Spectaclecase
Threeridge
Purple wartyback
Elephantear
Spike
Yellow sandshell
Pistolgrip
Ebonyshell
Wabash pigtoe
Washboard
Sheepnose
Round pigtoe
Monkeyface
Wartyback
Pimpleback
Mapleleaf
Elktoe
Flat floater
Rock pocketbook
White heelsplitter
Creek heelsplitter
Flutedshell
Giant floater
Salamander mussel
Creeper
Paper pondshell
Mucket
Butterfly
Plain pocketbook
Higgins' eye
pearlymussel
Fatmucket
Yellow sandshell
Fragile papershell
Black sandshell
Pondmussel
Threehorn wartyback
Hickorynut
Pink heelsplitter
Fat pocketbook
Pink papershell
Bleufer
Lilliput
Fawnsfoot Deertoe
Ellipse
Spectaclecase
Threeridge
Purple wartyback |
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Pearls
In the 1800s, it was common for people to collect mussels and
look for treasure on the Upper Mississippi River; that treasure
was freshwater pearls found in native mussels. Some historians
have compared this treasure hunt to the gold rush in California.
The fever to find a pearl was so intense that people literally
killed
millions of mussels. In some areas of the river, entire mussel
beds were eliminated. But the effect of the pearl rush on mussel
populations
was minor compared to the rush to make buttons out of mussel shells.
Natural pearls |
Photo: Mississippi River Pearl Jewelry Co. |
Buttons
In 1889, the German button maker Johann
Böpple pioneered
the use of freshwater mussel shells in America. Special machines
punched
out buttons by the millions; the best buttons came from mussels
with thick shells, like the yellow
sandshell and the pistolgrip.
Sixty button factories were located in the Mississippi River
Valley by 1899–these factories harvested over 21,000
tons of shell in the vicinity of Muscatine, Iowa. Less than
ten years after
its
inception, the industry supported thousands of workers and was
valued at over $23 million (1998 US dollars).
In the early
1900s, portions
of the Illinois River were considered the most productive mussel
stream per mile in America. A clammer could make about ten
dollars
a week (and more if he found a pearl) compared to a dollar a
day for the average laborer in 1899. By 1922, the freshwater
mussel
fishery was considered one of the largest and most profitable
inland fisheries in
the U.S.
A fascinating account of the button industry is told by the
fictional Billie Button in the booklet “The
Story of My Life by Billie Button” . The button industry declined rapidly after 1930
in response to overexploitation and the dwindling supply of
marketable shells.
For example, harvest
of mussels from Lake Pepin (an impoundment of the Upper Mississippi
River near Lake City, Minnesota) dropped from more than 3,000
tons
to just 150 tons between 1914 and 1929 as mussel beds were literally
wiped out.
Mountains of shells rose up alongside
the Mississippi as clammers made a living harvesting mussels
to supply the button industry. |
Click for larger scale |
In 1914, the U.S. Bureau of Fisheries established
the
Fairport Biological Station to develop methods to culture freshwater
mussels as an alternative to harvesting mussels from the
rivers.
Between 1914 and 1919, many of the Upper Mississippi River states
adopted harvest regulations, but these regulations occurred
too
late to save the mussel fishery.
Fairport Biological Station,
1920. From the left, the temporary lab, the tankhouse,
the boathouse, shed, and main laboratory. |
Click for larger scale |
A
summary of the button industry and culture activities can be found
in
“An Historical Analysis
of Mussel Propagation and Culture: Research Performed at the Fairport
Biological Station”.
Cultured Pearls
Commercial shelling had a resurgence in the 1950s because mussel
shells from the Mississippi River were found to be excellent seed
material for the growing cultured pearl industry. Kokichi Mikimoto
of Japan discovered that when spherical beads created from the
shells
of freshwater mussels were placed into marine pearl oysters, they
served as exceptional nuclei as the oyster surrounded the beads
with secretions from the nacre (this is what gives pearls their
opalescent sheen).
Kokichi Mikimoto (photo: Mikimoto Company, Japan) |
Cultured pearls |
Photo: Mikimoto Company, Japan |
To process a cultured pearl, freshwater mussel
shells are sliced, cubed, and rounded and are implanted in a marine
oyster, which lays its own nacre over the bead.
The cultured pearl
process |
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Photo: Tom Watters, Ohio State University |
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By 1990, the expansive
industry boasted retail sales exceeding $3 billion (1998 U.S. dollars).
Ultimately about 90% of the weight of a cultured pearl is the
shell
of a native freshwater mussel!! The harvest of freshwater mussel
shells for cultured pearls is a destructive process because
much
of the shell is lost during the processing--a ton of shell produces
about 40 to 60 pounds of nuclei.
In the Upper Mississippi River System, at least 18 species,
half of which are considered endangered, threatened, or a
species
of special concern by at least one of the states bordering the
Upper Mississippi River, presently have some commercial value.
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