Meeting Abstract
Shark skin has drag-reducing properties that increases swimming speed in some species and provides the inspiration for biomimetic materials. Previous research has shown that dermal denticle morphology varies regionally along the body and correlates with swimming performance across species. In sharks, the skin acts as an exotendon that is controlled by internal muscular pressures and skin stiffness. Our goal is to assess differences in skin tensile properties regionally in three species of shark (Carcharinus limbatus, Sphyrna lewini, and Isurus oxyrinchus) using a materials testing system. We hypothesized that there are differences in the tensile strength and stiffness of skin at different regions of the body in an individual and between species. Strength (MPa) is the maximum stress that can be applied to a material before it fails, and stiffness (MPa) is the ability of skin to resist deformation in response to stretching. Juveniles from each species were obtained and skin was dissected from the underlying fascia and muscle at seventeen anatomical landmarks. Skin samples were oriented along the collagen fiber angles and stretched at a strain rate of 2 mm/sec until failure. A stress strain curve was generated for each sample and maximum strength (MPa) and stiffness (MPa) were calculated. We used a two way ANOVA to determine regional and species differences. This study provides data on skin mechanics within and between species and will provide information on the role of skin on shark movement.
