Seas off St Kilda Special Protection Area: business and regulatory impact assessment

An assessment of the business and regulatory impacts of classifying the seas off St Kilda Special Protection Area.

Purpose and intended effect

Title of Proposal: Seas off St. Kilda Special Protection Area (SPA)


The Scottish Government is committed to a clean, healthy, safe, productive and biologically diverse marine and coastal environment that meets the long term needs of people and nature. In order to meet this commitment our seas must be managed in a sustainable manner - balancing the competing demands on marine resources. Biological and geological diversity must be protected to ensure our future marine ecosystem is capable of providing the economic and social benefits it yields today.

The EU Wild Birds Directive (2009/147/EC as codified) requires Member States to classify as Special Protection Areas (SPAs) the most suitable territories for wild birds. Building on the work of the SPA Review Working Group and taking account of existing guidelines on the identification of SPAs (JNCC, 1999), Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) have identified 14 sites which they consider essential for marine SPA status. These proposals include sites supporting wintering waterfowl, important areas for red throated divers, terns, European shag and foraging seabirds.

The Seas off St. Kilda SPA is located in Scottish marine waters situated about 50 km northwest of North Uist in the Western Isles of Scotland. It covers 3,995 km2 of mainly offshore waters and encloses the St Kilda archipelago, consisting of the four islands of Hirta, Dun, Soay and Boreray, and the sea-stacs of Stac an Armin, Stac Lee and Levenish.

Seas off St. Kilda SPA supports regularly occurring populations of European importance of the following migratory species, foraging at sea during the breeding season:

  • northern gannet (Morus bassanus),
  • northern fulmar (Fulmarus glacialis) as part of an assemblage,
  • common guillemot (Uria aalge) as part of an assemblage, and
  • Atlantic puffin (Fratercula arctica) as part of an assemblage.

Seas off St Kilda SPA supports regularly occurring populations of national importance of the following Annex 1 species, foraging at sea during the breeding season:

  • European storm-petrel (Hydrobates pelagicus) as part of an assemblage.

In the site, water depths range mainly between 40m and 410m; shallow areas with less than 100m depth occur only at the very east of the site, while depths of more than 250m are reached only in the northwest (see Figure 2). The bathymetry shows that Seas off St Kilda SPA lies very close to the continental shelf edge, with water depth quickly increasing to the west and to the north of its limits. Shelf-break fronts are a typical phenomenon at the shelf edge and, like almost all fronts, are regions of enhanced plankton production, leading to a higher fish production (Mann and Lazier 1991). Shelf edges might also have a function in concentrating marine organisms both in acting as a barrier to species confined to shallower waters, and as a geological feature guiding the migration of fish species (pers. comm. D. Tobin).

The combined effect of current and waves creates low-energy seabed environments in most of the site. In the vicinity of the archipelago, however, moderate-energy seabed environments also occur (McBreen et al. 2011). In the southwest of the site, rock and reef habitats are prevalent; the northwest is dominated by a mosaic of subtidal coarse sediments and sand and muddy sand habitats (McBreen et al. 2011).

Like most of the continental shelf edge, Seas off St Kilda is an area of high intensity nursery grounds of mackerel Scomber scombrus (Coull et al. 1998; Ellis et al. 2012). Northern gannets typically have a highly varied fish diet (Nelson 2002) and common species consumed in UK waters include mackerel Scomber scombrus, sandeel Ammodytes marinus, sprat Sprattus sprattus and herring Clupea harengus (Hamer et al. 2000).


The EU Wild Birds Directive requires member states of the EU to identify SPAs for:

  • rare or vulnerable bird species (as listed in Annex I of the Directive); and
  • regularly occurring migratory bird species.

And to do so in the geographical sea and land area where the Directive applies.

The EU Wild Birds Directive was adopted in 1979 by the EU member states due to increasing concerns about declines in Europe's wild bird populations caused by pollution, loss of habitats and unsustainable exploitation. The EU Wild Birds Directive recognises that wild birds, many of which are migratory, are a shared heritage of the member states and that their conservation needs international co-operation. The creation of a network of protected sites, including SPAs, is one of several conservation measures that contribute to the protection of rare, vulnerable and migratory bird species.

Further work is required to complete a marine UK-wide network of SPAs at sea in order to meet the needs of seabirds and waterfowl. The Joint Nature Conservation Committee (JNCC) has been working over the past decade on behalf of all the countries’ Statutory Nature Conservation Bodies (SNCBs) to complete a programme of data collection and analysis to inform the provision of advice on possible sites. Natural England, Natural Resources Wales, and the Department of Environment Northern Ireland (DoENI) are considering several possible marine SPAs in English, Welsh and Northern Irish inshore waters, including extensions to existing seabird colony SPAs and entirely marine SPAs.

The network of marine SPAs in Scotland is being progressed by Scottish Natural Heritage (SNH) where these fall largely within 12 nautical miles from shore and by Joint Nature Conservation Committee (JNCC) where they fall largely beyond 12 nautical miles. SNH and JNCC have identified 14 sites which they consider essential for the completion of a list of marine SPAs. These proposals include sites supporting wintering waterfowl, important areas for red throated divers, terns, European shag and foraging seabirds.

Evidence in this BRIA is drawn from the work of statutory nature conservation bodies and consultants ABPmer and eftec[1]. It brings together the science-led arguments for classification and the projected potential social and economic consequences of such action. This will inform Scottish Ministers of the possible impacts of classifying the SPA, and due to requirements of the Birds Directive this will be for informational purposes only as the decision to classify SPAs can only be on the basis of scientific evidence. The site has been identified for classification as an SPA due to the confirmed presence of biodiversity features detailed above.

This BRIA examines the socio-economic impact of classifying the Seas off St. Kilda site as an SPA. The assessment period covers the 20 year period from 2015 to 2034 - reflecting the time horizon within which the majority of impacts are expected to occur. As with any socio-economic assessment related to environmental classifications, the findings should be considered as estimates, and in cases where greater uncertainty exists, such as for fisheries, are deliberately presented as worst-case scenarios to build in necessary caution.
In addition a range of scenarios are presented to account for the inherent uncertainty associated with such proposals. Lower, intermediate and upper scenarios have been developed to reflect the requirements for management measures, the spatial extent of features and the extent to which OSPAR/BAP[2] features are already afforded protection. The intermediate scenario is viewed as the best estimate. The estimated impacts across the three scenarios commonly vary quite significantly.

Rationale for Government intervention

The EU Wild Birds Directive (2009/147/EC as codified) requires Member States to classify as Special Protection Areas (SPAs) the most suitable territories for wild birds. The Scottish Government is responsible for identifying SPAs for Scotland.

In addition, the Scottish Government has a number of international commitments to deliver a network of MPAs. Scotland’s marine environment provides: food; energy sources (wind, wave and tidal power, minerals and fossil fuels); routes and harbours for shipping; tourism and recreational opportunities; and sites of cultural and historical interest. Scotland’s seas contain important distinctive habitats and support a diverse range of species that require protection in order to be conserved or for recovery to be facilitated. Due to the competing demands placed upon Scotland’s marine resources, more effective management is required so that a balance between conservation and sustainable use can be struck. Currently there is not sufficient protection in place to ensure that the marine environment is properly protected and complex ecosystems safeguarded.

The SPAs will form part of an ecologically coherent network of well-managed MPAs that is vital to conserve and regenerate our seas, in turn protecting the many goods and services they provide now, and for generations to come.



Back to top