Evan Prasky is a marine and environmental sciences graduate student at Northeastern University. He studies the socio-ecological interactions between sharks in humans. His expertise is in shark depredation and how it affects the shark populations in the Gulf of Mexico. For shark week, we asked Evan to shed some light on some common beliefs about sharks.
This conversation has been edited for brevity and clarity.
What is one interesting fact about sharks that most people don’t know?
Select species of sharks are increasing in the United States. Around the world, however, shark populations face a genuine threat of extinction through overexploitation.
How do you think global warming has had an impact on the shark community?
Due to rising waters and warmer temperatures, select shark species have increased their territorial bounds northward, as such species have been moving up into previously unknown waters, like in the Gulf of Maine. Migration patterns of sharks along the Eastern coastal United States are primarily driven by temperature.
Scientists have documented large migration patterns where sharks move north in the Winter and south in the Summer. As significant seasonal changes occur, there are large migrations of both sharks and fish to move into more nutrient-rich waters.
Do you think shark movies like Jaws and 47 Meters Down are realistic?
Oh geez, movies like that are not realistic at all. The ocean is like the dark: people fear the unknown, and it’s easy for your mind to fixate on this fear. If you can’t see something but think it’s there, your mind will play tricks on you.
Hollywood and other entities like movies, social media, and the news play into that fearmongering to get people to watch content. These stories are great at captivating audiences, but in all actuality, they are not true. You’re more likely to get struck by lightning than you are to be in a shark attack. In fact, you’re more likely to get into a car accident on the way to the beach than you are to be in a shark attack.
Even so, when a shark attack does occur, most are nonfatal.
Are there certain things that attract sharks, or is there a certain way that they attack?
Shark attacks are primarily caused by mistaken identity. They’re attracted by something that looks like prey, so a shimmer of light can look like a bait fish, a fish scale, or something similar. Impaired visibility, murky water, and external factors that cloud one of the shark’s senses usually cause misjudgment.
If sharks wanted to eat humans, there would be far more attacks and fatalities than currently occur. Most shark bites are exploratory and release once they realize we are not what they thought. When a bite does occur, there isn’t a follow-up, and the victim is usually released. It’s like us going to touch something we haven’t felt before.
However, they do it with their mouth because they don’t have hands. The movies severely exaggerate what happens when someone gets bit. Sharks aren’t attracted to human blood like they are attracted to the blood of other animals.
What is the importance of having sharks in our ocean’s ecosystems?
Sharks exist at all levels in the food chain. I want to compare an ecosystem to a portfolio where sharks and other fish at the species level are stocks in this portfolio. Diversification makes a more resilient portfolio less likely to fail. Removing sharks will decrease the diversification of this portfolio and, in turn, put everything else at risk.
Sharks have many functions in our oceans; they regulate food systems, transport nutrients, and are indicative of ocean health.
Humans have glorified them, demonized them, and even tried to eliminate them from the systems they’re in. We have overfished and overexploited sharks around the world. They are slow-growing, and several species take many years to undergo a complete reproductive cycle.
When sharks are removed from ecosystems, trophic cascades occur. Negative impacts on ecosystems due to the loss of sharks are a genuine threat.
What is shark depredation, and why is it important to study the effects on sharks?
Shark depredation is the partial or complete removal of your hooked fish by a predator while reeling in your catch. It’s a frequent occurrence in tropical and subtropical waters. Down into the South Atlantic and the Gulf of Mexico, there are a lot of coastal shark species that do this.
When recreational anglers try to catch fish and sharks bite them in half while reeling their catch in, it can lead to disappointment since these people invest a lot of money and resources into these fishing trips. I study the conflict when that situation occurs.
Shark populations in the United States have seen robust stabilizations and increases in the past twenty years or so due to the implementation of regulations protecting sharks. There is a greater abundance of sharks, but more recreational anglers are on the water simultaneously. This increase in depredation could decrease support for shark conservation.
Is there is a possibility of sharks going extinct in the next generations?
There’s a possibility in certain areas, but it is unlikely to occur in the United States. The United States has some of the most robust fisheries and conservation science practices in the entire world. We are doing a great job of protecting shark species here.
In other parts of the world, gaining a solidified understanding of population statuses takes longer, and translating knowledge into action is a slow process. If policies cannot be implemented, species will likely go extinct in select areas.
What is a fin trade ban?
Sharks are not a commercially viable fish; however, they have an abundance of meat on their bodies. Their meat needs to be treated correctly to be appropriately enjoyed.
A common misconception is that they’re only sought after due to their fins, but globally the shark meat trade is more commercially viable than the shark fin trade. This is likely due to the cruel practice of shark finning, which has made it more publicly known. Shark finning is the process of removing shark fins, in some cases, while the animal is still alive. This causes the shark to be thrown back into the ocean, where it drowns and suffers immensely.
While this practice has been banned in the United States since 1993 it occurs elsewhere due to the fact that Fins are more valuable and can be stored in large quantities on vessels without the shark bodies attached. The focus of the fin trade is usually pinpointed to Asian countries, but that itself is incorrect and European countries like Spain are also part of this largely controversial practice.
In early 2023 we’ve seen historic success in enacting protections for shark and ray species around the globe. Through CITES (the Convention on International Trade and Endangered Species of Wild Fauna and Flora), 60 additional shark species were added for protection under Appendix II, which prohibits international trade of selected species. These protections help reduce both the shark fin and meat trade with goals to reduce the over-exploitation of sharks globally to ensure humans do not hunt sharks to extinction.
Here in the United States, we have had protections in place since 1993 to protect against the overharvest of sharks. While our government has banned shark finning through initial fisheries management plans, in late 2022, the Senate passed a bill to end the shark fin trade within the United States.
How can people become more informed about sharks?
There are a lot of good organizations to support. To name a few, Save Our Seas Foundation, Atlantic White Shark Conservatory, The Shark Trust, Saving the Blue, and Sharks4Kids. Additionally, the support of graduate students is always helpful, and donating to organizations like Minorities in Shark Science (MISS) helps diversify a growing science field and provides young scientists with a safe and inclusive space. While watching Discovery Channel’s Shark Week and National Geographic’s Shark Fest, I’d use caution as their primary driver for those shows is entertainment, and if you want to learn more, explore some of the organizations I mentioned.