Climate Change Destroys Sharks' Hunting Abilities

A team of marine ecologists found that sharks growing and hunting abilities will be affected significantly due to an increase in warmer oceans along with higher CO2 levels. Ocean acidification has already impacted sharks' ability to feed, and by the end of the century sharks may no longer be predominant, according to a study at the University of Adelaide in Australia.

"In warmer water, sharks are hungrier, but with increased CO2 they won't be able to find their food," said Professor Ivan Nagelkerken, from the Australian Research Council and lead author of the study. "With a reduced ability to hunt, sharks will no longer be able to exert the same top-down control over the marine food webs, which is essential for maintaining healthy ocean ecosystems."

The researchers found that warmer and more acidic ocean water will increase sharks' energy requirements. A combination of warmer ocean water and high CO2 levels destroys sharks' sense of smell, which is their key tool to detect food. This eventually reduces the sharks' metabolism along with their growth and developments.

With increasing levels of CO2, sharks take a long time to locate food and at times, they no longer hunt for food altogether. This results in smaller sharks and a declining population as well. Other large predatory marine species are also affected by these factors.

"One-third of shark and ray species are already threatened worldwide because of overfishing," said Professor Sean Connell, a marine ecologist at the University of Adelaide. "Climate change and ocean acidification are going to add another layer of stress and accelerate those extinction rates."

The findings of this study were published in the journal Scientific Reports.

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