The evolutionary edge that fueled great white shark dominance for millions of years could soon become its greatest downfall.
The ocean’s most iconic predators maintain warmer body temperatures than the surrounding seawater and are paying an increasingly steep price for it. As the oceans warm due to climate change, they now face the risk of potentially fatal overheating, according to a new report in Science.
Several large tuna species and sharks, known as “mesothermic” species for the way their bodies run hot, require more fuel to maintain their temperature and are thus confronting a “double jeopardy” of warming oceans and declining food, mainly from overfishing. As water temperatures climb, these species will be forced to relocate to cooler waters.
“If you’re a shark, you can’t just pop down to the supermarket and buy more food,” said Nick Payne, lead author and associate professor at Trinity College Dublin, Ireland. “We’re seeing animals move with climate change in every biome on land and in the sea; this is just another example of that mechanism.”
Since it was quite a bit warmer during the Holocene Thermal Optimum a few thousand years ago, does the article suggest how the mesothermic species survived?
It’s more common for orcas to hunt in groups like wolves. I’m 99.999% sure that orcas will eat tuna as well as sharks. They are known to have attacked and killed a pod of narwhals also. There’s a good reason orcas are called “killer whales.”
What puzzles me is the J Pod of orcas that lives in the Puget Sound and Strait of Juan de Fuca off the north Olympic Peninsula. They only eat salmon which are overfished by humans so the orcas are starving and the babies are dying. The coastal orcas eat pinnipeds which are a dime a dozen out there.
Which suggests they’ll survive this warming. Unfortunately the OP didn’t include a link to the research paper, so we don’t know if the authors explored this at all.
We do know they’ve been around for millions of years, and temperatures were much warmer back then. For example, 50 million years ago the earth was more than 15°C warmer than currently.
