On a brisk August night Dortheus Mentansan slipped into the calm ocean in a wood outrigger canoe with a lantern tied to the bow. A slight, solemn man with the precise paddle stroke that comes from 30 years of practice, Dortheus counts himself as a descendant of the original clan that settled here in the Mayalibit Bay region of Indonesia's remote Raja Ampat islands. Clouds blocked the moon, but Dortheus had no trouble navigating.
Soon several grayish forms—mackerel—took shape in the lamp-lit water: darting, disappearing and reemerging. Dortheus herded the quarry to a cut in the limestone bluffs, where reddish-brown rocks formed a shallow corral. The water's surface roiled as two dozen glistening fish splashed about. Dortheus stepped into the ankle-high water with a triangular net and scooped their bodies into the canoe, where they thumped against its walls for several minutes, robotically opening and closing their mouths.