Effects of subchronic exposure to aluminium in acidic water on bioenergetics of Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) were exposed for 36 days to water from the ac idified (pH 5.2) Fossbekk River (Norway) with 50 mug.L-1 of aluminium (Al) added as AlCl3, or to circumneutral water (pH 6.6) from Ims River (Norway), Food consumption, cardiac output, swimming activity, and growth rate were measured to determine the effects of sublethal levels of Al in acidic water on the bioenergetics of the fish. Food consumption was reduced in acidic w ater and Al during the first 12 days, but was not significantly different f rom the control group during the rest of the exposure. A significant decrea se in body weight was concomitant with the reduction in food consumption. T he fish also kept losing weight during the rest of the exposure despite the return of their appetite to normal. Cardiac output of the fish exposed to acidic water and Al was not significantly different from the control group after 36 days of exposure. Swimming activity remained significantly elevate d throughout the exposure to acidic water and Al. These results indicate th at sublethal levels of Al can alter the energy budget of Atlantic salmon li ving in acidified surface waters, (C) 2001 Academic Press.