Eels are highly sought after in China and elsewhere in East Asia and about 350 million are trafficked out of the EU every year.

The trade in eels is worth a staggering €3bn (£2.7bn) annually.

Europol said the majority of arrests were in Spain, France and Portugal.

Eels were once a staple food of the poor but consumption has declined by 95 to 99 per cent in recent decades and they are now endangered.