DOI: 10.5061/dryad.931zcrjwc
title: Data from: Resilience of juvenile freshwater pearl mussels to thermal stress

description: 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 (&lt; 5%) and not affected by the temperature treatments,
 while growth rate was positively affected by temperature. Our results
 suggest that juvenile mussels can survive short periods of heat stress
 when other environmental conditions are favourable. Future studies should
 therefore address how heat stress affects survival in combination with
 other stressors, such as reduced availability of dissolved oxygen.
description: # 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 #### File: FPM\_temperature\_mortality.xlsx **Description:** Records of mortality carried out two times a week during the experiment ##### Variables * Date: measurement date * Treatment: mussels were exposed to control temperature ("Control"), mid temperature ("Mid") or high temperature ("High") * Boxes: box number indicating replicate * Dead: number of juvenile mussels counted dead * Living: number of juvenile mussels counted alive  #### File: FPM\_temperature\_O2.xlsx **Description:** Measurements of water temperature and dissolved oxygen ##### Variables * Date: measurement date * Feeding: measurements were carried out "before" and "after" feeding of mussels * Treatment: mussels were exposed to control temperature ("Control"), mid temperature ("Mid") or high temperature ("High") * Box: box number indicating replicate * O2: dissolved oxygen in mg/L * Temperature: water temperature in degree Celsius