This will disrupt ecosystems as mesotherms are typically apex predators that exert disproportionate control on species below them in the food chain, said Edward Snelling, co-author and physiologist at the University of Pretoria. “These species are being pushed closer to their physiological limits, which could have consequences for where they can live and how they survive,” said Snelling in a press release. “These animals are already operating on a tight energy budget, and climate change is narrowing their options even further.” Using tiny sensors on a range of fish, including basking sharks weighing over three tons, researchers calculated how much heat fish produce and lose in real time. From this, they calculated that a one-ton warm-bodied shark may struggle to remain in waters above 62.6° Fahrenheit  (17° Celsius) without taking countermeasures. Discovering these “hidden heat budgets” could prove critical to any hope of conserving them or mapping protection areas, researchers said.…