Unionoid Treasure Hunt

For the last few weeks, the stream team has gone mussel crazy. We have been, for the most part, contributing to Hannah’s project of obtaining DNA samples from freshwater pearl mussels (Margaritifera margaritifera) all over the drainage of the east branch of the Swift River. This local stream (about an hour north of Worcester) holds a large, healthy population of this globally imperiled invertebrate. The project may turn out to be especially interesting from a conservation standpoint because of the fact that several human-made dams fragment the stream, likely stunting gene flow through the population.

The first step to gathering DNA samples is finding Mussels. The relative ease of this process ranges from the lucky find of twenty under one rock to an excruciating hour of no mussels. Although on some of these hot days we would love to dunk our heads right in the stream to find mussels (which Hannah actually does regularly with a mask and snorkel) we generally use viewing buckets to see clearly into the water. These excellent tools are crafted out of paint buckets with the bottoms replaced with Plexiglas. For hours every day, we crawl through the stream, bent all the way over, with our heads firmly stuck in buckets. To the average hiker peeking through the trees at the stream that must be a very strange sight!

Me walking through the stream with a bucket of mussels.
Me: walking through the stream with a bucket of mussels.

Once we have found 20-25 mussels, we select 10 to be sampled. To do so, we open the mussels’ shells slightly with the tip of a pipette and extract a piece of tissue from the mantle about the size of a pencil tip. These “clips” are stored in Ethanol in small vials for future analysis. The mussels are then photographed against a ruler and released.

Clipped, measured and photographed.
One Margaritifera margaritifera clipped, measured and photographed.

It’s hard to stay focused for too long when we are working in such a beautiful place. Late July is the beginning of New England’s blueberry season, so the forest’s sunny patches are covered with little blue temptations. Hannah won’t let me eat any berries until she has cell phone reception and the number for poison control on her phone… Maybe she’s the smarter of us.  Sometimes when Hannah is taking notes at a site, and Gaby and I are left to sit, the combination the soft sun filtering through the hemlocks and the soft woodsy breeze is a stronger sleeping serum than anything else I can imagine.  The forest is obviously the best place to be!

Here's Gaby overtaken by the spell of the forest.
 Gaby is overtaken by the spell of the forest.