World's First Shark Sanctuary (VIDEO)

Sharks may have once been at the top of the food chain, but with 73 million now killed each year and 30 percent threatened with extinction, island countries from the Bahamas and Honduras to Palau and Guam are taking action to protect them by introducing conservation-friendly laws and shark sanctuaries, reports The New York Times.

Keeping shark populations at healthy levels doesn't just positively impact the environment. Countries have also been swayed by campaigners, like the Pew Center, who argue that there are economic benefits of tourism. In a study by the Australian Institute of Marine Science, they estimated that the annual value to the tourism industry of an individual reef shark that swims through these sites was $179,000, or $1.9 million over its lifetime. If a poacher kills a single reef shark, it would only bring an estimated $108.

To take a closer look at what happens at these shark sanctuaries, watch CNN's video coverage of the world's first shark sanctuary in Palau, set up by a politician and shark conservationist in September 2009.