The occurrence of the barnacle Elminius modestus in Shetland

Abstract

During surveys of rocky shores in Shetland, the Australasian barnacle Elminius modestus was found at 3 out of 42 transect sites and at 6 out of 11 shores searched for its presence. Large populations were present only in Vidlin Voe with a few individuals present at other sites including Lerwick Harbour. These observations extend the northern recorded limit of distribution of E. modestus by approximately 450 km.The spread of the Australasian barnacle Elminius modestus Darwin along the coasts of the British Isles has been followed with interest by marine biologists since the animal was first found in the region of Portsmouth in 1946. Crisp (1958) describes the spread of Elminius up to 1957 and reviews the factors which are important in encouraging or restricting the spread of the species. On the west coast of Scotland, Elminius is common in the Clyde and a few individuals have been recorded on settling panels in Dunstaffnage Bay near Oban (Barnes & Stone, 1972). On the east coast of Scotland, Elminius is known to be common in the Firth of Forth and a few individuals have been recorded from the Tay Estuary (Jones, 1961). Thus, the previous recorded northern limit of distribution of Elminius modestus lies at about 56° 30′ N. Our brief report describes how Elminius has now been found in the northernmost part of the British Isles.As a part of the programme designed to monitor the effects of the oil terminal now being built at Sullom Voe on the north-east coast of the Shetland mainland, we have been concerned with the survey of plant and animal populations on rocky shores.