The answer to the question of whether sharks have been found in the Mississippi River is a complex one. The Mississippi River is, after all, an enormous body of water stretching from Minnesota to the Gulf of Mexico and encompassing many states and water systems in between. It’s inevitable, then, that some shark sightings will occur. But whether or not these sightings represent a “population” of sharks native to the Mississippi remains a highly contested issue.
On a practical level, sharks simply don’t have the capacity to live in fresh and brackish waters for very long — the waters of the Mississippi are too warm and too turbid for shark populations to survive for any extended period of time. Plus, there’s the matter of food availability. Sharks need ample amounts of appropriate prey, and the creatures living in the Mississippi — paddlefish, mussels, and the like — simply don’t provide enough of a food source to sustain a large population.
And that’s not to mention the damming of the river, and all of the various locks that have been installed to control the flow of water between states. These modern river management techniques can prevent species from migrating upstream and downstream, and pose an even greater obstacle for sharks that might otherwise in habit the Mississippi.
That’s not to say, however, that sharks have never been found in the Mississippi. In fact, shark sightings have been reported as far upriver as St Louis — some 1,000 miles from the Gulf — and as far south as Louisiana, the farthest spot to the south that most freshwater shark species can venture. Some of these waters, like certain areas near the mouth of the Atchafalaya River, are saltier and contain more sediment, allowing sharks access to the resources they need. Elsewhere, like the mouth of the Yazoo River, freshwater species may find refuge for a time.
What’s more, structures like weirs and water diversions can create ideal environments for a variety of species — including sharks — to, in a sense, be “trapped” in one spot. This, plus migratory patterns that might see sharks passing through the area on their way to or from the Gulf, can increase the likelihood of a sighting. And, indeed, the occasional shark within the Mississippi’s boundaries has been seen on the Rare Species Tracker, suggesting that the occasional spot of luck — or, perhaps, a stray individual — can produce the occasional sighting.
No matter its origin, a shark in the Mississippi River is certainly news. But whether or not these sightings indicate the presence of an established population of sharks in the Mississippi remains unclear. There’s no doubt that food and environment pose major hurdles — but what other factors might be at play?
Abnormal Weather Patterns
Abnormal weather patterns can have a major influence on the populations of species across the world. In places where the weather is cyclical and seasons change, the populations of fish — and whales, dolphins, sharks — can adapt to fluctuating water temperature, salinity, and food resources. But major weather events, like flooding, can throw ecosystems out of whack, driving species into habitats or waterways where they are not typically found.
During the 2020 floods along the Mississippi River, for example, reports of an unusual number of fish — some of which were later confirmed to be sharks — began to trickle in from the banks of the river. This suggests that flooding and other weather events may be bringing sharks into the Mississippi on occasion — though, again, the transient nature of these phenomena makes it unlikely that they will stay for long.
Human Impacts
Like any other species, sharks also face the ever-present threat of human activities. The effects of fishing, pollution, and habitat destruction make it exceedingly difficult — even impossible — for certain species to survive in their native habitats. For species living near the sea, further threats associated with climate change and industrialization may drive them even closer to rivers like the Mississippi.
But while human activities can certainly bring the occasional shark into the Mississippi, the intermittent nature of these impacts makes populations of sharks in the Mississippi even more unlikely. Plus, the effects of fishing, pollution, and human-made dams could actually be driving sharks away from the river, rather than toward it.
Sightings and Species
All in all, there’s a lot to consider when trying to answer the question of whether sharks have been found in the Mississippi River. While the occasional shark sighting can be exciting and scary in equal measure, it’s important to note that there is still no confirmed evidence of a native shark population within the Mississippi’s boundaries.
The most recent shark sighting occurred in January 2021, and involved a specimens that was identified as a blacktip shark. But other species, including bull and hammerhead sharks, have been spotted in the Mississippi over the years. Combined with the data and research, these individual sightings can provide the best clues as to what species may live — or, more accurately, move through — the Mississippi.
The Role of Citizen Science
At the moment, the waters of the Mississippi remain something of an enigma. Available data paints a complex picture of what we can expect, and anecdotal evidence of shark sightings is always interesting, but conclusive proof of a native shark population still eludes us.
In such a situation, the importance of citizen science efforts should not be overlooked. If a pattern of increased shark sightings in the Mississippi River emerges, then this could point to the existence of a shark population — or, more realistically, migrating individuals. But with no established way of tracking, cataloguing, and analyzing the data, this is all speculation. The use of citizen science, then, could be an invaluable tool for understanding and monitoring the populations of sharks in the Mississippi.
Greater Awareness
At the end of the day, understanding the impact of our activities — from coastal development to fishing to simply visiting the river — on the creatures inhabiting the Mississippi is key. With greater awareness of how our interactions with the environment can affect species like sharks, we may be better equipped to prevent our activities from damaging populations and habitats.
Ultimately, sharks — and the complex and ever-changing stream of life that flows through the Mississippi — are no exception. The answer to the question of whether or not sharks live in the Mississippi River may remain a mystery for some time. But with an understanding of the complex environment and the influence of human activities, we can begin to piece together what’s going on below the surface.
Man-Made Barriers
Man-made barriers can have a huge impact on the movements of species around the world. In addition to the locks and dams used to control the river’s flow, the Mississippi is dotted with weirs and other structures designed to monitor water levels and manage the flow of water around the states it passes through.
These structures can provide ideal environments for some species, like mussels and fish, to thrive — and, occasionally, for sharks to take refuge for a time. Weirs can also act as a kind of natural barrier, preventing species from moving further upstream or downstream. As such, the combination of dams, locks, and weirs along the Mississippi can create an environment where some species can exist, even if it’s just for a short while.
The Role of Climate Change
The effects of climate change on both animal populations and their habitats are becoming increasingly evident. Rising sea temperatures, ocean acidification, and deforestation are just a few of the phenomena that are making it hard for species around the world to adapt — and, in some cases, even to survive.
In the Mississippi River, higher temperatures could encourage the growth of saltier water areas and, in turn, provide additional resources for sharks. But this could also force some species out of their native habitats, making it even harder for them to survive. Furthermore, the long-term effects of climate change on both the aquatic and terrestrial ecosystems of the Mississippi are not yet known, and could have profound implications for species like sharks.
Continued Interest and Conservation
The question of whether sharks have been found in the Mississippi River will probably remain unanswered for some time. Sharks simply don’t have the right adaptations to survive in its waters for very long, and the many obstacles they face — from food availability to climate change to human activities — make it hard to sustain a population.
Still, the occasional sightings of sharks in the Mississippi can spark interest and encourage conservation efforts. With the support of the scientific community, the increasing use of citizen science, and a greater awareness of our impact on the environment, we may be able to better understand — and even protect — the creatures living in and around the Mississippi.
