Egg Development and Early Life History of the Korean Southern Spine Loach, Iksookimia hugowolfeldi (Pisces: Cobitidae)

한국고유종 남방종개 Iksookimia hugowolfeldi (미꾸리과)의 난발생 및 초기생활사

Egg development and early life history of Korean southern spine loach, Iksookimia hugowolfeldi, were observed in the present study. Eggs were obtained after injecting females with 0.5 mL/kg of Ovarprim. Eggs were artificially fertilized using the dry method in the laboratory. Number of spawned eggs were $1,933{\pm}530per$ individual. Mature eggs were slightly adhesive with light yellowish coloring, and they measured $1.35{\pm}0.03mm$ in diameter. Hatching of the embryo occurred 56 h (50%) after fertilization at water temperature $25^{\circ}C$, and newly hatched larvae were averaged of $5.6{\pm}0.18mm$ in total length. At 5 days after hatching, larvae averaged $7.8{\pm}0.31mm$ in total length and their yolk sacs had been completely absorbed. Beginning at 15 days after hatching, the fish entered the juvenile stage and reached $13.2{\pm}0.87mm$ in total length. At 100 days after hatching, the band patterns and external form of juvenile were similar to those of adults, and they averaged $49.2{\pm}4.29mm$ in total length.

한국 고유종 남방종개 Iksookimia hugowolfeldi의 난발생 및 초기생활사를 밝히기 위하여 조사를 실시하였다. 성숙한 개체 복강에 Ovaprim (0.5 mL/kg)을 주사하여 12시간 경과 후 복부 압박법으로 채란하여 건식법으로 인공수정 시켰다. 산란된 난은 평균 $1,933{\pm}530$개로, 약한 점착성을 띤 밝은 노란색의 분리침성난이었으며, 난경은 $1.35{\pm}0.03mm$였다. 수온 $25^{\circ}C$에서 수정 후 56시간(50%)에 부화하였으며, 크기는 전장 $5.6{\pm}0.18mm$였다. 부화 후 5일에는 전장 $7.8{\pm}0.31mm$로 난황을 모두 흡수하여 후기자어기로 넘어갔으며, 부화 후 15일에는 전장 $13.2{\pm}0.87mm$로 지느러미 기조가 모두 정수가 되어 치어기로 이행하였다. 부화 후 100일에는 전장 $49.2{\pm}4.29mm$로 성장하고 외부형태 및 체측반문이 성어와 비교적 유사하였다.