A diagram of the general flow of the experimental procedures described in this paper, including the number of animals used per experiment.

The Histogram of larvae hatched within an observation window between 48 hpf (1 hZT at 2 dpf) and 82 hpf (12 hZT at 3 dpf) in absolute (relative) hatching time (HT, hpf).

Principal component plot with the first two principal components of the explanatory variables for swimming behaviour during the light dark challenge assay: distance moved (D), velocity (V), acceleration (A), angular velocity (Ω), meandering (M), and percentage immobility (PI) displaying 65.6% of the total variance. Hatching time (HT) is represented by colour.

Network of non-zero partial correlations between the explanatory variables for swimming behaviour during the light dark challenge assay: distance moved (D), velocity (V), acceleration (A), angular velocity (Ω), meandering (M), percentage immobility (PI), and hatching time (HT) is represented by colour. The network is thresholded to lFDR < 0.20. Positive partial correlations are indicated by dark blue lines and negative partial correlations by light blue lines. Line width corresponds to the strength of correlation.

Parameters for swimming behaviour during the light dark challenge assay: (A) distance moved (D, mm), (B) velocity (V mm s^–1), (C) acceleration (A mm s^–2), (D) meandering (M, °mm^–1), and (E) angular velocity (Ω, °s^–1), and the variation thereof in standard deviation (SD, F–J), for the light (white bars) and dark (black bars) challenge phase of the essay. Shading indicates hatching during night time (dark shaded) and day time (not shaded). All values are mean ± SE. Letters indicate significant difference (RM Two-way ANOVA with Geisser-Greenhouse corrections, time of the day and phase as factors, Sidack’s post hoc test, p < 0.05, N = 167).