This is Mann, a long narrow island that is pinched in the middle where it is only a few meters from ocean to lagoon side. Deep water Mian Pass separates Mann from the small Mian Island to the north, and there are some nice pinnacle reefs in the lagoon to the right of the pass.
On the northern end of Mann is a natural shallow cove. The two dark lines across it are walls of rocks set there by Marshallese fishermen many years ago. During high tides, sought-after food fish like mullet and juvenile jacks cross the walls and get caught inside the barriers as the tide goes out. No one presently lives on this island (as part of the lease agreement for the atoll by the US government), but Marshallese fishermen still come up here periodically to use the fish trap.
