The world's smallest whale population?

Abstract

The North Pacific right whale (Eubalaena japonica) was heavily exploited by both nineteenth century whaling and recent (1960s) illegal Soviet catches. Today, the species remains extremely rare especially in the eastern North Pacific. Here, we use photographic and genotype data to calculate the first mark-recapture estimates of abundance for right whales in the Bering Sea and Aleutian Islands. The estimates were very similar: photographic = 31 (95% CL 23-54), genotyping = 28 (95% CL 24-42). We also estimated the population contains eight females (95% CL 7-18) and 20 males (95% CL 17-37). Although these estimates may relate to a Bering Sea subpopulation, other data suggest that the total eastern North Pacific population is unlikely to be much larger. Its precarious status today-the world's smallest whale population for which an abundance estimate exists-is a direct consequence of uncontrolled and illegal whaling, and highlights the past failure of international management to prevent such abuses.

Figure 1.

Locations in the Bering Sea and Aleutian Islands of eastern North Pacific right whales individually identified (a) through genetics or (b) through photographs. Lines connect sightings of the same individual in different years. The pentagon shows the critical habitat established by NOAA in 2007. (a) Red, 1997; yellow, 1999; green, 2002; pink, 2004. (b) Green, 1998; dark blue, 2001; yellow, 1999; pink, 2004; orange, 2000; white, 2008.