Okinawa amberjack - Okinawa amberjack

A marine fish belonging to the order Perciformes and family Acanthidae of the class Osteichthyes. It is found in the western Pacific Ocean, from the Izu Islands, Tosa Bay, the Ryukyu Islands, the East China Sea, southern Taiwan, the Philippines, Papua New Guinea, the northeast coast of Australia, to the Samoa Islands. Its body is ovoid, high and laterally flattened, with a body length of 1.8 to 1.9 times its body height. Its caudal peduncle is low and short, and its head length is 3.1 to 3.6 times its caudal peduncle height. Its eyes are very large, more than half the head length. The interocular space is narrow and sunken. Its mouth is large and oblique, with the rear end of the upper jaw slightly extending beyond the anterior edge of the pupil. It has broad, villiform tooth bands on both the upper and lower jaws, and the outer row of teeth on the upper jaw is somewhat large. The vomer (the bone at the front end of the skull floor) and palate also have a band of villiform teeth. The edge of the main operculum is smooth and has one spine. The lower and rear edges of the preoperculum have somewhat strong serrations, and there are two small spines at the corner. The interoperculum and hypooperculum have weak serrations on their edges. The gill rakers are spear-shaped and longer than the gill lobes. There are 23 to 25 gill rakers in total. The body and head are covered with relatively large comb scales that are difficult to remove. The spines on the rear edge of the scales are long and thin, arranged in a comb shape, and pointed at the tips. The snout, around the eyes, both lips and preoperculum are scaleless. There are 30-32 pore-like scales on the lateral line. The dorsal fin has 10 spines and 11-12 soft rays, with the 4th or 5th spine being the longest. The base length of the soft rays is extremely short, less than half the base length of the spines. The anal fin has 3 spines and 11-12 soft rays, with the 3rd spine being the longest. The rear edge of the caudal fin is slightly rounded. The pelvic fin reaches the beginning of the anal fin, and the innermost soft ray is attached to the side of the body by a fin membrane. The body is pale reddish yellow with 10 or more dark red horizontal bands. There are many vertical bar-shaped spots of the same color between the head and the horizontal bands on the side of the body. The edges of the soft rays of the dorsal and anal fins, the edges of the pelvic fins and the rear edge of the caudal fin are black. Juvenile fish, measuring 12.3 mm in length, have a round body, large head, thick and long preopercular spines, and strong spines on each fin that lack serrated leading edges. Adult fish live in rocky areas at depths of 100-240 meters or on nearby sandy and muddy bottoms, and can be caught by fishing, longline, and bottom trawl, although catches are small. They can reach a maximum length of about 34 cm, but most are around 20 cm. They are served grilled with salt or stewed.

Initially, an individual found in the Ryukyu Islands was described as a new species, P. multifasciata , in 1973 (Showa 48), but in 1988 it was determined to be the same species as this one known from Celebes Island.

[Kunio Amagaoka August 20, 2021]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

硬骨魚綱スズキ目キントキダイ科に属する海水魚。伊豆諸島、土佐湾、南西諸島、東シナ海、台湾南部、フィリピン、パプア・ニューギニア、オーストラリア北東岸を経てサモア諸島までの西部太平洋に分布する。体は卵形で体高が高く、側扁(そくへん)し、体長は体高の1.8～1.9倍。尾柄(びへい)は低くて短く、頭長は尾柄高の3.1～3.6倍。目はきわめて大きく、頭長の2分の1より大きい。両眼間隔域は狭くてくぼむ。口は大きく斜位で、上顎(じょうがく)の後端は瞳孔(どうこう)の前縁をわずかに越える。上下両顎に幅の広い絨毛(じゅうもう)状歯帯があり、上顎の外列歯はいくぶん大きい。鋤骨(じょこつ)（頭蓋(とうがい)床の最前端にある骨）と口蓋骨にも絨毛状の歯帯がある。主鰓蓋骨(しゅさいがいこつ)の縁辺は円滑で、棘(きょく)が1本ある。前鰓蓋骨の下縁と後縁にやや強い鋸歯縁(きょしえん)があり、隅角(ぐうかく)部に小さい棘が2本ある。間鰓蓋骨と下鰓蓋骨の縁辺に弱い鋸歯がある。鰓耙(さいは)は槍(やり)形で、鰓葉より長い。全鰓耙数は23～25本。体と頭部ははがれにくいやや大きな櫛鱗(しつりん)で覆われる。鱗(うろこ)の後縁の棘は細長く櫛(くし)状に並び、先端でとがる。吻(ふん)、目の周り、両唇および前鰓蓋骨は無鱗。側線有孔鱗数は30～32枚。背びれは10棘11～12軟条で、第4棘または第5棘が最長。軟条部基底長はきわめて短く、棘部基底長の半分以下。臀(しり)びれは3棘11～12軟条で、第3棘が最長。尾びれの後縁はやや丸い。腹びれは臀びれ始部に達し、もっとも内側の軟条は鰭膜(きまく)で体側に付着する。体は淡赤黄色で、10本以上の暗赤色の横帯がある。多くの垂直の棒状の同色の斑紋(はんもん)が頭部と体側の横帯の間にある。背びれと臀びれの軟条部縁辺、腹びれの縁辺、および尾びれの後縁は黒い。体長12.3ミリメートルの稚魚では体が丸くて、頭が大きいこと、前鰓蓋骨棘は太くて長いこと、各ひれの棘は強大で、棘の前縁に鋸歯がないことなどの特徴をもつ。成魚は水深100～240メートルの岩礁域やその近くの砂泥底にすみ、釣り、延縄(はえなわ)、底引網でとれるが、漁獲量は少ない。最大全長は34センチメートルほどになるが、20センチメートル前後のものが多い。塩焼きや煮つけにする。

　当初は、南西諸島からとれた個体が1973年（昭和48）に新種、P. multifasciataとして記載されたが、1988年にセレベス島から知られていた本種と同種とされた。

［尼岡邦夫　2021年8月20日］

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