Lake-Dwelling Freshwater Peal Mussels

What is the scientific name for the freshwater Pearl Mussles?

Margaritifera margaritifera

Where to freshwater Pearl Mussels typically live?

On the beds of clean, well-oxygenated, fast-flowing rivers & streams w/ coarse sand/fine gravel 

How do freshwater Pearl Mussels bury themselves in the sand/gravel & between boulders?

W/ their muscular foot

Why are the mussels usually orientated towards the flow in fast-flowing rivers?

Reduces likelihood of being washed away by currents, facilitates filter-feeding

Why is the current conservation status of freshwater Pearl Mussels poor?

• Past pearl fishing

• Habitat modification & fragmentation

• Poor water quality

• Excessive siltation

Why are the habitats of freshwater Pearl Mussels kept secret?

Risk of poaching for their small pearls

True or false: prior to 2014, lakes were recognized as habitats for freshwater Pearl Mussels

False

In what county were freshwater Pearl Mussels observed residing in a lake?

Kerry

What were the conditions of the lake where freshwater Pearl Mussels were found?

Still water, depths up to 9 meters, with plants (all goes against what was previously thought to be known about the pearl mussels)

How does the distribution of freshwater Pearl Mussels in lakes compare to in rivers?

Randomly distributed rather than clustered together - especially in depth

What is the estimated total population of freshwater Pearl Mussels in the lake they were discovered?

150,000-200,000

Describe the lifestyle of freshwater Pearl Mussels in running waters.

• Male releases sperm into river

• Females inhale it (passive reproduction)

• Glochidia (larval stage) released after fertilization

• Brood to female fish gills (used for nourishment)

• Drop off & burying themselves deep in the gravel for 5-6 years while growing

• Emerging to surface & live for up to 140 years 

What challenges & adaptations do freshwater Pearl Mussels have to make when living in still lake water?

• Reproduction: aggregation of lake mussels during breeding & the absence of directional flow?

• Host selection: brown trout, Atlantic salmon, or artic char?

• Feeding behavior: phytoplankton food sourse? Active syphoning of food in absence of flow? Problem of pseudofaeces around their shells? 

• Habitat & behavior of juveniles: buoyancy of glochidia? Habitat selection of juveniles (where are they found)? 

Are lake-dwelling freshwater Pearl mussels unique to Ireland? Where else might they be found?

Probably due to its mild climate; along the Atlantic coast in places like Scotland & Norway