Intra-individual temporal variance of distance to bottom appears to be affected by prior housing conditions. Panel (A) shows the average variance of distance the fish were from the bottom during the entire 12 min behavioral test period. The size of the housing tank is shown on the X-axis and the fish density is shown by the legend. Bars marked by at least one common letter represent groups that are not different significantly (p > 0.05). Note the lack of significant differences among any groups found by Tukey’s HSD and that tank size effect and the tank size × fish density interaction was found by ANOVA to border, but did not reach, the level of significance. Panel (B) shows the variance of distance zebrafish were from the bottom as a function of 30-s intervals. The upper line-graph shows the performance of fish housed in 1.5 L tanks, the middle line-graph the performance of fish housed in 10 L tanks and the lower line-graph the performance of fish housed in 50 L tanks. The fish density of fish is shown by the legend. The vertical semi-transparent gray bars indicate the period during which still images of zebrafish were shown on the computer screen, and the broken lines with the arrowhead indicate the short period of administering a computer animated expanding dot. Mean + S.E.M. are shown. For detailed statistical results, see Table 1 and the section “Results.”
|
