Effects of skeletal deformities on swimming performance and recovery from exhaustive exercise in triploid Atlantic salmon

The occurrence of spinal deformity in aquaculture can be considerable, and a high rate of deformity has been suggested in triploid smolts in Tasmania. However, the physiological performance of fish with skeletal deformities has not been addressed. The swimming performance and oxygen consumption of triploid Atlantic salmon smolts with either a vertebral fusion (platyspondyly) or multifocal scoliosis were compared to normal (non-deformed) triploid smolts. Fish with vertebral fusion attained swim speeds similar to normal fish, whereas scoliotic fish were unable to attain comparable swim speeds. Routine and maximum oxygen consumption was higher for deformed fish compared with normal fish, translating into apparent increased routine metabolic scope in vertebral fusion fish, and equivocal scope in scoliotic fish compared with normal controls. Deformed fish developed a lower excess post-exercise oxygen consumption compared to non-deformed fish, suggesting they are either incapable of sustained anaerobic activity or possess an increased recovery capacity. These data suggest that skeletal deformity has differential effects on swimming performance depending upon the type of deformity but imposes a significant metabolic cost on salmon smolts.