Foywonder has broken the news of a new mutant/radioactive shark in the Mississippi River movie coming soon called Jaws of the Mississippi. Finally, a shark movie that dares to have a shark swim up the Mississippi River and maybe even threaten my hometown of Rock Island, Illinois. That would rule.
the plot:

A massive hurricane devastates the Gulf of Mexico, with it a US government’s top-secret anti-bioterrorism facility. When one of its highly radioactive chemicals spills into the ocean it triggers mutations in a great white shark, enabling its adaptation to survive in freshwater. As this shark reeks havoc on local Mississippi River towns it poses the additional risk of spreading this radioactive material and contaminating the entire freshwater system of the United States. Local fisherman Ward and his hillbilly crew are secretly hired to hunt down this shark, and when they find it threatening a group of teenage boaters, Ward must face his troubled past to save these kids and prevent further catastrophe.

Maybe Jaws of the Mississippi will fight Sharks in Venice for the sequel!
Official Active Entertainment site (the people who are also bringing us Chrome Angels!)