Other Marine Special Areas of Conservation in Shetland |
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| Mousa - candidate SAC
Mousa has been proposed as a candidate Special Area of Conservation on account of the presence of a large breeding colony of Common Seals Phoca vitulina.
The proposed site includes all the inter-tidal areas, the East and West tidal pools, and all the offshore rocks and skerries. The boundary includes an area of marine waters to a minimum distance of 0.5km offshore, which includes the shallow sub-littoral reef and sandbank communities which are important in maintaining a food supply for the seals. Common Seals usually forage close to haul out sites (within a few kilometres), and the marine area has been selected on this basis.
Yell Sound Coast - candidate SAC
The Yell Sound coast has been identified as a candidate Special Area of Conservation on account of its large concentration of otters Lutra lutra
Otters are found in coastal areas throughout Shetland but one of the greatest concentrations occurrs in the area around Yell Sound. They prefer low rocky coastlines with shallow water, feeding mainly around kelp beds on inshore fish such as eelpout, rockling and butterfish. Their holts (hadds) are usually dug out of soft peaty banks near the shore. A holt is a tunnel system used by Otters for resting, sheltering and breeding. Although Shetland otters spend many of their active hours in and around the sea, their coats are not designed for prolonged immersion in seawater. To keep their fur water-proof they must regularly bathe in fresh water burns, pools or lochs.
This site has been chosen because it supports almost 20% of the otters in Shetland and includes areas of the highest population density. The areas within the site contain the natural features essential for a thriving otter population - low rocky coastline, areas of peaty moorland and numerous sources of fresh water.
This site is proposed as a candidate Special Area of Conservation because it is an outstanding example of a complex lagoon system with a wide range of water conditions, substrata and diverse associated communities of marine life
The system comprises five shallow basins, up to 6 metres deep, and is extremely sheltered and undisturbed by human activity. The basins are separated from Brindister Voe and each other by shallow rock, boulder or shingle narrows, several of which are exposed at low tide. Salinity varies from brackish to fully marine and there is a gradation of habitats from still to fast-flowing water and from soft, peaty mud through coarse sediments including maerl to bedrock and boulders.
The small areas of extremely sheltered littoral sediment support filamentous green and brown algae and there are several beds of the tasselweed Ruppia maritima. The diversity of communities and species is high, particularly considering the lagoon's northern location and relatively small size. The Vadills contains several species rare or unknown elsewhere in Shetland, including the free living brown algae Ascophyllum nodosum f. mackaii which is known only from this single location is Shetland.
The Vadills is similar to the lagoons of the Outer Hebrides but, being in an area similar to sub-arctic seas, it differs in the composition and diversity of communities. It is the most complex and least disturbed lagoon system in Shetland and is unique in the British Isles.
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Common Seals are a widespread species on a global scale, though the sub-species Phoca vitulina vitulina is restricted to the North-East Atlantic. The United Kingdom supports about 40% of the population of this subspecies, with Shetland supporting about 25% of the UK population. Of the areas studied within Shetland, Mousa has been shown to support the largest single aggregation of breeding Common Seals. Recent counts indicate a population of about 600 breeding females (which equates to about 2% of the UK population and 1% of the European population). As Common Seal pups take to the sea shortly after birth in mid-summer however, accurate counts are difficult.
Although abundant in Shetland, the otter is one of the most threatened mammals in Europe where it has disappeared from large areas and become rarer in others. About 14% of the total UK otter population is found in Shetland - it forms a very important part of the European total and is of national and international importance. As Shetland otters are isolated from those elsewhere in their range, they may also be a genetically distinct race - they are smaller and have more clearly marked white throat patches.