Heat waves can have devastating effects on some marine predators, such as sharks, but other species can adapt, scientists have found.
According to the National Oceanic and Atmospheric Administration (NOAA), the frequency of marine heat waves has increased by about 50 percent over the past decade. They can lead to habitat loss and, in some cases, even the death of marine mammals.
Scientists want to understand how marine life responds to this trend. Using data from tagged animals in the northeast Pacific, they found how they redistributed after the 2014, 2015, 2019 and 2020 heat waves.
Some predators, including sharks, mammals, seabirds, sea turtles and tuna, have “almost completely lost their habitat” due to the heatwave, the study, published in the journal Nature, said. natural communication reported.
“There is a surprising diversity in the impacts between marine heatwaves and predators,” corresponding author Heather Welch from the National Oceanic and Atmospheric Administration (NOAA) told reporters. Weekly newspaper. “Predator habitats were displaced in all four cardinal directions; some predators tripled their habitat area during one heat wave and then almost completely lost their habitat area during another heat wave. Therefore, this is not A story of winners and losers, but a story of winners and losers. “It’s a story of how the impact of marine heatwaves is changing. To understand the full scope of impacts, we need to move beyond single-species, single-heatwave case studies to more comprehensive ecosystem-based surveys. “
Elliott Hazen, NOAA Southwest Fisheries Science Center
Bluefin tuna and blue sharks were the most habitat-loss predators during the 2015 heat wave. However, California sea lion and elephant seal habitat tripled due to the 2019 heat wave.
Some species can also redistribute themselves and change their migration patterns.
Between 2014 and 2015, between 11 and 31 percent of albacore, bluefin and yellowfin tuna habitat in Mexico was transferred to the United States.
Although the habits of these predators varied slightly, they were all “highly predictable,” the study reported.
“Importantly, we found that although the effects of marine heatwaves are highly variable, they are also highly predictable by models,” Welch said. “We can’t assume that future heatwaves will affect species the way past events do, but we can Predicting the impact of future heat waves in real time as they occur. Or better yet, we can predict the impact in advance.”
Dan Costa, UC Santa Cruz
This habitat change suggests that marine animals have early warning systems, similar in some respects to human weather forecasting, that can alert them to how heat waves will affect their habitats.
While research has looked at the long-term effects of marine heatwaves, little is known about the short-term effects.
It is hoped that this research will help predict where various species will be found, allowing better management of marine resources and preventing potentially dangerous encounters between humans and wildlife.
“Given the need for adaptive management tools to prepare countries and minimize future fisheries conflicts, the authors also use their model to demonstrate a dynamic ocean management tool that can change the distribution of each species,” the study said. Make daily forecasts.”
“This early warning system will help to proactively respond to new human-wildlife conflicts and changes in marine resource supply.”
“This early warning system is particularly important because we found that marine heat waves can redistribute species across jurisdictional boundaries (e.g., national waters, open oceans),” Welch said. “Redistribution of species jurisdictions has been observed in response to long-term warming (climate change), but we found that redistribution is also occurring due to short-term episodic warming due to heat waves. It will take time for countries to be proactive about species Good plan” entry or exit during a heat wave. “
All ocean basins have warmed steadily since the 1990s, except for marine heat waves.
According to NASA, the oceans absorb 90% of the heat from global warming, and 2020 was one of the hottest years on record.
Data from the University of Maine’s Climate Change Institute also shows that since mid-March 2023, the global average sea surface temperature has been above the highest level since accurate satellite temperature records began in 1981.
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