Ari Atoll has depths of around 300 meters on the eastern side, while on the west depths drop quickly to over 2,000 meters. Rasdhoo is connected to the northeast part of Ari by a submarine plateau with depths from 183 meters to 274 meters. Depths within Rasdhoo Atoll are to 35 meters while in Ari depths are mostly between 35 and 55 meters but reaching up to 80 meters in one part. Ari Atoll has no long stretch of the barrier reef, and all faces of the encircling reef have many passages into the atoll, except the south face, which has one break. The inside of the atoll is much encumbered with coral reefs, many of them dry at low tide, but the atoll has many thilas, for which the atoll is famous. Most of the thilas have interesting coral formations and are host to a profusion of marine life. All the reefs on the western side are big, hard coral reefs that appear naturally designed to protect the atoll from the fierce seas that prevail during the south-west monsoon. Heavy waves have pounded the west side, breaking off chunks of coral rock and in some places, long channels more than a meter deep have been cut into the reefs. On the eastern side the reefs are smaller with many more entrances, and as they do not get the heavy ocean swell of the western side, the corals tend to be more fragile.
It is from the deep waters on the outside wall of Rasdhoo-Madivaru that scalloped hammerhead sharks, Sphyrna lewini, rise in the early hours of the morning to accessible viewing depths. These residential sharks prefer to swim in large schools and are timid, but in clear waters, divers can get a good look at their peculiar head shape. They are easily recognized by the laterally extended snout with eyes at the tips of their T-shaped heads.
Scalloped hammerhead sharks, Sphyrna lewini, on the deep waters on the outside wall of Rasdhoo-Madivaru.
Rasdhoo-Madivaru has one of the most spectacular – and confusing – reef formations to be found in Ari Atoll. A narrow spur, like a suspension bridge, extends out from the reef of Rasdhoo-Madivaru part of the way across the channel rising to a peak at 13 meters. On the seaweed side of the spur, the reef descends almost vertically to around to around 200 meters.
The deep blue waters on the outside of the spur contrast with the turquoise blue reflecting from the sand floor at 30 meters on the inside of the channel. Along the spur is a profusion of fish life ranging from pelagics like schooling barracuda, trevally, and little tuna – which are rarely seen underwater although very common – to reef fish like blue-striped snapper, fusilier and schools of flame basslet.
Tailfin batfish are often seen on the outside wall.
On the outside wall are many sea fans, while on the spur is healthy hard coral. A school of tailfin batfish and often white-tip reef sharks are seen. At the end of the suspension bridge, a deeper, less interesting ridge continues across the channel, but another ridge turns at right angles leading into the channel. It dips and rises to another peak at nine meters. At this high point, four ridges converge like a mountain peak, and it is a favorite haunt of manta rays where they are cleaned by cleaner wrasse. There are fewer pelagics inside the channel but a greater abundance of small fish like damselfish, butterflyfish, blue triggerfish and schools of stripe fusilier.
Depths in the clear waters on the outside of the atoll can be deceptive, and it is easy to go too deep, so care should be taken, especially while engrossed in viewing the hammerhead sharks. It’s a good idea to take a compass on this dive if planning to explore the inner formations of the channels as orientation can be confusing.
At Kuramathi there are two wrecks close to the island, sunk by the dive school. The first was a local dhoni called Tomton sunk 20 meters from the jetty in 1976. It is not deep and is ideal for beginner divers. The other wreck sunk on the house reef in 1987 was a 30-meter steel cargo ship. It rests on the bottom at 18 meters with the top at 10 meters.
A 30-meter steel cargo ship was sunk on the house reef in 1987.
The house reef dive begins at the outside corner of the island and Kuramathee Kandu. At this point, a ridge at 20 meters cuts across the channel. The channel wall slopes gently from 10 meters to the sandy bottom at 27 meters. Inside the channel, another small ridge at about 10 meters cuts across the channel near the jetty, leaving a well-protected and interesting location with good coral growth and fish life. Head to Kuramathi Island Resort for this once-in-a-lifetime diving experience by clicking here.
(Source: Dive Maldives: A Guide to the Maldives Archipelago. Tim Godfrey. Atoll Editions, 2015)