Blood Respiratory Properties and the Effect of Swimming on Blood Gas Transport in the Leopard Shark Triakis Semifasciata

摘要: Changes in vascular pressures, blood respiratory properties and gas transport induced by swimming were investigated the leopard shark Triakis semifasciata (Girard). In resting sharks, mean ventral dorsal aortic pressures (systolic/diastolic) 6.8/5.6 kPa 4.5/3.9 kPa, respectively, only former increased significantly during swimming. Swimming also caused a significant decline venous Po2 (1.6 to 0.9kPa), O2 content (0.9 0.4mmoill−1) percentage saturation {SO2, 39 18%) but arterial variables not affected. A pH an increase occurred lactate concentration did or after An vivo dissociation curve compiled from So2 data for sharks resting, post-swimming recovery phases shows P50 of 2.04 as determined Hill transformation. The pH-bicarbonate plot this fish weak buffer capacity 9.3mmoll−11pHunit−1 average bicarbonateconcentration follow line which was compensated recovery. Neither oxygenated nor deoxygenated values affected CO2 equilibration, suggesting absence Haldane effect. Thus, at expense acidosis, can aerobically sustain long (up 60min) moderately intense (0.45 Ls−1, where L is body length) periods increasing cardiac output tapping its reserve. Introduction Most vertebrate circulatory