A great white shark, for example, would be able to detect a single drop of blood in an Olympic-size pool. Most sharks can detect blood and animal odors from many miles away. Another amazing thing about a shark's sense of smell is that it's directional. In this way, a shark can figure out where a smell is coming from and head in that direction. Sharks also have a very acute sense of hearing.
Research suggests they can hear low pitch sounds well below the range of human hearing.
Sharks may track sounds over many miles, listening specifically for distress sounds from wounded prey. In sharks, eyesight varies from species to species. Some less active sharks that stay near the water's surface don't have particularly acute eyesight, while sharks that stay at the bottom of the ocean have very large eyes that let them see in near darkness. Most all sharks have a fairly wide field of view, however, since their eyes are positioned on each side of the head. The most extreme example of this is the hammerhead, whose eyes actually protrude out from the head.