Effects of total dissolved gas supersaturated water on lethality and catalase activity of Chinese sucker (Myxocyprinus asiaticus Bleeker)

Abstract

Total dissolved gas (TDG) supersaturation caused by dam sluicing can result in gas bubble trauma (GBT) in fish and threaten their survival. In the present study, Chinese suckers (Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h. The median lethal concentration (LC(50)) and the median lethal time (LT(50)) were determined to evaluate acute lethal effects on Chinese suckers. The results showed that the LC(50) values of 4, 6, 8, and 10 h were 142%, 137%, 135%, and 130%, respectively. The LT(50) values were 3.2, 4.7, 7.8, 9.2, and 43.4 h, respectively, when TDG supersaturated levels were 145%, 140%, 135%, 130%, and 125%. Furthermore, the biological responses in Chinese suckers were studied by assaying the catalase (CAT) activities in gills and muscles at the supersaturation level of 140% within LT(50). The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase. CAT activities in the muscles were increased significantly at 3/5LT(50) (P<0.05) and then came back to the normal level. However, there were no significant differences between the treatment group (TDG level of 140%) and the control group (TDG level of 100%) on CAT activities in the gills before 3/5LT(50) (P>0.05), but the activities were significantly lower than the normal level at 4/5LT(50) and LT(50) (P<0.05).

Tolerance and Avoidance Characteristics of Prenant's Schizothoracin Schizothorax prenanti to Total Dissolved Gas Supersaturated Water

“…However, when TDG supersaturation was 130% and higher, differences in tolerance to TDG-supersaturated water were not evident between the two species. Chen et al (2012) reported Chinese Sucker weights and lengths of 39.54 § 7.63 g (mean § SD) and 11.54 § 0.91 cm, respectively, which were larger than the Prenant's Schizothoracin used in this study. We suggest that the life stage and species affected the tolerance of the two fish species and caused differences between them at lower TDG supersaturation levels (125% and less); however, the survival time was not affected by the two factors when TDG supersaturation exceeded a tolerable threshold (130% and higher).…”

“…However, Chinese Suckers exhibited a stronger tolerance than did Prenant's Schizothoracin to 125% TDG supersaturation (Figure 3). Dead Chinese Suckers were not observed by Chen et al (2012) at supersaturation levels of 120% or less. However, when TDG supersaturation was 130% and higher, differences in tolerance to TDG-supersaturated water were not evident between the two species.…”

“…Prenant's Schizothoracin showed a lower tolerance to TDG-supersaturated water than did those five other species. Chen et al (2012) and Huang et al (2010a) studied the acute lethal effect of supersaturated water on Chinese Sucker and Rock Carp at depths of 35 cm and 20 cm, respectively. Chinese Suckers exhibited similar behavior to Prenant's Schizothoracin in supersaturated water, as both species gathered at the bottom of the tanks to avoid the TDG supersaturation.…”

“…Only a limited number of studies have been performed in recent years to determine the impacts of TDG supersaturation on fish living in the upper Yangtze River. Chen et al (2012) and Huang et al (2010a) studied the effects of TDG-supersaturated water on Chinese Sucker Myxocyprinus asiaticus and Rock Carp Procypris rabaudi, respectively. These studies showed that these species exhibited different tolerances to TDG-supersaturated water.…”

Eco-environmentally friendly operational regulation: an effective strategy to diminish the TDG supersaturation of reservoirs

“…Prior studies reveal that the injury to fish is enhanced as the supersaturated TDG level and exposure time increases (Bentley et al, 1976;Huang et al, 2010;Chen et al, 2012). The endurance of fish with respect to supersaturated TDG is different depending on the growth period for the fish species (Liang et al, 2013).…”