I myself never realized how endangered the Hammerhead Shark was until today. it is really due to human activity.
Again according to http://edweirdo.hubpages.com/hub/North-America-Top-10-Endangered-Species-List , "Found in tropical waters around the world, the Hammerhead Shark is endangered due to both legal and illegal commercial and sports fishing practices. The Hammerhead is often caught as bycatch by longline and other commercial fishing methods, and once they're caught their mortality rate is 90%. The sharks are often caught intentionally for the sole use of their fins, which are used in Asian shark fin soup. The fish are caught, their fins sliced off, and then returned - still alive- to the sea, where they subsequently bleed to death. While this practice is banned in several countries, it continues elsewhere thanks to the high price paid in Asian countries. The estimated Hammerhead Shark population has decreased by more than 50% over the past 10 years." This is a scary thought knowing how damaging us, as humans, are to marine life.