Habitat point records from 1988-89 MNCR Loch Linnhe survey

Loch Linnhe forms the submerged western end of the Great Glen Fault which divides the highlands in two between Inverness and Fort William. With Lochs Etive, Creran, a'Choire, Leven and Eil adjoining the main loch it is the largest sealoch system in Scotland. Loch Linnhe opens into the Firth of Lorne and lies at the southern end of the Sound of Mull, off which Loch Aline branches. The area has more coastal development than most west coast lochs, and boasts two of the west coast's principal towns, Fort William and Oban. Its proximity to the Scottish Marine Biological Association laboratories at Dunstaffnage has lead to much research being undertaken in the area, including a major study on the effects of organic enrichment on sealoch benthos. Loch Eil and Linnhe have been studied over 20 years during the lifetime of a pulp mill which discharged waste into Annat Narrows. The area incorporates a wide variety of habitats, with wave exposures ranging from extremely sheltered to moderately exposed, tidal streams from very weak to strong, and salinities from low to normal. Sediments vary from soft muds to gravels, and bedrock and boulders occur down to at least 50 m. The island of Lismore is one of Scotland's largest coastal exposures of limestone. The area, excluding Lochs Leven and Etive, was surveyed in June 1989. With additional information from sites examined in 1988 and from previous studies, a total of 11 littoral and 30 sublittoral communities have been described. Rocky shores were dominated by fucoid algae, with barnacles becoming co-dominant on the more exposed shores. Much of the upper lochs had an impoverished fucoid community on mixed shores of stones and coarse sediment. Sedimentary communities ranged from those in muddy gravel to lugworm and mussel beds, with the tellin Angulus tenuis in cleaner fine sands on the more exposed beaches. In the sublittoral zone, kelp forests of Laminaria hyperborea and Laminaria saccharina, often with a rich undergrowth of red or brown algae, gave way to communities composed of brachipods, hydroids, sponges and ascidians. Brittlestar beds were common in tideswept areas, with horse mussel Modiolus modiolus and flame shell Limaria hians beds developing in the stronger currents. On stoney sediments, burrowing sea cucumbers were common. Fine muddy sands had populations of the bivalve Arctica islandica, and communities of seapens, Amphiura spp. and burrowing megafauna were widespread in the finer muds. From Loch Eil, through upper Loch Linnhe to lower Loch Linnhe there was a gradual increase in species diversity from the brackish reaches of the upper basins to the more exposed and slightly current swept areas adjoining the biologically rich Firth of Lorne. Loch Creran, with its serpulid reefs and other rich communities was rather different in character to the main basins of Loch Linnhe and Loch Eil. Eight communities and twenty-six species are considered to be of interest for their rarity or richness. The Annat Narrows area, a section of upper Loch Linnhe, the Lynn of Lorne including the islands of Lismore and Shuna, and Loch Creran are highly rated for their marine communities. Records currently considered sensitive have been removed from this dataset.

Organization: Joint Nature Conservation Committee