Morphometric study of Acipenser naccarii (Bonaparte, 1836) in fish farm individuals

The main objective of this study was to analyse differences and similaritie s in morphometric characteristics among specimens of the same year class of Acipenser naccarii (Bonaparte, 1836), comparing fish raised either in Ital y or Spain. All specimens were Fl of captive broodstock in Italy. Fifteen biometric variables were measured, and three derived indices were c alculated, on 30 individuals of 3+ year class from Lombardy (Italy) and 90 individuals of 1+, 2+ and 3+ year class from Riofrio (Granada, Spain). A st epwise discriminate analysis (SDA) was carried out, and the results were co ntrasted using a non-hierarchical cluster analysis. The two groups proved t o be similar. so a principal component analysis and a simple regression ana lysis were performed on all individuals, taking total length (T1) as the in dependent variable and all the biometric variables as dependent. The study revealed that although the Soljan index (i.e, ratio of mouth widt h to snout length) is related to TI, and is a valid taxonomic characteristi c, the CA index (i.e. relative position of the barbels) and FB index (i.e. ratio of snout length to width) are also valid characteristics for individu als longer than 57 cm, being independent of T1.