In 2003, NRDC spearheaded a successful lawsuit against the Navy to restrict the use of low-frequency sonar off the coast of California. Two years later a coalition of green groups led by NRDC and including the International Fund for Animal Welfare (IFAW), the League for Coastal Protection, Cetacean Society International, and Ocean Futures Society upped the ante, asking the federal courts to also restrict testing of more intense, harmful and far ranging mid-frequency types of sonar off Southern California’s coastline.
In filing their brief, the groups cited Navy documents which estimated that such testing would kill some 170,000 marine mammals and cause permanent injury to more than 500 whales, not to mention temporary deafness for at least 8,000 others.
And that's only just from testing off the coast of california.
https://www.scientificamerican.com/article/does-military-sonar-kill/
And that's only just from testing off the coast of california.