Are there bull sharks in Lake Michigan? The only sharks in the Great Lakes region are always in a glass-enclosed aquarium. Are there sharks in the lakes, too?
If there is, what species of shark might it be? A bull shark? Although this species is not as widely recognized as the “great white shark” from Jaws, it possesses an extraordinary ability. Its kidneys can recycle salts, an essential element for cellular function.
A shark in freshwater would ordinarily cause its cells to degrade and ultimately die due to the reduction in salt content. Bull sharks can live in freshwater, but are they in Lake Michigan? Let’s find out.
Are There Bull Sharks in Lake Michigan?
No, the probability that bull sharks inhabit Lake Michigan is exceedingly low. Although bull sharks prefer saline habitats such as marshes and coastal areas, they can survive in freshwater environments.
However, Lake Michigan is a large freshwater lake located in the northern United States, starkly contrasting the habitats of bull sharks.
Bull Sharks Explained
Ocean-dwelling animals frequently migrate into waterways, and they are called diadromous. The most well-known species capable of surviving in both salt and freshwater are tilapia and salmon.
Bull sharks are euryhaline and diadromous. A euryhaline species can survive in a wide range of salinities, including salinity, pure freshwater, and every other level. How do bull sharks do this?
Sharks possess organs that regulate the amount of sodium in their bodies. They absorb the majority of the salt in the form of urea. The kidneys, liver, gills, and rectal gland all regulate the shark’s body salinity levels.
Although most sharks use them to absorb or expel salinity in open water, the bull shark can also use them for a few other purposes. Bull sharks can reduce the amount of sodium that leaves their bodies when submerged in water.
The bull shark’s physiological adaptation to lower salt concentrations enables it to thrive in environments containing varying degrees of salt.
Bull sharks can spend their entire lives in freshwater, but they rarely do so. It is, therefore, not difficult to locate them so far up rivers. They may remain or depart for an indefinite period with the provision of food.
Little is known about the physiological capabilities of the bull shark, and it is unknown whether or not this knowledge will be advantageous in competition.
When sharks inhabit freshwater environments, such as Lake Michigan, the scarcity of food and mating partners are limiting factors.
Sharks inhabiting the ocean consume larger prey than the Great Lakes. It diverts their attention from their usual location. They see the transition from salt water to pure water to be stressful.
Bull sharks typically consume larger, skeletal fish and lesser sharks. On occasion, they pursue much larger prey, all of which are uncommon in fresh aquatic environments.
In addition to a lack of food, companionship, and salt, various factors impede sharks from accessing the upper Great Lakes. There’s a barrier near Chicago, where even a bull shark ascending the Mississippi River valley would have to pass through.
The purpose of this barrier is to prevent the entry of exotic animals into Lake Michigan. In addition, there’s a lock system in the St. Lawrence River from the Atlantic side, or the sharks would have to swim up the Niagara Falls.
The barriers pose a challenge, so don’t expect to see a fin popping out while swimming in the lake.
Recent Reports Spark Debate and Controversy
Michigan is not new to controversy from mountain lions in the state to Bull sharks in the lake. Forest Galande, a wildlife activist, biologist, and media personality, discussed the issue in an episode of “The Joe Rogan Experience” on December 19, 2019.
“Bull sharks have been spotted by observers stranded in the Great Lakes. Were you aware of that?” Galante asked.
“It’s tremendous. Sharks migrating from Louisiana to the Great Lakes via rivers become stranded there. Comedian Joe Rogan, the podcast presenter, confirmed, “Yes, I was aware of it. That is absurd.”
However, according to experts, there is no evidence that bull sharks inhabit the Great Lakes. Jeffrey Tyson, the director of the fishery management program for the Great Lakes Fishery Commission, stated, “At this time, there have been no officially verified sightings or captures of bull sharks in the Great Lakes.”
Michael Heithaus, a marine ecologist specializing in shark research at Florida International University, reached the same conclusion. He denied any sightings of sharks in the Great Lakes by email, as reported to the Associated Press.
The records of commercial fishing results maintained by the Great Lakes Fishery Commission run from 1867 to 2015. The most recent year for which records are accessible does not mention bull sharks.
As per Heithaus, the northernmost bull shark observation occurred in Alton, Illinois, in 2022, north of St. Louis. In 1937 on the Mississippi River, two fishermen captured a shark.
In 1995, near Rush Island, Missouri, a fisherman caught an additional bull shark while fishing on the Mississippi River. It was south of St. Louis at the time.
Bull sharks inhabit warm-sea coastlines worldwide. They are among the limited number of shark species capable of sustaining life in both freshwater and ocean environments due to the saline recycling capability of their bodies.
Upstream is the optimal location, according to Heithaus, to observe juvenile bull sharks, or sharks between the ages of three and five years.
However, according to Heithaus, a bull shark doesn’t travel far upstream, so it can’t get to the Great Lakes alone. Food in the lakes would be impossible to find, and the various climate zones make the water cold.
Previous Reports of Bull Sharks in Lake Michigan
Investigating instances of shark species discovered in Lake Michigan is unclear. Numerous individuals are believed to have observed fins popping from the water.
Most of the time, scientists have been unable to establish whether these phenomena occur with or without sharks. A single shark sighting in Lake Michigan was actual but only turned out to be a prank.
On April 25, 1969, two coho salmon fishermen got a 73-centimeter-long (29-inch) shark from the water approximately two miles from Milwaukee.
The discovery of the shark’s body adrift in the water caused considerable commotion among the local fishermen. Furthermore, this instance is the primary cause for the hazy recollection of sharks being discovered in the lake.
The event, however, was swiftly disproven. Two years ago, the proprietor of a nearby bar had the shark in his freezer after capturing it in Florida. He then instructed the mariners to dump the shark into the lake as a prank.
Numerous accounts have surfaced regarding sightings of sharks, tortoises, and other potentially domesticated animals in Lake Michigan. However, definitive evidence to support these claims has yet to materialize.
The presumption that sharks inhabit the Great Lakes is predominantly the result of “unfounded” legends and a few historical fabrications.
Reports have surfaced of bull sharks inhabiting rivers and other bodies of water. Still, it is improbable that they would establish a reproductive population in Lake Michigan.
Bull sharks have been discovered in the Mississippi River, a tributary of Lake Michigan. In contrast, dam structures obstruct sharks’ path from the ocean to Lake Michigan. This impedes their access to the Mississippi River.
Assertions that the bull shark inhabits Lake Michigan all remain unverified by the relevant authorities. A dead bull shark was on Lake Michigan, but how it got there remains a mystery.
Can Sharks Thrive in FreshWater?
A shark expert at the Field Museum of Natural History in Chicago, Kevin Feldheim, had an interesting suggestion. He says climate change could increase the likelihood of encountering a shark in the landlocked Midwest.
The potential for bull sharks to acquire an unfavorable reputation exists. They can attain lengths of up to 11 feet and masses exceeding 700 pounds. These exceptional predators do not reach maturity until 15 to 20.
As per National Geographic, bull sharks can swim through rivers and lakes because their kidneys process salt water. There have been hundreds of species of sharks discovered by scientists.
A few species exhibit transient viability when exposed to the salty, mildly saline conditions found in estuaries. The part where freshwater rivers and streams empties into the ocean is a bay, sound, or lagoon.
Bull shark migration from coastal regions to the north-central United States could extend significantly as summer temperatures rise. Feldheim disclosed to AccuWeather that he oversees the Field Museum’s Pritzker Laboratory.
Still, experts believe that spotting a shark in freshwater is extremely unlikely. The lock-and-dam systems on the Mississippi River could prevent sharks from migrating further inland.
According to Oceana, bull sharks are facing the risk of extinction. Although they and other shark populations globally have experienced overfishing, their biggest problem is accidental fishing.
“Most of these accidental catches occur when these sharks are upriver,” Oceana states on its website. Furthermore, although culling operations occasionally target bull sharks to improve shore safety, these approaches have proven ineffective in protecting humans from sharks.
Are there bull sharks in Lake Michigan? The existence of bull sharks in Lake Michigan remains debatable. Lake Michigan is different from other lakes in that it’s low in saline levels and well-mixed water columns.
Although bull sharks are notoriously adaptable and might be capable of surviving in freshwater environments, there is no firm evidence that they are present in the lake.
Remember that official reports of bull shark sightings in Lake Michigan are not always accurate before proceeding. It requires scientific research and reliable sources to determine whether or not a particular species inhabits a given ecosystem.