The research efforts deal with the relationship between cardiac output and pericardial pressure in swimming sharks and continues preliminary findings of positive pericardial and enhanced venous pressures during activity. Using indwelling catheters we will measure blood pressures and determine respiratory blood gas levels in resting and active sharks and determine rates of anaerobiosis as indicated by lactate levels. Finally we will begin to examine effects of P0 , temperature, and swimming speed on the oxygen consumption rate of swimming Triakis and determine its aerobic scope for activity. The research deals with the energetics of locomotion in sharks using a water tunnel treadmill that has been adopted for simultaneous measurement of bloodflow, oxygen utililization, swimming motions, heart rate, etc. at various swimming speeds. The results are important to our understanding of biomechanics of swimming in fish. Dr. Louis E. Burnett (University of San Diego) plans to study blood gas transport in a number of fish (mainly sharks) during exercise in a water tunnel treadmill/respirometer. Particular emphasis will be placed on the role of pH and carbon dioxide levels in regulating oxygen delivery to the tissues.
