Needlefish - Datsu (English spelling)

A general term for marine fish belonging to the order Beloniformes and family Belonidae of the class Osteichthyes. Many of these fish are large, reaching over 1 meter in length. Their bodies are long and slender, covered with small, round scales. Their mouths are large, and both the upper and lower jaws are significantly elongated, with numerous pointed teeth. Their scales have no spines. Their dorsal and anal fins are opposite each other at the rear of their bodies. Their pectoral fins are positioned high, and their pelvic fins are positioned ventrally with six soft rays. Their lateral line runs under their bodies. They have no pyloric caeca, and their intestines run straight. They are found in tropical and temperate seas around the world. Some species live in freshwater. They swim near the surface of the water and prey on small fish with their long mouths and sharp teeth. They lay eggs equipped with sticky threads. A total of 32 species from 9 or 10 genera are known worldwide, and six species from four genera are known from Japan: the Polyphemus genus, Polyphemus gracilis, Polyphemus natalensis and Polyphemus pacificus, Polyphemus occidentalis, Polyphemus nigricans and Polyphemus occidentalis.

The needlefish Strongylura anastomella is found along the coasts of Japan from Hokkaido to Kyushu, as well as in Primorsky Krai, the Korean Peninsula, and China. It is 1 meter long, with a laterally compressed body and a caudal fin that is straight above and below or slightly concave inward. There are no ridges on the caudal peduncle. The bones are blue-green. It is a common species along the coast of Japan, and spawns in coastal seaweed beds around May. It is considered the most delicious of the needlefish species found in Japanese waters.

[Tetsuji Nakabo]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

硬骨魚綱ダツ目ダツ科Belonidaeに属する海水魚の総称。全長1メートル余りになる大形魚が多い。体は細長く、小さい円鱗(えんりん)で覆われる。口は大きく、上下両顎(りょうがく)は著しく延長し、多数のとがった歯を備える。鱗(うろこ)に棘(とげ)がない。背びれと臀(しり)びれは体の後方に対在する。胸びれは高位にあり、腹びれは六軟条で腹位にある。側線は体の下方を走る。幽門垂はなく、腸は直走する。世界中の熱帯や温帯の海に分布する。淡水域に生息する種もある。水面近くを遊泳し、長い口と鋭い歯で小魚を捕食する。粘着糸を備えた卵を産む。世界で9属ないし10属32種が知られており、日本からはヒメダツ属ヒメダツ、ダツ属ダツとリュウキュウダツ、ハマダツ属ハマダツ、テンジクダツ属オキザヨリとテンジクダツの4属6種が知られている。

　ダツStrongylura anastomellaは、北海道から九州までの日本各地沿岸、沿海州、朝鮮半島、中国に分布する。全長は1メートルで、体は側扁(そくへん)し、尾びれは上下に直線的かまたはわずか内側にくぼむ。尾柄(びへい)部に隆起線がない。骨は青緑色である。日本沿岸の普通種で、5月ごろに沿岸の藻場で産卵する。日本近海産のダツ類中で美味とされている。

［中坊徹次］

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