Cross-sectional structure and validation of the timing of annulus formation in otoliths of the Antarctic fish Notothenia coriiceps Richardson (Nototheniidae)

To validate the timing of annuli in otoliths of immature Notothenia coriiceps Richardson. a time-series of samples were taken over a complete year. Light and scanning electron microscopy (SEM) techniques were used to examine the structure of sectioned otoliths. Six growth regions were identified in the otolith sections and micro-increments were also evident. The timing of growth and annual nature of annuli revealed by SEM were demonstrated. Annuli revealed by SEM and light microscopy techniques were shown to correspond, supporting the hypothesis that annuli visible by using light microscopy represent one year. Using SEM the potential errors due to light illumination artefacts and the pseudo-hyaline features could be avoided.