Wedge pufferfish - Wedge pufferfish

A marine fish belonging to the order Tetraodontiformes and family Mola. It is found in various locations south of the Chubu region of Honshu, as well as in tropical waters around the world. Its body is strongly laterally compressed and somewhat long. The dorsal and anal fins are paired at the very back of the body. It does not have a true caudal fin, but a rudder fin (clavus) is located at the tail. When the mouth is closed, it becomes a vertical slit. This type of mouth is not seen in other fish. It reaches a total length of 50 centimeters. It spawns from January to March, and the eggs are pelagic and separate. It undergoes significant metamorphosis during its juvenile stage. Immediately after hatching, the larvae are covered in a thin bony membrane similar to the shell of a boxfish. Eventually, numerous spines develop on this shell, the body height increases, and an underdeveloped tail fin also appears. As it grows, the spines recede, the body height decreases, and the tail fin disappears. It is caught using tuna longlines, and its meat is edible.

[Keiichi Matsuura]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

硬骨魚綱フグ目マンボウ科に属する海水魚。本州中部地方以南の各地、および世界中の熱帯水域に分布する。体は強く側扁(そくへん)し、やや長い。背びれと臀(しり)びれは体の最後部で対在する。真の尾びれはなく、舵(かじ)びれclavusが尾部にある。口は閉じると垂直の裂孔となる。このような口はほかの魚にはみられない。全長50センチメートルに達する。産卵期は1～3月で、卵は分離浮性卵。幼期に著しい変態をする。孵化(ふか)直後の仔魚(しぎょ)は、ハコフグの甲らに似た薄い骨性の膜に包まれている。やがて、この甲らに多数の棘(とげ)が発達し体高も大きくなり、未発達の尾びれも生じる。成長するにつれて棘は退縮し、体高は小さくなり、尾びれは消失する。マグロ延縄(はえなわ)で漁獲され、肉は食用となる。

［松浦啓一］

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