Monday, July 20, 2015

I'm Pretty "Sueur" There Are No Mussels Here

Since Molly and Brooke conquered the Chippewa early last week, it was my and Maya's turn to join Mark and head to the Le Sueur river to aggregate more mussels for our glycogen analysis. We got up bright and early Friday morning and drove out into the cornfields.

The river that greeted us was noticeably different than the rivers we've seen so far. The current was strong, and there were deep holes you wouldn't want to step into with a weight belt on. There were downed trees everywhere; at one site, they had created a dam that was ~30 meters wide and ~35 meters long! 

In addition, there was so much suspended sediment that there was no chance of spotting anything farther than three inches away from your face! This meant we were forced to feel around for mussels, but unfortunately we caught many more mussel-sized rocks. We were only able to aggregate enough heelsplitters and pocketbooks at one site instead of three.

One of our data sheets. As you can see, we did not find any live mussels at this site (although we did see a softshell turtle!!)

15 years ago, the Minnesota DNR found plenty of mussels at these sites. Where, then, have they gone, and why? Maya and I are really interested in thinking about this question and looking at whether land use changes could be a factor here. 

Because of the difficulty in finding enough mussels, and heelsplitters in particular, our team has decided to change one of our target species from the White heelsplitter (Lasmigona complanata) to the more common Three-ridge (Amblema plicata). Hopefully this will make it easier to complete our research!

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