Warm-blooded fish may disappear in the conditions of ocean warming.

Large warm-blooded fish, such as sharks and tuna, owe their dominant position to their ability to retain their body heat, but there is a price to pay for this advantage. According to a new study published in the journal Science, these mesotherm species require almost 4 times more energy than other fish, and as the oceans warm, their ability to generate heat faster than they lose it may lead to these already vulnerable species being on the brink of extinction. A small number of fish species, such as tuna and some sharks, have evolved the ability to retain metabolic heat in their bodies—this strategy is known as mesothermism. It allows these species to improve their physiological capabilities. However, despite their advantages, these species dominate as top predators in the ocean, but maintaining an elevated body temperature and high activity requires significant energy expenditure. Nonetheless, the energetics of warm-blooded mesotherm organisms, which can have a substantial impact ...