New Data on Cape Cod Great White Sharks

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New Data on Cape Cod Great White Sharks

Cape Cod, MA –A new study sheds light on the residency patterns and hunting behavior of white sharks off Cape Cod, Massachusetts, which has become a white shark hotspot over the past decade.  During the summer and fall, white sharks patrol the shoreline in search of seals, bringing them close to popular beaches where people recreate. To assess the extent of potential overlap between sharks and recreational water users, scientists from the Atlantic White Shark Conservancy, Arizona State University, and the Massachusetts Division of Marine Fisheries examined tagging data to determine how much time white sharks spend in shallow water close to shore. The study, which was published in the journal Wildlife Research last week, found that white sharks off Cape Cod spent almost half of their time at depths of 15 feet or less. Although the overall risk posed to humans by white sharks is low, there is a high potential for overlap between white sharks and recreational water users, and the results have clear implications for shark-related public safety practices in the region.

            “White sharks are regularly spotted off our coastline during the summer and fall, the peak of Cape Cod’s tourist season, but until now we didn’t know just how much time they spent in shallow water close to shore,” said lead author Megan Winton, a research scientist at the Atlantic White Shark Conservancy, a nonprofit that provides funding and resources for scientific research to improve public safety and educate the community about white sharks. Winton and her coauthors, Dr. James Sulikowski and Dr. Gregory Skomal, analyzed tagging data collected by the Massachusetts Division of Marine Fisheries off the coast of Cape Cod during the summer and fall of 2017. The tags recorded temperature and depth data and were used to characterize the habitat preferences of white sharks when in the area. Sharks spent 95 percent of their tracked times at depths of 0–100 feet and water temperatures ranging from 48 to 69 degrees Fahrenheit.  White sharks spent almost half (47%) of their time at depths of less than 15 feet but frequently traveled further out, alternating between the surf zone and deeper offshore waters.

The results provide the first glimpse into the habitat use of white sharks off Cape Cod, and Winton hopes the results will improve beach-goers’ awareness of sharks. Since 2012, there have been four unprovoked attacks by white sharks on humans along the coast of Cape Cod, including one fatal attack, the first in Massachusetts since 1936.  The findings reinforce current public safety messaging regarding sharks along Cape Cod and suggest that water users may reduce their risk of a negative interaction by staying close to shore and adhering to ‘shark smart’ safety tips. Cynthia Wigren, CEO of Atlantic White Shark Conservancy, said “The results of this study have greatly improved our understanding of white shark behavior near swimming beaches. It’s important to remember that the overall risk posed to humans by white sharks is low, but people should be aware that white sharks are present along Cape Cod’s beaches during the summer and fall and proactively modify their behavior to reduce their risk.”