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As the tide goes out at dusk, three men equipped with diving gear are walking into the open sea. A fourth one keeps watch to alert them if he sees police or witnesses. The divers are wading through the shallow, warm water in search of animals with a leathery skin and sausage-shaped body that crawl out from under the rocks to graze along the sandy seabed: sea cucumbers. Until 2014, these slimy, slow-moving creatures were only used as fishing bait in southern Spain, but then word spread that their dried body walls were a prized delicacy called bêche-de-mer, and even considered an aphrodisiac, in places like China, Hong Kong, Singapore and Japan.

Some 10,000 tonnes of dried sea cucumber are traded internationally, the equivalent of 200 million live animals, each year – and that doesn't include aquafarming. As the once-ample supply of sea cucumbers starts to dwindle in the Indo-Pacific, fishermen in Spain are racing to pluck the unassuming creatures from the seafloor. Close behind them are a cadre of less nautically-inclined opportunists: drug dealers eager to cash in on the booming trade.


While the divers are collecting the sea cucumbers one by one, a unit from the Spanish military police force is watching them from afar with binoculars and thermal imagers. “It’s like a game of cat and mouse,” says Jose Antonio de la Torre, who heads the Nature Protection Service (SEPRONA) of the Guardia Civil in Cádiz in the southwest of Spain. “Once they pull them out of the water, that’s when we intervene.”

China’s appetite for sea cucumbers goes back centuries but, until recently, commercial fisheries were limited to the Indo-Pacific Ocean. The soaring demand among its growing middle class has all but depleted the regional stocks in the last few decades and driven fisheries to the Mediterranean and northeastern Atlantic Ocean where sea cucumber fisheries are generally not regulated. A global analysis by Steven Purcell, an expert on sea cucumbers at Australia’s Southern Cross University, found that 70 per cent of the world’s fisheries were already fully or over-exploited in 2011. The much-favoured Japanese spiky sea cucumber, for example, has been exploited throughout its natural range and is considered endangered by the International Union for Conservation of Nature (IUCN). The species is now being bred and cultivated on a large scale.

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While the Pacific has been largely stripped of its sea floor bounty, Europe is starting to take stock of its potentially lucrative supply. Turkey capped the annual catch limit at 2,500 tonnes for 2020 and Italy declared a moratorium on all fishing and transport of sea cucumbers in 2018 in order to assess its available stocks. In Spain, however, sea cucumber fisheries are not regulated – except in the northern region of Galicia where harvesting of the Holothuria forskali species is allowed – and most illegal catches occur along the southern coast. The sheltered rocky bays and beaches make it easy for divers to poach a few hundred animals per hour.

Sea cucumbers may appear to be simple, inconspicuous creatures but they are the vacuum cleaners of the ocean. They brush their sticky tentacles along the sandy seabed and stuff a mixture of silt, decaying algae and other waste particles into their mouths. Similar to their above-ground counterparts, the earthworms, sea cucumbers perform the thankless task of recycling decomposing matter and bacteria and pooping it out as clean sand.


Because sea cucumbers rely on external fertilisation for reproduction, illegal exploitation can cause local populations to collapse. Males release their sperm into the water and females release their eggs at the same and they need to be close enough to each other for fertilisation to occur. In areas where mature animals have been overfished, the few eggs and sperm find it difficult to reach each other.

The cascading effects on marine ecosystems become apparent within months. Mercedes González-Wangüemert, a biologist based in the ancient port city of Cádiz, has been studying the sea cucumber species of the Mediterranean and northeastern Atlantic since 2004 and is now the research director of an aquaculture firm called Guatizamar. One of her field surveys took her to Ria Formosa, a protected coastal lagoon in the Algarve region of southern Portugal, where highly sought-after Holothuria arguinensis are harvested illegally. A dried kilogramme of this nubbly, brown-orange species can sell for at least €250 (£230), according to González-Wangüemert.

Holothuria arguinensis can grow to 40 cm and normally feed among the sand, mud and seagrass meadows of the lagoon. At one of the study sites, González-Wangüemert was shocked to find only two individuals per hectare during the summer of 2018 where she had observed some 200 just six months before. Parts of the shallow lagoon that used to be filled with seagrass are now devoid of plant life: “It’s completely covered in mud. If you touch the bottom with your hands, it’s impossible to see anything,” she says. All that is left is a smell of rotten eggs by hydrogen sulfide-producing bacteria in the oxygen-depleted water.

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Holothuria arguinensis is one of the five sea cucumber species that are of high culinary value in the Mediterranean and northeastern Atlantic. As a result of the regional overexploitation, Cádiz suddenly became an illegal fishing hotspot in 2016 and attracted many opportunists looking for a quick win. Even street dealers who’d normally sell cannabis from North Africa jumped at the new opportunity and started collecting slimy sea cucumbers near the beach. It turned out to be a lucrative, but less risky business.


Licensed fisheries are entitled to catch seafood such as razor clams, cuttlefish and octopus along Andalusia’s coastline, but sea cucumbers find themselves in legal limbo because people in Spain don’t want to eat them. The local police seized more than a tonne of sea cucumbers at the start of summer 2016, according to the La Voz de Cádiz newspaper. Since then, interventions have become the new normal.

De la Torre says that today it is mostly licensed fishermen that catch sea cucumbers to earn themselves a bonus. “There’s a difference between catching a protected snail and a sea cucumber that isn’t protected specifically. Catching [sea cucumbers] is always more beneficial because the penalty is not that high and serious.”

The Spanish Guardia Civil and police in Cádiz have ramped up their surveillance in the last four years and are patrolling the coastline from spring to early autumn when the water is warmer and calmer and most of the illegal harvesting occurs. Their investigations have also led to the rooftop of a city centre building and, in May 2019, to a Chinese restaurant where 340 kg of dried sea cucumbers and nearly 300 seahorses – a protected animal – were ready to be exported internationally. Sea cucumbers weigh ten times more when they are alive so the rough maths would add up to some 18,000 individuals. Serious offences may result in fines of up to €60,000 (£56,000) but no jail time because of the lack of legislation. It is unlikely that Spain will follow its Mediterranean neighbours and regulate the fisheries anytime soon.

“The central administration of the government won’t permit it because these species are not in demand in Spain,” says Francisco Javier Gutierrez, who managed to obtain a licence to import sea cucumbers to Spain and from there send them to China and the United States. His company, GutierrezAleu M.T., harvests and processes sea cucumbers as well as shark fins at an industrial plant somewhere in Europe – he declined to disclose the country, but two of the four species the company advertises are endemic to the Mediterranean Sea. Sea cucumbers and shark fins can be traded and shipped from Madrid–Barajas International Airport as long as they are not caught in Spanish waters. “It is a big market”, says Gutierrez who has been exporting seafood products to Asia for the past ten years. But the future of the sea cucumber trade remains uncertain, he says. "If the fishing volume isn’t regulated, it will be threatening and finally reducing the available stocks of sea cucumbers."

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And the demand shows no sign of slowing down. On 24 February 2020, China banned the trade and consumption of wild animals in the wake of the Covid-19 pandemic, which has been linked to wild animals carrying the virus that were sold at a market in Wuhan. The temporary ban, which is expected to be signed into law later this year, covers only wildlife that is already protected by law and terrestrial animals that are "of important ecological, scientific and social value” a category that doesn’t include the oft-overlooked sea cucumbers.

Sea cucumber expert González-Wangüemert believes that aquafarming could, with the right science, provide a sustainable solution to the overexploitation of wild animals. Like most edible species, Holothuria arguinensis are found at depths of 10 to 25 metres. But because sea cucumbers need large areas to move freely and feed, farms operating in coastal lagoons can potentially cut off people’s access to the ocean. There are few successful large-scale aquafarms dotted around the globe, mainly in China, Madagascar and Australia.

In 2019, González-Wangüemert’s company obtained a licence to set up a 20-hectare hatchery in an estuary near Cádiz. The goal: Creating Europe’s first commercial sea cucumber farm to breed Holothuria arguinensis. Although females release millions of eggs in one spawning event, only few offspring will survive. Juvenile sea cucumber will then be moved from the tanks to the seawater for fattening and growth.

“The bêche-de-mer from our species tastes similar to octopus,” says González-Wangüemert. “I like it so much.” The odd-looking creatures are packed with nutrients and known to contain substances that may help fight cancer cells, but whetting the appetite of consumers in Europe, she says, is virtually impossible. You eat with your eyes first, after all.

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