조피볼락, Sebastes schlegeli의 초기생활사 동안 생존율 향상을 위한 생물학적 연구 - II. 자치어기의 에너지수지

Biological Study on the Increment of Survival Rate during Early Life Cycle in the Rockfish, Sebastes schlegeli (Teleostei: Scorpaenidae) - II. Energy Budget of the Larvae and Juveniles Stages

조피볼락의 출산 후부터 치어기에 이르기까지 경과한 일수별로 성장, 호홉, 배설, 섭식 및 동화효율 등을 측정하여 에너지수지를 분석하였다. 출산후 자어의 전장은 4.56~5.49mm (평균 4.97mm, n=20)였으며, $20^{\circ}C$에서 1일 평균 성장률은 0.50mm였다. 출산후 경과일수에 따른 건중의 관계식은 $16^{\circ}C$에서 DW=$0.0380e^{0.1120D}$($r^2$=0.9049), $20^{\circ}C$에서 DW=$0.0324e^{0.1394D}$($r^2$=0.9239)였다. 비체중 산소 소비율 및 암모니아 질소배설률은 개체의 크기가 증가할수록 감소하였으며, $16^{\circ}C$에 비해 $20^{\circ}C$에서 높았다. 섭식율은 $16^{\circ}C$에서 자치어기의 25일 동안 65.8cal를, $20^{\circ}C$에서는 89.2cal를 섭취하여 $20^{\circ}C$에서 높게 나타났다. 동화효율은 수온에 따라 차이는 없었으며, 출산 후 20일째에는 $16^{\circ}C$와 $20^{\circ}C$에서 86.2% 였다. 출산 후 치어로 성장하는 동안 호홉에 비해 체성장에 더 많은 에너지를 이용하였으며, 수온이 높을수록 성장률이 빠르게 나타났다 출산 후부터 치어로 성장하는 동안 누적 섭식에너지에 대한 총성장효율은 43%~47%, 순성장효율은 50%~55% 였다.

In order to estimate energy budget of the rockfish, Sebastes schlegeli juvenile, during the period from parturition to juvenile, of rockfish were reared at constant condition of water temperature($16^{\circ}C$ and $20^{\circ}C$). Energy used by the reared juveniles were calculated from estimates of data on growth, oxygen consumption, nitrogen excretion, feeding and energy content. After parturition, total length of juvenile was 4.56~5.49mm(average 4.97mm, n=20), and the average dally growth rates were 0.50mm at $20^{\circ}C$. The weight-specific oxygen consumption and nitrogen excretion rates decreased with increasing body weight. Temperature significantly affected oxygen consumption and nitrogen execretion rates, with the higher rates at $20^{\circ}C$ than $16^{\circ}C$. During the 25 days from parturition to jllveniles, feeding rates were 65.8cal at $16^{\circ}C$, and 89.2cal at $20^{\circ}C$. The assimilation effeciency estimated by nitrogen content of food and egested feces were 85.21% at $16^{\circ}C$ and $20^{\circ}C$. During the period from parturition to juvenile, energy was used the higher in body growth than in oxygen consumption. The gross growth efficiencies($K_1$)and net growth efficiencies($K_2$) of the rockfish, Sebastes schlegeli juvenile ranged from 43% to 47% and from 50% to 55%, respectively.