The Fish Did It!

A few years ago a friend of mine bought a house with a pond and shorty after they moved in found out there were mussels living in the pond. Something under the cover of darkness was eating them and discarded broken open mussel shells all along the edges of their pond. "But how did they get their in the first place?" was the question she posed to me one evening.

The pond in question.

I thought this was going to be a bit of a challenge and that I would have to study the hydrology of the area mapping the streams which flow through the swamps nearby looking for those two tough mussel who crawled this way there and then created all the future generations. Or maybe it was a bird flying overhead who lost its lunch and dropped a pregnant mussel into the pond.

Not being a hundred percent able to remember how freshwater mussels reproduce, after all its been 26 years since I took invertebrate zoology in college,  I did a quick Google search. BAM! There is the answer; fish!

Graphic swiped from University of Vermont

If you look at the graphic you'll see something called a glochidia which forms a cyst or a little cocoon on a fish were it hangs out and goes through a metamorphosis until it falls off the fish and finishes it life cycle.  Long ago the previous owner of the pond had it stocked with bait fish, so when the bait fish were introduced into the pond somewhere on one of those fish was a glochidia or two. Once they completed their use of the host fish they fell off and reproduced over and over again.

So, is there anything cool about freshwater mussels you ask? Oh, heck yeah!

 1) They produce freshwater pearls.
 2) The United States contains over three hundred different species of freshwater mussels which inhabit all 50 states. The United States contains 1/3 of the estimated 1,000 species of freshwater mussels known worldwide. Some states have conservation programs to help the mussels avoid becoming locally extinct. 
3) They range in size from a tiny pebble to as big as a dinner plate.
4) If you happen to be a racoon, river otter, or muskrat they are one of your favorite foods.
5) Freshwater mussels can live up to 100 years and if you want to know how old the mussel is all you have to do is count the rings. Each year mussels much like trees add new growth ring.



Want to know more check out some of these websites.
http://www.uvm.edu/~pass/tignor/mussels/
https://blogs.illinois.edu/view/7360/546179
https://www.dgif.virginia.gov/wildlife/freshwater-mussels/