How long do they live? Freshwater pearl mussels can live well over 100 years and one was found to be 280 years old [1]!

Where are they found? They are native to European freshwater streams, but they can also be found in Northern American and Canadian streams [2].

What do they eat? No one really knows for sure what they eat, but since they are filter feeders scientists believe they live off really small creatures, such as krill and plankton [1]. Being a filter feeder isn’t all it’s cracked up to be since any changes in water quality can be detrimental to these mussels.

What do they look like? Like most bivalves, Freshwater pearl mussels are protected by two hard shells that hinge at one end. They also have a foot that allows them to burrow in the sand and a siphon that filters water, food and waste in and out of the mantle. They usually grow to be around 13 cm long, but one was found that was 17 cm long [2].  See figures 1, 2, and 3.

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Figure 1. Freshwater pearl mussels burrowed into the river bed.
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Figure 2. Pictured here. 3 mussels not in their natural habitat.
Margaritifera margaritifera [[Boldie]] Joel Berglund
Figure 3. The inhalant siphon is that fleshy looking thing you see in the picture.

How do they reproduce? I’ll begin with the fact that males and females both exist in a population, but they can change to hermaphroditic if need be (oh the life of a mussel). There’s a good reason for this fun fact, you see males release their sperm into the water and females ingest the sperm to fertilize the eggs they are carrying. Sperm reaching its destination is dependent on if females are in the proper location of the water flow, so a little shift in water flow and some females don’t get sperm. They don’t let that bother them too much, though, because the female will just self-fertilize. Freshwater pearl mussels reach sexual maturity around 20 years old and they don’t seem to stop reproducing until they die [3], which is a hallmark of negligible senescence. That’s a very long time to be making babies if you’re the 280 year mussel mentioned above.

How do scientists know how old they are? By counting the growth bands on the shell of the mussels [1].

So what are we lacking? There’s no genome information for Margaritifera margaritifera uploaded to the NCBI website, so that would be a good start. There seems to be no evidence that superoxide dismutase or catalase activity is contributing to extended life span in this species either [4].

Conservation status: According to the IUCN Red List, Freshwater pearl mussels are critically endangered due to habitat destruction, such as loss of gravel beds to burrow in, and man made pollution.

Tracking down how long-lived animals achieve their superpowers is a hobby of mine, so please let me know if you have any information to contribute to this species.

  1. Degerman, Erik. Restoration of freshwater pearl mussel streams. 2009. Accessed 10/4/2016.
  2. Animal Diversity.org. Margaritifera margaritifera
    http://animaldiversity.org/accounts/Margaritifera_margaritifera/#lifespan_longevity
  3. Bauer, G. “Reproductive strategy of the freshwater pearl mussel Margaritifera margaritifera.” The Journal of Animal Ecology (1987): 691-704.
  4. Fernandez, Carlos, Eduardo San Miguel, and Almudena Fernandez-Briera. “Superoxide dismutase and catalase: tissue activities and relation with age in the long-lived species Margaritifera margaritifera.” Biological research 42.1 (2009): 57-68.