NIEUWENDIJK - On an autumn morning on a small Dutch canal, fisherman Aart van der Waal pulls up a fish trap stuffed with squirming eels - not for the pot, but as part of a bold initiative to save the critically endangered species.
Weighed and recorded, the serpentine swimmers are then carried several hundred metres (yards) across a dike in a plastic bucket, before being released back into the water on the other side with an unceremonious splash.
Once in the Haringvliet, a North Sea estuary some 15 kilometres (nine miles) downstream, the rescued eels will complete their final freshwater swim, before tackling an arduous 7,000-kilometre journey to spawning grounds in the central Atlantic Ocean.
Twice a week, Van der Waal sets out on his flat-bottomed boat to pull up the traps as part of an ambitious plan to help save Europe's decimated eel population, an indicator species for the health of the continent's estuaries and seas.
As part of "Eels Over The Dikes", some 50 volunteers consisting of professional and recreational fishers backed by funds from a fishing-industry foundation, the Dutch government and the European Union, lend a hand to help these mysterious creatures get back to the sea.
Over the last three decades, European eel numbers have been devastated, falling by as much as 99 per cent in some areas, according to EU figures. One of the main reasons is that eels, which migrate from sea to fresh water and back, often find their paths blocked or are killed or injured when they swim through pump houses, sluice gates or hydro-engineering projects. Poaching and over-fishing, pollution and climate change also play a role in the decline of the eel population, which "European member states are doing too little to save," European MPs said last month.
Young transparent eels are known as "glass eels" and they have become particularly prized in Asia over the last 15 years, mainly to be fattened in farms, as a result of which the price of glass eels in the mid-2000s exceeded that of caviar.
The European eel (Anguilla anguilla) is now listed as critically endangered by the International Union for Conservation of Nature (IUCN) on its Red List of Threatened Species.