Spectacle case pearly mussel facts for kids
Quick facts for kids Spectacle case pearly mussel |
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| Mature and young Cumberlandia monodonta | |
| Conservation status | |
| Scientific classification | |
| Genus: |
Cumberlandia
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| Species: |
monodonta
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| Synonyms | |
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Margaritifera monodonta Say, 1829 |
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The spectaclecase (scientific name: Cumberlandia monodonta) is a type of freshwater mussel. It lives only in the United States. Sadly, it is an endangered animal. Both the U.S. Fish and Wildlife Service and the IUCN say it's at risk.
A scientist named Thomas Say first wrote about this mussel in 1829. He called it Unio monodonta. Later, in 1912, another scientist, A. E. Ortmann, changed its group to Cumberlandia.
The number of spectaclecase mussels has dropped a lot because of human activities. This is why it's listed as "Endangered" by the Endangered Species Act and the IUCN. Building dams has caused big problems. Dams hurt the mussel's home and food supply. The Endangered Species Act says the spectaclecase is highly threatened. It also says it has a low chance of getting better on its own.
Contents
About the Spectaclecase Mussel
Physical Features
Spectaclecase mussels have long, oval-shaped shells. They can grow to be over 9 inches long. The shell feels mostly smooth. If it gets dry, it might crack at the back end. Young mussels have light yellowish-green shells. Older mussels have shells that turn dark brown or black.
Life Cycle and Reproduction
Scientists are still learning a lot about the spectaclecase mussel's life. Males might become ready to have babies at 4 to 5 years old. Females might be ready at 5 to 7 years old.
The mussel's life cycle has many steps. Male mussels release sperm into the water. Female mussels take in the sperm while they are filter feeding. The fertilized eggs grow into tiny larvae called glochidia. In late spring, the female mussels release these glochidia into the water.
These tiny glochidia need to attach to a fish for a short time. This is a necessary part of their growth. Scientists have found two fish species that host them. These are the Hiodon tergisus and the Hiodon alosoides. More research is happening to find other host fish.
What Spectaclecase Mussels Eat
Adult spectaclecase mussels bury themselves in the riverbed. They eat by filtering water. Their diet includes tiny algae, bacteria, and other small bits of food in the water.
Where They Live and How Many There Are
The spectaclecase mussel lives only in the Mississippi, Ohio, and Missouri River basins. They are most often found in larger rivers. They like to live in groups in calm water. You can find them between large rocks or stuck in firm mud. They hide from strong currents under big rocks or ledges.
In the past, these mussels lived in at least 44 streams. By 2014, they were found in only 20 streams. This means their living area shrank by 55%. Also, the groups of mussels are now very spread out. They only cover short parts of a river. A recent review showed their living area has not changed since they were listed as endangered.
How Humans Affect Mussels
Losing and Damaging Homes
Mussels are losing their homes, and their homes are getting damaged. This is the main reason their numbers are dropping. Things that hurt them include dams, changing river paths, pollution, mining, and too much sediment.
Dams and River Changes
Dams and changing river paths are still a big threat. They change how sand and dirt settle in the river. Too much sediment can make it hard for mussels to eat and breathe.
Mining Impacts
Mining in rivers and for gravel harms water quality. Coal, oil, and gas mining also threaten mussels. They add more silt to streams. They also change how water flows and make the water dirty. Lead mining can put heavy metals into the riverbed. These metals are harmful to mussels.
Protecting the Spectaclecase Mussel
Small, Separate Groups
Most of the remaining mussel groups are small and far apart. This makes them very open to danger. For example, a chemical spill could wipe out a whole group. Also, because they are so spread out, they can't easily move to new areas. This means their living area will keep shrinking without human help.
When groups are separated, they can't share their genes easily. This can lead to inbreeding. Inbreeding can make the mussels less healthy. A recent study found that mussels still have good gene diversity. But all groups have been separated to some degree.
Invasive Species
Zebra mussels are found where spectaclecase mussels live. Zebra mussels are an invasive species. They attach to native mussels and harm them. Once attached, zebra mussels can stop native mussels from moving. They can also make it hard for them to open their shells. They also eat the same food, leaving less for the native mussels.
Spectaclecase mussels are especially at risk from zebra mussels. This is because spectaclecase mussels live in clumps. If zebra mussels attach to one, they could harm a whole group.
Climate Change and Temperature
Spectaclecase mussels will have trouble moving to new areas as the climate changes. This is because rivers are broken up by dams. Also, mussels don't move much. They are sessile creatures.
A study looked at how climate change affects mussel groups. Scientists found that mussel diversity would drop a lot. This is because they would lose suitable places to live.
Conservation Efforts
How Their Status Was Listed
The spectaclecase mussel was first looked at for endangered status in 1984. This list encourages more research on species.
The IUCN first listed the mussel as "Near Threatened" in 2000. They changed its status to "Endangered" in 2012. On March 13, 2012, the U.S. Fish and Wildlife Services officially called it endangered. This was because its numbers were dropping. A plan to help it recover was started in 2014. But a full recovery plan is still being made. Its endangered status has not changed since 2012.
What's Being Done Now
Recovery Plan and Priority
There isn't a final recovery plan for the spectaclecase mussel yet. It only has a recovery outline. The mussel is listed as a 4 on the Endangered Species Act's recovery scale. This means it faces a big threat. It is the only species in its group, and it has a low chance of recovery.
However, some scientists suggest reclassifying it. If it were grouped with other Margaritifera species, its priority number would change to 5. This would show it's part of a larger group. But its chance of recovery would still be low.
Counting and Watching
Many states are watching mussel groups. These include Alabama, Arkansas, Illinois, Iowa, Kentucky, Minnesota, Missouri, Tennessee, West Virginia, Wisconsin, and Virginia. They do surveys in specific places to count mussels.
Host Fish Research
When the mussel was first listed, scientists didn't know which fish hosted its glochidia. Now, two host fish species are known. More research is happening to find other host species.
Genetic Studies
Scientists have done genetic research. This helps them understand how healthy current mussel groups are. It also helps them plan for new groups. More research will help manage and restore mussel groups.
Restoring and Protecting Homes
Many public lands protect the mussel's historical and current homes. These include state parks and wildlife areas. The Nature Conservancy (TNC) has created special reserves. These reserves are along two river systems in Tennessee, Virginia, and Kentucky. These areas have spectaclecase mussels. TNC has also started projects with local communities. These projects help protect water animals and their homes.
Some Federal programs also help restore river homes. These include the Wildlife Habitat Incentives Program and the Environmental Quality Incentive Program. Federal agencies are working on these programs.
Lab Successes
In 2018, scientists successfully grew hundreds of spectaclecase mussels in a lab. Moving these lab-grown mussels to wild groups could help them recover. Also, new tests can identify mussel larvae on wild fish. These tests can help find more groups of spectaclecase mussels.
Images for kids
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Mature and young Cumberlandia monodonta
