Sharks and rays belong to a group of cartilaginous fish called elasmobranchs, which have been swimming in the world’s oceans for 450 million years. The resilient species have survived five mass extinction events, and are older than dinosaurs, trees, and Mount Everest.
But despite their resilience, many species of sharks and rays today are threatened by human activities, including overfishing, habitat loss, and climate change. In fact, according to a new study led by researchers from the University of Vienna in Austria, more than one third of the shark and ray species known today are severely under threat.
The study, which was recently published in the journal Biology, found that higher carbon dioxide levels were having a negative effect on sharks and rays, ranging from impacts on the animals’ senses to changes in the skeleton during embryonic development. An examination of fossil records found that higher CO2 levels had contributed to the extinction of individual shark and ray species in the past.
But the study also found that global warming could be creating opportunities for sharks and rays. Rising sea levels and higher temperatures have historically expanded shallow coastal habitats and warm waters, supporting species biodiversity.
But according to the research team, the rapid environmental changes, combined with the impacts from human activities, outpace the ability of sharks and rays to adapt, making it unlikely that they will benefit from global warming.
Protecting sharks and rays is crucial not only for their survival but also for maintaining entire ocean ecosystems. Without top predators, these ecosystems could collapse, impacting both marine life and the people and industries that depend on it.
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Sharks and rays benefit from global warming – but not from CO2 in the Oceans
Photo, posted November 27, 2007, courtesy of Laszlo Ilyes via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
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