Thursday, September 17, 2015

Grubbing for mussels with the Upper Sangamon River Conservancy

Grubbing for mussels with the Upper Sangamon River Conservancy

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Now and again it strikes me that the things I enjoy doing are not the things most other people enjoy doing.

Take grubbing for mussels.

This activity involves sinking your hands into a streambed and working your fingers through the sand and gravel to feel for the shells of mussels--smooth, hard, vertically-oriented disks, which might be as small and compressed as the face of a man’s wristwatch, or larger and thicker than an adult’s hand.

It’s difficult for me to say why I enjoy this activity. There’s something primal in the mental state it induces, akin to states induced by hunting and fishing and foraging, but beyond that, I’m not quite sure how to characterize it. I can say

that I’m not alone in losing myself as I grub. One of the rules when you’re with a group is not to grab the hands or feet of fellow grubbers underwater, especially when they’ve got that faraway, raccoon look on their face.

So there are select other people who enjoy grubbing for mussels, or who are at least find it tolerable in the name of citizen science. That explains how more than twenty of us wound up on our hands and knees in the shallow water of the Sangamon River on the Saturday morning of Labor Day weekend, in an effort organized by the Upper Sangamon River Conservancy (USRC). We were there, just downstream of the covered bridge at the Lake of the Woods Forest Preserve, to collect as many live mussels as we could in a little over an hour of searching, repeating a survey I participated in back in 2012.

Our findings this time around were quite similar. We collected 310 individual mussels including representatives of 15 different species, versus 314 and 13 in 2012. Neither of the two new species, a threehorned wartyback and a fawnsfoot, came as a big surprise, given the location and habitat, but it’s still cool that they were found.

Our most massive specimens were plain pocketbooks, some of which probably would have tipped the scales at more than two pounds (although weighing them wasn’t on the agenda). Our biggest specimens for shell circumference were pink heelsplitters, which grow to the size of a small dinner plates. The common names for many freshwater mussels are equally colorful and descriptive; among those we found were also pistolgrips and pimplebacks, threeridges, deertoes, Wabash pigtoes and fatmuckets.

The mussels we collected looked to be in good condition, they represented a wide range of ages and some of them were gravid. According to Sarah Douglass, a field biologist with the Illinois Natural History Survey at UI who oversaw the scientific aspect of our survey, “it means they’re living well into maturity and reproducing.”

Douglass pointed out that our findings also provided other important indications about the health of the river. The continued presence of mussels there suggests the habitat has not been significantly degraded in recent years, and mussel reproduction in the stream also signifies that certain fish species are thriving there, since the larvae of freshwater mussels live on specific fish early in their development.

Would you like to experience the Sangamon for yourself and learn more about the life it supports? Check out the Upper Sangamon River Conservancy. It’s a group established in 2009 that seeks to “preserve, maintain, monitor, and promote public use and awareness of the Sangamon River.” Information available at New members are always welcome.