OCR board members and Acoustic Ecology director Jim Cummings sent a follow-up article on the 2004 Hanalei Bay melon headed whale “embayment” citing a paper by Bob Brownell which put the “lunar connection” of this event to rest.
The Navy sponsored an extensive modeling of the Hanelei stranding event and presented the findings at the Fall 2004 Acoustics Society meeting. (“Analysis of melon-headed whale aggregation in Hanalei Bay,” David Fromm et. al JASA 2004)
While Dr. Fromm’s presentation was interesting, it was also fraught with data gaps – such as an analysis of the frequencies and signal types used in the exercises. The study was also presented in the context of when the exercises began – which was not well correlated to the agitated whales.
A critical element that was omitted from the study was that the warships were calibrating their sonar prior to commencing the exercises. These calibrations were coincident to the “embayment” of the whales.
There were a number of other troubling omissions and assumptions that did not square with the incident – including the “lunar” connection. All tolled, it was a well funded, beautifully presented model based on exculpating assumptions – and ultimately signifying very little. The paper has not been published after peer review, and remains in abstract form in the J. Acoustical Society of America (JASA)
Hallway comments from closely linked (Office of Naval Research- ONR) sponsored scientists seemed to agree that the modeling was an expensive “CYA” presentation (their words).
Noise impacts from military communication sonars are much more widespread than the US Navy would like to admit. ONR is funding research on the impacts, and the science is good, but their priorities seem more focused on how to prevent these embarrassing stranding events from occurring – such as spatial-temporal planning and “recoverable threshold” testing on marine mammals.
We believe that the Navy could accomplish their mission safely if they chose to examine the signal characteristics that are agonistic and then crafted communication signals that are more benign.
We are working on a metrics system that can qualify noise by loudness as well as “roughness” – the characteristic that distinguishes the differences between alarming sounds and pleasant sounds that may be equally loud. Hopefully this ‘metric’ will provide design guidance in the tempering of mid-frequency communication sonar signals.