Will Climate Change Bring More Sharks North?

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For decades, the Jersey Shore has been a top destination for beachgoers from not just New Jersey, but parts of Eastern Pennsylvania, some southern regions of New York State, and the five boroughs of New York City. Sharks have rarely been seen along the Jersey Shore, let alone attacked anyone there (with one notable exception in 1916). Experts remain confident that sharks are unlikely to attack beachgoers along the Jersey Shore, but climate change may bring sharks north in higher numbers — including an 800-pound great white shark spotted off the Jersey Shore early last month.

As climate change warms the world’s oceans, sharks that have previously occupied southern waters are swimming north. The Jersey Shore is only one of many northern locations already seeing greater numbers of sharks — even communities as far north as Cape Cod, Massachusetts have reported shark sightings.

Experts suggest that bull sharks and blacktip sharks will be among the shark breeds most likely to move north as the oceans become warmer. Other experts say that the overall number of sharks seen in northern regions won’t change, but instead, when they’ll be seen might differ. With oceans steadily warming, sharks that travel north can stay for longer, meaning they could be seen before summer reaches full swing.

Changes in shark activity in the Southeast may portend similar future changes in the Northeast. In North Carolina, studies have shown that sharks there are spending more time in brackish water (a mix of fresh and saltwater) than in ocean saltwater. These studies correlated the sharks’ movement to rising brackish water salinity and temperature, both factors that can be attributed to global sea-level rise. They also observed similar trends in many different kinds of fish, all of which are relocating to waters with more habitable temperatures.

The movement of non-shark fish may also lead to shark movement. Non-shark fish are common shark prey — sharks rarely attack humans unless provoked first — so sharks may follow them to their new homes. Sharks are thus moving north for two reasons — warmer temperatures and more prey on which to feed. Experts note, however, that it is in sharks’ nature to migrate often, so the ongoing research into their whereabouts can make it difficult to achieve precise indications of where sharks will relocate and in what volume.

Will Climate Change Bring More Sharks North?Even if shark migration can be difficult to pinpoint, scientists do keep track of some individual sharks. Miss May, the 800-pound great white shark seen off the shore of Cape May last month, has long been on the radar of the OCEARCH Global Shark Tracker. The tracker first detected Miss May in February, and since then, the shark has tended to occupy waters near Cape May County. Two years ago, the tracker also found that another Great White Shark named Mary Lee was swimming in waters only 20 miles east of Belmar, New Jersey — one of the Jersey Shore’s most popular tourist towns.
In the event of a shark encounter, certain precautions can be taken to increase one’s chances of escaping without injury. Expert advice on how to avoid injury or death during a shark spotting can be found here.

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