The risks military sonar poses to a number of species in the ocean, especially cetaceans, is vast and has been known about for quite some time. The topic received international attention when there was a mass stranding of Cuvier's beaked whales, Blainville's beaked whales, and northern minke whales in the Bahamas in 2000. These were determined to be a direct result of mid-frequency active sonar use.

A paper published in Frontiers in Marine Science in 2017 is one of many that have pointed out this issue.

"Subsequently attention has been drawn to other mass strandings coincident with naval exercises, including events preceding the 2000 mass stranding. The list of species for which mass strandings have been linked to naval exercises has also increased to include other beaked whales, dwarf and pygmy sperm whales (Kogia spp.), pilot whales (Globicephala spp.), several dolphin species (Stenella sp. and Delphinus delphis), and harbor porpoises (Phocoena phocoena). In particular, there have been several mass strandings in the northern Indian Ocean coincident with naval exercises—including one of the largest (200–250 dolphins)—which have received little attention. Changes in beaked whale behavior, including evasive maneuvering, have been recorded at received levels below <100 dB re 1 μPa (rms) and mass stranding may occur at received levels potentially as low as 150–170 dB re 1 μPa. There is strong scientific evidence to suggest that a wide range of whale, dolphin and porpoise species can also be impacted by sound produced during military activities, with significant effects occurring at received levels lower than previously predicted."

The paper goes on to outline the latest science up to its point of publication, and implicated a number of whale and dolphin species as being affected by this technology. Even frequencies well below military radar have been observed to have significant impact on animal behaviour and physiology.

For example, tagged blue whales in the Southern California Bight displayed behavioral responses to experimental mid-frequency active sonar. Although the sound levels produced in the experiments were orders of magnitude below most military systems, the blue whales responded by stopping feeding, increasing swimming speed, and traveling away from the sound source.

The paper also describes elevated heart rates and other abnormal physiological responses.

"A young male beluga whale was exposed to mid-frequency sound frequencies [19–27 kHz;140–160 dB (no reference level given)] and exhibited significantly increased heart rate, with the rate increasing with the intensity of the sound level (Lyamin et al., 2011). Heart rate increased no matter how many times the whale was exposed to the sound and the animal showed no signs of habituation. The respiration rate of the animal also increased significantly at the beginning of exposures. Such “severe tachycardia” is the heart's reaction to a stressor. This started at very low noise levels (i.e., 140 dB), suggesting a relatively severe physiological stress response to anthropogenic noise exposure in this whale. One would expect similar, substantive, yet not readily observable and effectively “hidden” stress responses to occur in other cetacean species with similar physiologies (such as beaked whales)."

There have also been a large number of dolphin strandings linked to military sonar use. In June 2008, a mass stranding of common dolphins was associated with a naval exercise in Falmouth Bay, UK, and at least 26 of these animals died. The researchers who evaluated the stranding event determined “naval activity to be the most probable cause of the Falmouth Bay [mass stranding event]”

It's important to note that although there are many stranding events that have occurred coincident with the presence of naval exercises, even when strandings do not occur coincident with naval exercises, this does not mean there have been no deaths or other negative impacts. The paper makes that quite clear.

It's not easy to collect data on these animals. Much of the data presented in the paper took more than a decade to accumulate. Regardless, there is a growing consensus and a variety of instances of observable and measurable impacts this type of testing and technology has on these animals.

Many militaries have committed to investigate and mitigate their activities to protect marine mammals, but who is following up on this to make sure they do their due diligence? Should militaries around the world be allowed to conduct such testing during peacetime when it has such detrimental impact on the environment?

Beyond sonar affects on marine life, military activity around the globe has been responsible for an enormous amount of environmental degradation and death, their very existence threatens our planet in ways we are not aware of. While some will inevitably feel military's are necessary, perhaps we have to consider how we might become a less warring society, as opposed to buying into the idea that we will always be at war - even when we purposefully create those wars.

Humans are in a time where we are being invited to re-orient our place within nature, within life. Treating others in a moral and ethical manner is paramount to progressing forward as a species. What holds us back from doing this? What would need to change?