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THE LAIR OF THE SLEEPING SHARKS

By Nigel Marsh and Helen Rose

 

Image freediving and stumbling across a cave full of sleeping sharks, and not just small sharks but bull sharks and tiger sharks, that is what happened to Ramon Bravo in 1969. He was free diving off the Mexican island of Isla Mujeres when he discovered the sleeping sharks and his find created quite a bit of interest, leading to a team of researchers to visit the island and produce a famous story for National Geographic magazine.

 

As a young boy in Australia I read that incredible story in National Geographic with great interest and vowed to one day visit that special dive site. Well it took me 40 years, but I finally visited Isla Mujeres for myself to see the sleeping sharks, but things didn’t quite go to plan.

 

Located 5km off Cancun, the party capital of Mexico, Isla Mujeres is a far more laid back and low key destination, with lovely beaches, small motels, tasty restaurants and also some great diving. Since I first read about the island, and those mysterious sleeping sharks, many other diving attractions have been found, as around this rocky island are countless reefs and shipwrecks packed with marine life. But over the last few years Isla Mujeres has become famous as a shark diving mecca, not for the sleeping sharks but for another reason, whale sharks, as huge aggregations of these giant sharks appear north of the island over the summer months. But we had timed our visit over winter as the main thing we wanted to see was the sleeping sharks.

 

We booked five days of diving with local dive operator Casa Del Buceo, and this proved to be a very wise choice as they run a small but professional operation, with daily boat dives to the best dive sites in the area. We thought five days would be enough time to visit the local reefs and shipwrecks, plus checkout the cave of the sleeping sharks, but then we didn’t factor in two variables - the weather and Mexican food!

 

We arrived on Isla Mujeres and instantly fell in love with this magic island, it was just our sort of destination; easy going people, low key accommodation and surrounded by great dive sites. Unfortunately we arrived to find the wind howling from the east, wiping out half of the available dive sites, including the cave of the sleeping sharks. We prayed that the weather would improve during our stay, however we ended up sitting the first day out, not because of the wind, but because of a case of Montezuma’s revenge, which kept me close to the toilet all day and night!

 

The next day the wind was still blowing, but my stomach felt a lot better. We were worried that we wouldn’t get in the water, but Pablo Hernandez Cruz, the owner/manager of Casa Del Buceo, pointed out that they still have plenty of good dive sites on the sheltered western side of the island. So our first dive in the Caribbean was to be at a site called the MUSA Underwater Museum.

 

Located in only seven to 10m of water this artificial reef was started in 2010 and consists of over a thousand concrete sculptures in twelve galleries. The MUSA project was the brain child of Dr Jaime Cano, the local head of Mexico’s Environment and Natural Resources Secretariat, he commissioned British sculptor Jason Taylor to build an artificial reef that would take some of the impact off the local reefs and create something special to increase the areas biomass of marine life.

 

Following our guide Enrique, we explored this unusual dive site for almost an hour, visiting several of the galleries which have names like ‘the silent evolution’, ‘the garden of hope’ and ‘the promise’. The first sculpture we came across looked like a giant Christmas decoration, while nearby was a large dolls house. We then swam around hundreds of sculptures of people standing, which was actually very creepy, and got even weirder as nearby there were sculptures of people bowing with their heads in the sand. We ended the dive exploring a life sized VW beetle made of concrete. In the short time these sculptures have been on the bottom they have become lightly decorated with corals, seaweeds and sponges, but are only home to small groups of reef fish.

 

We saw a lot more reef fish on our next dive at a site called Manchones Reef No.1. This site was just brilliant, a rocky reef with caves and ledges to explore in depths to 11m. The reefs of the Caribbean look nothing like the reefs we are use to in the Indo-Pacific region, less colourful but still covered in pretty fans, soft corals, sponges and hard corals. But as the reefs around Isla Mujeres have been protected from fishing pressures since 1996, they swarm with Caribbean reef fish, especially thick schools of grunts. It was just enchanting swimming around and through these immense schools of grunts, they were everywhere and we encountered four species from this family – blue-striped grunts, white grunts, Caesar grunts and French grunts. Other fish species we encountered included moray eels, porkfish, trunkfish, hamlets, parrotfish, rock cods, globefish and some beautiful angelfish.

 

Invertebrate species appeared to be limited, but we did see shrimps, crabs, crayfish, sea stars, sea urchins and sea cucumbers, but surprisingly no nudibranchs. A highlight was the beautiful flamingo tongue, a lovely small shell with a beautifully decorated mantle. This was one signature species of the Caribbean we had hoped to see, and once Enrique pointed out one we found them everywhere.

 

The next day the wind continued to blow, so we explored more of Manchones Reef at sites called the Coral Gardens and No.2. Schools of grunts again had our cameras working overtime, but we also encountered barracuda, jawfish, hogfish, gropers, several southern stingrays and a number of turtles, including the largest loggerhead turtle we have ever seen.

 

The following day the wind got even stronger and all diving was cancelled; it looked like we were going to miss the cave of the sleeping sharks. Back in 1972, the shark researchers, led by the late great Eugenie Clark, discovered that the water in the caves was unusually rich with oxygen and had a lower salt content than the surrounding water, possibly caused by upwellings from the mainland. They discovered five species of sharks used the caves, including species that would normally never stop swimming such as tiger sharks, Caribbean reef sharks and bull sharks. The sharks would rest in the cave for hours at a time, breathing the oxygen rich water. The researchers theorized that the sharks were not actually sleeping but just lethargic, and even a little high, from the narcotic effect of the high oxygen content of the water. They also thought that the low salt content would help to loosen parasites on the sharks’ skin, allowing them to get cleaned while in the cave.

 

It was extremely exasperated that we had come all this way but wouldn’t get to see the amazing sleeping sharks, but the free day gave us a chance to explore more of the island, checking out the shops, enjoying a swim in the calm water on the western side of the island, photographing the abundant sea birds and partake of the local cuisine and beer (we had actually been enjoying these each day).

 

The weather improved for our final day of diving, not enough to explore the cave of the sleeping shark, but good enough to explore one of the local shipwrecks. Around a dozen shipwrecks are scattered around Isla Mujeres, most being scuttled as artificial reefs for divers to enjoy. We would have loved to explore them all, but the dive we did on Gunboat C58 was just spectacular.

 

Tying up to the buoy above the wreck we found that there was a strong current running (common we later learnt at most of the wreck sites as they are quite exposed), so Enrique gave as a detailed briefing and put in place a crossover line so we could all get to the mooring line without expending too much effort. We jumped in to find the visibility over 30m, and quickly made our way to the bottom at 25m. The ship, a former US Navy minesweeper, was scuttled in the 1980s and is now a haven for fish. But the first thing that impressed us were the dozen spotted eagle rays cruising around the wreck.

 

After watching the rays for a while Enrique led us through the wreck, along several passageways and into a few rooms, then to the stern area where schools of grunts and goatfish were sheltering. Inside the ship we were protected from the current so had a great view of the soaring eagle rays as they swam laps around the wreckage.

 

Dropping under the stern we got a big surprise to find a sleeping shark, we may have missed the cave of the sleeping sharks, but we did get to finally see a sleeping nurse shark. This species is closely related to the tawny nurse shark often seen on reefs in the Indo-Pacific region, with both spending a lot of time sleeping during the day. As we explore more of the wreck we encountered a huge green moray eel, gropers, hogfish, angelfish and a school of trevally. Our bottom time ended way too quickly on this wonderful shipwreck.

 

For our final dive we headed to Lavandera Reef, and although it was hard to believe this reef was home to even more fish than Manchones Reef. Covering the rocky reef, so you could barely see the coral, were schools of grunts and barracuda, but we also saw moray eels, crayfish and even a large spider crab. But the wonderful angelfish were a highlight here, as we saw all four of the local Caribbean species - the queen angelfish, blue angelfish, gray angelfish and French angelfish.

 

We had a brilliant time diving the reefs and wrecks of Isla Mujeres, but left the island a little frustrated, as we not only missed the cave of the sleeping sharks, but dozens of other wonderful reefs and wrecks that surround this Mexican island paradise.

 

INFORMATION

Getting There

Numerous airlines fly into the international airport at Cancun, from there you can either catch a taxi or a bus to the port and then a ferry over to Isla Mujeres.

 

Diving

Isla Mujeres can be dived year round, with whale sharks seen over the summer, June to August being the best months. Water temperatures vary between 26°C to 30°C and visibility 15m to 30m. Numerous dive operators are located on the island, but we had a great time diving with Casa Del Buceo.

 

Money

Mexican peso or US dollars, numerous ATM machines are located on the island.

 

Language

Spanish is the official language, but English is also widely spoken.

 

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