The shark tooth necklace has long been espoused as a symbol of male strength, potency and masculinity. Such necklaces first came to prominence with the surfing culture of the 1960s and really exploded in the 1970s, partially due to the book and movie Jaws.
Many surfers would wear the shark tooth necklace as a charm or talisman to bring them good fortune, keep away evil spirits and protect them from accidents and shark attacks.
There is an Hawaiian legend of a young warrior who dove into the sea and fought with a sea god. He emerged victorious wearing a necklace of shark teeth. So, the shark tooth necklace represents power and protection from the evil of the seas, including protection from being bitten by a shark.
Hawaiian culture views the shark as not only a potential predator but also that some sharks are the embodiment of gods, family deities, and ancestors called 'aumakua. The wearing of a shark's tooth on a necklace is not only felt to provde protection, but also a way of honoring this important member of the sea.