Sowerby's beaked whale (Mesoplodon bidens) COSEWIC assessment and status report: chapter 1

Assessment Summary – November 2006

Common name : Sowerby's beaked whale

Scientific name : Mesoplodon bidens

Status : Special Concern

Reason for designation : This small beaked whale is endemic to the North Atlantic Ocean where it is found mainly in deep, offshore temperate to subarctic waters. Little is known about its biology, fine-scaled distribution, and abundance. It belongs to a family of whales (Ziphiidae) in which acute exposure to intense sounds (especially from military sonar, but also from seismic operations) has led to serious injury and mortality. Seismic operations are currently widespread and military activities involving the use of mid- and low-frequency sonar likely occur at least occasionally in the habitat of this species off Canada’s East Coast. Although there is no direct evidence that such sound sources have affected this species, there is strong evidence for lethal effects on individuals of related species. Thus there is reasonable cause for concern about the potential effects on individuals of this species. The potential population-level impacts of this type of mortality are unknown.

Occurrence : Atlantic Ocean

Status history : Designated Special Concern in April 1989 and in November 2006. Last assessment based on an update status report.