Shark fossils date back to the Late Ordovician Period, when a few scales date back to 450 million years ago. AFP VIA GETTY IMAGES
If you asked Valentina Di Santo what was the most surprising finding from her latest research project, she would quickly answer, “Well, first, [the fact that] there is not much known about the effect of climate change on elasmobranchs! Sharks and ray are an important group of meso- and top predators but studies to understand the effect of climate-related stressors have been scarce, especially when compared to the vast literature on the effect of climate change on physiological responses of bony fishes.” As one of the oldest and most diverse group of marine vertebrates, elasmobranchs (sharks, skates, rays and sawfishes) have survived multiple extinctions our planet has previously faced. Wipe-outs that killed off their mighty ancestors and even dinosaurs were no match for sharks… but could they finally be facing a foe even they can’t win against?
Enter climate change.
Due to climate change, our oceans are currently experiencing severe changes, including a rise in temperature, a rise in sea level, and an increase in acidity. Ocean acidification was of particular interest to the Assistant Professor of Functional Morphology at Stockholm University because, as she puts it, “understanding intraspecific variation in responses to stressors is key to identify which traits make individuals and group of elasmobranchs more or less vulnerable to the effects of environmental change.”
Because climate change has already begun, scientists have little time to test how severely it impacts different species. It’s important therefore, that researchers focus on the different characteristics (known as ‘physiotypes’) that make individuals more or less vulnerable to rapid warming and acidification. Some of these traits include body size, local adaptation to fluctuating chemical and physical conditions, age-at-maturity. “One of these [important] traits is, for example, locomotor performance,” adds Di Santo. In many animals, locomotor performance plays a fundamental role in determining their fitness. Locomotor performance is closely related to the morphology of the structures responsible for it, such as limbs and fins. In elasmobranchs, it influences vital functions such as reproduction, migration, predator avoidance, small-scale movements, and more. By delving into the literature, the Di Santon’s team was able to integrate findings from previous work on locomotion of marine sharks and rays to identify characteristics that outline potential vulnerabilities and strength of sharks and rays under climate change.
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Melissa Cristina Márquez, Forbes, 6 March 2023. Full article.
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