Nature Diary: European eels
One of our most threatened native fish species now regarded as ‘critically endangered’
European eels: spend several months travelling from their spawning grounds in the North Atlantic
Now is the time of year to look out for young glass eels (or elvers) in Irish rivers and canals.
These tiny worm-like creatures spend several months travelling from their spawning grounds in the mid-North Atlantic. Arriving in European waters, they swim into estuaries and move upstream to spend between nine and 14 years in our rivers.
They come out at night to feed on earthworms, slugs and snails and then hibernate each winter in the mud bed of rivers. Over time, they transform into yellow eels (brown/black to olive green with yellowish underside) before maturing fully into silver eels (purplish black in colour).
Then, they will head back downstream to the sea and swim with the currents across the Atlantic Ocean to mate and die in the Sargasso Sea in the Gulf of Mexico. In 2011 the European eel was classified as ‘critically endangered’ on the All-Ireland IUCN Red Data List for Freshwater Fish, Amphibians and Reptiles, making it our most threatened native fish species.
It’s illegal to catch them and the ESB has been urged to create safe passages through the hydroelectric turbines on the River Shannon.