noun
flotsam crab (Planes cyaneus)
A species of crab that lives on floating objects in the open ocean. Scientific name: Planes cyaneus.
オキナガレガニは流木や海藻に付いて漂流する。
The flotsam crab drifts by clinging to driftwood or seaweed.
The name literally means 'offshore drifting crab', from 沖 (offshore), 流れ (drifting), and 蟹 (crab).