Good news, swimmers of Western Australia! Provided you bring a waterproof smartphone into the water and ignore the natural beauty around you in favor of your Twitter feed, you might live:
Known as the Shark Monitoring Network, the system uses buoyed monitoring devices to pick up the signal from acoustic tags that scientists have attached to individual sharks. When a tagged shark swims within range of one of the monitors, its species, size and location is automatically recorded. That information is then transmitted via satellite to a computer, which immediately posts the information on the Surf Life Saving Western Australia (SLSWA) Twitter account.
Here's an example of the system in action:
And hey, if a shark tries to eat you without first being detected by one of these sensors, just show him your phone and he's sure to acknowledge the error and swim away.