A different goose barnacle on the Assynt coast
There have been several buoys washed up recently in the Bay of Stoer (NC0328) festooned with goose barnacles. From a photograph taken by Louise Tunstall on 18th November 2020 (photo 1), these appear to be the common goose barnacle Lepas anatifera. This is the largest and most frequently encountered species of some six found in British waters, but we have also had locally the smaller species Lepas pectinata, with finely-ribbed shell plates. Article at this link.
On 14th October, however, Anne Nicoll came across something subtly different on Clashnessie beach (NC0531), adhering to short lengths of egg wrack Ascophyllum nodosum (photo 2). At about 25mm long, the capitulum (shelled part) is about the same size as L. anatifera. However the single median plate, of the five which make up the capitulum, has a conspicuous ‘neb’ or umbo (photo 3) and a disc-shaped base. This identifies it as the buoy barnacle Dosima fascicularis. Definitely a different goose barnacle on the Assynt coast.
It is normally found ‘attached to small or very small objects such as feathers or straws, supplemented in larger specimens by its own float’. This float is secreted by the barnacle and is described as having the ‘texture of expanded polystyrene’.
The buoy barnacle is said to be ‘often stranded on the south and west coast of the British Isles’. However NBN has only two records from mainland Scotland, both on the north coast of Sutherland, at Portskerra Old Harbour (NC878668) on 23rd August 2014 (Mike Kendall) and Balnakeil (NC389692) on 25th August 2014 (Les Pearce, Badnaban). Most of the other Scottish records are from the Inner and Outer Hebrides, with examples in July and August 2020 from Rum and Skye.
Another ocean wanderer wrecked upon our shores, which might have gone unrecorded, if Anne had not gathered it up.