Kamuruchi (English spelling) snake head

A freshwater fish belonging to the family Cobweb family, suborder Cobwebs, suborder Cobwebs. The name Kamulchi is its Korean name. Along with the closely related Cobwebs, it is commonly known as snakehead. Its body is thick and cylindrical. Its head is vertically flattened and snake-shaped. Its mouth is large and slightly slanted, and its teeth are sharp. The bases of its dorsal and anal fins are long, and the rear end of its tail fin is round. Its entire body is covered in scales, its surface is slimy with mucus, and its lateral line is divided into an upper lateral line and a lower lateral line. Its back is blue-black, and its ventral side is pale. There are two black vertical lines behind the eyes, and large black spots form two rows, one above the other, on the sides of its body. They have an accessory respiratory organ (suprabranchial organ) consisting of two mucous membranes in the suprabranchial cavity, and breathe air inhaled through their mouth. This makes them resistant to oxygen deficiency and allows them to live in polluted water.

It is a carnivorous fish that prefers shallow muddy bottoms with slow currents and overgrown with aquatic plants and floating plants, and attacks small fish, frogs, birds, and even animals. It is highly resistant to cold and heat. The spawning season is from May to August, and males and females work together to float the stems and roots of aquatic plants on the water surface to create a simple floating nest about 1 meter in diameter. They lay floating eggs in the nest, and the parent fish of both sexes protect them under the nest until the hatched fry leave the nest. They hibernate in the mud during the winter. They reach maturity at 25 cm in one year and 35 cm in two years. After several years, they reach 80 cm to 1 meter in length. They are native to the Heilongjiang River Basin in northeastern China, north of the Yangtze River Basin, and rivers and lakes in the plains of the Korean Peninsula. There are records that they were introduced to Japan around 1923 (Taisho 12). They are currently distributed in ponds and swamps in Honshu, Shikoku, and Kyushu.

The flesh is white and delicious when fried, but it can be a second intermediate host for the spinognathus rotundus, and since there are encysted larvae in the muscle, it is extremely dangerous to eat it raw.

A closely related species is the Taiwanese loach Channa maculata , which was introduced to Japan from Taiwan and is older than the Japanese loach. It once thrived widely in the Kansai region, but has recently been driven out by the Japanese loach and its habitat has narrowed, and it can only be found in reservoirs around Himeji City, Hyogo Prefecture.

[Tetsuji Nakabo]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

硬骨魚綱スズキ目タイワンドジョウ亜目タイワンドジョウ科に属する淡水魚。カムルチーの名は朝鮮名。近縁のタイワンドジョウとともにライギョ（雷魚）と俗称される。体は太い円筒状。頭部は縦扁(じゅうへん)しヘビ形である。口はやや斜めに大きく裂け、歯は鋭い。背びれと臀(しり)びれの基底は長く、尾びれの後端は丸い。全身が鱗(うろこ)に覆われ、体表は粘液質でぬるぬるしており、側線は上側線と下側線に分断されている。体色は背部が青黒色、腹側が淡色。目の後方には2本の黒い縦線があり、体側には大きい黒斑(こくはん)が上下2列をなしている。上鰓腔(じょうさいこう)に2枚の粘膜からなる付属呼吸器官（上鰓器官）があり、口から吸い込んだ空気を呼吸する。このため酸素欠乏に強く、汚濁水でも生息が可能である。

　水草や浮き草の茂った流れの緩い浅い泥底を好み、小魚やカエル、鳥や獣類まで襲う肉食魚である。耐寒・耐暑性に富む。産卵期は5～8月で、雌雄が共同で水草の茎や根を水面に浮かべ、直径約1メートルの簡単な浮き巣をつくる。巣の中に浮性卵を産み、孵化(ふか)した稚魚が巣離れするまで、雌雄の親魚は巣の下で保護をする。冬の間は泥の中で冬眠する。1年で25センチメートル、2年で35センチメートルになり成熟する。数年して80センチメートルから1メートルになる。原産地は、中国東北部の黒竜江流域から揚子江(ようすこう)流域以北および朝鮮半島の平野部の河川や湖沼。日本への渡来は1923年（大正12）ごろという記録がある。現在は本州、四国、九州の池や沼に分布する。

　肉は白く揚げ物などで美味であるが、有棘顎口(ゆうきょくがっこう)虫の第二中間宿主となり、筋肉中に被嚢(ひのう)幼虫がいるので、生食はきわめて危険である。

　近縁種として、日本には、カムルチーより古く、台湾方面より移入されたタイワンドジョウChanna maculataがいる。かつては関西地方に広く繁殖していたが、最近はカムルチーに追われて生息域を狭め、兵庫県姫路(ひめじ)市周辺の溜池(ためいけ)でみられるにすぎない。

［中坊徹次］

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