How long can a bull shark stay in fresh water?
Scientists think that bull sharks can stay in fresh water for quite some time. They usually live in shallow estuaries (where the salt and fresh waters meet) and travel up rivers and into river fed lakes. While it’s not easy to tell how long a bull shark has been in fresh water, they have been found 2,000 miles upstream in rivers in the United States and South America. They can live in fresh water for up to 3 years.