Category: Maldives 2025

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2025 wrap-up: Biosphere Expeditions in the Maldives – 14 years of coral reef conservation

Four divers, a reef and a white transect tape
A team surveying a reef along a 100 m transect tape

In 2025, Biosphere Expeditions continued its long-standing citizen-science project in the Maldives, focusing on coral reef health through hands-on volunteer expeditions. Since 2011, these marine surveys have been an important constant of local reef conservation, blending scientific rigour, citizen science and immersive adventure.

The 2025 expedition brought together diverse teams of volunteers and scientists aboard a liveaboard vessel, each group contributing to Reef Check-standard surveys across multiple atolls. These surveys involve underwater assessments of coral cover, fish populations and other ecological indicators to track reef health across time.

A group of people standing on the top deck of a boat
One of the expedition teams

Long-term monitoring reveals trends: Outer reefs doing well, inner reefs in slow decline

A special emphasis on revisiting long-term monitoring sites allows Biosphere Expeditions to build multi-year datasets that reveal trends in reef resilience and degradation. The expedition’s work has resulted in annual scientific reports and many publications in the literature. 

During the 2025 expedition, citizen scientists surveyed 11 reefs and documented a mixed picture of reef conditions: some sites showed stable or improving coral cover, especially on ocean-fed outer reefs, while inner lagoon sites, more exposed to warming and stress, continued to struggle. 

Resilient outer reefs in Ari atoll had maintained levels of coral cover and had reasonably good reef fish populations with 50 – 60% hard coral cover on the deeper surveys (6 – 10 m depth). Some reef sites within atolls showed a further recovery for hard coral cover since the 2016 mass coral bleaching, reaching 40 – 50% cover on more shallow sites (3 – 5 m depth). However, other inner reefs continue to show a ‘phase-shift’ to a non-coral dominated status with opportunistic / fast-growing benthic fauna such as the coralliomorph Discosoma smothering the reef surface at one site (Dega Thila) and currently preventing the re-establishment of corals and other benthic groups.

A colourful reef with a moray eel hiding inside
A healthy outer reef
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Maldives: Hope

Update from our Maldives coral reef and whale shark expedition

We have found some hope in the gloom. The last reef we assessed, was – in the words of Simon, our expedition scientist – “what a reef should look like”. Great coral cover, quite a few fish, almost no bleaching and very little coral disease. So the expedition ended on a high, as well as some outstanding karaoke, especially from the crew, who had some impressive dance moves in store.

In between the weather tried to thwart us, but we are undeterred, dodging and weaving the squalls, laughing at the sheets of rain and delighting in the sunshine.

We checked lots of reefs like clockwork. And this is exactly what makes an expedition: a journey with a purpose. Our purpose was assessing reef health, revisiting sites and continuing to add to what is now an impressive 12-year database.

Thank you, expeditioners – none of this would exist without you. We hope we also brought some clarity to your own purpose and thinking during what was an all-round very successful expedition.

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Maldives: Sickness & Health

Update from our Maldives coral reef and whale shark expedition

Group 2 is now also qualified – well done – and checking those reefs.

The stories are as mixed as has been the weather. There are some quite healthy reefs and some that are sick.

Fish are scarce, especially grouper, because there is immense fishing pressure due to (over)tourism and a very active grouper fishery that sells them off as food fish, mainly to Hong Kong as live fish for restaurant aquariums there.

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Maldives: Round 2

Update from our Maldives coral reef and whale shark expedition

Here we are back again with a smaller, but equally keen group 2.

The weather has turned and it’s more windy, greyer and rainy now. But underwater it’s wet anyway.

We’ve done our check-out dive and are well into our training sessions now. Lectures, pointy dives and fish test today. The proof will be in the pudding.

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Maldives: Stable recovery

Update from our Maldives coral reef and whale shark expedition

Group 1 has checked all the reefs on its schedule, well done!

All were repeat surveys to track reef health and development over the years, one of the great advantages of citizen-scientist-funded expeditions, which can fund projects sustainably and reliably for many years (since 2011 in the case of the Maldives), generating long-term datasets that result in many insights and scientific publications.

None of this would happen without the many, many citizen scientists over the years who come to fund and help with this research and conservation work. Thank you!

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Maldives: Mantas and corals

Update from our Maldives coral reef and whale shark expedition

We’re in the groove now and checking those reefs like clockwork – well done team 1.

We moved to Alifu Dhaalu (South Ari) atoll and studied a couple of sites there, as per our schedule. They were outer sites and coral cover was unchanged from when we visited them last in 2023 (still few fish, as has been the case for more than a decade now – they are just being overfished). The good coral cover, however, is positive news, showing some resilience.

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Maldives: Half checked

Update from our Maldives coral reef and whale shark expedition

Team 1 is delivering and so is the weather – and the reefs.

After two days of intensive training, we’ve checked our first reef, well half of it, were it not for our very own two Daft Punks reeling in the survey line whilst people were still busy with the survey :))

But that’s exactly what the very first survey is for – after 48 hours of crash coursing – to get familiar with how it all comes together underwater. So no sweat and same again this morning, as per ze schedule, ja!

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Maldives: On board

Update from our Maldives coral reef and whale shark expedition

Liveaboards in the harbour

Expedition scientist Simon and I have arrived on our liveaboard base in the Maldives and are setting up as we speak.

The liveaboard harbour is – against expectations – still here and has not been filled in for housing. We have a quiet corner amongst other liveaboards although there is some hammering and shouting going on as I type this as last minute repairs are done.

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