Sharks get a bad rap, but unjustly so. Ever since blockbuster Jaws depicted sharks as bloodthirsty sea monsters, these animals have been the victims of exaggerated fears and a subsequent increase in hunting and culling. Shark attacks are extremely mediatized and may, therefore, appear more frequent than they really are. In 2014, shark attacks around the world accounted for three human deaths and on any given year they generally do not exceed ten. As a point of comparison, lightning kills anywhere between 6,000 and 24,000 people per year.
That isn’t to say that sharks aren’t impressive creatures. Their sandpaper skin and inexhaustible supply of sharp teeth are effective at keeping most predators at bay while their flexible cartilaginous skeletons offer them a quick and efficient range of movement. Additionally, certain species live over 100 years. But not all sharks are created equal. There are over 400 species of sharks in the world’s oceans — measuring between 8 inches to 35 feet long — with each species having its unique appearance, environmental preference, feeding habits and crucial role in its particular ecosystem.
While some species of sharks survive on plankton, most sharks are apex predators, i.e. predators that reside at the top of the food chain and ensure the good health of their ecosystem. For years, studies have been revealing that the elimination of sharks can cause “disastrous effects” including the collapse of ecosystems and the death of coral reefs. More recently, a study found that the decline of the world’s sharks actively contributes to global warming.
Sharks Help Prevent Climate Change
What differentiates sharks from lightning? A lot, certainly. For one, we’ve seen that lightning kills many more people worldwide. Another major difference is that while climate change could cause a 50 percent increase in lightning flashes across the continental U.S., an increase in our shark population could curb climate change.
In fact, new research has revealed that sharks play an important part in preventing global warming. The decline in our global shark population — due to overfishing and culling — leads to their prey becoming overabundant and eating carbon-storing vegetation in larger quantities.
One of the study’s authors, Dr. Peter Macreadie, explains that carbon is stored in blue carbon ecosystems in the ocean, with seagrasses, salt marshes, and mangroves being among ‘the most powerful carbon sinks in the world.” Indeed, blue carbon ecosystems capture and store carbon 40 times more efficiently than tropical rainforests such as the Amazon. This carbon is often stored for thousands of years.
Loss of sharks leads to turtles, crabs, and stingrays being free to reproduce and feed unimpeded, which in turn has repercussions all the way down the food chain. This process is known as “trophic downgrading.” Their numbers unchecked, these species subsequently feast overabundantly on the ocean’s vegetation, releasing ancient carbon in great quantities and posing a catastrophic environmental risk. If just one percent of the ocean’s carbon-storing vegetation is lost, this would result in “460 million tons of carbon” being released annually, the equivalent of pollution created by 97 million cars.
In recent years, overfishing and culling have wiped out 90 percent of the world’s sharks and other top ocean predators. Considering that sharks have been around for over 420 million years —longer than dinosaurs —unrestrained human interference is messing with an environmental balance that has been in place for millennia. As Dr. Macreadie rightly states: “It’s time to take a good look at the way in which nature helps mitigate climate change for us and try to do everything we can to let that natural process operate,” mainly by taking sharks into consideration. Indeed, their survival significantly matters to our own.
The naturally occurring balanced function of an ecosystem is a minute science. When humans exploit species and environments, they are rapidly undoing thousands of years of natural balance where each animal plays a distinct and vital role in its surroundings. Human greed cannot go on unchecked, and we must realize that we cannot continue to exploit our oceans to capacity without serious consequences. Over 100 million sharks are killed each year. No need to be a scientist to realize that such unbridled destruction results in harmful and far-reaching outcomes. “Whenever you remove those keystone fish and birds that sit at the top of the ecosystem, everything falls apart,” warns Dr. Macreadie.
Threats to Sharks
Sharks may be apex predators in the oceans, but humans predate on them for reasons ranging from the trivial — shark leather belts and shark teeth souvenirs — to the downright shameful — sharks being caught by accident in commercial fishing or finned for soup. This results in some shark species being endangered and shark population as a whole having declined dramatically. Some of the major threats to sharks include:
- Shark fin soup: Having surged in popularity in the 1990s, this dish is solely responsible for an estimated 26 to 73 million sharks being killed in 2000 alone. To produce shark fin soup, sharks are caught, have their fins hacked off and are then thrown back into the ocean to die slow and painful deaths.
- Nutritional supplements: Endangered species of deep sea sharks are hunted to produce shark liver oil, sold to gullible consumers who believe it can cure everything from fatigue to serious diseases. Shark cartilage pills are also sold and promoted as having anti-cancer properties, a ludicrous and unfounded claim, as sharks are also susceptible to cancer. While companies assure that the cartilage and liver they use are “by-products,” this has been proven to be false.
- Commercial fishing: Sharks — along with turtles, dolphins, and other marine animals — often become the unfortunate victims of fishing nets. Aside from overfishing depleting the fish populations ocean predators feed on, trawling by fishing boats captures and kills countless untargeted animals as by-catch. A particular U.S. fishery reportedly catches and discards 400,000 sharks per year.
- Recreational fishing: Sharks are also hunted and killed for sport. Their body parts — including their teeth, skin, cartilage — are kept as trophies or sold for commercial profit as trinkets and souvenirs.
- Culling: Environmental conditions and pressure placed on marine ecosystems are causing sharks to search for food closer to where humans live, thus increasing their contact with us. Sharks are also purposefully attracted to coasts to be killed by fishermen — who often use dolphins as shark bait. Sharks are curious animals and sometimes come close to swimmers and surfers to investigate. That’s not to say that an encounter with a shark isn’t dangerous. Still, it is important to note that only ten percent of encounters with sharks are fatal.
- Sensationalistic media coverage: Sensationalized stories depicting sharks as bloodthirsty animals who intentionally predate on humans put these important animals at risk. They perpetuate widespread ignorance about these animals and ignore how crucial they are in ensuring the health of our oceans. Some people have even been influenced to campaign for Great White sharks to have their protected status revoked and for shark culls to occur.
It is vital to spread awareness of the fact that decimating sharks directly threatens our own global survival. Whether most people realize it or not, sharks play a crucial role on our planet, balancing ecosystems and thus fostering healthy ocean environments that help prevent climate change.
Indeed, the oceans comprise our largest and most important ecosystem: as we’ve seen, it sequesters more carbon than all our rainforests combined — removing almost half of it from our atmosphere — it also produces more oxygen than terrestrial ecosystems and serves to regulate global temperatures and weather. Sharks play a key role in ensuring our seas retain a healthy equilibrium. We’ve not experienced the dire consequences of an ocean devoid of these crucial animals, and we’d be well advised to ensure we never do. Much more terrifying than Jaws is the prospect of a future without sharks.
Aside from spreading awareness of their plight, each of us can help sharks in small but significant ways. An essential first step is not buying or consuming shark products — including shark liver oil or cartilage pills, trinkets made from shark teeth, cartilage or skin, shark fin soup and shark meat, which can often masquerade as imitation crab, lobster or shrimp. To avoid unintentionally supporting the accidental killing of sharks in commercial fishing, you can also leave fish off your plate. By not eating seafood, one person can save 225 fish and 151 shellfish per year, as well as countless dolphins, porpoises, turtles and sharks killed as bycatch.
Lead image source: Albert Kok /Wikimedia