Rising ocean temperatures are reshaping shark habitats and migration routes along the U.S. East Coast and the Gulf of Mexico, according to recent scientific studies. While overall shark populations are not necessarily growing, changing marine climates are pushing certain species into regions where they were once less common, raising questions about potential shark-human interactions ahead of the Discovery Channel’s Shark Week.
How Warming Oceans Are Altering Shark Migration Patterns
Oceans have absorbed more than 90% of the surplus heat accumulating in the climate system over the past decade, according to data from the National Oceanic and Atmospheric Administration. This historic warming has forced marine species to adapt by shifting their ranges, feeding grounds, and nursery habitats.
For bull sharks, that means moving critical nursery areas farther north. Shannon Barry, a researcher in the Department of Ocean Engineering and Marine Sciences at the Florida Institute of Technology and lead author of a recent study, noted that near-shore habitats used by juvenile bull sharks are shifting into preferred temperature ranges as U.S. Atlantic waters warm. Adults typically maintain a temperature range of 26 to 30 degrees Celsius, while juveniles tolerate 20 to 34 degrees Celsius.
Did you know? Bull shark evidence indicates a new nursery population has become established in North Carolina, driven poleward by climbing water temperatures, according to researchers.
Great White Shark Winters in the Gulf of Mexico
A separate peer-reviewed study published in the journal Wildlife Research challenges previous assumptions about great white shark migration. Researchers tracking 92 white sharks tagged between Nova Scotia, Canada, and Jacksonville, Florida, found that 57 of the animals spent significant time in the Gulf of Mexico or the Straits of Florida between December and May.
The tracking effort utilized satellite-linked smart position and acoustic tags as part of a long-term project led by OCEARCH. Chris Fischer, founder and expedition leader of OCEARCH, stated on the group’s site that the research confirms the Gulf serves as a regular winter habitat for the population, underscoring the deep connectivity of Atlantic Ocean ecosystems.
Understanding Shark Encounters and Safety in U.S. Waters
Despite shifts in marine geography, unprovoked shark attacks remain extremely rare. The Florida Museum places the odds of being attacked by a shark at 1 in 11.5 million, making individuals far more likely to be struck by lightning, which NOAA calculates at 1 in 1.2 million in a given year.
Florida leads the nation in unprovoked shark bites due to its more than 8,000 miles of coastline and millions of annual beachgoers. According to TrackingSharks, seven shark bite attacks occurred across five states—Florida, California, Georgia, New York, and Texas—as of July 5.
Pro Tips for Swimmers: To reduce the risk of a shark encounter, it is recommended to swim with a buddy rather than alone, avoid the water at dawn or dusk during low-light conditions, stay away from active fishing areas, leave shiny jewelry behind, and refrain from splashing, which mimics the sound of struggling prey.
Frequently Asked Questions
Are shark populations increasing along U.S. coastlines?
Not necessarily. While rising temperatures are not necessarily causing an overall population boom, they are pushing certain sharks into new or northern regions where they were once rarely seen.
Where do great white sharks go in the winter?
Many great white sharks travel thousands of miles from Canada and the northeastern United States to spend the winter months in the Gulf of Mexico and the Straits of Florida, according to OCEARCH tracking data.
What are the odds of a shark attack?
According to the Florida Museum, the odds of experiencing a shark attack are 1 in 11.5 million.
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