Spawning Behavior, Egg and Larvae Developments of Maroon Clownfish, Premnas biaculeatus

A pair of maroon clownfishes with an indonesian native, reared in recirculation culture system to develope its aquaculture techniques. Courtship, spawning behavior, egg developments and rearing of the maroon clownfish larvae were documented. The larval development were described with illustrative figures. The spawning was occurred 8 times between Feburary and August 2004. The gravid female spawned during 15:00-20:00. The male mainly took care of the eggs supplying oxygen by water currents using their pectoral fins, anal fin and mouth. The fertilized eggs were separative-adhesive and oval in shape, and $1.99{\pm}0.03\;mm$ in longer diameter and $0.88{\pm}0.03\;mm$ in shorter diameter. The fertilized eggs were in deep-orange color. Cleavage occurred in 30 minutes after fertilization, and the egg reached 2 cells stage in 1 hour 10 minutes after fertilization at $27.0^{\circ}{\pm}0.5^{\circ}C$. The embryo was formed in 23 hours 40 minutes after fertilization. Hatching began in between $120{\pm}2$ hours and $150{\pm}12$ hours after fertilization at $27.0^{\circ}C$ in the incubator. Total length (TL) of the newly hatched larvae was 3.22 mm with mouth and anus opened. Ten days after hatching, mean TL of the larvae were 6.21 mm with 28 dorsal fin rays, 17 anal fin rays and 28 caudal fin rays. Nineteen days after hatching, mean TL of the larvae were 9.34 mm. At this stage the larva had three white bands on the body, and they began to feed on commercial diet.

Maroon Clownfish, Premnas biaculeatus의 산란습성과 난 발생 및 자치어의 외부형태발달

해수관상어의 한 종인 maroon clownfish, Premnas biaculeatus의 안정적인 종묘생산기술개발의 일환으로 자연산란 후 난 발생과 초기생활사를 구명하였다. 짝짓기 및 산란 후 수컷과 암컷은 가슴지느러미와 입을 이용하여 알 관리를 하였으며, 주로 수컷이 하였다. 수정란은 진홍색을 띤 분리 침성부착란으로, 장경 1.95-2.01 mm ($1.99{\pm}0.03\;mm$), 단경 0.83-0.91 mm ($0.88{\pm}0.03\;mm$)의 타원형이었다. 수온 $27.0{\pm}0.5^{\circ}C$ 조건하에서 수정 1시간 10분경과 후에 최초 난할이 시작되어 2세포기가 되었다. 수정 후 23시간 40분에는 배체가 형성되었고, 부화는 120-150시간 사이에 이루어졌다. 부화 직후의 자어는 전장 3.10-3.44 mm (평균 $3.22{\pm}0.07\;mm$)로 타원형의 적갈색 난황(평균 장경 $0.58{\pm}0.08\;mm$, 평균 단경 $0.46{\pm}0.04\;mm$)을 복부 전반부에 가지고 있었으며, 근절 수는 9+17=26개이고 입과 항문은 열려있었다. 부화 후 10일째 치어는 전장 5.64-6.89 mm (평균 $6.21{\pm}0.69\;mm$)로 성장하였고, 등지느러미 28개, 뒷지느러미 17개, 꼬리지느러미에 28개의 기조수를 보였다. 부화 후 19일째 치어의 전장은 8.32-10.98 mm (평균 $9.34{\pm}1.11\;mm$)이었고, 3개의 백색 가로띠가 주황색 몸체에 생기기 시작했다.