Fig. 3. (A) Heart rate (beats min^-1), (B) stroke volume (ml beat^-1) (C) cardiac output (ml min^-1) and (D) ventilation rates (beats min^-1) of eight Cancer magister. Crabs were monitored during a 3 h control period in normoxia, food was administered and cardiac parameters followed for a further 1 h in normoxia after which, hypoxic conditions of 3.2 kPa were initiated for 6 h. Normoxic conditions were then restored for an additional 6 h. Values are means ± S.E.M.