[File:Whale shark Georgia aquarium.jpg|thumb|360px|right|alt=Photo of shark in profile surrounded by other, much smaller fish |The
whale shark, the world's largest fish, is classified as
Vulnerable.
]]
Threatened sharks are those vulnerable to
endangerment (
extinction) in the near future. The International Union for Conservation of Nature (
IU) is the world’s oldest global environmental organization. It evaluates threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened: