In dire straits: Could a fishing ban save the elusive European eel?

However, the dramatic decline in the European eel’s population over the past half century has been so devastating that the species is now at risk of suffering the same fate as the passenger pigeon. In 2008, the International Union for Conservation of Nature took steps to classify the European eel as endangered (Anguilla AnguillaAt the same time, the European Union adopted comprehensive eel legislation, including seasonal fishing bans and catch limits, to help eel stocks recover.

But a recovery has not materialized, and scientists now say only urgent and drastic action can save the iconic fish. report By 2024, the International Commission on the Exploration of the Sea (ICES), a regional fisheries advisory body whose research formed the basis of the EU’s eel regulations, now urges that “all habitats should be fished to zero.” To many biologists, closing eel fisheries, at least temporarily, seems like a last resort after years of neglect. “We’ve had a century of, ‘We knew the problem was there, but we didn’t address it,'” Willem Dekker, a Dutch biologist credited with architecting the EU’s eel regulations, told me.

Eels are both a familiar element of European culture and a mysterious species to anyone who has studied them. Aristotle tried to solve the mystery of eel reproduction as early as 300 BC, eventually concluding that the fish must miraculously emerge from the muddy riverbed. At the time, no one had ever seen eels reproductive organs, nor had anyone ever witnessed eels breeding in the wild. This was a blank page in the scientific record, and to this day, a breeding pair of European eels have never been photographed.

European eels are born in the Sargasso Sea, an amorphous body of water that borders not land but shifting ocean currents in the Western Atlantic. The tiny, transparent larvae are carried by ocean currents to the Atlantic coast of Europe and the Mediterranean coast. Here they complete their first metamorphosis, becoming longer, more transparent “glass eels.” The glass eels swim up freshwater streams and rivers where they establish long-term homes, living for years or decades as longer, darker “yellow eels” before finally transforming into shiny, fertile, mature “silver eels.” At that point, some unknown force calls the European eel to swim down to unfathomable depths, traveling some 1,000 miles back to the Sargasso Sea, where they spawn and die.

The European eel’s ovaries and testes only really developed on its way to the Sargasso Sea, and it wasn’t until the late 1700s that the ovaries of females from the Comacchio Lagoon were first identified through careful dissection. Finding the testes took even longer. At the time, the young Sigmund Freud, a medical student on his way to becoming the greatest philosopher of sexual repression, was one of many men who clutched a scalpel and toiled to find the male eel’s reproductive organs. (Freud had spent the spring of 1876 in Trieste, about 100 miles northeast of Comacchio, dissecting healthy Adriatic eels for his Vienna supervisor, but without success.)

The mysterious life cycle of eels defies standard fisheries science. To develop management plans, biologists often rely on a number called spawning stock biomass (SSB), which is calculated as the total biomass of reproductively mature fish. Because reproductively mature European eels hide far away in the dark depths of the Atlantic Ocean, there is no way to accurately estimate the SSB of this species. “Fish stock assessment is a routine task that involves a lot of mathematical processing,” says Willem Dekker. “There are procedures for how to do it.” In the case of European eels, “it is much more difficult to carry out these tasks without knowledge, without data, and without solid models that make life a lot easier.”

It has also yet to be figured out how to artificially breed and farm eels. Scientists have successfully induced European eels to reproduce in the lab through hormone treatments, but lab-grown eels rarely live longer than three months due to the difficulty of identifying the environmental conditions and diet the eel larvae need to survive. This forces farms to rely on a supply of wild-caught glass eels, which they then grow to commercial size. The strongest market for European eel larvae is in Asia, where traffickers ship huge quantities of glass eels to meet Japanese demand for eels, in direct violation of a 2010 EU law that bans the export of eels outside the EU.

Unable to rely on aquaculture to meet market demand and relieve pressure on wild eel stocks, management authorities have had to focus on more direct conservation strategies. However, the causes of the European eel’s dramatic decline are not simple, so they are struggling to find a solution. Data collection has revealed that the number of glass eels arriving on European coasts has declined by 15 percent each year since 1980. Several factors are clearly responsible for this long-term decline, but the extent of each is unclear.

Apparently, overfishing is only one piece of the puzzle, as EU fishing restrictions have not brought about a recovery. Another problem is the disruption of important migration routes and habitat destruction caused by dams, hydroelectric plants and land reclamation. Diseases such as the eel herpes virus, heavy metals and pollutants are also known to reduce eels’ reproductive potential, and a warming Atlantic Ocean may be shifting the ocean currents that eels rely on to complete their life cycle. A recent surge in illegal trade of juvenile eels to Asia has undoubtedly dealt a further blow to eel populations.

“People want clear answers, and we can’t provide them,” acknowledged Caroline Durif, one of the current chairs of the ICES Eel Working Group. Asked why eels are declining so rapidly, Willem Dekker replied, “We don’t know. Absolutely not. With fishing, with habitat loss, with pollution, with all of that, nobody knows.”

To ban the capture of European eels as proposed by ICES, the European Parliament would need to repeal and amend current EU directives that require countries to take measures to help eel stocks recover. But this is unlikely to happen, given that a resolution calling for a new approach to regulation received the support of 80% of attendees at a 2023 Commission vote. “There is no will to ban them, and a ban would not help,” Andrew Carr, chair of the Sustainable Eel Group (SEG), a non-profit coalition of conservationists, scientists and commercial fishermen, said in a video call from his home in the UK. “Eels are much more complicated than that, and you can’t save them by stopping fishing. What’s needed is a very controlled level of fishing, but one that addresses all the environmental factors.”

Durif acknowledges that the EU still needs to be persuaded by the scientific community before it can accept a zero catch limit. “The EU has made a special request to ICES to see if it can measure the effectiveness of the regulation, but they keep saying that it can’t,” Durif said. He noted that the recommendation of the ban follows the precautionary approach, a principle generally agreed upon in fisheries, that is, implementing even the most extreme management measures, aimed at reaching a certain population. “We cannot recommend catching less fish because we don’t have the data to determine whether hydropower or fishing is causing more mortality.” [than a ban]or more precise advice.”

The mystery surrounding eels has allowed different groups with their own priorities to shift the blame for this collapse. SEG argues that the focus of control should be to ensure that glass eel fisheries, distributors, farms, smokehouses and retailers, which account for around 90% of the legal European market, operate within existing EU regulations. The group is also working to eradicate smuggling to Asia, drawing up standards that all commercial operators must follow for SEG certification.

Carr has written to the EU for more than a decade and told officials gathered in The Hague about the problem of illegal glass eel trafficking. “It took a long time for eels to become an EU anti-smuggling priority,” he said. Police crackdowns accelerated in the late 2010s. In 2017, the discovery of $547,000 worth of glass eels hidden under crates of other legal fish at Heathrow Airport led to headlines saying “Smuggling makes eels ‘as valuable as cocaine'”. Operation LAKE, run by Interpol from 2022 to 2023, led to 256 arrests on suspicion of illegal eel smuggling.

Eel fishermen across Europe fear that the ban will threaten their livelihoods and say authorities should address other known causes of mortality. In Sweden, it is estimated that the threat from the country’s 2,300 hydroelectric plants, whose turbines routinely rip migrating eels to shreds, is equal to or greater than that from fishing. On the coast of Hönø Bay in southeastern Sweden, also known as the Eel Coast, a group of fishermen and activists are campaigning to preserve the region’s eel-fishing tradition. The tradition dates back to the Middle Ages, when eels were currency used to pay taxes, rents and debts, and survives in the form of traditional eel dinners in fishermen’s huts. Daufvid Hermansson, a local historian and director of the Eel Coast Cultural Heritage, criticizes policymakers for avoiding the issues of hydroelectric turbines and habitat degradation in favor of the “easy solution” of fishing restrictions. “Less than 1% of fully grown eels that leave the Swedish coastline are fished,” he claimed.

But scientists are almost unanimous in their insistence that imposing a fishing ban is necessary, if not necessarily sufficient. “We don’t want to kill the fishery. The tradition should remain. It’s natural. It’s the history of the place. But if we have to stop fishing for five years, let’s stop fishing for five years. The population is declining and we are in danger of soon falling below the species’ survival limit,” contends Giuseppe Castaldelli, a biological consultant for the Po Delta Park, which manages the Comaccio Lagoon.