Meeting Abstract
130.3 Monday, Jan. 7 Etiology of spinal deformities in captive sandtiger sharks Carcharias taurus HUBER, D.R.*; NOAKER, D.E.; STINSON, C.M.; TATE, E.E.; ANDERSON, P.A.; BERZINS, I.K.; The University of Tampa; University of South Florida; University of South Florida; The University of Tampa; Mystic Aquarium; One World, One Water, One Health dhuber@ut.edu
Spinal deformities plague captive sandtiger sharks Carcharias taurus. Husbandry practices, animal behavior, nutritional physiology, and spinal biomechanics were explored to identify the causes of spinal deformities to develop better husbandry guidelines and reduce dependence on wild stocks for exhibit specimens. Spinal deformity is associated with collection locale and method and usually manifests within 4 years of captivity with affected sharks characterized by lethargy. Aquarium size is negatively associated with disease prevalence and captive sharks (regardless of condition) spend 95.5 % of their time actively swimming and only 0.5 % gliding, suggesting abnormal locomotion that lacks equivalence of phases. Affected sharks spend less time gliding than healthy sharks, which is coupled with constant lateral stress on the spine due to non-linear swimming that accounts for 99.7% of locomotion (regardless of condition). Blood chemistry revealed that affected sharks are deficient in potassium, zinc, and Vitamin C, which play critical roles in skeletal development and maintenance. Biomechanical analyses revealed that the flexural stiffness of spinal columns from healthy sharks was greater than that of affected sharks due to greater second moment of area. The force required for spinal buckling, as well as the compressive stiffness, yield strength, yield strain, ultimate strength and mineral content of individual vertebrae were significantly greater in healthy sharks. However, the compressive stiffness and ultimate strength of vertebrae from healthy specimens were lower than those of other species, suggesting an inherent predisposition for spinal deformity in captive settings.
