Effects of acid water and aluminium on smolting and seawater tolerance in Atlantic salmon, Salmo salar

• Published in: Aquaculture Vol. 82; no. 1; p. 383
• Main Authors: Staurnes, M., Blix, P., Reite, O.B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1989
• Subjects: Brackish; Freshwater; Marine; Salmo salar
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/0044-8486(89)90435-3

Seawater tolerance of 1-year-old 20-55 g smolting salmon (Salmo salar ) was assessed during Apr-May after 1 and 5 weeks exposure to 8-10 degree C freshwater. Plasma and tissue ion levels, and gill Na-K-ATPase activity, were analysed every other week. Initially relatively high control levels of Na-K-ATPase peaked in mid-May, and full seawater tolerance occurred then. Enzyme levels and seawater tolerance were reduced in treated groups after 1 week, and further after 5 weeks, to parr levels in the Al-exposed group, probably through metal-induced enzyme inhibition. Hypoosmoregulatory capacity was linearly related to Na-K-ATPase activity in all groups. Relative Na-K-ATPase activity of exposed as compared to control group was linearly related to differences in their plasma Na levels, indicating the role of the enzyme in maintaining plasma Na in freshwater at smolting.