When it comes to the thoughts of sharks, many people will respond with fear. As a result of this fear, myths, and hatred, it's not uncommon to hear sharks referred to as 'monstrous.'
That's because they are widely regarded as dangerous killers that will attack and eat any living thing that comes near them. However, the fact remains that sharks are an essential part of the marine ecosystem, whether humans believe it or not.
As Humans, we kill sharks faster than they can ever hope to reproduce and replenish their population. As a result, sharks are disappearing in their millions. Maybe by learning the truth, more people will protect these fish.
Myth #1: Sharks are man-eating animals
Contrary to popular belief, sharks are not interested in eating people. Negative shark encounters are often a case of misidentification.
For instance, a splashing surfer can look like an injured animal, so some sharks will investigate by biting. The shark will often let go once it realizes it hasn't captured its usual prey. Sharks like a diet of oil-based meats, whereas we are blood-based, meaning we can taste like our least favorite food to them (1).
Sharks are wild animals, and they can be dangerous. There have been incidents of shark attacks that led to human fatalities. However, sharks kill less than five people each year.
There are nearly five hundred different sharks in our oceans, but about a dozen species are known to be potentially dangerous to humans. For example, compared to dying in a shark attack, you stand a greater risk of being killed by lightning, dying from stroke/ heart disease, or even a car accident.
Myth #2: Sharks don't get cancer
The misconception that sharks can cure cancer dates back to the 1970s when research at the John Hopkins School of Medicine, Baltimore, discovered that cartilage could stop new blood vessels from growing into tissues of malignant tumors. This research began with experiments on rabbit cartilage but soon followed with shark cartilage.
In addition, a Florida scientist experimented with sharks by exposing them to known carcinogens and noted that the fish did not develop tumors (2).
However, it has been known for over 100 years that sharks can get cancer.
In 2013 Australian researchers discovered a great white shark with a tumor on its lower jaw, the first documented tumor in this particular species. This misconception plays a primary role in promoting the hunting and killing of sharks to harvest their cartilage to produce cancer-fighting remedies. This trend has dramatically destroyed shark populations.
According to Scientific American, North American shark populations have decreased by up to 80% in the last decade. So far, efforts to harvest this compound and use it to treat cancer in humans have not produced positive or conclusive results (2).
Myth #3: Eating portions of shark can improve your health
In many cultures, shark meat has been consumed for centuries. Its primary purpose is for medicinal benefits. It's believed that shark meat improves blood circulation, kidney health, and eyesight. However, research that has come out shows that shark meat can be dangerous for humans, especially pregnant women and children.
This is because all seafood contains some levels of mercury. Sharks, in turn, consume large quantities of smaller fish, and with time, they will accumulate higher amounts of mercury and other chemicals like arsenic, urea, and lead in their bodies. They can also absorb some of these chemicals through their skin (3).
In addition to being used for meat, sharks are also killed for their livers. One of the main components of shark liver oil is a compound called squalene. Squalene and its derivative squalane can be found as ingredients in cosmetic products, ranging from anti-aging cream to lip gloss.
Unfortunately, much like the devastatingly inhumane practices accompanying shark-finning, squalene fishers often extract the animal's liver only to throw the remaining remains back into the ocean. The practice is known as “shark liver-ing” (4).
The United Nations released a report stating that more than fifty shark species are fished for their liver oil, several of which appear on the International Union for the Conservation of Nature's (IUCN) Red List. Deep-sea sharks are the most sought-after since their livers can make up 20% of their body weight.
These pelagic sharks are at such a significant risk of overfishing that scientists have concluded they should not be caught at all. The ironic thing about shark killings is that squalene exists elsewhere in nature; mostly, it is found in olives, amaranth seed, sugarcane, rice bran, and wheat germ. Meaning there is a more natural way to obtain this compound instead of killing sharks for it (5).
Myth #4: Sharks have no predators
The greatest threat to sharks is us; as humans, we kill millions of sharks each year for pieces of their bodies, especially fins.
However, as apex predators, sharks play a critical role in marine communities. They help maintain the delicate and sensitive balance of marine life. They are at the top of the food chain and help regulate other sea animal populations; if not, there will quickly be an imbalance. This kind of imbalance is particularly noticeable in coral reefs.
Another way to look at it is that sharks are the doctors of the sea. Sharks feed on old, sick, and weak prey, preserving healthier fish populations, many of which are necessary to keep these habitats alive (6).
In addition to Humans, sharks have other marine predators.
Orcas have been shown to eat mako, great white, and other sharks by flipping them over to stun them and larger sharks eating smaller sharks, including ones of the same species.
However, the onslaught of sharks is so much, and it comes mainly from human activities: Sharks are frequently caught as bycatch after entangling in fishing nets, trawl nets, and baiting lines. Unfortunately, many of these sharks are discovered and released when they are already dead.
We are hurting sharks more than they are hurting us.
Written by Danielle Dillman (@danielle_dillman)
Marine Scientist| Aquariums| Elasmobranchs| Conservation Education
Sources & References
Handbook of Industrial Chemistry and Biotechnology 13th Edition Pg. 859-861. Source: https://www.springer.com/gp/book/9783319522852