Wind and moderately heavy seas the past couple of days have made heavy work of the diving and video deployment, but this morning we woke to a calm Peros Banhos lagoon, where working underwater this morning was a real pleasure. It has been said that we need some difficult days to make us appreciate the good ones.

The exciting discovery today is that red-footed boobies are now breeding in the western islands of Peros Banhos atoll. We saw some nests with juveniles in the Scaevola bushes on Ile Diamant, the northernmost of the long western chain of islands in the atoll, and a very surprising 23 nests on Ile Petite Mapou two islands south. As with the islands of Salomons Atoll, these birds have not been recorded here since at least 1996, when the first survey was done. We hope to find that they might be nesting on more of the islands as we head south down the chain of islands tomorrow.

The varied science schedule has meant some very active manoeuvring backwards and forwards for Neil Sandes and the Pacific Marlin. The crew continue to give more than you could ever reasonably expect and Les ‘Gandalf’ Swart has been nicknamed for his magician-like skills in producing fixes and improvements on equipment.

Today a small group of us took the opportunity to go ashore on Moresby Island to visit the mangrove forest that was only discovered two years ago by two of expedition members (Pete Carr and Anne Sheppard) with Colin Clubbe from the Royal Botanic Gardens, Kew. We had to walk around half the island on the ancient fossil reef flats, trying to avoid the moray eels that were hunting for crabs and which seemed quite interested in our feet. We tried to find our way into the forest at a couple of points without success and were driven back by the dense vegetation and lack of mangroves! Luckily we navigated to the centre of the island and the mangrove forest.

This is one of only two islands in the entire archipelago that has mangroves, the other being Eagle Island. There is only one mangrove species in Chagos (Lumnitzera racemosa), which unfortunately is under threat from the encroaching coconut palms. This was evident from our visit today with little sign of mangrove seedlings, and in the areas you would expect to see these young plants the ground was covered with rotting coconuts and fallen palm leaves.

Pete spent the rest of the afternoon mapping the entire forest with his GPS in order to document the extent of this area for the very first time. The mangroves were stunning and in flower, with nesting red-foot boobies in the trees. Some of us headed back to the Pacific Marlin to prepare for the afternoon dive and en route came across a pod of about 100 bottlenose dolphins which thoroughly enjoyed leaping around the boat for about 15 minutes before we reluctantly headed back.

Previously in this series:

Conserving Chagos: Science Expedition to World’s Largest “Ocean Park”

Conserving Chagos: Starting Out

Conserving Chagos: Manta Rays

Conserving Chagos: Last Day around Diego Garcia

Conserving Chagos: Salomons Atoll

Conserving Chagos: Stormy weather

Conserving Chagos: Nelsons Island