While doing a habitat assessment on the Huron River, I was lucky enough to see a pocketbook mussel in the process of attracting a fish host and managed to get some pictures and a video of it.
Please excuse the poor video quality- it looks like a bubble got trapped on our underwater camera lens! But you can make it out. The mussel is buried in the sediment, positioned so that its opening is facing up. The mussel is extending a part of its mantle into the current to use it in its reproduction process.
Mussels reproduce by releasing their glochidia (microscopic larvae) in the presence of fish. The glochidia latch onto the fish’s gills and fins where they dwell for days or weeks, depending on the species and water conditions. During this time the glochidia develop into microscopic juveniles and eventually drop off the fish. If they land in a suitable place, they can create a new mussel bed.
Therefore, since fish are integral to a mussel’s life cycle, the mussels have developed ways to get a fish’s attention. By extending the colorful mantel into the current, the mussel acts like an angler’s fish lure! When a fish gets closer- the mussel shoots out the glochidia!
Special acknowledgments go to Ryan and Marty of ECT, for experiencing this really cool find with me.