Meristic character analysis and skeletal anomalies during growth in reared sharpsnout seabream

Abstract

Sharpsnout seabream (Diplodus puntazzo) is a species currently reared in Mediterranean fish farms. In order to detect the main types of body deformation in sharpsnout seabream. 120 specimens (60 juveniles and 60 adults) taken from a Mediterranean hatchery were examined. In juveniles and adults non-significant differences were found in the number of vertebrae, dorsal spines and pectoral fin rays. Moreover, the number of anomalies varied with age. The juveniles presented 28 types of anomaly, the adults 25. The most important anomalies for juveniles (in terms of frequency of occurrence) were anomalous neural arch or spine (47%), anomalous hemal arch or spine (43%), fusion of hypurals (67%) and presence of calculi in the terminal tract of urinary ducts (43%), while for adults were anomalous neural arch or spine (43%), fusion of hypurals (90%) and fusion of epurals (37%). While anomalous hemal arch or spine and presence of calculi in the terminal tract of urinary ducts decreased with age, fusion of hypurals and fusion of epurals increased. Lordosis and kyphosis were found in a slight form only in juveniles and with a low frequency of occurrence. These decreased or disappeared in adults. No mortality was detected either in juveniles or in adults. In any case, these anomalies did not influence the growth performance of juveniles and no lethal anomalies were detected.