Blue Hole is a

blue hole A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock ( limestone or coral reef). Their existence was discovered in the late 20th century by fi ...

dive site off the western coast of

Guam Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic ce ...

. It is variously described as "Guam’s signature natural feature dive," "the most requested dive site on Guam," and "one of Guam’s most popular divesites". It is located in northern

Agat Bay Agat Bay is a bay on the west coast of Guam. Its northern boundary is the Orote Peninsula, occupied entirely by Naval Base Guam, which itself lies within the village of Sånta Rita-Sumai. The bay stretches south along the coast of the village of ...

, just south of the entrance to

Apra Harbor Apra Harbor, also called Port Apra, is a deep-water port on the western side of the United States territory of Guam. It is considered one of the best natural ports in the Pacific Ocean. The harbor is bounded by Cabras Island and the Glass Breakwat ...

. Despite being very close to the southern coast of the

Orote Peninsula The Orote Peninsula is a four kilometer-long peninsula jutting from the west coast of the United States territory of Guam. A major geologic feature of the island, it forms the southern coast of Apra Harbor and the northern coast of Agat Bay. Its t ...

, sheer cliffs mean that it is done exclusively as a boat dive, typically out of

Cabras Marina Cabras may refer to the following places: * Cabras, Sardinia, a town in Italy * Cabras Island, on Guam * Pino Cabras (born 1968), Italian politician * Ilha das Cabras, an island in the municipality of Ilhabela, São Paulo, Brazil * Ilhéu das Cab ...

in Apra Harbor, located 20 minutes away. The top of the underwater

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

begins at about and drops to more than . However, the sinkhole is located next to a wall and there is an opening that allows exit at about , putting it just within the limits of an advanced recreational dive, depending on certifying agency. The opening of the sinkhole appears to be a heart shape to divers within it. While entry to the site is done while the dive boat is hooked into a mooring buoy, exit typically requires deploying a

surface marker buoy A surface marker buoy, SMB, dive float or simply a blob is a buoy used by scuba divers, at the end of a line from the diver, intended to indicate the diver's position to people at the surface while the diver is underwater. Two kinds are used; on ...

in east-to-west current and pickup in the open ocean. It is common to see large

pelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that do live on or near the bottom, and reef fish that are associated with coral re ...

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...

s along the wall. The reef flat at 60 feet has several coral patches and schooling Tisch .

References

External links

* Agat Bay Tourism in Guam Landmarks in Guam Underwater diving sites in Guam {{Guam-geo-stub

See also

References

External links