Table 2.

Summary of results

Rearing group (number of animals)
Color pairBW (12)DW (12)Red (12)Green (7)Blue (12)
Blue/green-1.65±0.51-2.45±0.40-2.84±0.44-1.41±0.28-2.94±0.39
Blue/red-1.76±0.46-3.23±0.51-2.69±0.77-1.11±0.62-1.14±0.36
t-testsP<0.05-NSP<0.01P<0.01
Green/red+0.30±0.310.80±0.42-0.12±0.36+1.23±0.76+1.48±0.44
t-testsP<0.05-NSP<0.01P<0.001
  • Values are averaged bin numbers (positions in experimental tank) ± S.E.M. Bin number 0 was at the centre of the tank. A negative (or positive) value means that the first color in the respective color pair (leftmost column) was less (or more) efficient in driving the optomotor response than the second color. The dim-white light (DW) group served as the reference in all t-tests. No tests were performed on the data obtained with the blue/green color pair, since the ANOVA (Table 1) did not detect any significant differences in that set of data.

    The animals in the red group chose positions in the experimental tank that were not significantly different from the positions preferred by the fishes in the DW group. In all other groups, including the BW (bright-white light) group, the positions of the animals differed significantly from the positions of the fishes in the DW group.

    NS, not significant at the 5% level.