I should add here that small craft will vary in location along this very long river as well as in season.  Of course, the same is true anywhere with some semblance of seasons.  In this case, I saw all these boats about two-thirds of the distance between New Orleans and Saint Paul MN, i.e., the south Upper Mississippi.

I’m guessing the boat below is a commercial fishing vessel, river style.  I’d seen a similar boat traveling on a trailer down the street an hour or so earlier and wondered about that tank forward of the cockpit.  I’m not surprised the two crew are as bundled up as they are, given the temperature was well below freezing.  

A couple days later I saw this and assumed they were fishing again, until

they came closer and I read the USGS sign on the side.    Hydrographic survey maybe?

Another USGS survey boat was operating a dozen miles to the north in Montrose IA.

Now this one still puzzles me.

The helmsman here drifted along the shore while another person was on the bow, but 

what are the rings holding thin rods in the water?  Only once was the net used, and that was to scoop out a “dead” or stunned fish but then after some examination, the crew member returned the fish to the water.

All photos and all questions, WVD.

Related:  I love this 1981 documentary on life on the Ohio . . . produced by the University of Pittsburgh.