To find out if and organism nicely records its environment, you need to do experiments in which variations in the environment are manipulated or closely monitored. In case of freshwater mussels it it not very easy to keep them happy and alive in an aquarium, so I did the experiments in the field. The two field sites were fish ladders in the rivers Rhine and Meuse, that are made for enabling migratory fish to move upriver past a dam or weir.
Freshwater mussels do not attach themselves like blue mussels do, but sit in the mud instead. They can move around quite a bit and muskrats think they’re delicious, so we devised a steel cage for them to live in. I collected some mussels from the river Linge, and bought some other in the pet shop (yes, they sell them there, because people apparently like to have them in their garden ponds). Collection of animals and installation of these experiments involves a lot of work with waders on, and can sometimes be quite cold!