State of Nature 2024 - Freshwater Fish

The Isle of Man’s freshwater environment supports nine known fish species: European Eel, Brown Trout, Sea Trout, Atlantic Salmon, River Lamprey, Brook Lamprey, Three-spined Stickleback, Nine-spined Stickleback and Minnow. Of these native species, five are known to be of conservation concern. The European Eel and the Atlantic Salmon are of greatest conservation concern, followed by amber listed River Lamprey, Brook Lamprey and Sea Trout.

Salmon and Sea Trout are classed as migratory species, spending part of their lifecycle at sea. The main rivers frequented by these species are the Sulby River in the north, the Neb which flows into the sea at Peel and the rivers Dhoo and Glass which enter the sea at Douglas. Over the past 10 years, Brown Trout populations have remained stable with 80% of monitored sites showing grades within excellent to average densities. Salmon scores were excellent to average in only 40% of sites monitored.