March 13, 2012

Mussels, Ecosystems Suffer Without Freshwater

A drastic decrease in the population of freshwater mussels could have dire effects on fish and humans alike. Zoologist Caryn Vaughn from Oklahoma´s Aquatic Research Facility in Norman has been researching these freshwater mussels for over 20 years. She says she´s concerned about the drastic decrease in mussel population that´s occurred in that time.

Vaughn told the National Science Foundation “This one river that we´ve been working in for over 20 years, we probably lost a third of the mussels in that river because of water levels.

Freshwater mussels act as tiny water filtration systems that lie almost dormant in river beds. The constant filtering done by mussels provides a benefit for humans as well as the ecosystems in which they live.

Vaughn works with and studies the 55 species of mussels that call Oklahoma home. Across North America, more than 300 mussel species exist. With colorful names like “Pistol Grip”, “Fatmucket”, and “Bankclimber”, the invertabrates play a very important role in river ecosystems. However, poor irrigation practices, severe drought, and harvestation have threatened the mussel population. According to Vaughn, “Almost 70 percent of the species are considered threatened in some way. They´re the most globally threatened freshwater organism there is,.”

For many years the beautiful and iridescent inner shells of the mussels had been harvested to make ornate jewelry and buttons. The shells were even used to make the small beads placed in oyster shells to create pearls. Thanks to synthetic materials and availability of cheap plastic, this kind of mussel harvestation has all but ended.

Now, our need for water is now the biggest danger to freshwater mussels according to Vaughn. “We probably could have saved a lot of them if we had better water management practices in place at the time of the drought. So we really need to take what we know and use that to help them manage the resources, so we can keep the mussel populations, while meeting human needs,´ said Vaughn. That´s a difficult thing to do.”

Mussels need a lot of water to thrive and reproduce.

“Freshwater mussels can´t move very far. So the way they get around is by sticking their larvae on a fish. And the fish takes it to a new habitat,” says Vaughn.

The key to restoring and reviving the mussel community may lie in diversification. In her studies, Vaughn has found that the more types of species are found in a river bed, the healthier the animals are.

“When the fatmucket and the bankclimber are together, do they do something different than mussels when they are just by themselves? They´re definitely in better condition when they´re in more diverse beds,” says Vaughn.

Vaughn and her team are trying to attach a monetary value to the work the mussels are doing in the rivers. If the team can create a sort of “price tag” on the amount of filtration the mussels perform in a river, they will be able to calculate the cost saved in modern filtration techniques by city and state governments.

Vaughn hopes that this kind of approach will spur these government bodies to take action to protect and preserve the mussels.


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