Abstract
The tolerance of desert pupfish, Cyprinodon n. nevadensis to acid water was tested by exposing a group of fish for 14 weeks to alkaline water resembling their natural habitat (pH 8.3) and another to sublethal acidity (pH 6.3). The difference in mean times to loss of equilibrium at pH 4.2 (sublethal = 19.2 ± 2.93 hours; control = 17.9 ± 5.37 hours) was not statistically significant, indicating a failure to acclimate to the sublethal acidity.
A reciprocal transfer experiment was performed with a sublethal (pH 6.3) and a control group (pH 8.3) to learn whether reproductive performance would compensate for acid stress. Reproductive performance was measured by egg production (eggs gm^−1^ day^−1^) and frequency of egg laying. In the first portion of the experiment the two groups were acclimated to their respective conditions for 3 weeks prior to a 3‐week measure of reproductive performance. The two groups were then reversed and tested again for 5 weeks. Reproductive performance of a control group was monitored for the 11‐week experimental period. No adaptation of the reproductive function occurred, since the transferred controls and acclimated sublethals were not statistically distinguishable. The sublethal group did not recover its reproductive capacity after transfer to the control level, suggesting either that permanent damage to some portion of the oogenesis process might have been suffered as a result of the acid exposure, or that the recovery was delayed beyond the 5‐week duration of this portion of the experiment.