Responses of brook trout (Salvelinus fontinalis) fry to fluctuating acid, aluminum, and low calcium exposure

Brook trout fry were exposed for 30d to temporal combinations of 2 water qualities: 1) pH 5.21, 51 μg/L total Al with 2.39 mg/L Ca (baseline); and 2) pH 4.59, 329 μg/L total Al, with 1.56 mg/L Ca (pulse). Although continuous exposure to the latter conditions caused nearly complete mortality, exposures alternating between the 2 conditions caused much less mortality. Fish experiencing 18 d of baseline conditions before their first pulse exposure had mortality rates equal to fish never experiencing a pulse, indicating acclimation to acid/Al/low Ca stress. -from Authors