Seychelles plastic waste: who is polluting Aldabra atoll

About 500 tonnes of plastic waste have piled up on Aldabra, a protected atoll in the Seychelles and a UNESCO World Heritage Site. A new study by researchers at the University of Oxford shows that much of it does not drift in from distant shores. It comes from vessels operating in Seychelles waters or passing close by, including fishing boats from European Union countries.

A paradise you cannot enter

Aldabra is the world’s second-largest atoll. Entry is officially forbidden, and its near-total isolation has made it an ideal natural laboratory for studying evolution. UNESCO added the atoll to its list in 1982. Today no more than twelve researchers live there permanently, at the La Gigi research station on Picard Island.

But the beauty comes with litter: plastic lies on the beaches and clogs the mangroves. The scientists did not bring it there, and they have repeatedly tried to clear it. In 2019 they collected 25 tonnes of waste, a more than respectable result for a dozen people.

A cleanup that will never end

Collecting the waste is not enough. It has to be removed, otherwise the island simply ends up with another dump. But Aldabra lies roughly 1,000 kilometres from Mahé, the main Seychelles island, which makes removal far more complicated and expensive. The one-off removal of the waste collected seven years ago cost the equivalent of about 190,000 Czech crowns per tonne.

Removing all the waste from Aldabra would cost more than 100 million crowns. According to researchers’ calculations from 2020, such a cleanup would take about 18,000 hours of human labour. On top of that, currents keep bringing in new waste, so the work would never be finished.

A problem for the whole archipelago

The situation on Aldabra reflects a problem facing the entire archipelago. Every day the ocean deposits litter on the beaches of some 115 Seychelles islands. For a country that lives off tourism and sells clean beaches and the image of an untouched tropical paradise, this is a blow to the economy. The money to clear waste that the islanders did not produce has to come from the already limited resources of local communities.

The problem cannot be solved until it is clear where the waste comes from. Alex Albinsky and Noam Vogt-Vincent of the University of Oxford set out to find out. Their work was published in the journal Maritime Pollution Bulletin. They used satellite data on the movements of fishing and cargo vessels over five years, from 2018 to 2022, and ran computer simulations of the paths of billions of virtual pieces of debris. The result is a map showing how risky a vessel’s presence in a given spot is for the Seychelles.

The trail of EU fishing fleets

The result for fishing vessels is clear-cut: according to the study, 50–66 percent of all fishing-related waste on the Seychelles coast comes from fishing within the Seychelles’ exclusive economic zone. These are waters within 200 nautical miles (about 370 kilometres) of the shore, where the state has full control over marine resources. They are rich in tuna, and tuna fishing provides jobs and foreign-currency revenue, primarily in euros.

Most of the large vessels that lease fishing licences come from European Union countries. They work in two ways: with longlines, which trail baited hooks for many kilometres, and with purse seines, huge circular nets used to encircle schools of tuna. The fishing is legal: the EU and the Seychelles have long-term agreements. The most recently signed one allows 38 EU-registered vessels, mostly Spanish, to fish until 2030. In return, the European Union pays the Seychelles 5.75 million euros a year.

A by-product of such a deal is unavoidable waste: torn nets, fishing lines, buoys and ropes. The ocean carries them to the shores, including the Aldabra reserve. And cleaning it up there would cost roughly as much as the Seychelles earns from the EU agreement in a year.

Waste with no owner

But European fishermen are not the only ones to blame. For non-fishing waste the picture is different: 90 percent of the litter that comes from merchant ships is linked to just five busy shipping routes in the western Indian Ocean. These ships neither fish in the Seychelles nor head for the archipelago. They simply sail past.

It turns out that a significant part of the problem arises not thousands of kilometres away, but from heavy shipping right next to the Seychelles. For the islands themselves this changes little: they pay to clear waste that was largely created by neither residents nor tourists. The new study does not send a bill to any particular country or fleet, but it shows much more precisely where to look for those responsible for at least part of this pollution.

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Around Prague, based on reporting by ekolist.cz