From PBS Newshour:

Sonic cannons, which fire sound waves 100 times louder than a jet engine, pose dangers for marine life that communicate by sound. Whales and dolphins, for example, depend on echolocation to feed and communicate with their family groups.

http://www.pbs.org/newshour/rundown/white-house-approves-controversial-sonic-cannons-ocean-energy-exploration/

From Archangel Michael's March 2014 Message to the humans:

All aspects of Creation on your Earth are awakening, the Mineral and Animal Kingdoms, as well as the Devic and Elemental Kingdoms, and they are assuming their proper roles again as the guardians and caretakers of the Nature Kingdom.  The whales and dolphins, who are the record keepers for the history of planet Earth, and the cosmic telepathic communicators between Earth and this galaxy, are desirous of reestablishing their relationship with humanity.  You have forgotten; however, they have not.  They have willingly and lovingly served humanity down through the ages, only to be killed and maimed. Please help to stop this abomination, beloveds. The dolphins and whales resonate to the element of water, and therefore are very conscious of your emotional frequency patterns. They have suffered along with you down through the ages.  Many blessed souls have blended their energies with these beautiful Beings, and are endeavoring to make you aware of how precious and important they are in the complex scheme of evolution.

http://ronnastar.com/messages-aam/messages-aam/775-aam-03-2014.html