Abstract

The horn fish, Hemiramphus sajori TEMMINCK et SCHLEGEL, is widely distributed in the coastal waters of Korea, Japan and Taiwan. On April 13, 1983, mature adults of the horn fish were collected from Changson channel, Namhae. The authors carried out artificial insemination on the field, and incubated the eggs and reared larvae in the laboratory. And these larvae were reared for about two weeks in glass jars, fed brine shrimp nauplii. The eggs of this species are demersal and adhesive, with 4 to 6 filaments at the animal pole and a filament at the vegetal pole. The diameter of these eggs varies 1.80 to 2.00 mm. The hatching took place in ca. 376 hours after fertilization. During the incubation period water temperature fluctuated between $13.5^{\circ}C\;and\;20.0^{\circ}C$. The newly hatched larvae were elongate in shape $7.40{\sim}8.00$ mm in total length with $40+16{\sim}17=56{\sim}57$ myomers. Many melanophore were distributed on the head, both sides of dorsal body contour, peritoneum and ventral line of the tail part. Four days after hatching, the larvae were from 9.00 to 9.65 mm in total length, at this tims the larvae absorbed the yolk completely, and became postlarvae. Fourteen days after hatching, the larvae attained 13.25 mm in total length, with 14 rays of the dorsal fin, 13 rays of the anal fin, and 4 rays of pectoral fin. The lower jaw has somewhat projected.

1983년 4월 13일 경상남도 남해군 삼동면 지족리앞 창선해협에 설치된 죽방염정치어장에서 성숙한 학공치를 채집하여 현장에서 인공수정시켜, 실험실로 옮겨와 실내에서 난발생과정과 부화자어를 관찰한 결과를 요약하면 다음과 같다. 난은 구형이며 침성난으로 동물극부근에 $4{\sim}6$개, 식물극부근에 1개의 부속계가 있으며, 난경은 $1.80{\sim}2.00mm$이고, 많은 소유구를 가진다. 사육수온은 $13.5^{\circ}C{\sim}20.0^{\circ}C$ 범위에서 수정후 약376시간만에 첫 부화를 하였다. 부화직후의 자어는 전장이 $7.40{\sim}8.00mm$(평균, 7.68mm)이며 근절수는 $40+16{\sim}17=56{\sim}57$. 꼬리지느러미에 8개의 지느러미 원기가 생긴다. 부화후 3일째의 자어는 전장이 $8.95{\sim}9.40mm$이며 brine shrimp유생을 먹기 시작한다. 부화후 4일째의 전장 $9.00{\sim}9.65mm$의 자어는 난황을 완전히 흡수한다. 부화후 14일째의 전장 13.25mm의 자어는 아래턱이 조금 돌출되며 가슴지느러미에 4개, 등지느러미에 14개, 뒷지느러미에 13개의 지느러미줄기가 나타난다.

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