FIG. 1.

Absorbance values measured at wavelengths between 250 and 700 nm for each concentration within sets of six serial dilutions (A–F) of sperm samples of zebrafish Danio rerio. The R²-values reported are for the correlation between visible wavelength (higher than the vertical dashed line) and absorbance indicating that there was no single maximal absorbance peak within the visible wavelengths, meaning that any visible wavelength would be appropriate for measurement of samples for sperm concentration.