Sharks primarily live in saltwater, but some species can be found in brackish and freshwater. Sharks and rays (Elasmobranchii) are a subclass of the cartilaginous fishes ( (Chondrichthyes). The species in this subclass have jaws, paired fins and nostrils, a heart with its chambers in series, and skeletons made of cartilage rather than bone. The North Sea is … Read more