Hi Amber Olson,

Do you let the otoliths dry before you mount them in resin? Drying otoliths for around 3 weeks (or >48 hours in a 48 degree Celsius oven) tends to make the rings more obvious.

What is the thickness of your section using the isomet saw? We use sections ~400 micrometers thick, then mount them use PE resin on a slide with a coverslip. We view the slide on a black stage with a drop of water under the otolith area for contrast. We use reflected light and Leica imaging system (scope/camera).

If you have tried these then you may have a difficult to interpret species. A quick google for the species you are working on should uncover whether or not they are ok to interpret.

Hopefully this helps

Andrew

Hi Amber Olson,

How long did you allow the resin (containing the otolith) to dry in the oven? In our case, it takes around 3 days to allow the resin to fully harden. Thereafter we cut the otoliths and have them polished, leaving a consequent thickness of 0.25mm. For the attachment of the transversely sectioned to glass slide, we used the nail enamel which makes the ring marks more visible. Best regards.

Try rinsing the slides with ultrapure water followed by sonication (also in ultrapure water). Sonication should ensure removal of any remaining epoxy dust from polishing. As previously suggested, thickness is key for viewing (~200 um).