Meeting Abstract

78.1  Sunday, Jan. 6  The Biomechanics of Fatal Mandibular Fracture: A Blunt Trauma Injury Observed in North Atlantic Right Whales Killed By Vessels. CAMPBELL-MALONE, R*; BALDWIN, KC; DECEW, JC; RAYMOND, JJ; MOORE, MJ; TSUKROV, I; Brown University; Univ. of New Hampshire; Univ. of New Hampshire; Univ. of New Hampshire; Woods Hole Oceanographic Institution; Univ. of New Hampshire regina@whoi.edu

The North Atlantic right whale, Eubalaena glacialis, one of the most critically endangered whales in the world, is subject to high anthropogenic mortality. Vessel-whale collisions were indicated in the deaths 21 (52.5%) of the 40 right whales necropsied between 1970 and December 2006. Of those, at least 9 deaths (22.5%) resulted from blunt contact with a vessel. To reduce collision mortality, speed restrictions are proposed for vessels traversing critical habitat, although the effects of speed on collision outcomes have not been specifically evaluated from a biomechanics perspective. Ultimately, we seek to evaluate the efficacy of speed restrictions for reducing blunt collision mortality using a finite element (FE) model. Complete, transverse fracture of the right whale mandible, an injury seen only in right whales killed by vessels, is used as a proxy for mortality in the model. Vital for that model are the material properties and biomechanical behavior of the right whale mandible determined in the present study. The average apparent densities for trabecular (0.4258 g/cc �0.0970) and cortical bone (1.2370 g/cc �0.0535) indicate that the bone is of relatively low density. Average ash content for trabecular bone (64.38% �1.1330) is comparable with values from other species, indicating that low density results from a reduction of bone mass, not mineralization. Uniaxial compression testing was also used to determine Young�s modulus of elasticity and Poisson�s ratio. These are the first data capable of addressing the link between fatal vessel-whale collisions and vessel speed using biomechanics.