Habitat point records from 1990 UMBSM Harris and Lewis sealochs survey
Six lochs were surveyed by UMBSM/NCC during a visit to Harris and Lewis in 1988 (Howson 1989). Six more were subsequently surveyed in August 1990: Loch Stocknish, East and West Loch Tarbert and Lochs Erisort, Leurbost and Grimshader. Loch Stocknish, on the south-east facing coast of South Harris, is classed as a fjordic `B` type loch by Milne (1972). It is short (4km), has one sill and its inner basin reaches a depth of approximately 40 m. Most of the loch is sheltered from wave action and there are areas of tide_swept sediment in the narrow entrance channels. East Loch tarbert and the Erisort-Leurbost system are classified ad fjords with fjard-like characteristics (Fairbridge 1968). Both have a number of islands protecting the inner loch from wave action and consequently a large range of exposures were encountered in the littoral and sublittoral. East Loch Tarbert has a deep basin (66 m) situated to the north of Scotasay and a tide-swept narrows between Scalpay and South Harris. This loch has extensive areas of shelly sediment which at the time of the survey were being dredged for scallops. Softer muds were found in Loch Ceann Dibig near the head of East Loch Tarbert. Loch Erisort is the longest loch in this series (12 km). It reaches a depth of 56 m near the mouth, but is shallow behind its main sill. It has areas of littoral and sublittoral exposed bedrock but, with Loch Leurbost, was also noted for having a wide range of sediments. At the mouth of Loch Erisort, concealed behind a group of islands, there is a complex of shallow, sheltered channels and small lochs, some of which are brackish. Loch Grimshader is a small (2.5 km) `B` class fjord (Milne 1972) although it has been described as an ob by Earll and Pagett (1984). It has a single basin (maximum depth 13 m), a narrow, shallow, tide-swept entrance and steep bedrock slopes just outside the entrance. West Loch Tarbert is very different in character from the east coast lochs. It is a large open bay, rarely deeper than 30 m and is very exposed to the west. There are no sills, although there is an area of deep water (50 m) in the Soay Sound. The sediments are predominantly muddy sand. There are a considerable number of fish farms throughout these lochs, particularly in Lochs Erisort and Leurbost, and evidence of nutrient overloading was found in localised areas with poor water circulation in Lochs Stocknish, Erisort and Grimshader. There is one SSSI adjoining the north shores of West Loch Tarbert, and the outer region of Loch Erisort is rated as of marine biological importance. Much littoral work has been carried out by Smith (1979, 1982, 1983, 1984) and Powell et al. (1979) but there have been few sublittoral studies in this area. In the present survey seventy nine sites were surveyed, of which 61 were sublittoral (4 where suction samples were taken) and 18 were littoral. Thirty two habitat/community types are described. Infralittoral bedrock communities ranged from rich Laminaria hyperborea forest in the wave and tide exposed areas to dens L.saccharina in the most sheltered regions. In West Loch Tarbert the kelp forest communities were heavily grazed and the deeper communities effected by scour. Examples of exposed circalittoral bedrock with Leptometra celtica, Swiftia pallida and Diazona violacea were found at the entrance to the east coast lochs. Loch Erisort held a particularly wide range of sediment communities including the species-rich sill, the shallow and seemingly undisturbed sediment with dense Virgularia mirablis and Philine aperta and the shallow, soft muds with very large Suberites domuncula. A dense bed of Ocnus planci, rarely found in such numbers, was found towards the head of the loch. Seventeen habitat/community types and 17 species have been provisionally assessed to be of Local, Regional or National importance. Records currently considered sensitive have been removed from this dataset.
dataset
name: 1990-UMBSM-Harris-and-Lewis-sealochs-survey.csv
0152fd74-1c34-40fd-a3f8-c2f33d1e9fd3
eng
Holt (1991) Surveys of Scottish sealochs. Sealochs of the Islands of Harris and Lewis. Part II Earll, Pagett (1984) A classification and catalogue of the sea lochs of the Western Isles Lewis, Powell (1960) Aspects of the intertidal ecology of rocky shores in Argyll, Scotland. II. The distribution of $Chthamalus stellatus$ and $Balanus balanoides$ in Kintyre. Howson (1989) Surveys of Scottish sealochs. Sealochs on the Isles of Harris and Lewis. Greenwell, Perkins (1979) Studies in the distribution and biological impact of the effluent released by Albright and Wilson Ltd., Whitehaven. 5. Trawl and dredge survey, 1977-78 Powell, Holme, Knight, Harvey (1978) Survey of the littoral zone of the coast of Great Britain: Report of the shores of Devon and Cornwall. Smith (1978) Shores of west Inverness-shire and north Argyll with emphasis on the Mollusca. Smith (1982) Littoral Mollusca of Loch Sween and the surrounding area Smith Ed: Boyd, Bowes (1983) Marine Mollusca of Islay and Skye. Smith (1983) The shores of Lewis: Marine flora and fauna.
oceans
Marine
Marine Recorder
JNCCMNCR10000031
Habitat
MNCR
-7.335646778
-6.168197037
58.33266492
57.74925686
1990-08-18
1990-08-31
publication
2007-05-14
This survey was extracted from a Marine Recorder snapshot.
Comma Separated Values
Unknown
Open Government Licence v3.0
no limitations
Digital and Data Solutions, JNCC
custodian
Digital and Data Solutions, JNCC
pointOfContact
2018-05-17