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Are There Sharks in the Great Lakes?
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Our Purpose and Values
The Great Lakes Freshwater Shark Search Project exists to investigate one of the most persistent open questions in North American natural science: are there sharks in the Great Lakes?
We are explorers and scientists. We take the question seriously because the Great Lakes deserve serious attention: 94,000 square miles of freshwater that the world largely assumes it already understands. We are not convinced.
We recruit Shark Searchers: observers stationed on the shorelines of all five Great Lakes, trained in the GLSP Classification Protocol, and committed to logging what they see. Every report filed under our five-tier system enters a permanent scientific record. Every honest Tier 1 is part of the work that makes a Tier 5 possible.
We educate the public about sharks, not as threats, but as among the most remarkable animals on earth. Bull sharks have survived in freshwater on multiple continents. Greenland sharks have outlived every human civilization. The question of whether any shark has reached the Great Lakes is not a joke. We are the organization that treats it that way.
Gannett Outfitters and the Great Lakes Freshwater Shark Search Project were established in Charlevoix, Michigan in 2020.
Great Lakes Sharks
The Great Lakes Freshwater Shark Search Project (GLFSSP) is a citizen science and conservation organization dedicated to the systematic investigation of shark presence in the Great Lakes basin.
Founded in Charlevoix, Michigan in 2020, the GLFSSP operates through a network of trained volunteer observers, called Shark Searchers, stationed across all five Great Lakes. Every sighting is documented under the official GLSP Classification Protocol, a five-tier system that takes field reports from initial anomaly observation through peer-reviewed scientific confirmation.
Our vision is a network of regional clubhouses around the Great Lakes where members and the public can learn about freshwater sharks, engage with citizen science, and participate in the search. Lake Michigan, Grand Traverse Bay, and Little Grand Traverse Bay have generated the highest concentration of reported freshwater shark sightings in recent years.
Frequently Asked Questions About Great Lakes Sharks
Are there sharks in the Great Lakes?
There are no confirmed, scientifically documented sharks living in the Great Lakes. The lakes are freshwater and far from any ocean, which makes them an unlikely habitat for most shark species. However, the Great Lakes are vast — Lake Superior alone covers over 31,000 square miles — and reported sightings continue to generate curiosity. The Great Lakes Freshwater Shark Search Project (GLFSSP) exists to take those reports seriously and investigate what, if anything, is out there.
Can bull sharks survive in freshwater?
Bull sharks are one of the few shark species capable of surviving in freshwater environments. They have been found in rivers and lakes around the world and are known to travel hundreds of miles inland via river systems. While there is no verified evidence of bull sharks in the Great Lakes, their documented freshwater tolerance makes them the most frequently discussed candidate when it comes to Great Lakes shark speculation.
Has anyone ever seen a shark in Lake Michigan?
Reported sightings of large, shark-like creatures in Lake Michigan have circulated for decades. While none have been officially verified or documented by marine biologists, the Great Lakes Shark Patrol takes these reports as valuable data points in the broader search for freshwater sharks. Lake Michigan — with 1,638 miles of swimmable shoreline — remains one of the most actively monitored bodies of water in the GLFSSP search effort.
What is a freshwater shark?
A freshwater shark is any shark species capable of surviving in low-salinity or fresh water. Bull sharks are the most well-known example, but river sharks of the genus Glyphis are also true freshwater species found in parts of Asia and Australia. The possibility of undocumented or migratory freshwater sharks reaching North American inland waterways is the central question driving the Great Lakes Freshwater Shark Search Project.
What is the Great Lakes Shark Patrol?
The Great Lakes Shark Patrol is the community and awareness arm of the Great Lakes Freshwater Shark Search Project, founded in Charlevoix, Michigan. We recruit Shark Searchers — volunteers who commit to watching the Great Lakes shorelines and reporting unusual activity. Our mission is equal parts exploration, education, and community. We also support global marine conservation efforts and hope to establish a network of regional clubhouses for members across the Great Lakes basin.