Protected areas for mobile marine species: consultation on proposals to designate four new Marine Protected Areas in Scottish waters

Sea of the Hebrides pMPA

Site description

Sea of the Hebrides pMPA is the largest of the four sites, and is proposed to protect basking sharks, minke whales, fronts and geodiversity features. Fronts are created by cool nutrient-rich water mixing with shallow warmer water. They are areas of high productivity and create feeding grounds for predators of all shapes and sizes. Minke whales are the smallest member of the baleen whales, which feed by engulfing large mouthfuls of fish such as sandeels and sieving out water through their baleen plates. Basking sharks are the second largest species of fish in the world and feed solely on zooplankton.

Conservation Objectives and Management Advice

The conservation objectives of this site are to conserve the features, meaning to keep the status of the features in favourable condition. This does not include where there is alteration of the feature through natural processes.

Basking sharks are considered to be most sensitive to collision with vessels, and somewhat sensitive to entanglement in fishing gear and disturbance from underwater noise. Minke whales are sensitive to underwater noise (leading to disturbance and possibly injury), entanglement in fishing gear and collision with vessels. SNH also note the importance of sandeels as prey species of minke whales within the site.

SNH advises that, in order to conserve basking sharks and minke whales, risk of injury and death should be minimised, access to resources within the site should be maintained, and supporting features should also be conserved.

The management advice to reduce these pressures includes:

• Use of best practice to reduce risk of boat collision;
• Reduce disturbance from noisy activities through best practice mitigation;
• Exclusion of drift and set net fishing gear;
• Further development and adoption of best practice to avoid entanglement in creel ropes;
• Management of fishing activities for key prey species e.g. herring and sprat;
• Exclusion of targeted fishing for sandeels;
• Use of best practice to reduce fishing bycatch;
• Consideration of new or altered ferry routes to reduce collision risk; and
• Minimising impacts to sandeel habitat through appropriate siting of new developments.

Fronts could be sensitive to changes to tidal flow and seabed topography. SNH advises that, in order to conserve fronts, the extent and distribution of the feature, functions of fronts and supporting processes should be maintained. There is no management advice for fronts.

The geodiversity feature, marine geomorphology of the Scottish shelf seabed, is sensitive to physical change through sediment removal and temperature changes. SNH advises that, in order to conserve this feature, the extent and integrity of the feature should be maintained, functions of the feature should be maintained and the surface of the feature should be unobstructed. The management advice to reduce these pressures recommends avoiding impacts on the most sensitive, carbonate-producing habitats (such as maerl beds and horse mussel beds) by considering siting of new developments and reducing intensity of static gear within the feature.

Sustainability Appraisal

The SEA concluded that, under the intermediate management scenario, designation of the Sea of the Hebrides pMPA could have a minor beneficial impact on the environment and provide potential for future benefits. The negative impacts from fishing displacement would be negligible and these would be outweighed by the environmental benefits of reducing fishing pressures and replacement of some ADDs.

The SEIA found that the total economic cost from the Sea of the Hebrides pMPA, under the intermediate management scenario, could be £16,000 in GVA impacts (related to commercial fishing impacts) and £344,000 to all other sectors. The sectors with the greatest economic impacts would be finfish and shellfish aquaculture, and ports and harbours. Table 4 shows the cost impacts from the Sea of the Hebrides pMPA for relevant sectors. The principal costs to finish aquaculture under this scenario would be the cost of replacement of ADDs with 'cetacean-friendly' models and the increased assessment costs. The latter is also the source of costs to ports and harbours, and shellfish aquaculture.

Table 4: Quantified Economic Costs for the Sea of the Hebrides pMPA (£'000) costs discounted over assessment period (2019-2038), 2019 prices