Over millions of years sharks and rays have evolved to become perfectly adapted to the ocean environment. However, some of the traits that have helped them become so successful have also made them vulnerable to human impacts.

Bull sharks are widespread coastal and freshwater sharks inhabiting shallow waters in bays, estuaries, rivers, and lakes. They have a unique ability to reduce or increase the saltwater concentration in their blood which enables them to penetrate hundreds of kilometres up rivers.

80% of all pollution in seas and oceans comes from land-based activities.

http://aqua-marine-life.com/underwater-fact-20/