Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling

Starfish feeding rate was quantified by measuring the shell length of consumed blue mussels (Dial Caliper DialMax Metric, Wiha Division KWB Switzerland). Based on a previously described relationship between shell size and tissue dry weight for mussels in the study area (Moron et al. 2020), the dry weight of consumed mussels was estimated. Starfish individuals were weighed at the start of the experiment, during the heatwaves, in between heatwaves and the upwelling event, directly after the upwelling event and at the end of the experiment.

Starfish activity was measured as righting response (i.e., time needed for the starfish to turn back onto their oral side after being placed on their aboral side) before the beginning of the heatwave treatments, at the end of the heatwaves, before, during and at the end of the upwelling event, and at the end of the experiment.