Salmon and freshwater fishes of the Inner Hebrides

Abstract

SynopsisApart from limited studies on salmon and sea trout no previous investigation of the status and distribution of Inner Hebridean freshwater fishes has been made. Only euryhaline fishes were able to recolonise Hebridean freshwaters after the last glaciation. Thus seven indigenous, freshwater fishes have been recorded in the Inner Hebrides: Atlantic salmon, trout, Arctic charr, three- and ten-spined stickleback, European eel and brook lamprey. Trout occur both as anadromous and sedentary forms but charr as the sedentary form only.Flounders penetrate far upstream and may be found in lochs while grey mullet occur seasonally in streams a short way inland from the sea. In contrast to the Outer Hebrides there are established populations of non-indigenous species; American brook charr occur in lochs only on Eigg and Mull and pike and perch only on Islay.Populations of rainbow trout are artificially maintained. On some small islands, freshwater bodies are temporary so that there are no permanent fish populations while on others, where freshwaters are present as ditches and small streams, only eels can exist. A survey showed that freshwater eels were the most widely distributed fish, followed by trout and three-spined stickleback in that order.Salmon and sea trout are found in all the major river systems and are also caught in nets on the coasts of the larger islands. These coastal fisheries also exploit salmon in passage to river systems elsewhere in Scotland.