The polychaetes of Lewis and Harris with notes on other marine invertebrates

In July 1976 six rocky littoral sites and eight rocky sublittoral sites in Lewis and Harris were sampled for polychaetes. The sites ranged from those on the exposed west and north coast to more sheltered east coast sites.

A total of 107 species were recorded during the survey and are presented in an annotated species list. Syllidae are the dominant family both in number of species and number of individuals present, although the Serpulidae, Spionidae and Sabellidae are also well represented. Similarity of habitats sampled at different sites makes it possible to relate differences in species composition to the conditions prevailing at these localities. Such comparisons are made for four habitats—Corallina officinalis, sediment under stones on the shore, Laminaria holdfasts and the upper shell valves of Pecten. Twenty polychaete species were found in the C. officinalis habitat, 24 species in sediment under stones on the shore, 61 species in laminarian holdfasts and 22 species on the upper shell valves of Pecten.

In general the sublittoral macroinvertebrate fauna, although lacking the Lusitanian elements found in the warmer waters of south-west England and Ireland, was found to have a high species diversity and to exist in an environment virtually free from man-made pollution.