ABSTRACT
This chapter discusses what happens to respiratory and cardiovascular function in teleost fish exposed to unavoidable changes of body temperature. In the aquatic environment, smaller animals are unable to maintain body temperatures far from the water temperature. The effects of temperature on acid-base status have been studied in several teleost fish. Temperature changes substantially affect the ability of the fish heart to maintain cardiac adaptations that permit adequate function under conditions crucial to survival. At elevated temperatures, the heart rate and the velocity of cardiac contraction increase, whereas the force contraction usually decreases. Considerable information is available for the effects of stimulation frequency on force development of vertebrate hearts. With the adaptation of cardio-respiratory functions to temperature, the teleost fish is able to alleviate the impact of changing temperatures on gas transport. In contrast to ectothermic tetrapods vertebrates, teleost fish tend to maintain a constant O2-extraction of the gas exchange organ, when faced with changes of ambient temperature.
