(CNN)Two Chinese nationals have been given 10-month suspended prison sentences and fined over $8,000 each for attempting to smuggle live baby eels out of France.
The pair -- a 20-year-old woman and 43-year-old man -- were arrested on Monday at Paris' Charles de Gaulle airport en route to China, after they were found with some 60 kilograms (132 pounds) of the fish concealed in their luggage.
They were carrying juvenile eels, also known as elvers, in specially built containers with hand-held refrigeration devices concealed in their luggage, a spokeswoman from the Bobigny courthouse which handled the case told CNN.
The traffickers were also ordered to pay fines of €7620 ($8,497) and €7455 ($8,313).
The spokeswoman said that a third Chinese national had escaped from the airport, leaving another suitcase containing an additional 30 kilograms (66 pounds) of elvers.
In total, the baby eels had a resale value in China of up to €180,000.
The fish were given by customs to an organization which specializes in protecting the species.
A kilo of European eel can fetch upwards of $5,500 in China. This has led to a spike in smuggling in recent years, with some 15 million specimens seized in the European Union in 2018, mostly in Spain, France and Portugal, according to Europol. This marked a 50% rise on the year before.
The agency estimates that between 300 million to 350 million eels are trafficked illegally from Europe to Asia every year, a trade worth around $3.3 billion.
"Trafficking of the European eel is the world's great wildlife crime in both traded individuals and market value," said Andrew Kerr, chairman of the Sustainable Eel Group, a conservation NGO. Around 25% of European eel stocks are affected, he added.
Huge Asian demand for eels
Japanese eels used to be the main source of eels in Asia, but stocks have collapsed due to overfishing, said David Baker, a marine science expert at Hong Kong University.
This has given rise to a thriving traffic in European eels -- listed as endangered since 2009 -- which have in turn seen their numbers depleted, he added. Trade in the fish has long been restricted, and in 2010 the EU banned all eel exports.
European eels have an unusual lifecycle. Adults spawn in the Sargasso Sea, in the North Atlantic Ocean. After eggs hatch, young eels drift with ocean currents for over 3,700 miles (around 6,000 kilometers), before entering Europe's freshwater rivers, where they remain for 10 to 25 years until they reach maturity.
European eels are trafficked during this intermediate stage of development. "They are easier to harvest when they are small and you can fit more into a small space," Baker told CNN. They are usually poached in Western Europe, especially in Spain, then sent to China or Japan, he added.
"Traffickers slip them into oxygenated plastic bladders, place them in hand luggage and fly them to Asia on a commercial flight," he said. The eels are sometimes "laundered" with a stopover in Northern Africa, which doesn't have a ban on exports like the European Union, he added.
In April 2018, Europol announced that it had arrested 10 members of an organized crime group who were trying to smuggle 350 kilos (772 pounds) of live eels from Spain to China via Morocco.
"Most of the demand seems to emanate from Asia, where eel is considered a delicacy, as opposed to Europe and the US where it is often seen as a pest," Baker said.
His team has developed a method to identify the provenance of seized specimen. "We take a sample from the fish, extract its DNA and sequence parts of its genome," he said. "This allows us to identify which species it belongs to, specifically whether it is European eel or not."
More recently his team created a tool to analyze the eel's DNA by testing a sample of the water it was contained in, which could potentially return results in under 24 hours.
CNN's Saskya Vandoorne and Diane Karcher-Mourgues contributed to this article