European eel (Anguilla anguilla)
The European eel can be found in many rivers in the SLRT area, although they maintain a low profile and are not often seen by anglers. It is a catadromous species, meaning it spawns in the sea but migrates into freshwater to feed and gain condition before returning to the sea to spawn. The spawning grounds of the European eel are located in the Sargasso Sea (in the North Atlantic Ocean), meaning that eels found in Skye and Lochalsh rivers have travelled approximately 5,000 km.
There are still many unanswered questions about the life cycle of the European eel. Adult eels lay their eggs in the Sargasso Sea, and it is thought that the eggs are carried by the Gulf Stream towards the European Continental Shelf. The eggs hatch during this stage of the journey and young eels emerge and continue to be carried by currents toward the Shelf. Once young eels enter freshwater rivers (normally in May and June), they darken in colour and are referred to as elvers. These elvers will utilise both brackish and freshwater habitats. After the initial entrance into freshwater, eels will feed and grow in these habitats at which point they are referred to as yellow eels. Yellow eels can remain in freshwater for up to 20 years. Once the eels are ready to spawn, they re-enter the marine environment and begin their migration back to the Sargasso Sea. Eels in this final life stage are called silver eels, referring to their silvery colour.
Similarly to Atlantic salmon and brown trout, numbers of European eels are in decline across Europe and as a result they have been listed as a Threatened Species on the IUCN Red List.