Estimates of Chilean blue whale annual abundance from 2004–2012 and POPAN superpopulation abundance (measured from January/February in each year).

<p>Estimates and 95% confidence intervals are, from left to right, Pradel left sides (red), Pradel right sides (black), POPAN left sides (red), POPAN right sides (black), with POPAN superpopulation estimates for POPAN left and right sides respectively.