In the following sections, ‘status and monitoring value’ summarizes the extent of our current knowledge of the biotope complex in each SAC, makes a provisional assessment of the relative importance of the site from a conservation-related perspective, and assesses its usefulness to a brittlestar bed monitoring scheme of the type outlined in a previous section.

The presence of an Ophiocomina bed has been noted. This was recorded on algal-crusted rock ridges at about 25 m depth (Howson, 1988). The substratum, depth, and the strong tidal streams in the Sound of Papa indicate that use of an ROV would be the most appropriate means of gaining further information on the extent and density of brittlestar aggregations here. This might be a good site to include in a monitoring programme, as it occupies a near-pristine environment close to the northern geographic limits of the UK. The diverse bed off the island of Foula (Howson, 1988) should also be investigated further, owing to the unsusually high diversity of brittlestar species recorded in it.

There are probably no likely human impacts in this area, other than those associated with unpredictable major pollution events such as the Braer oil spillage.

Brittlestar aggregations here appear to be localized and not very extensive. Their conservation importance in this area (and value for monitoring purposes) is therefore probably low.

The density of human habitation in the Loch nam Madadh area is low. Lochmaddy township discharges some sewage into the loch. There are a number of sites leased for salmon or shellfish cultivation, all in the outer islands and channels of the loch system (Howson, 1991). A small amount of fuel oil contamination and general marine litter is likely to arise from the ferry terminal and other boating activities in Lochmaddy Harbour. Significant human impacts on brittlestar aggregations in the area appear unlikely.

The state of knowledge of the biotope complex in this area essentially mirrors that described above for Loch nam Madadh. The brittlestar aggregations appear to be confined to rock and boulder patches, and occupy only a small proportion of the benthic environment. This site is therefore not of major importance for these biotopes.

Small discharges of sewage effluent take place from housing in the Arisaig area, but the local population density is so low that the effects of this will be minimal (Howson, 1990). Sites have been leased for salmon and shellfish farming in Loch Ailort, Loch Ceann Traigh and Loch Moidart, and there are further experimental aquaculture-related activities in and around the Sea Fish Industry Authority research station at Ardtoe. The effects of aquaculture are likely to be limited to areas of restricted water circulation in upper Loch Ailort and the north channel of Loch Moidart. As in Loch nam Madadh, there are probably no current management concerns relevant to brittlestar beds.

The biological diversity and recognized conservation importance of Strangford Lough have led to its major biotopes being mapped in some detail (Erwin, 1977; Magorrian et al., 1995). Ophiothrix and Ophiocomina aggregations are extensive, occupying a large area towards the mouth of the lough. Strangford Lough is therefore a potentially useful site for monitoring of these features. The work of Magorrian et al. (1995) shows that RoxAnn ^TM is an effective tool for mapping the extent of these dense beds.

Strangford Lough supports a much larger human population than any of the Scottish SACs discussed above. The largest town is Newtownards on the northern shore. Other villages contribute to a total lough-side population of about 60,000. There are seven main sewage outfalls discharging effluent after various degrees of treatment (Service, 1993). The finer sediments have an organic carbon content mostly in the range 2 - 5% (one station with a value of 6.8% was found). The sediments therefore have a high organic content, but are within the range recorded for naturally-enriched sea loch sediments. It would be interesting to monitor the extent and density of the brittlestar beds in relation to any future changes in the volume of organic effluent discharged into the lough.

Some parts of Strangford Lough have been heavily impacted by trawling for the queen scallop Aequipecten opercularis (Service & Magorrian, 1997). The greater part of the area showing the physical effects of trawl activity lies to the north of the lough’s brittlestar beds, and so far these appear not to have been damaged.

Little has been recorded concerning the extent and history of the Ophiothrix beds in this area. The observation that the bed on Roa Island appears to be expanding is interesting and deserves further investigation, particularly with respect to the effect that this may have on the existing benthic communities. The Irish Sea coasts in this area experience a variety of significant human impacts, including sewage pollution, and monitoring of brittlestar beds here could usefully add to our presently limited knowledge of the effects of human-induced environmental change on this biotope.

There is no detailed information available on the extent of brittlestar beds around the Llyn Peninsula. This situation could be rectified using a combination of RoxAnn^TM, diving and ROV surveys. The relative importance of the area for the biotope and its potential as a monitoring site cannot therefore be assessed at present.

The overall human impact on brittlestar beds around the peninsula is likely to be very low at present. Expansion in oil or gas extraction in the Irish Sea may be the most likely future source of concern, if any developments take place in this particular area.

The Ophiura aggregations in the Wash are well-documented but have not been subjected to detailed scientific study. Little is known of their dynamics but they could form part of a monitoring programme for the site. Visual observations or remote sampling would be the required methods, as beds of this kind are unlikely to be detected by acoustic surveys.

The Wash is subjected to a wide variety of human influences. The lack of detailed information on the ecology of the Ophiura aggregations precludes any current assessment of the likely impact of human activities upon them.

Brittlestar beds have been shown to be very extensive along this coast, occurring on a variety of substrata, and to include examples dominated by Ophiothrix fragilis, Ophiocomina nigra and Ophiura albida (Pagett, 1984; Foster-Smith et al., 1996). This candidate SAC probably contains some the best examples of such beds in any of the ‘demonstration’ sites, and should therefore be included in any planned monitoring programme.

The benthic biotopes in the area must experience some sewage input from the coastal communities, but this is unlikely to be of much significance along this open, current-swept coastline. Overall, however, the North Sea is heavily influenced by human activities, and it would be valuable to have long-term data on the response of brittlestar beds to future trends in water quality and pollutant concentrations along this coast.

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