Figure 3

Movement and rearing pH. The number of times each animal (X ± SD) crossed between zones was continuously recorded for 20 min. Y values were calculated by dividing control stimulus (plain pond water) moves by the experimental stimulus (extract or metal) moves. Hence, Y axis values above 1 indicate that the animal moved less during experimental treatments than under control conditions. Letters are Tukey multiple comparisons. Identical letters indicate no significant difference between values.