The physiological responses of 1- to 2-year-old rainbow trout to low pH are dependent on the environmental calcium concentration. Trout, maintained for 5 days in moderately hard water ([Ca2+] = 1·6–2·7 m-equiv/1) at a mean pH of 4·3, developed a major blood acidosis but exhibited only a minor depression in plasma ion levels. In acidified soft water ([Ca2+] = 0·3 m-equiv/1), only a minor acidosis occurred, but plasma ion levels fell and there were substantially greater mortalities. Lethal bioassays performed on fingerling trout over a range of pH levels (3·0–4·8) revealed an important influence of external [Ca2+] on resistance to acid exposure. Terminal physiological measurements on adult fish succumbing to low pH in soft water indicate the singular importance of iono-regulatory failure as the toxic mechanism of action under these circumstances.
The Influence of Calcium on the Physiological Responses of the Rainbow Trout, Salmo Gairdneri, to Low Environmental pH
- Views Icon Views
- PDF LinkPDF
- Share Icon Share
- Search Site
D. G. McDONALD, H. HŌBE, C. M. WOOD; The Influence of Calcium on the Physiological Responses of the Rainbow Trout, Salmo Gairdneri, to Low Environmental pH. J Exp Biol 1 October 1980; 88 (1): 109–132. doi: https://doi.org/10.1242/jeb.88.1.109
Download citation file: