Pisces (Fish)
Over 1,000 species of fish have been recorded in the north-eastern Atlantic and North Sea but only 90 species of bony fish have been recorded in Hebridean waters, although this list is incomplete. At least 18 species of shark occur in Scottish waters, but only five species, including skates and rays, have been recorded in Hebridean waters.
There are only six indigenous freshwater species as only euryhaline species were able to colonise the lochs after the last glaciation.
Over 1,000 species of fish have been recorded in the north-eastern Atlantic and North Sea but only 90 species of bony fish have been recorded in Hebridean waters, although this list is incomplete. At least 18 species of shark occur in Scottish waters, but only the dogfish and the basking shark have been recorded in Hebridean waters along with cuckoo and thornback rays.
After the last glaciation, only euryhaline fish were able to colonize the Outer Hebridean fresh water lochs; therefore, there are only six indigenous, freshwater species: salmon, trout, charr, three- and ten-spined stickleback and the freshwater eel. Some lochs are periodically invaded by the sea and 20 marine species have been recorded in inland waters. Both salmon and sea trout occur in all the larger freshwater systems and sea trout are in many of the minor ones. Brown trout and eels are widely distributed, whereas charr are found only in Lewis and parts of North Uist.
Additional Information
The Marine Life Information Network
Knowledge of the Marine Environment. Part 2: Seas