I’m sure you remember the haunting theme song for the classic shark-attack movie – Jaws. The drama it creates sums up the terror that has been cultivated within us toward sharks. But are sharks really the villains they are portrayed to be?
In honour of Shark Awareness Day, we chatted with a couple students and practitioners of marine biology from Caribbean. They shed light on the massive creatures of the sea and what we learned about sharks and climate change was quite interesting.
Here are 4 reasons why sharks are the true heroes of our oceans and could be influential in turning the tables on climate change.
Sharks are the gatekeepers of balance in our marine ecosystem.
We’re quoting Tricia on that point.
Tricia King, an environmental storyteller, born on the Caribbean twin-island of St. Kitts and Nevis shared with us that the way Hollywood casts sharks contributes to shark killings worldwide, which is unfortunate because this negatively affects the entire marine system, which in-turn affects us.
Just as bees play a foundational role in upholding Planet Earth, so do sharks.
As Tricia passionately expressed, “Diving into the ocean without sharks would be like looking at a painting without paint, unimaginable. We would not be able to retrieve the economic benefit that can be derived from ecotourism surrounding sharks presence in our waters.”
Sharis Garcia, from Trinidad and Tobago agrees with Tricia.
“Without sharks, the oceanic system can shut down,” she said, with emotion in her voice.
Sharks play a crucial ecological role on coral reefs
Sharis, who was inspired to get into marine biology when she was 8 years old and found shell-less and fin-less Leatherback turtles on a beach, says that humans are a larger threat to sharks than sharks are to them, which goes full-circle.
By killing sharks, we are removing the protectors of our reefs, which can lead to what ecologists call a “trophic cascade.”
The disappearance of apex predators, like hammerhead sharks, could affect all levels of the ecosystem. Without these majestic creatures preying on them, the population of smaller sharks called “mesopredators” would increase.
More of these means more consumption of herbivorous fish, which feed on algae. With reduction in the population of these fishes, algae can take over entire reefs, out-competing the slower-growing corals for spaces and curtailing the high among diversity that coral reefs support.
Added to this, “with rising temperature in the sea, algae grows at a faster rate and covers up the corals faster than ever before. It becomes too much for our reefs to handle, and they die,” Sharis shared.
Tricia drew it home, to the Caribbean region. “Ocean acidification is taking place on a worldwide level. It’s a reduction in the pH of seawater as the ocean absorbs large amounts of carbon dioxide. For large ocean states, like Caribbean islands, the acid dissolves calcareous species like lobster, conchs, shellfish, and coral. Our beautiful coral reefs are suffering greatly and they will cease to be lively habitats. As this happens, the food supply of sharks is lost, which affects the entire system.”
“When sharks are left with nothing, we are left with nothing. You can see if in the skeletal reefs off the coast of Toco, in Trinidad,” Sharis shared.
Sharks are the doctors of the ocean
Leah Fouchong, educator in the field of Earth Sciences, told us that sharks influence the oxygen levels as they play a balancing role in the food chain. “Sharks maintain the health of the ocean and remove sickness from our ocean. They eat marine life that is already dead or those that are ill. This helps to maintain healthy marine ecosystems.”
As Sharis put it, “when an animal dies and it’s decaying in the ocean, it returns to a carbon compound, carbonic acid increases acidity in the ocean. When sharks eat the carcass, it prevents this form of carbon and acid from being released into the ocean. The ocean is, after all, the biggest carbon sink in the world. We should keep it and everything in it protected and conserved, this includes sharks.”
Sharks are in charge of balancing species diversity.
Ashley Perez, an Environmental Scientist and Educator based in Puerto Rico shared that oceans simply cannot thrive without sharks. They play a keystone species role.
“Sharks keep fish populations in check and rid fish communities of diseases. They inadvertently influence the health of seagrass, reefs, and other habitats.Sharks play a keystone species role and often give us insight into the status of ecosystems as they are bioindicators, their presence and the fact that they are bio accumulators often signals the state of water quality.”
As apex predators, sharks have a valuable cascading effect on their habitats. Climate change is affecting all life on Earth, but as Ashely stated, it is very particular in our oceans.
“Warming oceans shifts the dynamic of global currents, impacting the habitats and locations they frequent. Truth is the ancestors of sharks and other organisms have adapted to warmer oceans in the past but an accelerated shift in climate is a different story when it comes to their slow evolution and slow reproduction rate,” Ashley pointed out.
Warmer, more acidic oceans affect sharks physiology and development in many ways. Sharks are essential in regulating ecosystems and a decline in sharks could have a devastating effect in the health of coral reefs, tourism, fisheries and the economy.
Sharks are clearly very important. What do these marine ladies have to say about it all?
Tricia’s message sums it all up really well:
Like everything in life we need a strong sense of BALANCE and sharks provide this in the marine environment. As apex predators they keep the marine food chains and by extension food web balanced.
We’re not saying you’ve got to go swimming with sharks, although you probably should. But let’s become advocates for the protection of sharks. After all, protecting sharks protects the oceans, which protects us.