Ile du Passe - A lagoon fish pass

In 2006 coral scientists started a decade long monitoring project to document the changes to this reef in the Chagos Archipelago of the British Indian Ocean Territory.
Ile du Passe - A Lagoon Fish Pass
Most of the water exchange, which occurs from the open ocean into the shallow lagoon of the Salmon Atoll, travels through the deepest cut in the ring of coral reef islands that make up the Atoll. The island next to this has been called Ile du Passe for navigational purposes, as the consequences of choosing the wrong gap in the island chain for ships would have been severe. However, this water mass moving through with the tides also means the reefs at this site experience high current velocities and are effectively a funnel for large predatory fish and sharks passing into the lagoon.
The larger predatory fish are of course supported by high populations of herbivorous fish and coral-eating fish such as parrotfish, that can also be seen in large schools at the site, and which play a key role in the calcium carbonate sedimentary cycle of the islands.
The reef-life itself is also clearly shaped by the waters rushing through the pass. There are abundant sea fans and finger-like soft corals along some sections of the reef, which thrive in areas of high currents, and large schools of fusiliers and trevally, which frequently swirl through the site.