Add noise pollution to the ills of in-ocean fish farms. Instead of coming out of the water, as they are now doing in Norway, and on-land farms are taking off around the world, fish farms use high volume noise to try to scare sea mammals away from their sites, and cling to the out of date in-ocean fish farm.
The problem? The noise blasts can carry as much as 50 kilometers and disturb seals and porpoises, some of which are endangered, and disruption of animal navigation done mostly by sound.
And here is the Herald newspaper article: http://www.heraldscotland.com/news/15270059.Health_of_whales__dolphins_and_porpoises_put_at_risk_by_underwater_alarms/.
"The marine mammals depend on sound to navigate the seas. Loud underwater
noises can cause permanent hearing loss, stress and disorientation
resulting in whales and dolphins beaching and dying."
And: "The number of ADDs has greatly increased in recent years as salmon
farmers try to find publicly acceptable ways of prevent seals from
eating their fish. In the past hundreds of seals have been shot, but the
US government is threatening to stop buying salmon from countries which
permit seal shooting"
And: "The revelations have prompted anti-fish-farming campaigners to file a
formal complaint to the European Commission alleging failures to protect
cetaceans from “deliberate and reckless disturbance”. They are
demanding an immediate ban on the use of ADDs by fish farms."
See this longer text for the abstract to the science: http://europeancetaceansociety.eu/sites/default/files/AbstractBook_0.pdf.