine sand with a diverse infaunal community). Moving further eastwards the sediment is gravelly with large pronounced ripples and small amounts of maerl. The southern part of the Sound is more sheltered and sediments are composed of fine sand with small amounts of silt. Sediment communities are variable in composition but are often dominated by algal mats in this southern part.

Fishing activities occur in the Sound of Barra. It is not currently possible to quantify the precise nature, intensity and extent of fishing activities as the only available data has been from Vessel Monitoring System (VMS) records (which are only located on vessels >15m in length) and anecdotal information that the majority of mobile gear fishing practice is at the eastern end of the Sound (which supports five scallop fishing vessels in South Uist). However, fishing activities within this area are likely to include those for crabs, lobsters and scallops, and the potential to include razorfish. Fishing activities that cause physical disturbance of the benthos, such as scallop dredging and / or hydraulic dredging, are a particular risk for the extensive maerl beds and Zostera beds within this area.

There is a seasonal prohibition (1 st March - 31 st October) on the use of mobile gear that applies to part of the Sound of Barra. This measure is contained in the Inshore Fisheries (Prohibition of Fishing and Fishing Measures) (Scotland)

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Order 2004. However, scallop dredging is specifically exempted from this restriction between certain periods, resulting in prohibition for only two short periods of the year; 1 st March - 1 st May and 24 th August – 31 st October. With regard to conservation of the sandbank qualifying interest within the Sound of Barra the above measures would have limited benefit (on the basis of generic knowledge regarding the impact of scallop dredging on benthic communities). With specific respect to the maerl sub-type these measures would have even less benefit as they would not result in i) a significant reduction in fishing events or ii) lengthy periods of low / no disturbance to enable significant recovery between fishing events.

Although there have been structural developments in recent years within this area (Eriskay causeway, jetties and moorings at North Bay and ferry terminals on Barra and Eriskay), the sandbank habitat appears to remain in good condition. There is no indication of present activities within the area likely to have significant deleterious effects, although this observation is based only on a relatively short timescale. There is potential for the causeway built between Eriskay and South Uist in 2000 to create modification over a much broader area (Harries et.al. 2007). There was evidence of patchy changes in abundance within the Zostera beds either side of the Eriskay causeway shown during the 2006 surveys. Although considerable changes in distribution of seagrass were noted from the comparative surveys from 2001 and 2006, there was no overall decline in abundance of this habitat.

With respect to structure and function, the Sound of Barra would be rated II: Structure well conserved for the degree of conservation of the structure, and II: Good prospects for the degree of conservation of the functions 1. In such a case, this site would be rated as a B-grade overall for H1110 sandbanks: Good conservation 1. It should be noted that if the maerl and Zostera areas are destroyed these would be virtually impossible to restore.

d) Global assessment Degree of representativity, area of qualifying habitat and consideration of structure and function are summarised as follows:

• All of the Sandbanks which are slightly covered by sea water all the time wholly meet the definition of habitat type H1110 • All four sub-types of subtidal sandbanks (H1110) are present within the Sound of Barra • The Sound of Barra contains approximately 7,200ha of qualifying subtidal sandbanks (H1110), and 0.4% - 0.09% of the estimated UK resource for Sandbanks which are slightly covered by sea water all the time • There were 15 Sandbank biotopes recorded within the Sound of Barra during the 2006 surveys, which represented a diversity of sandbank sub- types, ranging from impoverished and muddy sands to gravelly and clean sands, from sheltered eelgrass Zostera marina beds to deeper, exposed maerl beds • Extensive (~360ha) Zostera beds are present although the density of the Zostera is often low

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• Probably the most extensive area of maerl beds (~902ha) identified within the UK series to date is present within the Sound of Barra survey area. Although the abundance of live maerl is sparsely distributed this habitat still provides a complex niche for a diverse group of species • The structure and function of the Sound of Barra Sandbanks are good. There is human influence within the Sound that may cause further change, but despite considerable change in distribution of seagrass between 2001 and 2006 there was no overall decline in abundance of this habitat • The nearest sites of this qualifier are Loch nam Madadh and Sound of Arisaig. The Sound of Barra extends range representation by some 60km

Overall, in light of the above, the Sound of Barra is considered to be of global B grade (good value 1) for H1110 Sandbanks which are slightly covered by sea water all the time.

II. Reefs (H1170) a) Representativity (a measure of ‘how typical’ a habitat type is 1) The definition of ‘reefs’ is provided in the EC Interpretation Manual and refined in ‘The Habitats Directive: selection of special areas of conservation in the UK’ (McLeod et.al. 2005). Reefs can be either biogenic concretions or of geogenic origin (non-biogenic reefs). They are hard compact substrata on solid and soft bottoms, which arise from the sea floor in the sublittoral and littoral zone. Reefs may support a zonation of benthic communities of algae and animal species as well as the reef-forming substrate cementing another substrate e.g. bedrock, cobbles (concretions and corallogenic concretions).

A definition is provided by the EC for sublittoral: “Sublittoral and littoral zone” means: the reefs may extend from the sublittoral uninterrupted into the intertidal (littoral) zone or may only occur in the sublittoral zone, including deep water areas such as the bathyal.

The Sound of Barra falls within the definition of reefs, with the majority of the subtidal rock reefs occurring as isolated outcrops throughout the Sound but most extensively in the exposed western areas and, to a lesser extent, in the eastern part of the Sound (see Appendix C). There are a number of typical species within the reef areas such as a variety of red, brown and green seaweeds, sessile invertebrates such as sponges, bryozoans, hydroids and barnacles, and mobile invertebrates such as marine worms and snails.

Reefs occur widely around the UK coast, with a far greater range and extent of rocky reefs than biogenic concretions. There are a total of 19 designated SACs with reefs as their primary reason for selection, and an additional 14 SACs with this feature as a significant presence within the UK.

With regards to representativity, the Sound of Barra fully meets the definition of reefs (H1170), and are given a grade of B for this criterion: Excellent representativity 1.

10 Version 12: 9th April 2009 b) Area of habitat type on site compared to other sites The area of reef habitat is identified in Section 4, this being based upon the proposed site boundary (shown in Section 5).

The total surveyed area within the Sound of Barra (in 2001 and 2006) is approximately 12,500ha. The area of qualifying reefs cover approximately 40% of this area (4,400ha) (see Appendix and Appendix C). The extent of this habitat within inshore UK SACs with reefs as a primary reason for selection range from 196ha (Loch Creran) to 41,007ha (Pembrokeshire Marine/ Sir Benfro Forol), with an average extent of 9,200ha.

The total UK extent for reefs within the national territory i.e. within 0 – 200nm of UK waters is 7,180,000ha (Johnston et.al. 2008). However, prior to offshore reef areas being estimated in 2008, inshore SACs were compared against estimated reef habitat cover within 0 – 12nm of the UK coast only. The information database for offshore reef areas has been developed rapidly in the last couple of years. Therefore, sites being considered for designation in 2008 / 2009 are working to a different habitat area cover within the national territory compared to those considered years before this. This should be taken into account when comparing the grading for the ‘Area of habitat type’ criterion with previously selected marine SACs within Scottish inshore waters.

The Sound of Barra reefs contain approx. 0.06% of the estimated UK resource H1170. The Sound of Barra would be rated as a C grade on the basis of the dataform criteria (C = <2% 1).

c) Structure and Function (including richness of biotope/habitat) The marine benthic communities within the Sound of Barra are strongly influenced both by exposure to wave action and by tidal currents. Substrate type can be described as a mosaic of rocky reefs and sediment patches of varying size extending over the whole of the site.

The western part of the Sound is highly exposed with stable infralittoral rocky substrates dominated by tideswept forests of kelp Laminaria hyperborea communities that are often modified by sand scour and tidal currents. The channels in the mid part of the Sound are tide swept. Sediments here are generally sandy but where stable rock substrates occur, they are dominated by kelp communities with a diverse associated fauna characteristic of accelerated tidal currents. These communities are also modified by sand scour in many locations and where this is intensified the Laminaria hyperborea may be subject to periodic removal or fail to establish. At these locations a mixed kelp community may develop including Saccorhiza polyschides and Laminaria saccharina . Laminaria hyperborea forests also occur in lower energy environments such as can occur with increased depth. In these cases the stipe epibiota in general is less profuse and lacks significant abundance of filter feeding invertebrates.

The depth increases to the east, where most of the substrate is sandy due to lack of light penetration to support kelp forests. However, shallower rock substrates in this area support kelp forests, some of which show

11 Version 12: 9th April 2009 characteristics of accelerated tidal currents. Deeper rock surfaces are dominated by a turf of foliose red algae mixed with scour tolerant epifauna. With increasing depth the cover of red algae on the reefs decrease and there is an increased dominance of invertebrates similar to those of the shallower reefs.

The southern part of the Sound is more sheltered and sediments are composed of fine sand with small amounts of silt. Kelp communities in this area are those characteristic of more sheltered environments.

The intertidal rock reefs of the site support communities characteristic of a wide spectrum of exposure conditions. In the most exposed sites there are shores dominated by the barnacle Cthamalus sp. with patches of small mussels, a turf of coralline algae Corallina officianalis in the lower shore and a sublittoral fringe dominated by Dabberlocks algae Alaria sp.. With decreasing exposure levels the shores are dominated by the barnacle Semibalanus sp. and tufts of Bladder wrack algae Fucus vesiculosus become increasingly frequent. Moderately exposed shores are characterised by a patchy mosaic of the barnacle Semibalanus and Fucus vesiculosus and in the most sheltered conditions the shores are dominated by a dense blanket of Knotted wrack algae Ascophyllum nodosum .

The reefs within the Sound of Barra (19 subtidal biotopes) show a good diversity of biotopes. These biotopes compare favourably with, and geographically extend, nearby SACs with qualifying reefs such as those in Loch Sunart (27 biotopes were categorised as occurring on reef during the 2006 surveys), the Firth of Lorn (45 reef biotopes from video survey in 2005) and Loch nam Madadh.

At the time of writing it is not considered that sustainable fishing by creels will result in significant impacts with respect to the reef features within the Sound of Barra. There is a potential for interaction between mobile fishing gear and reef habitat within the Sound. It is not currently possible to quantify the precise nature, intensity and extent of such fishing activity within the area. However, it is thought that the majority of this fishing practice is at the eastern end of the Sound, which is known to support five scallop fishing vessels in South Uist.

Although there have been structural developments in recent years within this area (Eriskay causeway and Barra ferry terminal), the reef habitat appears to remain in good condition. There is no indication of present activities within the area likely to have significant deleterious effects.

With respect to structure and function, the Sound of Barra would be rated II: Structure well conserved for the degree of conservation of the structure, and II: Good prospects for the degree of conservation of the functions 1 for H1170. In such a case, this site would be rated as a B- grade overall (good conservation 1), without the necessity of consideration for the restoration possibilities.

12 Version 12: 9th April 2009 d) Global assessment Degree of representativity, area of qualifying habitat and consideration of structure and function are summarised as follows:

• All of the Reefs wholly meet the definition of habitat type H1170 • The Sound of Barra contains approximately 4,400ha of qualifying reefs (H1170) • There were 19 qualifying reef biotopes recorded within its boundary during the 2006 surveys, which were predominantly mosaiced rocky reefs and sediment patches of varying sizes, with kelp on rock and a range of associated faunal diversity • The structure and function of the Sound of Barra is good. There is human influence within the Sound, but there is no evidence that the quality of the site is adversely affected • The nearest sites of this qualifier are Loch nam Madadh, Loch Sunart and Lochs Duichs, Long and Alsh. The Sound of Barra extends range representation by some 60km

Overall, in light of the above, the Sound of Barra is considered to be of global B grade (good value 1) for H1170 Reefs.

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III. Harbour / Common seal ( Phoca vitulina ) a) Size and density of the population of the species present on the site in relation to the populations present within national territory The harbour seal Phoca vitulina is “the characteristic seal of sandflats and estuaries, but they are also found on rocky shores in Scotland”. The harbour seal “is widespread around the shores of the UK, but population density varies greatly from place to place. (Harbour) seal are found from Northern Ireland and the southern Firth of Clyde clockwise round the coast to the Thames estuary. The vast majority of (harbour) seal haul-outs are found on the coasts of Scotland, but with an additional important concentration on The Wash, and a smaller number in Strangford Lough, Northern Ireland” (JNCC 2). On the west coast of Scotland, harbour seals habitually utilise rocky shores, islets and skerries as haul-out areas to rest, pup and moult. The reasons for utilising such areas are considered essential to the harbour seal’s life and reproduction. There are a total of nine designated SACs with harbour seals Phoca vitulina as a primary reason for selection, and an additional two SACs with this species as a significant presence within the UK.

The UK inshore waters hold at least 28,300 harbour seals. This is a minimum figure, counted at coastal haul-outs during the moulting periods between 2000 and 2006, as updated by the JNCC FCS report in 2007 (JNCC 2007). Scotland holds the majority of the UK resource (approximately 80%) of the harbour seal, and the Western Isles is an important area supporting this species. There are currently no SACs for harbour seals in the Western Isles.

The highest concentrations of seals in the Sound of Barra have been predominantly distributed around the north-east of Barra, south-east of South Uist and west of the Sound of Eriskay, and Fiaray and Fuday.

The skerries, islets, undisturbed main island shores and offshore sandbanks in the Sound of Barra have consistently supported a significant breeding colony of the harbour seal in terms of the UK population. According to the surveys undertaken by the Sea Mammal Research Unit (SMRU) between 1992 and 2008, numbers of adults and pups combined within the Sound of Barra 3 have ranged from ~880 (August 1992) to ~100 (August 2008), with the average number for all counts within this time period at ~355. The population of harbour seals in this area shows an obvious decline from 1992 to 2008. However, a relatively stable population was reached in 2002, 2003 and 2006 (254, 206 and 179 respectively) but has continued with a further reduction in 2008 (97).

The first criterion to consider under the EC Natura 2000 Standard Data Form explanatory notes 1 for Annex II species is the population size and density of a species present on a site. This is assessed in relation to the population present within the national territory i.e. UK. An average count from the last four surveys has been calculated to represent the current population at 184

2 http://www.jncc.gov.uk/ProtectedSites/SACselection/species.asp?FeatureIntCode=S1365 3 N.B. The Sound of Barra harbour seal figures have been calculated using all the locations surveyed by SMRU in this area minus “SE South Uist” and “W Sth Uist” (sub-sections 12 and 13) as these survey boxes lie outwith the proposed boundary for the Sound of Barra.

14 Version 12: 9th April 2009 harbour seals within the Sound of Barra. This site represents 0.7% of the total UK population for this species.

The Sound of Barra holds an average of 0.7% of the total UK inshore waters population for harbour seals Phoca vitulina based on counts between 2002 and 2008. The Sound of Barra would be rated as grade C on the basis of the EC dataform criteria (C = <2%) 1.

b) Degree of conservation of the features of the habitat which are important for the species concerned and restoration possibilities The population for harbour seals is identified in Section 4, this being based upon the proposed site boundary (shown in Section 5). The harbour seals are considered to be a wide-ranging Annex II species. As such, the boundary of the proposed site has to correspond to the place within the natural range of this species, which presents the physical or biological factors essential to their life and reproduction.

The Sound of Barra is situated between the islands of South Uist and Barra in the Outer Hebrides. The coastline is characterised by remote rocky shores interspersed with small inlets and larger sandy bays, and undisturbed islands and skerries. The region experiences some of the strongest winds and largest waves in the UK. However, many of the marine communities in the Sound of Barra are indicative of a degree of shelter from the prevailing weather conditions. These indicative ‘sheltered’ communities and the consistent presence of harbour seals within the Sound of Barra give evidence of this site offering habitats that are well conserved in order to provide essential haul-out areas for this species of seal.

Although the population of harbour seals has fluctuated within the Sound of Barra, this species has consistently been recorded during surveys in this area for over 30 years. The immediate offshore areas around the Sound of Barra are essential for breeding, moulting and social interactions for seals. Adult harbour seals can remain very faithful to particular haul-out areas, moving around the same group of favoured locations depending on the prevailing weather conditions, on a seasonal basis and over a number of years. Large colonies are important in maintaining overall population size and are significant as sources of emigration to smaller or newly established groups.

In relation to marine activities that may affect the population of harbour seals, there are a few mariculture leases within the proposed area of the Sound of Barra. These consist of four sites that range from mussels to finfish aquaculture systems. These sites are located in three areas as follows: east of Traigh Mhor; north of Fuiay and Flodday; North Bay. Potential impacts on seals from aquaculture include disturbance issues from boat usage, and interactions with predator control methods.

There have been some structural developments in recent years within the Sound of Barra: Eriskay causeway; Barra ferry terminal (both in 2001). The Eriskay causeway was constructed across some recognised seal habitat. The most substantial decline for this population occurred between August 1992

15 Version 12: 9th April 2009 and August 2000 but have continued to decline since that time with no observed recovery in numbers relating to those in 1992 or 1996.

The average population of harbour seals within the Outer Hebrides between 1992 and 2006 was approximately 2,400. Although the numbers of harbour seals within the Sound of Barra declined substantially between 1992 and 2008, the overall number in the Outer Hebrides has declined only slightly over the same interval. This implies some movement or redistribution of harbour seals away from the Sound of Barra (Duck, C . pers. comm. , 2008). This information is based on surveys carried out in 1992, 1996, 2000, 2003 and 2006. However, the 2006 survey was incomplete (due to equipment malfunction), hence the east coast of Benbecula and North Uist were not surveyed.

With respect to the degree of conservation of the features of the habitat important for the harbour seal (Phoca vitulina), the Sound of Barra would be rated II: Elements well conserved 1. In such a case, this site would be rated as a B-grade (‘Good conservation’ 1) overall, without the necessity of consideration for restoration possibilities. c) Degree of isolation of the population present on the site in relation to the natural range of the species Genetic analysis has been undertaken on seals in Northern Ireland, the west and east coasts of Scotland, the east coast of England, the Dutch and German Waddenzee, the Kattegat/Skagerrak, Norway, the Baltic Sea and Iceland. The results of this have been reported by SMRU (2004). There was suggestion towards “six genetically distinct common seal populations in European waters (Ireland-Scotland, English east coast, Waddenzee, western Scandinavia, Baltic and Iceland) (Goodman 1998). There is probably very little movement of breeding animals between these populations. Within the Ireland-Scotland population there is probably occasional movement of animals between regions, but there is no evidence from satellite telemetry of any long-range movements (for example, between the east and west coasts of Scotland) comparable to those observed in grey seals. Similarly, studies of the movements of branded seals in the Kattegat/Skagerrak (Härkönen & Harding 2001) indicate that there is only limited movement within the western Scandinavia population. However, in both 1988 and 2002 phocine distemper spread rapidly among European common seal populations, suggesting that substantial movement of individuals can occur, although the genetics studies suggest these movements are unusual or that they do not usually result in seals moving between regions to reproduce.”

Harbour seals are known to roam from a localised area, although there is limited information about their reproductive and foraging movements (SMRU 2004). It may be possible to identify discrete sub-populations for harbour seals given that the haul-out sites used by Scottish common seals have a similar distribution to those used by grey seals. Harbour seals occur throughout the Outer Hebrides, predominantly around the coasts of North Uist, South Uist and Barra.

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The nearest site with harbour seals is Ascrib, and Dunvegan SAC. The Sound of Barra extends the range by approximately 68km.

With respect to isolation, the Sound of Barra would be rated B: population not-isolated, but on margins of area of distribution 1. d) Global assessment of the value of the site for conservation of the species Size and density of population, degree of conservation of the supporting habitat and degree of isolation are summarised as follows:

• The Sound of Barra has consistently supported a population of harbour seals for over 15 years of coordinated counts • The Sound of Barra hosts approximately 0.7% of the total UK inshore population of harbour seals based on an average calculated from 2002, 2003, 2006 and 2008 counts • The degree of isolation of the population within the Sound of Barra is limited, with seal movements extending to other seal locales • The current features of the habitat which are essential for harbour seals within the Sound of Barra are well conserved.

The Sound of Barra represents an important addition to the UK site series for harbour seals in terms of geographical range. The Sound of Barra is the only site for the species in the Western Isles, a region where harbour seals are significantly distributed. As defined in the Habitats Directive, the maintenance of geographical range is one of the key elements contributing to the achievement of favourable conservation status for a species. It is also one of the additional principles used in the UK to inform the site selection process. These additional principles, outlined on JNCC's website 4, interpret and supplement the Annex III site selection criteria described above.

In light of the site’s overall assessment, and taking its importance in terms of geographical range into account, the Sound of Barra is considered to be of global C grade for harbour seals Phoca vitulina (‘good value’ 1).

4 http://www.jncc.gov.uk/page-1473

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4. Summary of marine features within the Sound of Barra

Marine Features summary for Sound of Barra dSAC

Site name: Sound of Barra Grid Ref: 1. NF751026 Country: 2. Scotland (Western Isles) Area within boundary:3. ~12,500 ha Marine Biogeographic4. Situated between South Uist and Barra in the Region Outer Hebrides

Qualifying features: Global Annex I habitats Extent Grading Sandbanks slightly Estimated 7,200 ha B covered by sea water all the time (Subtidal sandbanks) Reefs Estimated 4,400ha B

Annex II species Population estimate Global Grading Phoca vitulina Population 184 (average counts from 2002, C (Harbour Seal) 2003, 2006 and 2008) (~0.7% of UK inshore population)

Recent data counts for Harbour seals in the Sound of Barra (SMRU):- 1992 – 879; 1996 – 581; 2000 – 281; 2002 – 254; 2003 – 206; 2006 – 179; 2008 - 97

Features present but not qualifying Global Annex I habitats Extent Grading Mudflats and Estimated 200 ha D sandflats not covered by seawater at low tide

Annex II species Population estimate Global Grading Tursiops truncatus D (Bottlenose dolphin) Phocoena phocoena D (Harbour porpoise)

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5. Boundary justification The boundary of the proposed site (Figure 3 and Appendix B) was selected by defining the most simple lines that incorporate both the qualifying habitat interests (Reefs and Sandbanks which are slightly covered by sea water all the time) and qualifying habitat that is essential to the life and reproduction of the proposed species harbour seal Phoca vitulina as pupping and moulting areas. This has taken into account the need to ensure that the site operates as a functional whole for the conservation of the habitat type and species and to maintain sensible management units.

The proposed SAC area extends from the west of Ceann a Gharaidh on South Uist to Gob Sgurabhal (including Fiaraigh) on Barra, and across to Curachan (island east of Barra) (from a point on land just south of Bruairnis (Rubha Liath)) and Rubha Mealabhaig, including Hairteamul (south-east of South Uist) (Figure 3). The boundary will encompass marine areas up to Mean High Water Springs (MHWS) on coastlines i.e. of the main islands as well as smaller islets and skerries.

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Figure 3 Proposed SAC boundary for the Sound of Barra (from OS datasource)

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6. References EC Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Flora (Habitats Directive) Goodman, S.J. (1998) Patterns of extensive genetic differentiation and variation among European harbour seals ( Phoca vitulina ) revealed using microsatellite DNA polymorphisms. Molecular Biology and Evolution, 15, 104- 118. Härkönen, T. & Harding, K.C. (2001) Spatial structure of harbour seal populations and the implications thereof. Canadian Journal of Zoology, 79, 2115-2127. Harries, D.B, Malthus, T.J., Karpouzli, E., Moore, C.G., Lyndon, A.R., Mair, J.M., Service, M., Mitchell, A. (2007) Biotope mapping of the Sound of Barra, Scotland. Scottish Natural Heritage Commissioned report No.258 (in print) (ROAME No. RO6PA04) Johnston, C., Turnball, C., Aish, A., Ridgeway, A. & Vincent, M. (JNCC) 2008. Progress towards completing the UK network of marine Special Areas of Conservation (SACs) for Annex I habitats and site proposals for Hatton Bank and Bassurelle Bank. http://www.jncc.gov.uk/PDF/comm_08P14a.pdf Joint Nature Conservation Committee. 2007. Second Report by the UK under Article 17 on the implementation of the Habitats. Directive from January 2001 to December 2006 . Peterborough: JNCC. Available from: www.jncc.gov.uk/article17 McLeod, CR, Yeo, M, Brown, AE, Burn, AJ, Hopkins, JJ, & Way, SF (eds.) (2005) 'The Habitats Directive: selection of Special Areas of Conservation in the UK'. 2nd edn. Joint Nature Conservation Committee, Peterborough. Available from the JNCC website at http://www.jncc.gov.uk/ProtectedSites/SACselection/default.htm SMRU 2004. Scientific Advice on Matters Related to the Management of Seal Populations: 2004. Report to the UK Special Committee on Seals, Advice 2004. SMRU SMRU 2006. Survey of harbour seal distribution in Shetland, Orkney, the Western Isles and Strathclyde, excluding the Firth of Clyde. A report for Scottish Natural Heritage. Draft. SNH Contract: 16765 http://ec.europa.eu/environment/nature/nature_conservation/natura_2000_net work/standard_data_forms/pdf/en-notes.pdf Standard data form explanatory notes, Natura 2000. Official Journal of the European Communities – OJEC107/20 . 24/04/1997 http://www.jncc.gov.uk/ProtectedSites/SACselection/species.asp?FeatureIntC ode=S1365 http://www.jncc.gov.uk/publications/JNCC312/habitat.asp?FeatureIntCode=H 1110

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7. Glossary

Bathyal Denoting or relating to an ocean depth of between 200 and 2000 metres (about 100 and 1000 fathoms), corresponding to the continental slope Bathymetry Measurement of the depth of an ocean or other large body of water Biogenic reef Produced or originating from a living organism Biotope A small area, such as the bark of a tree, that supports its own distinctive community Concretions 1) The act or process of coming or growing together; coalescence. 2) Any of various rounded or irregular mineral masses (e.g. cobbles, boulders) that are different in composition from the sedimentary rock that surrounds them. It is often found with a fossil as a ‘nucleus’. The size ranges from approximately 1mm to more than 1m and concretions are generally monomineralic (made up of only one mineral) Corallogenic Of coral origin Encrustations 1) to cover or overlay with or as with a crust or hard coating; 2) to form or cause to form a crust or hard coating Geogenic origin Reefs formed by non-biogenic substrata Hard compact substrata Rocks (including soft rock, e.g. chalk), boulders and cobbles (generally >64 mm in diameter) Littoral 1) of or relating to the shore of a sea, lake, or ocean; 2) (Biology) inhabiting the shore of a sea or lake or the shallow waters near the shore; 3) a coastal or shore region Non-biogenic reef Reefs composed of non-living organisms such as rocks, cobble, boulders Sublittoral 1) (of marine organisms) growing, living, or situated close to the seashore; 2) of or relating to the zone between the seashore and the edge of the continental shelf Swath echosounders Also known as Swathe or multibeam echosounders, used to acoustically survey the seabed for biological surveys in waters too deep and extensive for in-water dive / video surveys. The system is made up of active sensors that utilise acoustic energy to collect measurements of seafloor depth and character. Multibeam sensors pulse the bottom with a series of soundings normal to the track of the vessel and record the reflected echoes in an orientation parallel to the vessel track. This produces a swath of data that, depending on specific sensor and mission requirements, is normally several times the water depth. Like other acoustic sensors, multibeam sonars normally collect data in a series of transect

22 Version 12: 9th April 2009 lines that allow sufficient sidelap to avoid gaps in coverage. As a rule, the deeper the water, the wider the swath of data collected. Since the swath width is strongly influenced by water depth, some planning of transect spacing is needed to ensure that no gaps occur where water depth decreases. (http://www.csc.noaa.gov/crs/rs_apps/sensors/mult i_beam.htm )

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Appendix A Site assessment criteria for a given natural habitat type in Annex I (in accordance with Section A of Annex III)

The information available for each site is assessed against the Annex III criteria in the Habitats Directive, using the guidance provided by the EC for interpretation of these criteria and compilation of dataforms. This is in order to appraise site suitability, taking into consideration those habitats and species that are substantially represented.

The following summary of the gradings for each of the criteria used for assessment of all Special Areas of Conservation (SACs) has been edited from the European Natura 2000 Standard Data Form Explanatory Notes, which is available at: http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/stand arddataforms/notes_en.pdf .

Habitats a. Degree of representativity of the natural habitat type on the site (does it meet the definition ?) A: Excellent representativity B: Good representativity C: Significant representativity

Furthermore, all cases where a habitat type is present on the site in question in a non-significant manner must be indicated in a fourth category. D: non-significant presence

In cases where the site representativity for the habitat type concerned is classed as “D: non-significant”, no other indication is required for the other evaluation criteria concerning this habitat type on the site in question. In these cases the criteria “Relative surface”, “Conservation Status” and “Global evaluation” should not be marked . b. Area of the site covered by the natural habitat type in relation to the total area covered by that natural habitat type within national territory.

This criterion should be expressed as a percentage “p”. A: 100>= p >15% B: 15 >= p >2% C: 2 >= p >0 c. Degree of conservation of the structure and functions of the natural habitat type concerned and restoration possibilities ( including quality of biotopes ) This criterion comprises three sub-criteria: i) degree of conservation of the structure ii) degree of conservation of the functions

24 Version 12: 9th April 2009 iii) restoration possibility i) Degree of conservation of structure I: excellent structure II: structure well conserved III: average or partially degraded structure

In cases where the sub-class “excellent structure” is given the criterion A.c) should in its totality be classed as “A: excellent conservation”, independently of the grading of the other two sub- crirteria. ii) Degree of conservation of functions I: excellent prospects II: good prospects III: average or unfavourable prospects

In cases where the sub-class "I: excellent prospects" or " II: good prospects" are combined with the grading "II: structure well conserved" of the first sub-criterion, the criterion A.c) should in its totality by classed "A: excellent conservation" or "B: good conservation" respectively, independently of the grading of the third sub-criterion which should not further be considered.

In cases where the sub-class "III: average or unfavourable prospects"is combined with the grading "III : average or partially degraded structure" of the first sub-criterion, the criterion A.c) in its entirety should be classed as "C: average or reduced conservation" independently of the grading of the third sub- criterion which should not further be considered. iii) Restoration possibilities

The ranking system should be the following, using 'best expert judgement': I: restoration easy II: restoration possible with an average effort III: restoration difficult or impossible

Synthesis: applying to the overall grading of the three sub-criteria A: excellent conservation = excellent structure, independent of the grading of the other two sub- criteria.

= structure well conserved and excellent prospects independent of the grading of the third criterion

B: good conservation = structure well conserved and good

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prospects independent of the grading of the third sub-criterion

= structure well conserved and average / maybe unfavourable prospects and restoration easy or possible with average effort

= average structure/partially degraded, excellent prospects and restoration easy or possible with average effort

= average structure/partially degraded, good prospects and restoration easy

C: average or reduced = all other combinations conservation d. Global assessment of the value of the site for conservation of the natural habitat type concerned ( including contribution to range) .

The 'best expert judgment' may be used to assess this global value, and the ranking system used to express it should be as follows: A : excellent value B : good value C : significant value

Species a. Size and density of the population of the species present on the site in relation to the populations present within national territory

A: 100% >= p > 15% B: 15% >= p > 2% C: 2% >= p > 0%

Furthermore, all cases where a population of the species concerned is present on the site in question in a non-significant manner must be indicated in a fourth category.

D: non-significant population

In cases where the site representativity for the population concerned is classes "D: nonsignificant", no other indication is required for the other evaluation criteria concerning this habitat type on the site in question. In these cases the criteria "Conservation" "Isolation" and Global evaluation" should not be marked .

26 Version 12: 9th April 2009 b. Degree of conservation of the features of the habitat which are important for the species concerned and restoration possibilities This criterion comprises two sub-criteria: i) degree of conservation of the features of the habitat important for the species ii) restoration possibilities

i) Degree of conservation of the features of the habitat important for the species I: elements in excellent condition II: elements well conserved III: elements in average or partially degraded condition

In cases where the sub-class "I : elements in excellent condition" or "II: elements well conserved" is given the criterion B.b) should in its totality be classed "A: excellent conservation" or "B: good conservation" respectively. Independent of the grading of the other sub-criterion.

ii) Restoration possibilities. For this sub-criterion, which only needs to be taken into account when the elements are in an average or partially degraded condition, an approach analogous to that of criterion A.c.iii), should be used, adding an evaluation of the viability of the population under consideration. This should result in the system of grading as follows:

I: restoration easy II: restoration possible with average effort III: restoration difficult or impossible

Synthesis applying to classification of the two sub-criteria

A. conservation excellent = elements in an excellent condition, independent of the grading of the possibility of restoration

B: good conservation = elements well conserved independent of the grading of the possibility of restoration

= elements in average or partially degraded condition and restoration easy

C: average or reduced = all other combinations conservation c. Degree of isolation of the population present on the site in relation to the natural range of the species

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A: population (almost) isolated B: population not-isolated, but on margins of area of distribution C: population not-isolated within extended distribution range d. Global assessment of the value of the site for conservation of the species

A 'best expert judgment' may be used for this global evaluation, using the following ranking system: A : excellent value B : good value C : significant value

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Appendix B Figure 4: Proposed consultation map for the Sound of Barra SAC boundary

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Appendix C Figure 5: Map showing the qualifying habitat interests within the Sound of Barra (Harries et.al. 2007)

SOUTH UIST

ERISKAY

BARRA

Kilometres

30