Effects of temperature on the oxygen consumption rate and gill fine structure of hybrid grouper, Epinephelus fuscoguttatus ♀ × E. Lanceolatus ♂

Elevated ocean water temperature influences the physiological properties of fishes. This study is expected to characterize the oxygen consumption rate (OCR) and gill morphology in different temperature in hybrid grouper, tiger grouper × giant grouper (TGGGH). TGGGH specimens were distributed into four temperature groups starting from 22, 26, 30 and 34 °C within a recirculatory system under controlled conditions for 30 days in triplicates. Intermittent flow respirometry was directed to distinguish the impact of temperature on the OCR, and scanning electron microscopy was conducted to observe the gill morphology. Results indicated that the OCR of TGGGH increased significantly from 22.98 ± 1.16 mg O2 h−1 to 37.08 ± 1.56 mg O2 h−1 when temperature increased from 22 to 34 °C. Values of respired energy (RE) increased from 456.35 ± 11.41 Jh−1 at 22 °C to 737.88 ± 3.79 Jh−1 at 34 °C. Meanwhile, values of temperature quotients (Q10) were maximum at 22 °C–26 °C and minimum at 26 °C–30 °C. The favored temperature assessed from Q10 was between 26 °C and 30 °C. Gill lesions were significantly observed at 22 °C and 34 °C. The outcomes proposed that this fish species may neglect to maintain sufficient O2 uptake in future atmospheric situations. Thus, optimum oxygen consumption is required for maintaining the TGGGH in aquaculture environment.