Environment Agency Wales (EAW) believes that helping eels in their Welsh habitat is the best chance of keeping a domestic population in the face of huge drops across Europe.
It is estimated that the English and Welsh eel population has collapsed 70% since the 1980s. Eels spawn in the Sargasso Sea in the Caribbean, then make a two year journey on the Gulf Stream to Europe, with historically huge numbers coming into Welsh river systems.
The are an essential part of the ecosystem, acting as food for species such as otters and herons.
Speaking to the Western Mail, Andy Schofield of EAW said: "When elvers are born they are not self-propelling and it takes them two years to drift on the Gulf Stream and ocean currents from the Caribbean across to Wales, where they are filtered into our rivers.
"Some scientists think shifts in the ocean's currents, caused by the El Niño climate pattern, have led to changes in this cycle. Others think changes to the ocean's temperature could have a big impact on them and their food supplies.
"Maybe the plankton they feed on has disappeared and the elvers are ending up as food themselves. They are also prone to a parasite that feeds on their bladders.
"Just 30 years ago there were big eel populations on the River Wye. People were using dip nets to catch elvers and transport them live to the Far East, where they are considered a delicacy."
While it is thought that environmental factors are largely responsible for the drop in eel numbers, those which do make which can be helped.
Mr Schofield went on to say: "We are improving their habitats and making sure that our lifestyles have little impact on their adult lives".
"Eels can cross damp fields at night to get from pond to pond and will leave the water rather than tackle a waterfall, making them easy prey.
"In South Wales, we have created fish passes for salmon and trout, with tiny brushes to help eels make their way up the River Taff and other rivers.
"We believe that eels spend most of their adult lives here before leaving at around seven to 12 years old to return to the Caribbean to spawn."