Southernmost of the islands in the Mozambique Channel, the name Europa is evocative – one of Jupiter’s moons, a small splash of sand and reef named after a sailing ship from a distant continent and century.
Seven days of diving on this small island at 22 degrees south has been challenging, with waves of storms blowing up around the tip of South Africa and the cold ‘roaring forties’ farther south. Only our trip back to Mozambique on the Antsiva is becalmed as we cross the southern half of this part of the Indian Ocean that is only now becoming a focus for scientists. I’ve been looking at the Mozambique Channel for 8 years now, and though it is one of the smallest parts of the Indian Ocean (and the oldest!), it still takes 2 days of slow plodding by sail and motor to get across just half of it.
Europa is the remotest of the “Iles Eparses” or ‘scattered islands’. This small island is the single most important nesting site for green turtles in the whole Western Indian Ocean (and I’ve never seen so many large individuals on every foray from the ship), and has the largest breeding colony of sooty terns in the world – some 20% of the global population! The island has a small meteorological and military station keeping it safe from illegal and wandering fishing and other uses. And it shows in the turtles and terns, and in the reefs – they are among the most pristine that I’ve seen anywhere in the world, with 80% and more of hard coral cover, large groupers and snappers on every dive, and shoals of juvenile and adult reef fish on every dive. The 40+ kg groupers are so curious and unafraid that they come up and almost nibble on our hands and kiss our face-masks – and no one has dived here since the last expedition 5 years ago so they are not being fed by tourists!
Pascale Chabanet, Director of the IRD (French National Research Institute for Sustainable Development) in la Reunion, is the leader of the SIREME research project, financed by the FED European Funds for Development. This is the latest of several she has run to monitor and inventory the remote coral reefs of these islands. Her goal is to establish them as reference points of minimal human impact. With its southern location Europa even seems to have been spared the impacts of climate change – with no evidence of dead corals from the regional and global bleaching event earlier this year, and only sporadic evidence recorded in the early 2000s of dead coral from the 1998 bleaching event. The fish and turtle populations and lack of plastics and other rubbish on the beaches and in the water are testament to our impact almost everywhere else.
My interest here is in the gradient of coral diversity, coming south out of the high-diversity center in the Northern Mozambique Channel. Will the gradient in the islands of the channel mirror that already known for the East African and the Madagascar coasts? In past surveys I’ve done I’ve seen the numbers decline from about 300 species in northern Mozambique to 200 in central-southern Mozambique and 170 in South Africa. And on the smaller islands in the channel, I’ve found about 250 species in Mayotte and 200 on each of the Comorian islands and Glorieuses in the northern part of the channel. And on this trip, the final list will be about 170 species for Europa – reflecting the decline southwards, as well as its small size and isolation. Importantly, given the good health of the reefs in Europa, there is no evidence of species being lost because of threats or degradation.
After a week of dives there’s no question in mind that Europa, along with a small handful of others in the region – for example Aldabra atoll in the Seychelles, and St. Brandons in Mauritius – are the only remaining reference points of what we could call ‘pristine’ coral reefs in the Western Indian Ocean. These are extremely valuable as sites where nature is protected from direct human impacts. Current wisdom is that we should protect at least 10% of ocean sites, which means having well-planned and sustainable use of the other 90%. Part of the purpose of the 10% is to maintain the health of ocean systems such as coral reefs, and help replenish the 90% we do use.
Hopefully Europa and these other islands will remain as the sentinel sites of that 10%, the best of the best that we protect for the benefit of our future generations, and for nature itself.