Why can't sharks survive in fresh water?

Although there are a handful of species that live in freshwater, we tend to think of sharks as being ocean dwellers. But there is also a very unique shark that can live in both ocean and fresh water estuaries and lakes: the Bull Shark. read more

Most sharks, of course, live in salt water, and the previous answer regarding osmotic pressure causing the loss of vital salt should these sharks move into fresh water is the reason why most species can’t survive in such an environment. read more

But bull sharks can adapt their osmoregulatory processes to survive in a broad range of water salinities, from the salt water of the ocean to the fresh water of a lake. In the organism, the external environment and the internal environment of the organism are separated by a membrane across which substances can move. read more

It is due to high salt level in their body that would disrupt the vital chemical processes if they will be in a less saline water.Though some sharks do live in freshwater but most are unable to reproduce in fresh water. Recent research made in Lake Nicaragua has shed some light on the mystery of how some sharks can live in freshwater. read more