Walking along the riverbanks, lake sides, and pond shores across the world are empty open shells that were once the shield of protection to many freshwater bivalves, also known as freshwater mussels. I, personally, have even seen shells mixed into “river rock” on playgrounds. When I was a child, I even cut my foot on one hiding in the tiny pebbles of my parks swing set. I never thought much about them. When we would go to the lake to fish or swim, I would collect them like I was a mermaid princess collecting pearls. I would take them home and keep them in my fish tank, which helped my fish live for years. My beta fish named “fish” lived over 6 years because of his little friends (or a parent who lied… time will never know). How little did I know that twenty years later I would be doing the exact same thing. This time instead of a mermaid princess, I get to act in a scientific and ecological manner.
Worldwide some conservations and ecological organizations estimate upwards to 1,000 species of freshwater mussels and other organizations claim its more like 900 different species. North America houses a known 300 different freshwater mussel species. The US Fish and Wildlife Services claims the North America has the highest diversity in freshwater mussel species in the world. There are many hot spots for mussels in the US including but not limited to the Mid-West and the Appalachian Mountains. It is estimated that over 70% of the endanger freshwater mussels are found in these two areas. Tennessee by itself historically housed 129 of the nation’s freshwater mussel species. Now with in Tennessee, it is estimated to house only 40 species.
Pre-European Colonization (don’t get me started on that mess) times are in my opinion the most ecologically balanced times in North America. Natives understood the balance between nature and humans. The first uses of mussels in the now US, was by these Natives and was probably food based. Archaeologist and anthropologist have found multiple sites of discarded shells on the banks of rivers around tribal sites. They probably were not a primary food source for the tribes, but the evidence does point to a culinary use. Later, (when Europe sent a bunch of “Karenz” over) there was significant uptick in trade for the shells (FMCS 2020, Parmalee 2016).
During colonization and Pre-Modern day (prior to 1970s), freshwater mussels were harvested from riverbanks by the masses not for food or trade but for buttons. Yes, buttons. The “clammers” would use boats and drag the river bottoms looking for mussel beds. They would then shell the poor creature, sand down the roughness, and punch holes through out the shell. These punch outs would then be polished and punched for buttonholes. This type of harvesting lasted longer than it should have unfortunately. It wasn’t until the 1900, this type of industry slow due to massive die off of the natural mussel beds (FMCS 2020, Parmalee 2016).
So, what is so fascinating about freshwater mussels? Conservationists around the world are trying to save the species we have left. They act as a natural water filtration system as well as food for fish and crustacean. They are what is called a “niche” species. So basically, without them we won’t have freshwater ecosystems. They have a rough outer shell that is semi curved on both sides. The shell open for them to eat, breath, mate, and move (yes, they move). Inside is the organs and soft tissue. If you ever open one, it kind of looks like an oyster but smaller.
Freshwater mussels can live in almost any collection of freshwaters from pond and stream all the way to lakes and major rivers. Each species has its preferred depth and habitat. Also, the majority of freshwater mussel need fish to act as a host when mating. Some will even use their soft tissue disguised as a fish or prey to lure in the host fish. These may seem like simple creatures on the surface but they in fact are surprisingly in genius.
While we try to restore, what a boat load of people destroyed, there are still massive problems in their ecosystem that threatens the survival of the species. During the decades between 1930s to 1970s and even later there were over 80,000 dams built in the US, in an effort to use hydro power and control water flows and regulate flood waters. As well as dams the US dug canals and channels to divert water flows. There are over 18,000 canals in the US to this date. Both cause problems for the freshwater mussel by many factors. The waters become deeper in areas that were shallow before which can cause less area the mussels can survive in. It stops or impinges on the migration of the host fish species, causing reproduction to dwindle.
Newer problems like pollution is not only affecting the host and phytoplankton that they feed on but the mussels themselves. There are multiple studies showing the biological affects of heavy metals, chemical and other man made pollutants. These contaminations cause lower body mass, lowered behavioral movement, and lowered overall survivability for the individual. It’s like if you have to live in your neighbors trash dump. You can’t find food. You can’t find love. And you won’t survive long periods of time.
Lastly, invasive species are also causing a threat to the native freshwater mussels. Many species will come in on boats from other areas and take advantage of the new area. Other mussels, like the Zebra Mussel of Russia, leach off others for nutrients and other sustainable substances. There are new policies of how to maintain and care for the boats traveling in different waters, in order to slow the progression of the spread. However, it will take a lot of help from us as humans to undo our mistake.
Protecting endangered species should be a priority for conservationists. A creature like the freshwater mussel is overlook so many times. It is important to know how vital they are to the ecosystem and how not to cause them more harm. Things you can do to help the protect these creatures is 1. To vote in all elections. Do your research! 2. Cut down on plastic usage. Many plastics and industries run off contaminate the water. 3. Spread your knowledge! A lot of people don’t see freshwater mussels as creatures that need protection or that they even exist and why they are important.
Center for Biological Diversity. (2013). Retrieved July 30, 2020, from https://www.biologicaldiversity.org/campaigns/freshwater_mussels/index.html
Center for Biological Diversity. (2013). Two Tennessee River Mussels Protected Under Endangered Species Act. Retrieved July 30, 2020, from https://www.biologicaldiversity.org/news/press_releases/2013/tennessee-river-mussels-09-25-2013.html
Kathy Hawes, T. (2019, October 26). Tennessee Has Mussels! Retrieved July 30, 2020, from https://www.tcwn.org/post/2019/10/26/tennessee-has-mussels
Freshwater Mollusk Conservation Society. 2020. www.molluskconservation.org. Date access 01 July 2020
Loller, T. (2019, December 17). Freshwater mussels are dying at an alarming rate, and scientists want to know why. Retrieved July 30, 2020, from https://www.usatoday.com/story/news/nation/2019/12/17/freshwater-mussels-dying-tennessee-clinch-river/2672755001/
Parmalee, P. (2016, August 22). McClung Museum of Natural History & Culture. Retrieved July 30, 2020, from https://mcclungmuseum.utk.edu/exhibitions/tennessee-freshwater-mussels/
Platt, J. (2018, April 09). America’s Freshwater Mussels Are Going Extinct–Here’s Why That Sucks. Retrieved July 30, 2020, from https://blogs.scientificamerican.com/extinction-countdown/americas-freshwater-mussels-are-going-extinct-heres-why-that-sucks/
Sartore, P. (2019, December 16). A freshwater mussel apocalypse is underway-and no one knows why. Retrieved July 30, 2020, from https://www.nationalgeographic.com/animals/2019/12/freshwater-mussels-die-off-united-states/
USFWS, U. (2019). America’s Mussels: Silent Sentinels. Retrieved July 30, 2020, from https://www.fws.gov/midwest/endangered/clams/mussels.html
Xerces Society. (2020). About Freshwater Mussels. Retrieved July 30, 2020, from https://xerces.org/endangered-species/freshwater-mussels/about