I have a cousin who used to dive for mussles for a living. He's been in all the big rivers across the eastern and southern US. He has quite a collection of unique finds and some wild tales of critters in big water rivers. Tons of large sharks teeth and a very cool mortar and pestil made of stone from around the 1600s he found in the Scioto R in Ohio . No telling what all is in the bottom of the Ohio, Missouri or Mississippi rivers.g