절식한 대구 Gadus macrocephalus 치어의 대사율에 미치는 수온과 광주기의 영향

Abstract

A study was conducted to investigate the effect of water temperature and photoperiod on the oxygen consumption of the starved juvenile cod, Gadus macrocephalus (mean body weight 79.9±2.0 g) in order to assess metabolic response of this species at given conditions. The oxygen consumption rate (OCR) of G. macrocephalus was measured under&nbsp; the combination of four different water temperatures (7, 10, 13 and 16℃) and three different photoperiods (24L:0D, 12L:12D and 0L:24D) with an interval of 5 minutes for 24 hours using a continuous flow-through respirometer. In each treatment three replicates were set up. The OCRs increased with increase in water temperature under all photoperiod conditions (P<0.001). Mean OCRs at 7, 10, 13 and 16℃ ranged 793.7∼1108.4, 1145.7∼1570.3, 1352.8∼1742.5 and 1458.2∼1818.6 mg O2 kg-1 h-1, respectively. Mean OCRs of G. macrocephalus were the highest in continuous light (24L:0D) followed 12L:12D and 0L:24D photoperiod (P<0.001). Mean OCRs of fish exposed to the 12L:12D photoperiod was significantly higher during the light phase than during the dark phase under all temperature conditions (P<0.001). Q10 values ranged 3.19∼5.13 between 7 and 10℃, 1.41∼1.70 between 10 and 13℃ and 1.15∼1.35 between 13 and 16℃, respectively. Based on overall results, water temperature, photoperiod and their combinations exert a significant influence on the metabolic rate of juvenile cod. This study provides empirical data for estimating the amount of oxygen demand and managing the culture of cod under the given temperatures and photoperiods.