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

Abstract

Sharpsnout seabream (Diplodus puntazzo) is a speciescurrently reared in Mediterranean fish farms. In order to detect themain types of body deformation in sharpsnout seabream, 120 specimens (60juveniles and 60 adults) taken from a Mediterranean hatchery wereexamined. In juveniles and adults non-significant differences were foundin the number of vertebrae, dorsal spines and pectoral fin rays.Moreover, the number of anomalies varied with age. The juvenilespresented 28 types of anomaly, the adults 25. The most importantanomalies for juveniles (in terms of frequency of occurrence) wereanomalous neural arch or spine (47%), anomalous hemal arch orspine (43%), fusion of hypurals (67%) and presence ofcalculi in the terminal tract of urinary ducts (43%), while foradults were anomalous neural arch or spine (43%), fusion ofhypurals (90%) and fusion of epurals (37%). Whileanomalous hemal arch or spine and presence of calculi in the terminaltract of urinary ducts decreased with age, fusion of hypurals and fusionof epurals increased. Lordosis and kyphosis were found in a slight formonly in juveniles and with a low frequency of occurrence. Thesedecreased or disappeared in adults. No mortality was detected either injuveniles or in adults. In any case, these anomalies did not influencethe growth performance of juveniles and no lethal anomalies weredetected.