ABSTRACT
During the last several decades, studies on the aerobic metabolism of elasmobranchs have relied on the use of indirect calorimetry centered on small, generally sedentary species that acclimate well to the tight enclosures of a respirometer chamber and those that are easily maintained in captivity for long periods of time. By contrast, work on larger and obligate ram ventilating species has lagged far behind and typically features a paucity of measurements usually conducted over short durations of time on a few selected species. More recently, eldbased empirical models have been used to estimate the metabolic requirements of species too large to work with in the laboratory. The original view of the energetic
demands in sharks and rays was that they typically possessed lower metabolic rates relative to similar sized teleosts; however, this view is beginning to change as new data emerge on the metabolism of several large, actively swimming species. Nonetheless, several general important factors need to be considered when attempting to compare the energetic demands between elasmobranchs and teleosts and among elasmobranchs.
