Relationship between water temperature and oxygen consumption rate of the black scraper Thamnaconus modestus

Abstract

The black scraper Thamnaconus modestus was a commercially important fish species in the 1980s, but suddenly its commercial significance decreased in the 1990s mainly due to continuous overfishing. Recently, in order to reverse the depleted stocks of the black scraper and help the species recover, seed production technology has emerged. This has led to the farming of the black scraper in several parts of the southern coast of Korea. Since detailed research on its metabolism in relation to water temperature has been scanty, this was the investigative focus of the present study. The standard metabolism rates of the black scraper (9-10 months old, total length = 22.6 ± 0.8 cm, wet weight = 140.3 ± 13.9 g) were measured at seven different water temperature settings (12, 15, 17, 20, 23, 26, 28°C) to understand the relationship between metabolism and water temperature. Relationships between water temperature (WT) and oxygen consumption rate (OCR) were obtained as SOCR (weight-specific oxygen consumption rate) = 0.0117WT - 0.0135 (r2= 0.9351) and IOCR (oxygen consumption rate per individual) = 1.8160WT - 5.4007 (r2= 9428). The Q10 (temperature sensitivity), an indicator of the sensitivity of biological function to temperature, was analyzed. In our experiment, when the water temperature increased, the Q10 value decreased. The Q10 value was 6.27 in waters where the temperature ranged from 12-15°C and this was much higher than the values obtained in waters where temperatures ranged between (1) 15-23°C and (2) 23-28°C. Consequently, it was shown that the black scraper is a warm water species and inhabiting waters in the temperature range from 15-28°C is deemed appropriate.