Comparison of different ways to determine age for whole otolith

Pesci P;ALTEA, PAOLA;CABIDDU, SERENELLA;PALMAS, FRANCESCO;PORCU, CRISTINA;VITTORI, STEFANIA

2013-01-01

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Abstract

Age determination in Mullus barbatus Linnaeus, 1758 is generally made reading annuli in whole otoliths. They are usually seen against a black background, immersed in clear liquids. The aim of this paper is to compare the age estimation obtained with otoliths immersed in six different means (water, ethanol, glycerin, solutions of glycerin and ethanol) and dry, to understand which is the best way to read them. Coefficient of Variation (CV), Percentage of agreement (PA) and Relative Bias were calculated to evaluate the precision and accuracy. The analysis showed that age determination is more reliable when otoliths are immersed in a clear liquid (preferably a solution of glycerol and ethanol 2:1).