Overview
- An April 16 Science paper finds mesothermic fishes expend about 3.8 to 4 times more energy than similarly sized cold-blooded fish.
- A 10°C rise in body temperature more than doubles routine metabolic rate, which means warm-bodied predators must eat far more to keep up.
- Researchers merged biologging of body and water temperatures with hundreds of lab respiration tests, including data from basking sharks up to 3.5 tonnes.
- The team mapped heat-balance thresholds and reports a one-ton shark may struggle above about 17°C, prompting slower movement, blood-flow shifts, or deep dives to shed heat.
- Models point to shrinking summer habitat and poleward or deeper shifts, with overfishing and bycatch compounding risks and raising the chance of food web disruption.