STOCK DEFINITION AND GEOGRAPHIC RANGE Within the genus Mesoplodon, there are four species of beaked whales that reside in the northwest Atlantic. These include True's beaked whale, Mesoplodon mirus; Gervais' beaked whale, M. europaeus; Blainville's beaked whale, M. densirostris; and Sowerby's beaked whale, M. bidens (Mead 1989). These species are difficult to identify to the species level at se...