Western Rocky

Western Rocky, near the archipelago's southern edge, concentrates Mergui's character into one cluster of limestone islets. The centerpiece is a tunnel passing clean through the main rock, a torch-lit corridor where tawny nurse sharks rest in the recesses and lobster eyes glitter from the ceiling cracks; divers exit into blue on the far side feeling they have been let in on something. Around the islets, walls and boulder slopes hold tigertail seahorses, harlequin shrimp, ornate ghost pipefish, and frogfish in densities that keep macro guides busy, while trevally and rainbow runners work the outside water. Night dives here rank with the region's best.

您此行的高光时刻: The through-island tunnel with resting nurse sharks, elite macro walls, strong night diving

地形地貌: Limestone islets with a through-tunnel, walls, and boulder gardens

水流: Current splits around the islets; the tunnel is dived on the quieter windows.

危险因素: A genuine overhead passage with surge on some tides; save it for days when the water agrees.

保育: The tunnel's residents tolerate polite traffic; lights out of eyes and no blocking of the exits.

高氧（Nitrox）: 在此值得使用——各潜点深度落在富氧空气（nitrox）能有效延长免减压时间的区间（前提是持有相应认证）。