Northern Isles Area THE AYRES OF SWINISTER Ground Floor Stewart Building Site of Special Scientific Interest Alexandra Wharf Lerwick SITE MANAGEMENT STATEMENT ZE1 0LL Tel: 01595 693345 Site code: 1528 Fax: 01595 692565

Purpose

This is a public statement prepared by SNH for owners and occupiers of the SSSI. It outlines the reasons it is designated as an SSSI and provides guidance on how its special natural features should be conserved or enhanced. This Statement does not affect or form part of the statutory notification and does not remove the need to apply for consent for operations requiring consent. We welcome your views on this Statement.

Natural features of Condition of feature The Ayres of Swinister SSSI (date monitored) Coastal Geomorphology of Scotland Favourable, maintained (December 2006)

Features of overlapping SSSI Condition of feature Designation or Natura sites that are not (date monitored) (SAC or SPA or SSSI) notified as natural features of The Ayres of Swinister SSSI Common seal (Phoca vitulina) Favourable, maintained Yell Sound Coast SAC (August 2001) Otter (Lutra lutra) Favourable, maintained Yell Sound Coast SAC (June 2004) Otter (Lutra lutra) Favourable, maintained Yell Sound Coast SSSI (June 2004)

Description of the site The Ayres of Swinister Site of Special Scientific Interest is located at the seaward end of Dales Voe in Delting, in the north-east Mainland of Shetland. It can be seen clearly from the A968. The site represents an almost unique assemblage of three coastal landforms connecting the island of Fora Ness with the mainland. These include a good example of a shingle tombolo, along with a bay-head bar and a mid-bay bar. Tombolos and bars are formed by the deposit of sediments. Tombolos are narrow necks of land that connect an island to the mainland. They are generally formed of shingle, although rarely they comprise sand (e.g. St. Ninian’s). Bars are elongated landforms resulting from an accumulation of sediments and orientated

1 parallel to incoming waves. They are classified into two types: bay-head bars and mid-bay bars. Bay-head bars are formed where sediment is swept to the head of the voe by continual erosion and transport of material making up the enclosing cliffs, and by wave action on the sediment of the seabed. The origin of mid-bay bars is similar, but they are believed to have formed at a slightly lower sea level. That is, they were once bay-head bars when sea-level was lower (and therefore located further down the voe) but have since been inundated by the sea. The shallow lagoon area between the ayres contains extensive deposits of submerged peat, which provide some of the clearest evidence in the form of plant remains of the sea level rise that has affected Shetland since the last glaciation. As a result the site is an excellent locality to study the submergence of Shetland. The enclosed area of the Houb is a Marine Consultation Area, a non-statutory designation which recognises high quality and sensitive marine habitats and species. It is an unusual habitat with rarely encountered brackish conditions and communities characteristic of shallow but extremely sheltered coastal waters. The tidal channel at the south-east end of the North Ayre is regarded as one of the best examples of a gravel rapids community in Shetland, and contains a rich diversity of species, particularly molluscs. The site was monitored in December 2006 and was found to be in favourable condition. Natural processes were not disturbed. Extent and composition of the features had been maintained and were clearly visible.

North Ayre South Ayre

Past and present management North Ayre is currently used as a base for operations relating to the fish farm in Swinister Voe. Shore-based operations are restricted by conditions imposed on the planning consent (1989). These ensure that materials from the ayre are not used in any development/construction and that routine operations are restricted to an agreed area. A feed store is located at the north- west end of North Ayre. South Ayre is used only for the passage of sheep to the island of Fora Ness. In the past, peat was cut on the south-east side of the Houb, and it is likely that the whole area was used for rough grazing. The presence of ancient buildings on the North Ayre may indicate fishing-related activity in former times. The house at Newhall was originally built by a laird, but has now fallen into a state of disrepair.

Objectives for Management (and key factors influencing the condition of natural features)

2 We wish to work with the owners and occupiers to protect the site and to maintain and where necessary enhance its features of special interest. SNH aims to carry out site survey, monitoring and research as appropriate, to increase our knowledge and understanding of the site and its natural features. The EU Habitats and Birds Directives oblige Government to avoid, in SACs and SPAs, the deterioration of natural habitats and the habitats of species, as well as disturbance of the species for which the areas have been designated, where such disturbance could be significant in relation to the objectives of these Directives. The objectives below have been assessed against these requirements. All authorities proposing to carry out or permit to be carried out operations likely to have a significant effect on the European interests of this SSSI must assess those operations against the relevant Natura conservation objectives (which are listed on our website through the SNHi – SiteLink facility). 1. To allow natural processes of coastal evolution to continue without interruption or physical disturbance to tombolo and bar development The site is dynamic and evolves naturally as the submergence of Shetland continues. Changes tend to be most pronounced during storms and include erosion of the seawards edge of North Ayre, and the overtopping of North and South Ayres by shingle. These result in the steepening of the beach profile and slow migration of the ayre. Although conditions attached to the planning consent aim at minimising impact on the ayres, disturbance may be caused by activities relating to fish farming operations in Swinister Voe. In particular, vehicle tracking on the stable grassed areas of the North Ayre could result in fragmentation of the turf mat, leading to erosion during storms. Besides, the relatively recent construction of a coastal defence structure in the north-west of the site is likely to modify sedimentation and erosion patterns on the North Ayre. 2. To maintain the visual integrity of the landforms and sediments North Ayre serves as a base for aquaculture operations. To reduce visual impact of activities, minimise storage of fish cages and other material and restrict siting of any building or construction to the bedrock/till areas at the mainland end of the ayre. Other factors affecting the natural features of the site Oil Spills: The proximity of Sullom Voe Oil Terminal means that there is a small risk of a significant oil spill on the ayres. In the event that this should ever occur, it will be imperative that no mechanical clean-up operations should take place on the ayres as this is likely to undermine their structure and/or interfere with their evolution. Date last reviewed: 22 February 2011

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