September 14, 2023 — This year’s marine heat waves and spiking ocean temperatures foretell big changes in the future for some of the largest fish in the sea, such as sharks, tunas and swordfish.
The rising temperatures of the oceans are especially dangerous for these fish because warming makes their open-water habitats less suitable, scientists who study the species said. Loss of habitat could largely remove some of the most important predators — and some of the most commercially important seafood species — from the ocean.
One recent study, from Woods Hole Oceanographic Institution in Massachusetts, predicts that some large species could lose 70% of their habitat by 2100. It’s a sign that this year’s high temperatures aren’t an anomaly but a warning about what the ocean’s future could hold with climate change.
Species of large fish such as marlin and skipjack live in areas that are among the fastest warming ocean regions, projected to increase by up to 10 degrees Fahrenheit by the end of the century, said Camrin Braun, a marine scientist and an author of the Woods Hole study. That much warming would prompt widespread redistribution of the animals, potentially fundamentally changing sea ecosystems, Braun said.
“Across the board, with life histories so different, we see this consistent signal of loss of habitat,” Braun said. “For sure, their habitat will change. How they respond to that is an open question.”