Resilience of juvenile freshwater pearl mussels to thermal stress

Climate change poses a significant threat to freshwater ecosystems by causing increases of average water temperatures, and more frequent and extreme heating events. Freshwater mussels are declining globally, and the distribution of the freshwater pearl mussel (Margeritifera margeritifera) has decreased dramatically over the past century. Even though it is likely that climate change is contributing to the decline of the species, little is known about the specific mechanisms involved. Here, we test how short episodes of water temperatures above the known thermotolerance range affect the survival and growth of the early post parasitic juvenile phase of freshwater pearl mussels. We also test if previous experience with elevated water temperatures can modify survival and growth responses to subsequent high‐temperatures exposure. Mortality was very low in all treatments (< 5%) and not affected by the temperature treatments, while growth rate was positively affected by temperature. Our resu..., , , # Resilience of Juvenile Freshwater Pearl Mussels to Thermal Stress

[https://doi.org/10.5061/dryad.931zcrjwc](https://doi.org/10.5061/dryad.931zcrjwc)

## Description of the data and file structure

We tested how short episodes of water temperatures above the known thermotolerance range affect the survival and growth of the early postparasitic juvenile phase of freshwater pearl mussels.
### Files and variables

#### File: FPM\_temperature\_growth.xlsx

**Description:** Length measurements of juvenile mussels from the experiment.

##### Variables

* treatment: mussels were exposed to control temperature (\"Control\"), mid temperature (\"Mid\") or high temperature (\"High\") in the first temperature treatment; a sample of mussels was measured at the start of the experiment (\"start\")
* box: box number indicating replicate
* second exposure: mussels were exposed to control temperature (\"Control\") or high temperature (\"High\") in the second temperature treatment
* length: mussel length in mm

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