Tolerance of Juvenile Flatfish Paralichthys orbignyanus to Acid Stress |
| |
| Authors: | Wilson Wasielesky Jr. Adalto Bianchini Marcos H. S. Santos Luis H. Poersch |
| |
| Affiliation: | Laboratório de Maricultura, Departamento de Oceanografia, Fundaçäo Universidade do Rio Grande. CP 474, Rio Grande, RS 96201–900 Brasil;Laboratório de Zoofisiologia, Departamento de Ciências Fisiológicas, Fundaçäo Universidade do Rio Grande. Rio Grande, RS 96201–900 Brasil |
| |
| Abstract: | Abstract.— The tolerance of juvenile flatfish Paralichthys orbignyanus to acid stress, was studied in 30-L plastic tanks using ten flatfishes (95 ± 13 g) per treatment. Water pH was monitored every 3 h and re-adjusted to the test pH using either HCl or NaOH. The photoperiod was fixed at 12L:12D, water temperature at 23 ± 0.8 C, and salinity at 30 ppt. Fish survival and ventilatory rate were monitored daily. At pH 4.0, we observed 100% mortality and ventilation rates different from controls. At pH 5.2, there was 100% survival even after 96 h. However, ventilation rate was higher than in controls. At pH equal or higher than 6.0, we observed 100% survival and normal ventilation rates. The estimated pH which would kill 50% of test organisms were: 4.51, 4.50 and 4.40 after 48, 72, and 96 h of experiment, respectively. These results show that juvenile flatfish are relatively tolerant to acid stress. |
| |
| Keywords: | |
|
|
