Inland waters in the Inner Hebrides

Abstract

SynopsisThe Inner Hebrides make up only a small proportion of the land area but a relatively higher percentage of the area of standing waters of Great Britain. Analyses of the 1:63,360 maps have provided the total numbers of standing and running waters on the islands (1,542 and 1,615 respectively) and are the basis for estimating the total resource there. The majority of lochs are small and relatively low lying. Most of the streams too are small and rarely larger than 4th order. Chemically, the waters are variable and range from some very acid nutrient-poor lochs on Islay to the unique marl lochs of Lismore. The algae of these islands have only occasionally been sampled and relatively little is known either about the higher aquatic plant communities—the ones studied are similar to those on the mainland. Few studies of the invertebrates of the inland waters have been carried out, and none of the surveys has been comprehensive. A review of the published and new data has enabled a broad account of the invertebrate communities to be presented. Only 15 species of fish occur here and most of the waters are dominated by the indigenous salmonids (salmon, trout and charr), sticklebacks or eels. Comparisons of the inland waters of the Inner Hebrides with those of other island groups (the Outer Hebrides and Shetlands) and the mainland of Scotland (especially Tayside) show that they have greater afiinities with the latter.