The United States and Australia boast the highest concentration of sharks, according to SurferToday.com. Sharks inhabit all of the world’s oceans, although research suggests as much as 70 percent of the oceans are devoid of sharks. According to Shark Foundation, the Antarctic Ocean holds nearly 40 species, and the Arctic Ocean is inhabited by porbeagle, thresher and Greenland sharks.
The southern tip of Africa is also popular among sharks, but this doesn't mean that every part of the oceans surrounding these countries is filled with sharks. Swim Without Sharks suggests a list of beaches in which no sharks have ever been seen. Many of these beaches are in places such as California and Hawaii, where sharks are known to live.
Sharks are not territorial, and they will move to exploit food sources and to avoid predators. Additionally, some species migrate hundreds or thousands of miles each year. Accordingly, it is hard to define exact ranges for many shark species.
Not all sharks are limited to salt water. Bull sharks and river sharks occasionally venture into the freshwater rivers of North America and Africa. Despite the global presence of sharks, their numbers are declining drastically due to persecution, excessive harvesting and habitat destruction.