Chapter 14, Problem 9E

To count whale populations, the “capture” is done by means of a photograph, and the “tagging” is done by identifying each captured whale through their unique individual pigmentation and markings. To estimate the population of gray whales in a region of the Pacific between Northern California and Southeast Alaska, 121 gray whales were “captured” and “tagged” in 2007. In 2008, 172 whales were “recaptured.” Of these, 76 had been “tagged” in the 2007 survey. Based on these figures, estimate the population of gray whales in the region. [Source: Calambokidis, J., J.L. Laake and A. Klimek, “Abundance and population structure of seasonal gray whales in the Pacific Northwest, 1998—2008.” Paper IWC/62/ BRG32 submitted to the International Whaling Commission Scientific Committee, 2010.]