Formal comment to Gong et al.: Ecosystem scale acoustic sensing reveals humpback whale behavior synchronous with herring spawning processes and re-evaluation finds no effect of sonar on humpback song occurrence in the Gulf of Maine in fall 2006

[...]the authors compare recorded “feeding cries” with data from Alaska [24] and state that these calls are evidence for cooperative feeding behavior. [...]given the substantial uncertainties with respect to sound identification and behavioral context, Gong et al.'s [1] data on synchronous herring shoaling and humpback whale vocalizations is a potentially interesting finding. [1] point out, can be related to environmental conditions influencing detection range. [...]in order to smooth out expected daily fluctuations in song occurrence, our analysis looked at an 11-day time series before, during and after the OAWRS experiment and compared the 2006 data to two other years to compare the overall temporal trend of increasing song presence at the start of the fall migration. [...]we recorded the OAWRS signal 200 km from its source serendipitously. [...]our aim was not a full assessment of the impact of the OAWRS signal source on marine mammal behavior, for which, contrary to Gong et al.