Fig. 4From: Non-invasive quantification of cardiac stroke volume in the edible crab Cancer pagurusTime courses of heart beat signals of C. pagurus recorded with infra-red photo-plethysmography. Exemplary presentation of individual IR-PPG recordings between normoxia and hypoxia for three individuals. a-b)Â animal 1; c-d) animal 2; e-f) animal 3Back to article page