A grey seagrass grazer with a downturned snout and a notched tail fluke, met by staying still at the edge of a bed rather than by swimming at it.
To about 3 m and several hundred kilograms, grey-brown, with a broad downturned snout, no dorsal fin, and a horizontal tail fluke notched in the middle like a dolphin’s. The manatee, which does not occur in the Indo-Pacific, has a rounded paddle-shaped tail instead, so the tail settles it.
It eats seagrass and almost nothing else, and it feeds by ploughing the bed with that snout, leaving winding cleared trails that are visible from the surface and are usually the first sign that one is in the area. It has to surface every few minutes. Finding one is a matter of being still at the edge of a seagrass bed and letting the animal work towards you; swimming after a dugong ends the encounter. Populations are thin and slow to recover — a female produces one calf every few years — and the animal is threatened across most of its range by seagrass loss, boat strike and net entanglement.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.