Why Sharks Matter

Sharks are the perfect predator – formed by 450 million years of evolution having lived longer than the dinosaurs and surviving five major extinctions. They formed life as we know it and keep the oceans, our planet’s life force, healthy. We exist, in part, because sharks did – and still do.

There is also undoubtedly no other species on the planet that is more collectively hated and villanized. Even though sharks are the unsung heroes of our watery world – we spend most of our media attention on misconceptions and fear, blinding us to the fact their populations are decreasing at incredibly alarming rates.

Why should we care if sharks disappear?
When we tell people 150 million sharks are killed a year, they look at us with astonishment. After processing that startling fact, we are often challenged with a variation of “So what? The only good shark is a dead shark.” But love them or hate them, and for sure anyone who has watched Sharkwater or even dove with a shark has fallen in love, just as we have, we absolutely need sharks on this planet.

Sharks are important to our survival

The frightening reality is, like them or not, sharks play a crucial role on this planet. Remove sharks from the oceans and we are tampering with the very things critical to our survival.

Sharks keep our largest and most important ecosystem healthy. Our existence is largely dependent upon theirs. Sharks have sat atop the oceans’ food chain, keeping our seas healthy for millions of years. And the oceans produce more oxygen than all the rainforests combined, remove half of the atmosphere’s manmade carbon dioxide (greenhouse gas), and control our planet’s temperature and weather.

The shark’s critical role
As the apex predators of the oceans, the role of sharks is to keep other marine life in healthy balance and to regulate the oceans. Remove sharks and that balance is seriously upset. Studies are already indicating that regional elimination of sharks can cause disastrous effects including the collapse of fisheries and the death of coral reefs.

A world without sharks?
One study in the U.S. indicates that the elimination of sharks resulted in the destruction of the shellfish industry in waters off the mid-Atlantic states of the United States, due to the unchecked population growth of cow-nose rays, whose mainstay is scallops. Other studies in Belize have shown reef systems falling into extreme decline when the sharks have been overfished, destroying an entire ecosystem. The downstream effects are frightening: the spike in grouper population (due to the elimination of sharks) resulted in a decimation of the parrotfish population, who could no longer perform their important role: keeping the coral algae-free.

What legacy will we leave for our children?
We don’t hear how the elimination of sharks might impact our best natural defense against global warming. Or how our favorite foods might disappear as a side effect of the extinction of sharks. Or that we could lose more oxygen than is produced by all the trees and jungles in the world combined if we lose our sharks. But we should.

If you care about Climate Change, you should care about the sharks.
No one knows for sure what will happen globally if shark populations are destroyed, but one should fear the results. Two hundred and fifty million years ago, this planet suffered the largest mass extinction on record, and scientists believe this was caused in part by catastrophic changes in the ocean. Sharks play a keystone role ensuring our seas remain in a healthy equilibrium and do not reach that point again.

In the last 40 years, shark populations have plummeted – in certain areas, some species are down up to 99%. We could witness the extinction of the first shark species in our lifetime if we don’t turn the tide for sharks. Just as the wolves of Yellowstone have proven, there is nothing extra in nature. Apex predators play a critical role in their ecosystems – ensuring the health of every critical, interwoven component from the tiny plankton to the majestic whales. And no matter where you live – every second breath you take comes from the ocean. Do we really want to mess with that?

Julie Andersen is a passionate shark advocate and diver, a decade-long Team Sharkwater member, and co-founder of Shark Angels, Shark Savers, United Conservationists and Fin Free – all non-profits dedicated to the protection of animals she loves – @juliesharkangel

Bascompte, Jordi; Melián, Carlos J.; Sala, Enric. “Interaction strength combinations and the overfishing of a marine food web.” PNAS: Proceedings of the National Academy of Sciences of the United States of America.Vol. 102, No. 15. 12 April 2005. http://www.pnas.org/content/102/15/5443.long

Griffin, E.; Miller, K.L.; Freitas, B.; Hirshfield, M. “Predators as Prey: Why Healthy Oceans Need Sharks.”Oceana.org. July 2008. http://oceana.org/sites/default/files/o/fileadmin/oceana/uploads/Sharks/Predators_as_Prey_FINAL_FINAL.pdf
Heithaus, M.R.; Frid, A.; Wirsing, A.J.; Worm, B. “Predicting ecological consequences of marine top predator declines.” Trends in Ecology and Evolution. April 2008, 23(4): 202-210. http://www.lenfestocean.org/sites/default/files/Heithaus_Top_predator_declines_article.pdf

Myers, Ransom A.; Baum, Julia K.; Shepherd, Travis D.; Powers, Sean P.; Peterson, Charles H. “Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean.” Science, 30 March 2007. http://baumlab.weebly.com/uploads/1/2/4/4/12445281/myers_2007_science.pdf

Watson-Wright, Wendy; Kalojni, Gretchen. “Bringing fisheries on board.” Editorial. A World of ScienceOctober-December 2012, Vol. 10 No. 4: 1. http://unesdoc.unesco.org/images/0021/002180/218053e.pdf

University Of California, San Diego. “Research Shows Overfishing Of Sharks Key Factor In Coral Reef Decline.” ScienceDaily, 13 Apr. 2005. Web. 9 Jul. 2013.

“Effects of Losing Top Predators.” Lenfest Ocean Program Research Series. April 2008. http://www.pewtrusts.org/uploadedFiles/wwwpewtrustsorg/Reports/Protecting_ocean_life/Top_predator_loss_RSR_FINAL.pdf

“Sharks: Key to Healthy Oceans.” The PEW Environmental Group and the Bahamas National Trust. PEWenvironment.orghttp://www.pewenvironment.org/uploadedFiles/PEG/Publications/Fact_Sheet/Sharks%20Key%20to%20Healthy%20Oceans.pdf

Wake Shark and Ocean Education http://www.wakeproject.net/

Wild Aid http://www.wildaid.org/sharks

Shark Savers https://www.sharksavers.org/en/home/

The Global Shark Conservation Initiative http://www.tgsci.org/