Are bull sharks found in the Mississippi River? For many years, this has been a hotly debated question in the fisheries science and marine life conservation communities.
Despite being famously adaptable to fresh and brackish water habitats, bull sharks, which belong to the genus Carcharhinus, aren’t typically found in the upper reaches of the Mississippi drainage basin. Records of bull sharks in the Mississippi River itself remain sparse and anecdotal.
The Mississippi River lies well north of bull sharks’ natural range, which extends from Southern Brazil, up the East African coast, through the Indian Ocean to the South China Sea and other parts of the Pacific Ocean. Even within their own range, bull sharks migrate to more temperate waters only during certain times of the year.
Bull sharks are thought to prefer offshore marine habitats, sticking close to the coastal margins, where there’s plenty of food and shelter for them. Although some individual specimens of this species have been recorded in coastal lagoons and estuaries, there’s no evidence of their presence in the Mississippi River.
Contradicting this idea, however, is the presence of the Big Muddy, a 115-mile-long oxbow lake of the Mississippi River in Missouri, just south of St. Louis. Fisheries scientists believe that this oxbow lake may possess the environmental characteristics suitable for bull sharks – if only limited numbers of them, due to its distance from their native range.
A 2012 study conducted by the Center for Fisheries Ecology Research at University of Missouri-St. Louis concluded that the Big Muddy oxbow lake may contain the necessary conditions for bull sharks to enter and survive.
Moreover, researchers note that pollutants from runoff and agricultural activities in the Mississippi drainage basin could help create more ideal conditions for bull sharks in this area – as long as they don’t create an environment where they’re negatively impacted.
Conservation
The conservation of bull sharks in the Mississippi River faces several potential challenges. Firstly, their presence in the oxbow lake is limited by the time of the year, as bull sharks migrate to more suitable temperatures at different times. Secondly, it’s believed that the overall bull shark population of the oxbow lake could be quite small, limiting the prospects of a flourishing bull shark population.
Another challenge faced by conservation initiatives is the presence of other marine predators such as American alligators, American eels, snapping turtles and others. These predators could threaten the bull shark populations in the Mississippi River, as they are known to consume bull sharks and their prey items.
Moreover, since the Mississippi River is a highly commercialized waterway used for transport and industrial activity, pollution from these activities could negatively impact bull sharks, affecting their reproduction and population sizes.
Management
Efforts to protect bull sharks in the Mississippi River must focus on combating and reducing the effects of human activities on their natural habitats, as well as refraining from activities that disrupt their populations and threaten their survival.
Administrative agencies such as the U.S. Fish and Wildlife Service, state wildlife departments and the National Oceanic and Atmospheric Administration have identified key areas of the Mississippi River drainage basin where bull sharks may be present. Conservation initiatives seek to monitor these habitats and enforce regulations that protect bull sharks as well as their prey species.
In certain areas, such as New Orleans, La., bull sharks have been managed by introducing catch-and-release regulations and catch limits, in order to protect breeding stocks of bull sharks and their prey. Fishers are encouraged to release the animals back into the water, in accordance with state regulations.
Human Interactions
The presence of bull sharks in the Mississippi River could pose a danger to human swimmers, in light of the species’ fearsome reputation. However, bull sharks are generally timid and rarely attack humans, unless they’re provoked.
In fact, bull sharks are more likely to feed on smaller bottom-dwelling fish, shrimps and other invertebrates than they are on humans. Thus, in the right environment, they can be an asset to a healthy aquatic ecosystem.
In addition, they may be a boon to anglers and recreational fishers, as they create an attraction for other predatory species.
Research
It’s clear that there’s still much to learn about the bull sharks of the Mississippi River and their potential impact on its ecology and humans.
Research into the behavior, genetics and life cycle of these animals is important in order to understand how the species interacts with its environment and how best to manage its populations.
In addition, ongoing monitoring of the oxbow lake’s waters, in conjunction with surveys of nearby habitats, could offer further insights into the presence of bull sharks, their prey and the overall impact of the species on the Mississippi’s ecosystems.
Adaptation Tactics
In the event of a diminished population of bull sharks in the Mississippi River, biologists and conservationists may consider supplementing their numbers with captive-bred specimens. This could help reduce the mortality rate of juvenile bull sharks, while also providing them with a more hospitable environment, which can help them survive their first year.
In addition, biologists have suggested that certain facilities in the Mississippi River drainage basin be used to propagate bull sharks, as they are well-suited to a wide variety of environments, including brackish and even fresh water systems.
Such facilities could help support existing populations of bull sharks as well as encourage public participation in bull shark conservation through educational programs.
Economic Impact
The presence of bull sharks in the Mississippi River could also have economic benefits, as they can be an attraction for tourists and anglers. More importantly, they help maintain a balance in the aquatic food chain, which helps support a healthy ecosystem.
Preserving the presence of bull sharks in the Mississippi River has the potential to create jobs in the leisure and tourism industries, as well as promote research opportunities and provide habitat protection. As a result, the conservation of bull sharks in the river region could bring long-term economic gains.
This is especially the case in areas close to the Big Muddy, where conservation initiatives and management regulations have helped curbed the impact of human activities on bull sharks, as well as boosted their populations in the area.
