Can sharks live in freshwater?
Most sharks live only in the marine environment in full-strength saltwater. Some coastal shark species can survive in brackish estuaries with mixed fresh- and saltwater. Many juvenile sharks use these brackish areas as nursery grounds. There are only a couple shark species that are capable of surviving in freshwater for any length of time, and these have special physiological adaptations that allow this. These species are the bull shark (Carcharhinus leucas) and the speartooth shark (Glyphis sp.). Bull sharks have been captured ~2,100 miles (3,480 km) up the Amazon River, and ~1,700 miles (2,800 km) up the Mississippi River. Bull sharks have also been documented to traverse ~108 miles (175 km) of rapids in the Rio San Juan leading up to Lake Nicaragua from the Caribbean Sea. The speartooth shark has been captured over ~60 miles (100 km) up the Adelaide River in Australia. Though these sharks are capable of surviving in freshwater, there are no populations living in completely landlocke
