A bull shark off the coast of the Bahamas. Image: Wikimedia Commons
By Brooke Kansier
Let’s be realistic, here. The only sharks in the Great Lakes region can be found behind glass in an aquarium. Right?
But between Megalodon specials on the Discovery Channel’s Shark Week earlier this month, one title caught my eye: Monsterquest: Jaws in Illinois. Now, Chicago is home to a lovely aquarium, but the Shedd was decidedly not the topic of the re-run — rather, it told a tale sharks swimming up the Mississippi River as far as Illinois.
That may sound like a low-budget horror you’d catch on Syfy, but the phenomenon of sharks swimming up rivers — and even into lakes — is real.
But in the Great Lakes?
“There may be one kind of shark that could survive — some of the time — in the Great Lakes,” said Amber Peters, an assistant professor specializing in Marine Ecology in Michigan State University’s Department of Fisheries and Wildlife. “It couldn’t really deal with the winter temperatures, or the lack of food, but it’s possible that if one swam in it could live for a while.”
That one kind, the bull shark, isn’t as well known as the Jaws-featured great white, but it has a unique trick — its kidneys recycle salt vital to the animal’s cells. Normally, a freshwater dip would dilute the salt in a shark’s body, causing its cells to rupture and kill it, according to National Geographic. Recycling the salt its body already contains allows bull sharks to adapt to strange environments, like freshwater.
Bull sharks are one of a very few of the 375 species of sharks with this physiology-altering ability, and they do it better than any other.
Bull sharks have been found in freshwater around the world: thousands of miles up South America’s Amazon, in Central American lakes and as far up the Mississippi as Illinois, according to National Geographic.
They have been reportedly seen in Lake Michigan, although some instances, like this dead bull shark found on the lake’s shore, are a bit uncertain.
No shark reports have been scientifically documented in the lake.
The Illinois River has seen at least one documented case. Dams now keep any wandering sharks from entering the river.
Like similar cases with whales, many of these Great Lakes shark sightings are merely hoaxes, Peters said, spurred by all of the attention the species gets.
“People always want something exciting to talk about,” she said. “There’s not a lot of animals that have a whole week to themselves, that people look forward to.”
Very little is understood about the bull shark’s physiological abilities, and any competitive advantages it brings are as yet unknown.
The disadvantages to sharks of a freshwater environment, especially one like Lake Michigan, are clearer, according to Peters. There aren’t as much food and friends.
“The fish that are in the Great Lakes are overall much smaller than the prey items (sharks) can get in the ocean,” she said. “It takes them out of their normal environment. They have to deal with the stress from being in fresh instead of salt water. They don’t have normal prey and they definitely aren’t going to find mates.”
A bull shark’s typical diet consists of large, bony fish and smaller sharks. They occasionally go after much larger prey — all creatures that are scarce in most freshwater environments.
Of course, the lack of salt and companionship and appropriate grub are hardly the only obstacles keeping a shark from reaching the upper Great Lakes. Even a bull shark venturing up the Mississippi River basin would have to get through the electric barrier at Chicago that’s designed to keep invasive species out of Lake Michigan. And one venturing from the Atlantic coast into the St. Lawrence River would have to negotiate that seaway’s lock system — or swim up Niagara Falls.
Due to these barriers — and the sheer unlikelihood of the phenomenon — you shouldn’t expect to see any fins popping out of the surf at any regional beaches this summer.
For those interested in seeing some sharks, the region is home to the Shedd and some other great aquariums, including Ohio’s Greater Cleveland Aquarium, which even offers diving with sharks. The Sea Life Aquarium in Michigan added sharks to its roster earlier this year.
And there is always Shark Week highlights on the Discovery Channel’s website.
Or, you know, grab some popcorn and a VHS of Jaws.
Oh, please! Sharks in the Great Lakes? I’ve lived my considerably long life around the shores of the Great Lakes, particularly Lake Michigan. Sorry, but the idea that there are sharks in the Great Lakes is about as real as The Abominable Snowman, Yeti, Bigfoot, and all the other mythical creatures that SUPPOSEDLY live in various areas around the world.
I left Ohio and went to Georgia for a while in the’80s. It was easy to convince them that in the winter when the snow was deep, small “snow” sharks would swim up into the Great Lakes (Erie) through the back yards. You’d be amazed how many fell for it. One of my favorite lies.
Was born and raised on the lower coast of lake Michigan just outside of St. Joe. Have seen a lot in those waters but have never and will never see a shark in them. The fact that we have sturgeon, salmon, trout and catfish as big as we do in those waters proves that there isn’t a large predictor swimming around… I’ve never seen large bite marks on any fish other than bear or mountain lion in that area. Sharks also like to hunt in shallow warm water and I can tell you that none have ever been spotted in the surf just off shore. Sharks also prefer to feed on prey that they can ambush from the depths and not only have no surfers in the area ever been attacked there are no large land dwelling amphibious animals that they can prey on that would have a high enough calorie count for them to survive in waters that don’t get any warmer than 70 degrees fahrenheit on average through the hottest months in the summer. There’s a reason you see great whites on warm coasts through the winter and only ever up north in the summer. Food source… Seals provide a fat enriched diet that is loaded with calories that allow them to survive in colder climates main reason you see them primarily off the coast of california south and central america because of the seals and in australia and south africa because of the abundance of fish during the warm breeding season. Same thing goes for bull sharks. Only shark adapted to survive in the cold climate that the great lakes offer is the greenland shark and that won’t happen because the lakes aren’t deep enough for them to live.
A Bull Shark CAN LIVE IN FRESHWATER! All you people do your research! Great Whites Can’t LIVE IN FRESHWATER, THEY WOULD SINK AND DROWN. THE SALT CONTENT HELPS THEM STAY BUOYANT! As for a Bull Shark in Lake Michigan, they couldn’t survive a Winter, its too cold! If a boat from the Mississippi can make it to Lake Michigan so can a bull shark! A bull shark was caught in Alton Illinois in 1937. 15 miles north of St.Louis.
Of course there are great white sharks in the Great Lakes – the sharks simply attach a water salination device to their gills & presto – have salt will travel!
This is hilarious. Do people really think there was a great white shark caught in the great lakes?! HAHAHAHA!!! I’m not saying there has never been a shark in Lake Michigan, but they can’t survive because of the water (lack of salt their lungs need) and the cold water temps, not the food sources. And that article about the White shark in the great lakes is so bogus – if you believe it, read the other articles on the website and you’ll quickly realize that it’s not a satire website, not a legitimate news source.
There are plenty of chances for sharks to get into the great lakes. A person from Toronto recently caught a 3000 pound great white shark from lake Michigan. There have been reports of bull sharks as well as black fin sharks there. In lake superior there were pictures of a shark taken near McCarty’s Cove. Bull sharks have been found up the Mississippi River as far as Illinois, Minnesota and Wisconsin. There are reports of bull sharks having been caught in nets along the Saint Lawrence. Bull sharks are evasive and can live in Freshwater or salt water. People say the great lakes are to cold. That doesn’t seem to be the case from the evidence. In the case of lake superior it was suggested that the warm water discharge from a power plant could aid in the survival of a shark in the colder waters. Are there sharks in lake Erie. It wouldn’t surprise me. The lake is warmer than the other Great lakes and if there is evidence in the other lakes I have no doubt they are here as well. People say how would they get there as they would have to go over Niagara falls? They could go through the Welland canal and come from the other Great lakes. Supposedly there are interlocking underwater canals between the Great lakes. There are also open ocean cargo ships going into the great lakes. Large tankers, and bulk cargo carriers use a huge amount of ballast water, which is often taken on in the coastal waters in one region after ships discharge wastewater or unload cargo, and discharged at the next port of call, wherever more cargo is loaded. Ballast water discharge typically contains a variety of biological materials, including plants, animals, viruses, and bacteria. These materials often include non-native, nuisance, invasive, exotic species that can cause extensive ecological and economic damage to aquatic ecosystems along with serious human health problems. I’m beginning to believe that if Ontario actually set up a program to study and try and capture sharks in the Great Lakes that they would probably find them.
seriously people, there are NO sharks in the Great Lakes.
Documentation:
A. Never been a shark attack
B. Sharks can’t survive in the water temperatures that the great lakes attain in the Winter.
C. Fresh water kills ALL sharks within 6 months.
Don’t be foolish, although some of ya believe in Bigfoot too.
I rest my case
You do realize the massive amounts of undiscovered underwater caves and caverns dont you ? Nature always finds a way .
I I swim in Lake Michigan in the 70s and all I got was a bad ear infection and saw lots of dead fish floating around and got out of there as fast as I could and there were women and children swimming
If people have found alligators in ponds in IL why the hell do y’all not think so.eone wouldnt drop thier once pet bull shark in the lake or that they weren’t in the lake before all these prevent measures took place.
@sher there are 500lbs 10 foot Lake sturgeon
But what about a sturgeon this could be a abundant food source for sharks wich would probably keep the sharks alive sence I remember hearing some stories about the Great Lakes being connected to the ocean a long time ago not to mention the depths of the Great Lakes such as Lake Superior.
https://abcnews.go.com/International/watch-great-white-shark-disrupt-fishing-popular-australia/story?id=27387189
ABC news report Yes great whites live in lakes
From a science magazine.
It’s debatable. There was a string of shark attacks on the Jersey shore in 1916, in which three of the attacks occurred in a creek. The shark often linked to these attacks is the Great White Shark (though some scholars debate that it was a bull shark, simply because they have been known to live in freshwater).
There have been small great white sharks that have been caught in rivers in the past years, so it is possible, it’s just not as often seen as a bull shark in fresh water.
It’s debatable. There was a string of shark attacks on the Jersey shore in 1916, in which three of the attacks occurred in a creek. The shark often linked to these attacks is the Great White Shark (though some scholars debate that it was a bull shark, simply because they have been known to live in freshwater).
There have been small great white sharks that have been caught in rivers in the past years, so it is possible, it’s just not as often seen as a bull shark in fresh water.
People disappear out of there boats all the time. The large salmon population has dropped. Salmon are caught with teeth marks on them. The otters will not venture into water deeper than 20 feet any more. Several have washed up on shore in Michigan and Georgian Bay. Nope no Bull here ……except Bull sharks
C’mon man! 20-30-40 billion walleyes in there, for starters, and the 5-6-7 foot shark is gonna run out of food. Heck, it could always eat muskies..
They are there I’ve seen one!
It’s rainbow trout and no there’s 7 foot 500 pound surgeon in the great lakes I’m in thunder bay ont Canada and there here so
Madison – Read this story then if you think that… How about a Great White Shark?…
http://worldnewsdailyreport.com/fisherman-captures-3000-pound-great-white-shark-in-great-lakes/
There’s no such fish as a “rainbow pike.” You’re thinking of a pike cichlid, which are found in South America, and not in the Great Lakes.
@ sher I’m from Michigan and I can tell you there are definitely bigger fish than a 40lbs pike. Look up Lake Michigan sturgeon or just google biggest fish caught in the Great Lakes
Silly Americans… The biggest fish you will see in the Great Lakes is a 2ft Rainbow Pike weighing maybe upto 40 pds!! Not just that Bears and Sharks lol don’t mix … Like the article said watch Jaws!!!
The sharks deter all the barriers by moving into the Michigan when there are huge floods, that overflow the barriers. They just find a flooded way around. The bull shark is in Lake Michigan.
I live in Michigan and really do not understand why people keep having the fantasy of a Shark swimming up in the lakes. Fresh water and barriers. Kids should not have acces to seeing this content because it could make them scared for life or not want to go out and swim in the Great Lakes.
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