The Influence of Calcium on the Physiological Responses of the Rainbow Trout, Salmo Gairdneri, to Low Environmental pH

作者：Daniel G. McDonald, Helve Hōbe, Chris M. Wood · 发表于：Journal of Experimental Biology · 年份：1980 · DOI：10.1242/jeb.88.1.109 · 被引用次数：212 · 研究领域：Physiological and biochemical adaptations、Fish Ecology and Management Studies、Aquaculture Nutrition and Growth

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/l) 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/l), 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.