|Survival of silver catfish fingerlings exposed to acute changes of water pH and hardness|
Townsend, C.R.; Baldisserotto, B. (2001). Survival of silver catfish fingerlings exposed to acute changes of water pH and hardness. Aquacult. Int. 9(5): 413-419
In: Aquaculture International. Springer: London. ISSN 0967-6120, more
Calcium; Fingerlings; Hardness; Hardness; Hardness; P; Ph; pH; Survival; Water hardness; Marine
|Authors|| || Top |
- Townsend, C.R.
- Baldisserotto, B., correspondent
The aim of this study was to examine the survival of fingerlings of silver catfish, Rhamdia quelen, in water with different pH and hardness values. Fingerlings (1.60 ± 0.14 g; 5.67 ± 0.15 cm) were randomly assigned to 35 treatments (in triplicate) and maintained in 44 L polyethylene tanks (10 fingerlings/tank) for 96 h. Fingerlings were exposed to seven solutions of varying pH (3.5, 3.75, 4.0, 7.0, 9.5, 10.0, and 10.5) and five solutions of varying hardness (30, 70, 150, 300, and 600 mg.l-1 CaCO3). Survival was assessed at 12, 24, 48, 72, and 96 h. Fingerling mortality was 100% after 12 h exposure to pH 3.5 at all hardness levels, whereas mortality at pH 3.75, 10.0, and 10.5 decreased with increasing hardness. There was no mortality of fingerlings exposed to pH 4.0, 7.0, and 9.5 at all hardness levels. The results allow us to conclude that the hardness levels studied do not affect the survival of silver catfish fingerlings exposed to pH 3.5, 4.0, 7.0, and 9.5 for 96 h. However, the increase of water hardness improved survival of fingerlings of this species exposed to pH 3.75, 10.0, and 10.5.