For millenia after millenia, the quality of Iowa’s water came as a byproduct of a very
particular species; the freshwater mussel.
Lying peacefully across the river beds of practically every Iowa waterway, millions
of mussels main purpose is to filter out impurities, thereby releasing clean, freshwater back into
the channel.
While still abundant today in our creeks, streams, and rivers, the population size is
drastically smaller.
Whereas once it was said mussels blanketed river floors from bank to bank, today it takes
a more skilled eye.
Oh!
I got a trail.
Have a young pimpleback here.
Jennifer Kurth is a malacologist who specializes in freshwater mussels.
In fact she is so well acquainted with the animal that her mother sometimes jokes, that
she must be part mermaid.
I don’t know if you can actually see the trail here.
He came up over there and is trying to get out to deeper water.
Oh sorry, she is.
So that’s a female plain pocketbook.
Plain pocketbook is one of the species that has has male and female shell shapes.
This is a younger pimpleback.
And these guys don’t have male and female shell shapes.
The only way to know which way you have is to open it up and see if it’s pregnant.
As unimpressive as these shellfish may look, they are the foundation of ecosystems across
North America.
Improving the habitat for everything from insects and single-cell organisms to large
fish and even humans.
The United States is the hotspot for mussel biodiversity in the whole world.
It gets better as you go to the south and east, so Virginia, Tennessee.
I call them ‘Mother Natures water filtration system.’
They help to keep our water clean.
They’re filter feeders, so they actually have an incurrent syphon, where they bring
in the water and all the stuff that’s in it.
They separate it, and what they can eat they will.
And what they don’t eat they will actually bind up in mucus and deposit it on the river
bottom for other animals, scavengers like crayfish to eat.
And a single mussel, depending on the size and the age, can average about 10 gallons
of water per day, filtered.
So if you think about the historic numbers of mussel beds that we used to have here in
Iowa.
Um… our water was really pretty clean.
Of the 42 remaining species of mussels found in Iowa, the Boone River here in Wright County
is home to 11 different varieties of mussels, with three of them listed as threatened.
And the cool thing is this site has been sampled six times since 1982 and the number of species…
I believe they found 4 species here in 1982, and then it went down to zero for a while.
And then in 2009 I believe it had 8 or 9 species , and in 2015 is when we found 11 species,
so they’re definitely making a comeback here on the boone river which is exciting.
Of course for a comeback to happen, first a disaster must occur.
Mussels really declined in the first part of the 20th century, latter part of the 19th
century because they were massively harvested for the button industry.
You know Muscatine was known as the button capital of the world for a while.
They would just go out there with these massive racks and just take every single mussel they
could just because they didn’t want to leave anything for their competitors, whether it
was useable for not.
So they basically were harvesting in an unsustainable way.
Today commercial mussel harvesting is banned in the state of Iowa; but combined with modern
farming practices and increased development raising the silt levels of Iowa rivers, mussels
were pushed to the brink of extinction.Thankfully just as regulations were enacted, conservation
and education jumped to the mussel’s aid as well.
So we’re here at the Dubuque ice harbor with the Mississippi River Museum and we’re
harvesting our cages of infested fish.
Black sandshell!
To bring in the mussels that dropped of them over the season.
So these mussels will be used for recovery as far north as the Chippewa River in Wisconsin
and as far south as around Guttenberg in Iowa.
The harvesting crew of biologists, DNR employees, and volunteers are collecting thousands of
juvenile Higgins Eye Pearlymussels, an endangered mussel found throughout the midwest.
This mussel recovery effort is an excellent example of the interconnected nature of mussels
and the aquatic ecosystem they help maintain.
Higgins Eye are a part of a group of mussels that lure in their host fish and the females
have a part of their mantel, which is the part of the animal that builds their shell,
that um is modified to look like a fish.
And in the turbid water, apparently fish you know their vision declines just like ours
does and so they have just kind of basic lure.
It’s got like a frilly tale and a bit of an eyespot and the mussel is able to push
her gills up, where her larvae are stored and the fish will come down, sees that, thinks
it’s lunch, comes down and takes a bite.
In doing that it breaks open the female mussels gills and gets infested will the larvae of
the mussel then.
Over the coming weeks, the larvae will transform into juvenile mussels and fall off their host
fish to the river bottom.
If they settle into a suitable habitat, a new mussel bed will propogate.
These animals don’t have eyes.
They have photo receptive cells that can tell if it’s light or dark.
Itty bitty bundle of nerves that is kind of a brain but somehow they know what fish eat.
Jared McGovern is an educator at the National Mississippi River Museum and Aquarium and
events like the Higgins Eye harvest are the perfect experience for students to learn all
the wonders of these seemingly insignificant mollusks.
So these guys and gals right here…
YOU!
Are now a freshwater mussel.
On top of seeing the harvest up close and personal, Dubuque area students learn all
about the mussels Iowa history, their lifecycle, species identification practices, and of course
a firsthand look at their water filtration powers.
I put these animals in here… 8 o’clock.
It’s now close to 9 o’clock and in that time these animals have filtered about two
and half gallons of water.
Hands on field trips like Jared’s have the potential to change a student’s life.
Holding a mussel and learning how humans, wildlife, and the ecosystem depends on is
the kind of experience that builds conservationists.
But if not, they at least learn that the quality of their environment can hinge on something
as small as a freshwater mussel.
These are a keystone species.
They literally create a habitat with their body.
These animals as they grow they are in such mass that and such volume in certain areas
that they will they will cover the entire bottom of the Mississippi River.
And they’re going to create a physical structure for algae to grow on, algae that then attracts
insects, insects that attract fish, some fish even breed on these mussel beds…
So as a keystone species if it was not for this particular animal, that habitat would
not exist.
These animals are one of the coolest and one of the most important animals living in the
Mississippi River and in North America we have the most diverse population of anywhere
else in the world.
Funding for Iowa and Sky provided by…
The Resource Enhancement and Protection, conservation education program.
The Gilchrist Foundation, founded by Jocelyn Gilchrist furthering the philanthropic interests
of the Gilchrist family, in wildlife and conservation, the arts and public broadcasting, and disaster
relief.