Sharks are really neat creatures. And although they are stereotyped as dangerous or scary (queue Jaws theme music), they are also incredibly vulnerable.
The University of Miami’s Shark Research & Conservation Program has found that climate change will be particularly challenging for highly mobile marine mammals, including sharks. Because their body temperature depends on their outside environment, sharks have an ideal range for temperature, and even the slightest fluctuation can affect their functionality.
As water temperatures have gotten warmer in South Florida, we are seeing sharks move northward to places like North Carolina and New York. Warmer water isn’t just uncomfortable for sharks – it actually causes their heart rates and metabolisms to quicken, increasing their oxygen needs. If too cold, sharks cannot move as fast and may miss out on meals.
When it comes to rearing their young, shark mothers give birth in protected inlets that act as nature’s nurseries. These bays and lagoons have warm, controlled temperatures and provide protection from predators. The Indian River Lagoon has provided a safe place for mothers and pups, but a new study shows that rising temperatures are making more northern habitats suitable, such as Pamlico Sound, North Carolina. While the ecosystem of Indian River Lagoon has adapted to support the shark population with a strong food web, shifting species’ ranges can significantly alter the ecosystems.
Sharks on the move can mean trouble for human beachgoers. New York recently had its first shark attack in 70 years. What is a rare problem for us is a bigger problem for marine ecosystems. Florida waters depend on sharks as predators, and without them, we could see an explosion of fish, who in turn eat more of their prey than is sustainable. As top-level predators, sharks keep ecosystems running smoothly. Even different types of sharks moving in and out of an area can spell trouble, as different species eat different prey, posing additional economic threats for fishermen. Predators can also serve as indicators for bigger ecological issues, and shark migrations may be a sign of larger environmental change.
Climate change threatens to harm the living things we love, including sharks. That’s why climate action is so important, including reducing carbon emissions and protecting natural areas like estuaries. If we continue to accept climate change as status quo rather than making actual laws and enforcing safeguards, sharks and other marinelife will suffer and in turn, so will we.