Shark repellant technology is still a work in progress to some extent, but there are two main proven methods to keep sharks at bay. These predatory fish will stay well clear of other dead sharks when they smell them, and scientists have isolated the chemical source of the odour to several compounds, like copper sulphate. There are also examples of prey taking advantage of the shark’s sensitivity to certain smells, such as the Moses sole, which produces a soap-like substance called pardaxin that sharks hate.
One of the most effective repellants so far, though, exploits the electric sensitivity of the ampullae of Lorenzini on the shark’s nose, which it uses to detect prey and navigate. The device creates a local elliptical electric field that employs a particular waveform that all sharks are sensitive to. This causes uncomfortable (but not harmful) spasms in their snouts that intensify the closer they move to the source, ultimately forcing them to turn away.