Mataiva Lagoon – Mataiva & Makatea (Tuamotu)

15m Max

10-25m Vis

boat

Site Overview

Mataiva Lagoon is a unique and geologically fascinating dive site featuring a flooded karst landscape where freshwater springs bubble up through the lagoon floor creating surreal halocline layers and visual phenomena that exist at very few dive sites anywhere in the world. The flooded karst topography creates an underwater landscape of submerged pinnacles, channels, and depressions that differ dramatically from the typical flat lagoon floors found on other Tuamotu atolls, providing diverse micro-habitats that support an exceptional diversity of small marine organisms. Freshwater springs emerge from the limestone substrate at various points throughout the lagoon, creating shimmering halocline layers where fresh and salt water meet that produce mesmerising visual effects as light refracts differently through the two water densities. The unique combination of fresh and salt water environments supports an unusual mix of species that includes both typical reef organisms and species more commonly associated with brackish water habitats. The macro life diversity is exceptional, with numerous nudibranch species, seahorses, pipefish, and various shrimp species inhabiting the complex substrate created by the karst formations. The site is particularly renowned among experienced divers for its excellent night diving opportunities, where torch light reveals the full extent of the halocline phenomena and the diverse nocturnal community that emerges from hiding after dark. The geological uniqueness of Mataiva Lagoon makes it a site of scientific interest as well as recreational diving enjoyment.

Dive Briefing

"Descend from the boat into the unique flooded karst environment where the submerged limestone formations immediately create an unusual underwater landscape different from any other site in the Tuamotus. Freshwater springs bubble up from the lagoon floor at various points, creating shimmering halocline layers where you can swim through zones of mixed fresh and salt water that produce surreal visual effects. The karst pinnacles and channels create diverse habitats supporting an impressive diversity of small marine organisms that reward careful searching and patient observation. Nudibranchs are abundant throughout the site, with different species associated with the various substrate types created by the karst formations. Seahorses and pipefish inhabit the seagrass areas among the karst structures, their camouflaged bodies requiring patient searching. Shrimp gobies maintain their symbiotic burrows on the sandy patches between the limestone formations. For night dives, the halocline phenomena become even more dramatic under torch light, and the diverse nocturnal community emerges to create an extraordinary underwater experience."