Walleye pollock eggs from the Gulf of Alaska were reared to the juvenile
stage at 6-8°C to understand otolith increment formation and morphology.
The fish were immersed in a solution of alizarin complexone (ALC) once a
week for 6 hours. ALC binds readily to calcium and is laid down on the otolith
during the daily increment process. Here the ALC shows up as light bands
on the otolith.