This is part of a series of posts featuring stories, photos and video from a recent field research trip to Kiribati.

What explains the amazing rock formations on coasts of Kiribati?

Fluke coral growth? Ancient rock art like the Nazca Lines? Photoshop?

They are te ma – traditional fish traps – built from pieces of rock or coral collected along the shoreline.

When the tide is in, fish can swim along the “shaft” or through a direct entrance into the heart- or arrowhead-shaped openings.

When the tide recedes again, fish get trapped there and are easy prey. The shaft also helps point people to the place to collect the fish.

These traps can be found at Temaiku, the SE tip of Tarawa, just south of the airstrip.