General - Blue Hole National Park - Turneff Island
The Barrier Reef lies about half a mile off the windward side of the island. It is the longest barrier reef in the Western Hemisphere and the second longest in the world. To the east of the Barrier Reef are three separate atoll reefs. There is also a fourth atoll reef, Banco Chinchorro, just to the north in Mexican waters, which will be of particular interest to wreck divers. The three Belize atoll reefs are formed on two tiers of submarine ridges: Turneffe and Glover's on one ridge and Lighthouse on a separate ridge farther to the east. This accounts for their similar outlines and NE-SW orientations. Deep marine trenches separate the two ridges.
The Blue Hole is located about 11 km (7 miles) north of Half Moon Caye. It is part of the Lighthouse Reef System. The Blue Hole is the largest ocean sinkhole in the world, created by a collapsed underground cavern, hence giving the appearance of a dark blue circle amidst the turquoise sea. The Blue Hole is over 300 m (1000ft) in diameter and 135 m (450ft) deep. Below the shallop lip is a cavern filled with huge stalactites and stalagmites.
The Blue Hole became famous in 1972 when Jacques Cousteau sailed his ship Calypso to the Blue Hole to film inside.
The Turneffe Islands make up the largest of the three offshore atoll reefs in Belize and also are the most accessible from the mainland. Unlike the other two-Glovers and Lighthouse-there are over 200 cayes within the reef which are covered with mangroves. These have created land, lagoons, creeks and expansive flats. There are a few routes through from one side to the other, but these should only be attempted by those who know the waters well.
Closest to Belize City and easily accessible, Turneffe features spectacular diving suitable for every level of diver. Along the western reef line north of the Elbow, novice divers can feel comfortable on shallow reefs, removed from the steep and deep walls so typical elsewhere. A varied terrain, wrecks and an abundance of marine life make the eastern reefs on Turneffe's southern end sensational for seasoned divers. Current and walls make the diving here challenging but great for finding large pelagics.
Turneffe is the largest of the three atolls and the only one with an extensive cover of mangroves. Most established dive sites are limited to the southern end, but there is enough here for several weeks of diving.
With more than 200 mangrove islands, the atoll is a natural nursery for a wide variety of exotic fish, including the rare Whitespotted Toadfish, which is endemic to Belize. Other types of tropical marine life commonly viewed include eagle rays, playful dolphins, turtles, huge green morays, giant jewfish, nurse sharks, reef sharks, trunkfish, grouper, snapper, permit, and horse-eye jacks.
The Turneffe Atoll area stretches 30 miles long and 10 miles wide. It has often been described as a myriad of different dive destinations all bundled into one.
The depth of the water and distance from the mainland of Belize result in excellent underwater visibility, normally in excess of 100 feet and often ranging up to 150 feet.
The entire eastern shoreline of Turneffe
is protected by a continuous vertical reef approximately 35 miles (56 km)
long. From the crest of this reef, a narrow ledge falls away over a distance
of about 100 yards (91 m) until it reaches an average depth of between 55
and 65 feet (17-18 M) where the drop- off begins. Along this ledge are a
number of spur and groove formations which are host to a myriad of reef
There are few navigable entrances through the reef. In the southeast there is North Cut, some 400 yards (121 m) south of Cocoa Tree Caye. A little further south is South Cut just 150 yards (45 m) from Big Caye Bokel. The depth of both channels is only 8 feet (2.4 m) so their use is limited to small craft. They both provide access into the South Lagoon where a dive resort is situated on Caye Bokel.
On the southwest corner of the atoll there are entrances at Pirates Creek just above Big Caye Bokel, and Blue Creek, two miles (3.2 km) further to the north. Both entrances are only 5 feet (1.5 m) deep at the mouth although they do deepen to 8 and 13 feet (2.4 and 4 m) respectively. Any craft entering through these channels must exercise extreme caution. The mangroves create murky water inside the atoll and this obscures underwater obstacles.
Further north there is Rendezvous Cut on the west coast and Eastern Cut on the opposite side of the atoll. These entrances are much larger and are used by the diving trade from San Pedro. En route to Lighthouse Reef, the dive boats arrive at the Turneffe Islands about midmorning and usually dive at a site not far from Rendezvous Cut. Afterwards the boats enter through the cut and anchor long enough to allow the passengers a light lunch before proceeding through Eastern Cut and across to Lighthouse Reef.
On the east coast in particular, there are massive concentrations of fishes which come in close to the reef to feed. Here are the largest shoals of fishes I have ever seen. Hovering between 50 and 80 feet (15-24 m) are shoals of horse-eye jack, crevalle jack, black snapper, cubera snapper, mutton snapper and permit.
There are literally thousands of fish in a single shoal with more than one shoal often in sight. Individual fish sizes range from 5 to 30 pounds (2- 4 kg), but the size of all fish in any single shoal is always uniform, as they were spawned together and have grown together. The diver will frequently encounter this in shallow water where the fish will be 2 or 3 inches (5 or 8 cm) long, but as the fish grow they tend to disperse as they need more individual space to feed. Here, the concentration of nutrients and the resultant populations of smaller fish is so great as to sustain shoals of larger fish which feed on them. These, in turn, attract the pelagics, and lemon, Caribbean reef, blacktip and the occasional solitary hammerhead shark can be seen here.
The drop-off on the eastern side of the reef begins at 80 feet (24 m). Venturing deeper, divers will encounter some truly formidable scenery. Occasionally a large shoal will be silhouetted against the sun above the diver. Apart from the grouper and jewfish always associated with deeper waters, there are other surprises here. Tuna, especially skip jack tuna, and Spanish and king mackerel are common. Wahoo and cero are less common but still regularly sighted. On rare occasions divers have come face to face with an Atlantic blue marlin or a sailfish.
Throughout the remainder of the western coastline there are many creeks and cuts between the mangrove cayes within the atoll. The prevailing easterly winds have the effect of blowing sand and silt westwards and this has a detrimental effect on the reef. Coral that is constantly subjected to silt and other sediment eventually chokes and dies. This is all too obvious when comparisons are made between the different reef structures and their condition on either side of the atoll.
On the west, spur and groove formations dominate the underwater scenery with too many wide grooves of sand and few spurs of coral. There are one or two exceptions, but nobody searches for diving which is good to mediocre when excellent diving is found elsewhere on the atoll. This complete change of underwater terrain is a feature of this atoll reef alone and is largely due to the great number of mangroves which are absent on the other two atol reefs.