Table 2. Characteristics of received gray whale M3 calls.

M3	Signal Duration	Peak Frequency	3 dB Bandwidth	Mean Frequency	±σ Bandwidth
n = 2,368	(s)	(Hz)	(Hz)	(Hz)	(Hz)
Mean	1.79	38.1	4.17	48.1	44.9
SD2	0.0460	228	9.36	88.6	95.3
$\mathit{S}{\mathit{D}}_{\mathit{p}\mathit{e}\mathit{r}\mathit{c}\mathit{a}\mathit{l}\mathit{l}}^{\mathit{2}}$	0.0425	130	26.9	27.7	51.8
% SD2	52.0%	63.7%	25.8%	76.2%	64.8%
%$\mathit{S}{\mathit{D}}_{\mathit{p}\mathit{e}\mathit{r}\mathit{c}\mathit{a}\mathit{l}\mathit{l}}^2$	48.0%	36.3%	74.2%	23.8%	35.2%

All calls were received and measured on all four hydrophones. These quantities are highly dependent on the site-specific propagation properties. SD² is the variance of the mean values for each call and $S{D}_{percall}^2$ is the mean of the variances for each call across the four hydrophones. The relative contribution of each type of variance is shown as a percentage of the total variance.