Millions of eels journey from Bermuda to Britain and back
27 March 2015 Last updated at 09:27 GMT
Millions of eels have been arriving in the south-west of England having travelled thousands of miles from the Sargasso Sea near Bermuda.
After a decade spent in British waters they will attempt to return.
However, man-made obstacles have been getting in their way and some conservationist are trying to help.
Tim Muffett reports.