Biometry of the sagittal otoliths for three demersal fish species from the Eastern Adriatic Sea (Montenegro)

The otolith morphology, biometry and otolith size and fish length relationship of three demersal fish species: red mullet Mullus barbatus, common pandora Pagellus erythrinus and hake Merluccius merluccius were examined. Based on otoliths relative sizes P. erythrinus and M. merluccius have Large otoliths, while M. barbatus has Small sagittal otoliths. The relationships between otolith variables and fish somatic growth were described by a linear function. All relationships were statistically highly significant (p<0.001). Otolith length (OL) was found to be the variable most strongly related to fish size, with 61.2 – 95.3 % of the variability, while otolith weight had the lowest coefficient of determination (r2). No differences were found neither between left and right otoliths, nor between male and female otoliths in these relationships. For all species studied the relationships of otolith length, height and weight against total fish length were all found to have positive allometry, indicating that the accretion of otoliths is relatively faster than increase in fish body size. The shape indices of form factor (FF), roundness (RD), aspect ratio (AR), circularity (C), rectangularity (R) and ellipticity (E) were calculated and the relationships between otolith length (OL) and shape indices were determined.