Avoidance of Low pH in Selection of Spawning Sites by Brook Trout (Salvelinus fontinalis)

Brook trout (Salvelinus fontinalis) show a strong preference for upwelling water in selection of precise spawning sites. Advantage was taken of this behavior in observing discrimination of pH by 48 breeding females. When artificial aquifers delivered ambient (6.7), alkaline (8.0), and acid water (varied at pH 4.0, 4.5 and 5.0 in three trials), females clearly avoided upwellings of pH 4.0 and 4.5 in preference to alkaline and ambient upwelling. Discrimination was not evident at pH 5.0. As natural springs in the Adirondack area are likely to be alkaline, the strong preferences of brook trout for alkaline upwelling water for breeding sites assures a satisfactory environment through egg and larval stages for at least this environmental condition.