Tuna aerobic swimming performance: Physiological and environmental limits based on oxygen supply and demand (original) (raw)

Sustainable (aerobic) swimming performance in yellowfin tuna (Thunnus albacares) is examined through a model estimating red muscle oxygen demand and the cardiovascular system's capacity for oxygen delivery. At maximum oxygen delivery (25°C), red muscle oxygen consumption ((702RM) is estimated to be 0.197 ml O2/g/min, which is higher than previous estimates of maximum VOzRM. However, due to the high costs of swimming at high speeds, maximum sustained velocity at this rate would only be 3.7 fork lengths/s, which is lower than previous estimates for yellowfin. Hypoxia and reduced ambient temperature that may be encountered by yellowfin in the course of their natural movement patterns will decrease oxygen delivery capacity through effects on the cardiovascular system, limiting maximum VO2RM. Moderate swimming velocities could, however, be maintained at an oxygen tension of 75 mmHg, and at an ambient temperature of 15°(;. COMP BIOC. EM PHYSIOL 113B, 45-56, 1996.