This Greek island has a dark past. Now it's covered in rare seals

For half a century, Gyaros was off-limits to the world as a military prison and naval firing range. Then came an astonishing photograph.

The Sun is already high above the speedboat when Gyaros appears on the horizon, a desolate silhouette in the Aegean Sea.

As we draw closer, a hulking structure of red brick comes into view – the prison which gave the island the moniker "Devil Island".

We've journeyed just half an hour from Syros, the administrative heart of the Cycladic islands, southeast of mainland Greece. Sail in any direction and you'll find quintessentially Greek islands like Mykonos or Andros – whitewashed houses scattered on hillsides like sugar cubes tipped from a bowl, ferries arriving on schedule, tavernas open. 

Gyaros never got that memo. It offers only scree and scrub, appearing empty, lifeless even. But it is not. 

The reason is rooted in a particularly dark and violent period of Greece's history. An authoritarian regime followed by military training left this island untouched by development, a forgotten relic of a turbulent past. Then, in 2004, an unexpected photograph focussed attention on this apparently desolate place once more, but for very different reasons. 

Devil Island, it turned out, had become a wildlife haven, offering a sanctuary for a rare seal which was, at the time, threatened with extinction.

Isolation, violence and punishment long defined Gyaros, which was used to exile political prisoners as far back as Roman times. Its most brutal chapter, though, began in 1948, when the Greek state expropriated the property of its last 31 residents and turned it into a prison island.

While nearby islands built boutique hotels, Gyaros was sealed off from the world. Across two waves of political repression, more than 20,000 Greeks were sent to the island, mostly communists, writers, students and artists who had protested the people in power.

In the initial wave during the late 1940s, following the end of the Greek Civil War, prisoners were forced to live in tents through sweltering summers and freezing winters, labouring to build the brick walls of the prison.

After a pause, a second wave of imprisonment occurred during the military dictatorship of the "colonels" from 1967 to 1974. Officially a reformatory, where dissidents would be turned into "real Greeks", Gyaros was in reality a place of forced labour and torture, tucked far away from critical eyes. 

After the junta fell in 1974, the navy used the island as a bombing range until 2002. It still has no hotels, ferry connections or residents. 

Almost by accident, Gyaros received the strongest possible protection: human absence.

After the navy stopped its activities, fishermen began reporting sightings of Mediterranean monk seal around the island.

Then came a photograph. Taken by an amateur speargun fisherman in the early 2000s, it showed a monk seal mother and pup lounging on an open beach in broad daylight – a scene that had all but disappeared from the Mediterranean. 

"Personally, I had never seen it in Greece," says biologist Panos Dendrinos of the Hellenic Society for the Study and Protection of the Monk Seal, an Athens-based research group. "It looked like an ancient picture."

Once a common species, by the late 20th Century, the global population of Mediterranean monk seals had collapsed to just 350-450 individuals. Hunted for centuries for their fur, meat and blubber, coastal development also destroyed their habitat, while fishermen would kill them in retaliation for raiding their nets.

Classified as critically endangered, survivors became ghosts, retreating into remote sea caves to raise pups far from humans.

The fisherman's image prompted the first scientific expeditions to Gyaros, where a substantial colony of around 70 adult seals was found – possibly the largest in the Mediterranean at the time. But it was the animals' behaviour – seals nursing their young on open beaches – that truly stunned the experts. 

"That was their natural behaviour," says Spyros Kotomatas, biologist and senior marine conservation officer at WWF Greece, who worked for the Hellenic Society for the Study and Protection of the Monk Seal at the time. "Seals elsewhere behaved like Greeks in Athens – tense, alert. On Gyaros, they were relaxed."

It's unclear how long the seals had been on the island, but Kotomatas believes its long isolation created favourable conditions. While thousands of prisoners passed through, the human footprint was concentrated, he says, with the camps occupying only a small part of the coastline. Even during the bombing era, disturbance was sporadic and concentrated mainly in the south-east of the island, he adds, away from the areas where monk seals found their refuge.

"Seals are adaptable," says Kotomatas. "I've been inside a cave while a speedboat passed right by. I couldn't hear from the noise, but the seal remained asleep."

More importantly, the navy's presence meant fishing was not recommended, creating a rich feeding ground.

The discovery of the seals led to several developments in protection of the island, and in 2019 it was declared a Marine Protected Area (MPA), the first in the region.

From the speedboat, Antonios Burikas and Ventouris Bountouris scan the water. As officers from Greece's Natural Environment and Climate Change Agency (Necca), which took over surveillance of Gyaros from WWF in 2023, their job is to check whether anyone is fishing in the three-nautical-mile protected zone.

Today, the water is quiet. Only two pleasure yachts are anchored in the bay below the prison. The officers politely inform the captains that fishing is not permitted.

"More than the patrols themselves, it's the idea that we are patrolling that deters people," Burikas says.

Sea life around Gyaros had serious advantages long before anyone was actively protecting it. Fishing was banned for safety reasons by the navy, and never systematically opened to large-scale mechanisation.

Still, remote and regularly battered by high winds, it is hard to guard from illegal fishing. As the bombing range fell silent in the early 2000s, more boats moved in to exploit waters that had barely been fished for half a century. 

Constant boat patrols to prevent this was prohibitively expensive, so in 2017 WWF Greece built a remote monitoring system which transmits live feeds to Syros. When a vessel enters the protected zone, officers can dispatch a targeted response.

"It's more or less Big Brother," says Dimitrios Damalas, a fisheries expert at the Hellenic Centre for Marine Research (HCMR) in Anavyssos, Greece.

Between 2015 and 2023, illegal fishing incidents involving amateur fishers fell by 57%. Those involving professional fisheries fell by 85%. Surveys led by Damalas (some published and some as yet unpublished) have recorded more than 130 different species inside the protected waters, compared to 108 outside. Fish are more numerous and larger.

Maria Salomidi, a marine biologist at HCMR who has studied seagrass beds and reefs on Gyaros since 2009, would see slipper lobsters in impossible numbers as well as giant devil rays, marine turtles, dolphins, whales and monk seals.

"When we dive elsewhere, we'll mostly get out of the water frustrated," she says. "We see the degradation in the sea. Not in Gyaros… [It's] one of the last heavens on Earth, where you can hear the silence and see the night sky."

High on the cliffs and in burrows carved into rock, Gyaros hides another species vulnerable to extinction.

In 2015, researchers from WWF heard a group of Yelkouan shearwaters – black-and-white seabirds roughly the size of a rock pigeon – approaching Gyaros at night. It was previously unknown they were even there: the birds were thought likely to be limited to smaller, isolated islets.

Long-lived and monogamous, shearwaters return to the same partner and nesting site year after year. On land, their world contracts to a single burrow and egg.

"One bird can stay on the egg for a week, completely motionless," says Danae Portolou of the Athens-based Hellenic Ornithological Society, who has been leading efforts to monitor Yelkouan shearwaters in the Aegean Sea. "The other travels, then they switch."

The Gyaros colony is the second largest in the world, accounting for 15% of the global population. It's precisely the inaccessibility of the islands cracks and crevices – a habitat untouched by humans – which has allowed it to thrive.

Even here, though, the shearwaters face threats. Introduced rats eat their eggs and chicks – up to a third of their eggs are lost in this way. Worse still, feral pigs, which dig up burrows and prey on adult birds, have now been illegally introduced. "When a predator targets adults of a long-lived, low-fecundity seabird, the damage is devastating," says Portolou.

Culling of pigs, the more pressing of the two threats, has begun, but eradicating them speedily is critical, says Portolou.

It's not the only circumstance that is far from perfect on Gyaros.

While the seagrass meadows around the island are mostly healthy, the reefs are not. Overfishing elsewhere has removed large predators like groupers and sea bream, meaning smaller fish are overgrazing algal forests, which form the basis of the entire ecosystem. 

Salomidi's team is now actively restoring the reefs by planting lab-cultivated algae. Large fish such as groupers and sharks are returning, but many are still immature. "We may need decades to approach something close to a pristine state," says Damalas.

Things are also fragile politically. Even after Gyaros was designated an MPA, local small-scale fishing remained permitted seasonally, under strict conditions. But in 2022, under pressure from fishing organisations, the government opened the area, leading to a free-for-all which quickly impacted fish and seals. 

The government soon reversed course, declaring the island a strict no-take zone. Still, scientists remain concerned that Necca lacks sufficient capacity to protect the island. "Fishermen report that boats from other islands arrive at night and on weekends," says Damalas. "[Others] feel they have been respecting the rules for nothing."

In April 2026, a presidential decree, gave the island the highest level of protection and established a permanent legal framework. But experts also stress that Gyaros cannot be a stand-alone solution. 

While Greece has protected 18% of its marine territory, only a small fraction is actively managed. "Even if you protect Gyaros perfectly, if the wider sea is unprotected, [the] animals remain at risk," says Kotomatas. "The Mediterranean is one of the most intensively used seas on earth, and pressures from shipping, offshore energy, recreational fishing and marine heatwaves are only increasing."

A proper plan is needed, he says, for how different parts of the sea are used, so fishing, shipping, tourism and conservation don't end up working against each other.

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The participatory process used to design Gyaros' protected area gives a good example for others to follow, says Portolou. "It brought together lots of stakeholders to talk and discuss what they feel Gyaros is for them and what is necessary to be done," she says. "The process has taken time, but it's been worthwhile." 

In one piece of good news, monk seals are now recovering beyond Gyaros, driven by protection of key habitats and a change in attitudes among fishermen, who no longer dynamite animals in caves, says Kotomatas. 

As the speedboat turns away from the island, the abandoned prison fades into the distance. Somewhere near the caves below, monk seals nurse their pups on open shores.

"Gyaros is an island of hope," Salomidi says. "But we need a thousand Gyaroses across Greece – then we might be on to something.

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