p42
During the 1800s Key West's main industry was salvaging ship wrecks that sunk because of the coral reef or storms. The salvaged cargo was then auctioned off.  In the mid 1800s they were averaging one shipwreck per week.  By the late 1800s the salvage business declined due to increased technology and sailing ships replaced by steamships.  In 1912 the railroad increased Key West's tourist business.  The shipwreck Museum covers the salvaging history of Key West.
Treasure hunting has been a business in Key West in the 20th century.  The Mel Fisher museum covers Mel Fisher's successful search for sunken Spanish ships with treasure.  You can buy some of the sunken treasure if you have a lot of money.
Every evening you can catch performers and jugglers on Mallory Square working for tips.  My brother and I helped put one performer into a straight jacket and locked chains.  He did manage to get out.  Not an easy way to make a living.