Climate change is making small sharks smaller, malnourished and exhausted

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The researchers examined the effects of warming temperatures on the growth, development and physiology of Great Barrier Reef shark epaulettes, testing embryos and young in waters up to 31 degrees Celsius (87.8 degrees Fahrenheit).

The research team found that in warmer waters, shark embryos grew faster and used their yolk sac faster – their only source of food at this stage of development.

Creatures hatched earlier were born smaller and needed to feed immediately, but lacked energy, researchers at the ARC Center of Excellence in Australia for Coral Reef Studies at James Cook University and the University of Massachusetts said Tuesday.

There are over 500 types of sharks that live around the world and most give birth to live young. Some shark species, such as 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 resistance to change, even ocean acidification,” Jodie Rummer, co-author and associate professor at the ARC Center 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 survive?”

The Great Barrier Reef is the largest coral reef in the world, covering nearly 133,000 square miles and is home to over 1,500 species of fish, 411 species of hard corals and dozens of other species.

The last decade has been the warmest for global ocean temperatures. By the end of the century, the Great Barrier Reef is likely to experience average summer temperatures close to or exceeding 31 degrees Celsius, the researchers warn.

Rummer said rising ocean temperatures could threaten future sharks, including egg-bearing and vine-bearing species, because as the temperature rises, creatures will be born or hatch in environments they can barely tolerate.

“The study has a worrying future, given that sharks are already threatened,” lead author Carolyn Wheeler said in a statement.

“Sharks are important predators that preserve the health of ocean ecosystems. Without predators, entire ecosystems can collapse, which is why we must continue to study and protect these creatures,” added Wheeler, a doctoral student at the ARC Center of Excellence for Coral Reef Studies. , added .

UN reference report warns that sea level will rise faster than expected by 2100

“Our future ecosystems depend on us to take urgent action to limit climate change,” Rummer said.

The study was published in the journal Scientific Reports.

The oceans serve as a good indicator of the real impact of climate change – covering almost three quarters of the Earth’s surface, they absorb the vast majority of the world’s heat.
Although we often cannot see it, ocean warming has a profound impact on the entire world. A warmer ocean causes sea levels to rise, bringing problems such as dangerous coastal flooding. This leads to the loss of sea ice, warming the water even more and can affect jet flow, allowing cold Arctic air to reach further south, making winters more intense and threatening animals that depend on sea ice.

A warmer ocean also contributes to increased rainfall and leads to stronger and longer-lasting storms, such as Hurricanes Florence and Harvey.

Marine heat waves that have destroyed the ropes of Earth’s coral reefs have probably doubled in frequency and are expected to become more frequent and intense, an important report by the UN Intergovernmental Panel on Climate Change, found in 2019.

Jen Christensen, Ivana Kottasová and Drew Kann of CNN contributed to the reporting.

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