Research Document - 2007/044

Recovery Potential Assessment of western North Atlantic right whale (Eubalaena glacialis) in Canadian waters

By Smedbol, R.K.

Abstract

The Western North Atlantic right whale is listed as Endangered under the Species at Risk Act. This document presented analyses that were undertaken in support of the Recovery Potential Assessment of western North Atlantic right whale held in 2007. This evaluation will inform recovery planning for right whale in Canadian waters.

Population abundance is critically low, numbering approximately 325-350 individuals through 2003. The best available population model indicates a declining trend in abundance over the period of 1980-1995. If the 1995 growth rate was maintained, the population model predicts an average time to extinction of about 200 years. Critical Habitat was defined as including concentrations of right whale prey, especially stage C5 Calanus finmarchicus copepodites, and the environmental, oceanographic and bathymetric conditions that aggregate right whale prey at interannually predictable locations. An interim, science-based recovery target for right whale population abundance was provided: "An increasing trend in abundance over three generations”. Generation time for right whale is approximately 20 years; therefore the minimum time period necessary to achieve this target is around 60 years. It was determined that scope for allowable human-induced mortality does not exist currently, since population abundance was estimated as critically low and the population appears to be declining toward extinction. The two major known threats to right whale survival are vessel strike and entanglement in fishing gear. These to threats account for all known human-induced mortality. Other potential threats have been identified, but their effect on right whales is uncertain.

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