The effect of lordosis severity on juvenile sea bass (Dicentrarchus labrax L., 1758) swimming performance

摘要

The relationship between the lordosis severity and swimming performance in sea bass juveniles was investigated. In total, 149 experimental animals 110-130 days old that ranged from 1.44 to 3.44 g (mean(TW) +/- SD: 2.41 +/- 0.49 g) and 5.4 to 6.5 cm (mean(TL) +/- SD: 6.03 +/- 0.39 cm) were used in experiments to determine critical swimming speed (U-crit) in water that was 14 +/- 1 degrees C. Vertebral angle in normal healthy fish is 180 degrees. The lordosis severity in abnormal fish is indicated by a reduction in this value. Vertebral angles (phi degrees) of the experimental animals in this study ranged from 115 degrees to 180 degrees on the hemal region, and U-crit ranged from 32.67 to 44.73 cm s(-1). A significant reduction in U-crit was observed as lordosis severity increased (decreasing vertebral angle), showing that swimming performance was influenced by vertebral angle deformity in this species. This information has the potential to improve separation methods at commercial hatcheries.