The research team found that in warmer waters, shark embryos grew faster and used their yolk sac — their only source of food in this developmental stage — quicker.
The creatures hatched earlier, were born smaller, and needed to feed straight away, but lacked energy, researchers from Australia’s ARC Centre of Excellence for Coral Reef Studies at James Cook University and the University of Massachusetts said Tuesday.
There are more than 500 types of shark living around the world, and the majority give birth to live young. Some shark species, like epaulette sharks, lay eggs, which are left unprotected and must be able to survive on their own for up to four months.
“The epaulette shark is known for its resilience to change, even to ocean acidification,” Jodie Rummer, co-author and associate professor at the ARC Centre of Excellence for Coral Reef Studies, said in a statement. “So, if this species can’t cope with warming waters then how will other, less tolerant species fare?”
The Great Barrier Reef is the world’s largest coral reef, covering nearly 133,000 square miles and is home to more than 1,500 species of fish, 411 species of hard corals and dozens of other species.
Rummer said that rising ocean temperatures could threaten future sharks, including egg-laying and live-bearing species, because as temperatures rise, the creatures will be born or hatch into environments that they can barely tolerate.
“The study presents a worrying future given that sharks are already threatened,” lead author Carolyn Wheeler said in a statement.
“Sharks are important predators that keep ocean ecosystems healthy. Without predators, whole ecosystems can collapse, which is why we need to keep studying and protecting these creatures,” Wheeler, a PhD candidate at the ARC Centre of Excellence for Coral Reef Studies, added.
“Our future ecosystems depend (on) us taking urgent action to limit climate change,” Rummer said.
The study was published in the Scientific Reports journal.
A warmer ocean also contributes to increases in rainfall and leads to stronger and longer-lasting storms like Hurricanes Florence and Harvey.
Marine heatwaves which have killed off swathes of Earth’s coral reefs have likely doubled in frequency and are projected to become more common and intense, a landmark report from the United Nations’ Intergovernmental Panel on Climate Change found in 2019.
CNN’s Jen Christensen, Ivana Kottasová and Drew Kann contributed reporting.