Figure 5
From: Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types
Temporal evolution of the peak frequency of units C (a) and D (b), computed by a Fast Fourier transform of the signal. The error bars color code is: red when quantification error is the greatest source of error (Q), blue when intrinsic dispersion is the greatest source of error (ID). A letter corresponding to the largest source of error is given on top of each error bar. The line is the linear interpolation by least-square error of the points displayed in the graph (the coefficient of determination \({R}^{2}\) being close to 0.95).
