Interesting articles. P. vulgaris is mentioned there as not tolerating low salinity, and P. pugio is listed as tolerating a wide range of salinities. That said, I have a hard time believing the P. vulgaris and P. pugio species that live in the Chesapeake Bay are the same ones native (or established) to land-locked bodies of (extremly soft) surface water in 32 miles from the Arkansas border.
A good test seemingly would be placing them in and insulated minnow bucket in a refrigerator set below 41, and slowly letting it reduce the temperature of the water of Pk shrimp. I am curious about their behavior. On multiple occasions I've had mine stay viable that way for a week+ before (for bait), and then once this past summer they seemed to not take it as well (died or laid dormant on their sides). It may be the time of the year and acclimation is important, or that the water was chilled too quickly (may not have used an insulated bucket). Stocking density or oxygen content was not controlled so that may have played a part as well. For that matter I have not verified the refrigerator temperature either...
