This study presents a modified otolith preparation protocol to estimate the age of Anguilla from Lake Vistonida (NE Greece). In experimental attempts, 300 otoliths were processed using standard and modified eel ageing methods, producing low success rates (0%-20%) due to poor annuli visibility and structural damage. To overcome these limitations, a ten-step Fisheries Research Institute (FRI) modified Crack and Burn protocol, representing a species-specific adaptation of existing Crack & Burn methodologies, was developed, combining thermal treatment, polishing, acid bath and glycerin application. This method achieved 90% success in age determination and provided a reliable method for age reading (CV = 1.97).
Papadopoulou et al. (Tue,) studied this question.