The Mergui Archipelago's southernmost dive site, Western Rocky offers you an overwhelming choice of wall diving, reef diving, pinnacles and an impressive passage through the centre of the island. It is a small barren island, perhaps 60 metres wide with 2 smaller islets to the east which can be reached underwater from the main island or dived as a separate dive. Marine life ranges from the tiniest nudibranch to occasional whale shark visits.
Descending on the southern wall there is a large cavern that starts at 5 metres below the surface and drops to the seabed at around 25 metres. On the western side of the cavern is a large archway swim-though or window, through which sunlight streams. The cavern walls and ceiling are covered in zigzag clams, encrusting sponges and spinous sponges. Shrimps, crabs and lobster are numerous in the crevices and common lionfish are also present.
Just to the east of the cavern is the entrance to a tunnel that runs right through the centre of the island and exits on the northern side. The large passage entrance starts at 17 metres depth down to 24 metres, allowing divers to see daylight (just) for the whole 30 metres through the tunnel.
There is a large chamber inside but as the tunnel reaches the northern side it gradually narrows so that divers must progress in single file. The maximum depth in the tunnel is 24 metres and it splits into 2 exit passages that open to a fringing reef at a depth of 21 metres. The passage to the right is the larger of the 2 exits. The left passage may require removal of the scuba unit to squeeze through. A torch is needed to see into the darker ledges of the tunnel.
The tunnel is a prime example of how marine life prospers when out of the reach of fishermen. Everything inside the cave is big, most notably gigantic lobster and very fat nurse sharks. One nurse shark, about 3 metres long with a very wide body, may make it impossible for divers to continue through the tunnel, instead having to turn around and exiting the way that they entered.
If you exit the tunnel on the north side the prettiest section of the dive site is to the left, on the western tip of the island. Here anemones and pore corals proliferate with a myriad of fish life, including thousands of glassfish being hunted by trevally. Fimbriated moray eels are common and banded sea snakes can be seen.
The south side of Western Rocky is a wall dive with gorgonian sea fans, feather stars and sea whips protruding from the wall. There are some small rocks a short swim away from the wall, in deeper water where white tip reef sharks can be found.
The south wall also makes an excellent night dive. Red finger soft coral and orange cup coral provide the colour. Brown spiny lobsters and painted rock lobster are more numerous here than at any other Burma dive site and are often seen out of their crevices displaying their full length. Long haired hermit crabs, scaled hermit and giant crabs, plus sponge and decorator crabs are all present, as are wandering cowries and, if you are eagle-eyed,angler fish .
There are 4 small pinnacles to the east of the main island. These islets are worth a dive on their own or, in good visibility and when currents allow, can be reached from the eastern tip of the main island. Cuttlefish are common here as are big reef squid. Bearded scorpionfish are everywhere as are twin-spot lionfish and various moray eels including yellow margined, white-eyed and spot-faced morays. Pelagics like jacks, mackerel and chevron barracuda patrol the blue waters.
Western Rocky Pinnacle is located about 500m southwest of the main island. Starting at about 12m below the surface, this dive site consists of a large plateau from which finger-shaped reefs stretch out into the deeper water to a maximum depth of close to 40m.
As soon as you reach the top of the plateau you will notice the thick carpet of purple soft corals that cover most of this dive site; what a beautiful and rare sight! As you make your way over this lilac reef you will see that there is no shortage of life among the hard corals and rocky substrate. Numerous cracks and crevasses provide shelter to different types of moray eels whose heads stretch outwards, their jaws wafting oxygen rich water over their gills. You can also spot all manner of shrimps and other creatures that prefer to stay out of sight of predator animals.
At the section of the reef that extends out from the plateau from the north-western area to the south-eastern corner of the dive site, you will see large schools of snappers and also jacks and mackerel on the prowl.
Currents permitting, it is possible to swim all the way around throughout this dive, but you can also find shelter from the current, if needed, and still have plenty of reef to explore to last a whole dive. At the end of the dive just ascend to 5m, deploy your surface marker and drift along as you watch out for larger pelagics in the blue water, such as tuna or even a large ray.