West Coast of Outer Hebrides Special Protection Area: business and regulatory impact assessment

An assessment of the business and regulatory impacts of classifying the West Coast of Outer Hebrides Special Protection Area.

Purpose and intended effect

Title of Proposal
West Coast of the Outer Hebrides 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 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.

The West Coast of the Outer Hebrides proposed Special Protection Area (pSPA) is located along the western seaboard of the archipelago of the Outer Hebrides, from the island of Scarp, off north west Harris, west of North Uist, Benbecula and South Uist to the island of Sandray south of Barra (Figure 1). The pSPA encompasses most of the marine waters within the Sound of Harris and the Sound of Barra.

The area included within the pSPA supports a population of European importance of the following Annex 1 species:

  • Great northern diver (Gavia immer)
  • Red-throated diver (Gavia stellata)
  • Black-throated diver (Gavia arctica)
  • Slavonian grebe (Podiceps auritus)

It also supports migratory populations of European importance of the following species:

  • Common eider (Somateria mollissima)
  • Long-tailed duck (Clangula hyemalis)
  • Red-breasted merganser (Mergus serrator)

The West Coast of the Outer Hebrides pSPA comprises in total an area of 1321.7km2

Parts of the west coast of the Outer Hebrides, notably Harris, Lewis and some locations to the south of the island chain, have steep rocky shores and seacliffs bordered by deep water. However, much of the west coast consists of extensive lengths of calcareous sandy shore with numerous sheltered bays and inlets for birds to moult, roost, rest and feed. Sea depths within 10 kilometres (km) of the west coast are shallow and rarely greater than 30 metres (m), with the seabed gently and consistently falling to an eventual depth of 120m. The waters to the west of the islands are supplied with little sediment from the land or from tidal currents (Barne et al. 1997). The seabed sediment is generally thin, often less than 5m in depth and comprises mostly of shell-sand with some gravel. Further offshore, outside the soft sediments, extensive outcrops of bedrock occur.

This coast supports one of the largest unbroken expanses of kelp forest in Scotland and together with the mixed sand and gravel sediments these habitats are likely to support a diverse range of animal communities including molluscs, crustaceans, pelagic and demersal fish species.

Divers, Slavonian grebe and red-breasted merganser feed on a wide variety of fish that are associated with a range of seabed substrates. These birds catch fish by diving from the surface and pursuing their prey underwater. The fish species taken will be influenced by what is locally most readily available, but the diet of divers and mergansers can include haddock Melanogrammus aeglefinus, cod Gadus morhua, herring Clupea harengus, sprats Sprattus sprattus and gurnard Eutrigla gurnardus along with smaller species such as sand-eels Ammodytidae, pipefish Syngathidae, gobies Gobiidae, flatfish Pleuronectidae and butterfish Pholis gunnellus.

Slavonian grebe feed on small fish species but their diet also includes small amphipods and other crustaceans. Great northern divers also feed opportunistically on small crustaceans.

Common eider and long-tailed duck feed almost exclusively on molluscs and small crustaceans, diving from the surface to pluck their prey from the seabed.

Diving activity varies among species but average foraging dive depths for most are shallower than 15m. However, substantially greater maximum dive depths have been recorded for some species, particularly great northern diver (maximum dive depth of 55m; Ropert-Coudert et al 2016).

The presence of high densities of wintering waterfowl in the West Coast of the Outer Hebrides is indicative of the importance of these shallow and productive waters that also offer relatively sheltered areas. Eider are resident throughout the year, but long-tailed duck, great northern diver, black-throated diver and Slavonian grebe migrate long distances from their northern breeding grounds to reach wintering grounds such as the West Coast of the Outer Hebrides. Red-breasted mergansers are typically short distance migrants, using coastal areas in winter.

The Outer Hebrides are a stronghold for breeding red-throated diver which feed almost exclusively at sea within a limited foraging range. During the summer months, the West Coast of the Outer Hebrides is an important foraging area for a high concentration of red-throated diver nesting territories on adjacent islands including Mointeach Scadabhaigh SPA.


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 designating 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 designating the proposed West Coast of the Outer Hebrides 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.


Email: marine_conservation@gov.scot

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