How sensitive is a fish?

Hearing - fish have no external ear openings, but posses well developed sense of hearing, with water as a medium (better than air, in terms of sound). Hence, we should use it to your advantage - try to mimic the sound of bait with lures, or resort to stealth fishing.

Smell and Taste - large part of the fish's brain is used for this purpose. This sense is vital to fish. Sharks and rays rely heavily on this to locate food fish. Fish which live in clear water have a less powerful sense of smell than those living in muddied water or twilight depths. Scent can act as both a repellant and an attraction.

 

Bottom line:

With greater knowledge of fish, you will be able to locate and land more fish.