Even if at first sight, tourist activity at this picture-postcard site may appear excessive, the view of the lagoon relieves any feeling of oppression and one quickly gets lost in the amazing scenery bathed in natural light and filled with a serene radiance. The sea cliffs of the Gunner’s Coin gracefully stand on the horizon as a pirogue with highly coloured sails glides across the lagoon. At times, one can hear the chants from the red-roofed church, which contribute to the harmony of the setting.
Mauritian harmony in the shade of casuarinas
During church fancy fairs with booming sound systems, the place loses some of its peaceful aura. Nevertheless, one can buy some ‘samossas’ and local chilli cakes to be enjoyed on the beach a few metres away, under the shade of casuarina (filao) trees. Walking along the tiny inlet, one can come across some old woman and her granddaughter scaling and gutting fish freshly caught from the lagoon on a basaltic rock. Our encounter with the fishermen took place in a very natural and simple manner. A few minutes later, we were in a boat with Rajoo, who talks about the lagoon, ‘his’ lagoon, in a very passionate way. And off we were towards the barrier reef and Coin de Mire.
The Coin de Mire natural reserve and its white-tailed tropicbird
At 8 km from the coast of Mauritius, the Gunner’s Coin appears like a mirage surrounded by clear waters with beautiful shades of green, turquoise and blue. One can often cross the path of dolphins in these waters. A shoal of Stenellas (spinner dolphins) escorts us until we reach the islet. These small dolphins, whose average length is 2 m for an average weight of 75 kg, live in groups of 25 to 100 specimens. According to the Mauritian Marine Conservation Society’s marine biologists, who have been observing dolphins during the past fifteen years, the Stenella longirostris exclusively feed on small fish and squids. They go hunting in the open sea towards the end of the day and at night. They return to the waters off the coasts of the island early in the morning to rest and socialise. This species of dolphins is renowned for its spectacular jumps out of the water.
Upon getting closer to the islet, which is listed as a protected natural reserve, the display of natural beauty continues. Coin de Mire serves as a refuge for various seabirds which build their nests in its steep sea cliffs to lay their eggs. A horde of birds constantly fly in circles over the islet. Rajoo shows us the gracious silhouette of a white-tailed tropicbird (Phaethon lepturus) crossing the blue sky. ‘This bird is the emblem of our national airline,’ he explains. ‘We call it “paille-en-queue” because of the feathers at the tip of its tail, which look like twigs of straw, that’s why it was also named “paille-en-cul” in the past (straw-tail).’ During the outing, we had multiple opportunities to see these splendid birds making spectacular dives into the water to catch fish.
The diversity the coral heads as well as the abundant fauna show the good state of Coin de Mire seabed
After the enthralling show of seabirds flying over the islet, the sight of colourful corals through the translucent waters is an enticement to dive in. Equipped with flippers, masks and snorkels, we let Rajoo guide us to some of the hidden wonders of the depth. Soon, he offers us to let the sea current drift us towards the cliffs, where he would be waiting for us with his boat an hour later.
The underwater landscapes appear like an extension of the cliffs and are as stunning as from above. The diversity and the extent of the coral heads as well as the abundant fauna show the good state of Coin de Mire seabed, away from the overpopulated coastline of Mauritius. Hordes of damselfish hover over the coral outgrowths while one can admire various vividly coloured reef fish species with different shapes here and there. Some corals feature small multicoloured spiral tube worms (Spirographis), deservedly called ‘Christmas trees’, which retreat back into their shells as we approach, creating a dazzling effect. Keen observers can spot a curious moray sticking its head out of its hole, as if to check what’s going on. A shoal of small carangue fish vanishes in the blue of the sea before coming back around our dive group a few minutes later. We slip into the faults which gently slope down to the bottom at around 20 to 30 metres deep. We can see patches of sea whips, which are very dense at some sites around the island. A reminiscence of earlier dives.
Coin de Mire hold hidden treasures like cone shells, molluscs and lambis
Coin de Mire is very popular among scuba divers for its splendid exploration spots and for the ‘Djabeda’ shipwreck. Lying at 30 metres deep, the latter is well worth the detour for the fauna and flora that it harbours. Exposed to open sea currents, the Carpenters diving site, located at the southeastern tip of the Gunner’s Coin, promises a thrilling and adventurous diving expedition. One can explore underwater tunnels, caves and faults, some of which are draped with patches of sea whips. Among these coral flowers that spread out in the current like large fans, one can often encounter red mullets, fusilier fish, snappers and carangue fish. The patches of sea whips are also home to nudibranch and translucent prawns. The coral heads are well preserved and very lively and colourful thanks to the presence of common reef fish species that glean food from the corals. Further off the coast, Coin de Mire sites are less frequented and still hold hidden treasures like cone shells, molluscs and lambis which, of course, are a feast for the eyes only.
The Mauritian corals are still threatened
With a 240 km2 lagoon surrounded by a nearly uninterrupted 150 km barrier reef, Mauritius has a rich and diverse coral fauna. According to a Global Coral Reef Monitoring Network (GCRMN) report, some 160 hard coral species have been identified at 43 fringing reef sites around Mauritius. The state of health of coral reefs is monitored since 1998 by the Coral Reef Monitoring Network in Member States of the Indian Ocean Commission in the context of the GCRMN network. This initiative is financed by the World Environment Fund/World Bank and is presently supported by the Marine Protected Areas Network of the Indian Ocean Commission Countries project. The coral bleaching phenomenon which occurred between 2002 and 2003 has affected an important chunk of corals around Mauritius. However, the coral reefs have grown again in the recent few years and the growth of new specimens has been observed, particularly on the outer slopes of the reefs. Generally, the coral cover remains stable in spite of the disposal of agricultural and domestic waste in the water, which increases the algae cover. The fringing reef backdrop is dominated by branched Acroporas corals and table corals. Rodrigues Island stands out by its good coral cover, particularly on the outer slopes, but the flat station (‘platier’) is threatened by destructive fishing practices.
Corals around Mauritius today remain under the threat of cyclones, coral diseases, crowns of thorns (Acanthasters), coral bleaching and, of course, anthropic pressure.