East Mingulay SAC

The East Mingulay Special Area of Conservation (SAC) is designated to provide protection for reefs

The reef areas to the east of Mingulay in the Outer Hebrides are found within a wide trench in the seabed at depths of about 100 to 250 metres. Nine reef areas have been identified, formed by characteristic mounds on the seabed up to 150 metres high. An area of approximately 26 square kilometres supports reef habitat, including both biogenic and non-biogenic (rocky) reefs. The biogenic reefs, covering an area of about 5.4 square kilometres, are formed of the cold-water coral, Lophelia pertusa. Although L. pertusa is the main reef-forming coral in the northeast Atlantic and as a species is thought to be widespread, it rarely forms reef complexes in inshore waters (within 12 nautical miles of the coast). In fact, East Mingulay is unique in that it is currently the only known area with extensive cold-water coral reefs within UK territorial waters. Most of the East Mingulay Lophelia pertusa reefs form typical biogenic masses that host a large variety of associated species. The remaining reef areas within the site boundary include a rich mix of habitats and species developed on dead coral, boulders, and rocky and cobbly reef structures. Surveys of the East Mingulay reef complex have identified over 400 species, including a sponge Cliona caledoniae which was new to science (Van Soest and Beglinger, 2008). Find more about this SAC here.

This site now has fisheries management in place.

Read our response to the consultation on Fisheries Management measures here:

We do not support Approach 1, which would still permit the use of mobile demersal fishing gear in large parts of the SAC. We support Approach 2: the exclusion of mechanical and hydraulic/suction dredging and demersal trawling from the whole of this SAC, and designated zones closed to creels, long-lining and bottom set nets.

We agree with the management advice for the site, to remove/avoid pressure from mobile demersal fishing gear on biogenic and bedrock reef, and we agree that these activities should be prohibited on and around the reef features. However we are also concerned about the secondary effects of trawling on and around the reef and potential accidental damage by gear snagging. These reef features are unique in UK territorial waters, these being the only known areas of extensive Lophelia pertusa reef in our inshore waters, and such reefs are extremely productive in terms of biodiversity and habitat formation. This is further reinforced by peer reviewed surveys of the site and ocean acidification forecasting, which highlights that as ocean acidification risks dissolving cold water corals starting deeper, the Mingulay reefs present an important shallow water refuge from acidification. This potentially makes them the most valuable Lophelia reefs in the entire EU.

Scientific evidence indicates that biogenic coral reefs are susceptible to damage by smothering, compounded by increases in suspended sediment caused by passing trawls and dredges, and that sediment disturbance can result in changes to anaerobic respiration by sediment biota and alter nutrient exchange processes. Furthermore, the suggested buffer zones are based on trawler warplength and water depth, and just make sure that the trawl does not reach the reef when the vessel is still outside the zone. Seabed in the buffer zone will be trawled. No account is taken of the effects on the reef habitat of sediment re-suspended by trawling and deposited on the reef. East Mingulay reef contains corals and, for example, shark spawning grounds which are sensitive to sediment deposition. The tidal currents in the region are more than strong enough to move suspended sediments several kilometres. This was not taken account of in the designation of East Mingulay SAC due to lack of scientific evidence. From the SNH commissioned designation report:

“More work is required…to assess the effectiveness of this buffer in preventing fine grained
sediments re-suspended by trawling from smothering living reef habitat.”


“Particle re-suspension modelling is required to assess potential impact of sediments re-suspended by
trawling or dredging in the vicinity of the Mingulay cold-water coral reef complex.”

We understand that knowledge of the exact distribution of the reefs has been built up by one or two local skippers who trawl there fairly regularly, but this knowledge is not shared with other skippers.

If part of the SAC were left open to trawling it would be an open invitation for any skipper to come and, if unfamiliar with the area, potentially incorrectly navigate the reefs. This could cause huge amounts of damage particularly as there was also evidence presented that the larger prawns are to be found closest to the reefs. We are also concerned that a 100GRT vessel capacity restriction will have little or no impact on reducing damaging impacts on these smaller patches of reef and the surrounding seabed as the vessels using this area are considerably smaller than 100t. Therefore we support the prohibition of mobile demersal gear from the entire SAC (Approach 2) as a
precautionary approach to ensure the full protection of these reefs.
We acknowledge the management advice to remove/avoid pressure from static fishing gear and we agree that methods, such as creeling, do have some impact on delicate marine structures. However, we also acknowledge that creeling is potentially less damaging to habitats than mobile demersal
gear and we consider it a more environmentally benign practice at sustainable levels. We support Approach 2, which will allow the continuation in areas where the reef features do not occur. We suggest that this should be carefully regulated and licenced to ensure that creeling is carried out at sustainable levels within the designated zones. This arrangement may also provide a useful opportunity to conduct further research on the impacts of creels on seabed habitats, on which there is very little scientific information available, and this should be carefully monitored within the fishing zones (Approach 2) to ensure swift action can be taken if damage by creels to the reef is observed.
We suggest that long-lining and bottom set nets should not be permitted throughout the SAC, due the proximity of this site to known areas for black guilemot (on Vatersay and Barra), basking shark, bottlenose dolphin and grey and harbour seal colonies (Mingulay, Vatersay and Barra). While these
species are not designated for protection within the East Mingulay SAC, they are all Priority Marine Features that may move through or use the SAC sea area and may be at risk of entanglement and/or may be caught as bycatch.
The Outer Hebrides area is popular with wildlife and marine recreational tourism, which is important for the local community, particularly during the summer months. Marine tourism, particularly wildlife watching (for which the Outer Hebrides are a prime location), is a growing industry and has the potential to deliver a range of socio-economic as well as environmental benefits, such as data recording. However this industry relies on the local marine environment to be in good condition, to which well-managed marine protected areas will contribute.

Contact the Save Scottish Seas team

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