noun
swim bladder; air bladder
The gas-filled organ in fish that controls buoyancy. In everyday contexts, 浮き袋 is the usual term; 鰾 is a specialized or literary kanji.
See also: 浮き袋
魚のうきぶくろは浮力を調節する役割がある。
The swim bladder of a fish functions to regulate buoyancy.
鰾は魚類に特有の器官である。
The swim bladder is an organ unique to fish.
Common spelling for 'swim bladder' (also means 'floatation device').
Same reading and meaning, but 浮き袋 is the common everyday spelling and also means 'floatation device' (e.g., life preserver). 鰾 is a rare kanji specifically for the fish organ.
The kanji 鰾 is composed of 魚 (fish) and 票 (sign, mark), but the historical derivation is uncertain. The reading うきぶくろ is a jukujikun meaning 'float bag'.