Business · Ars Technica
As the oceans warm due to climate change, they now face the risk of potentially fatal overheating
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The evolutionary edge that fueled great white shark dominance for millions of years could soon become its greatest downfall.
Key facts
- 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
- Declines of great white sightings in False Bay, Mossel Bay, and Gansbaai, however, are multifaceted
- If you’re a shark, you can’t pop down to the supermarket and buy more food,” said Nick Payne, lead author and associate professor at Trinity College Dublin, Ireland
- A rare group comprising fewer than 0.1 percent of all marine life, mesothermic fishes—also including thresher and porbeagle sharks—trap metabolic heat to keep their bodies warmer than surrounding
Summary
The ocean’s most iconic predators maintain warmer body temperatures than the surrounding seawater and are paying an increasingly steep price for it. “If you’re a shark, you can’t pop down to the supermarket and buy more food,” said Nick Payne, lead author and associate professor at Trinity College Dublin, Ireland. A rare group comprising fewer than 0.1 percent of all marine life, mesothermic fishes—also including thresher and porbeagle sharks—trap metabolic heat to keep their bodies warmer than surrounding seawater. However, as fish grow larger, their bodies generate heat faster than they can shed it. This mismatch—driven by the physics of surface area and heat retention—triggers the overheating dilemma in warmer waters. 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.
“Many local and international conservation narratives now position the great white not as a villain, but as a keystone species essential to maintaining ocean health,” Nicolaides said. Declines of great white sightings in False Bay, Mossel Bay, and Gansbaai, however, are multifaceted.