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Scalloped hammerhead sharks (Sphyrna lewini) schooling, Cocos Island, Costa Rica, Pacific Ocean © naturepl.com / Jeff Rotman / WWF

Scalloped hammerhead sharks (Sphyrna lewini) schooling, Cocos Island, Costa Rica, Pacific Ocean © naturepl.com / Jeff Rotman / WWF

5 ways sharks and rays help ecosystems, other species and people!

13 Jul 2020

Keywords
  • plastic
  • tourism
  • biodiversity
  • climate change
  • dugongs
  • ecosystem
  • sharks
  • Ocean protector

This Shark Awareness Day, let’s celebrate some of the most enigmatic and misunderstood creatures of the blue – sharks and rays, which are crucial for the health of our planet! Here are five incredible ways in which sharks and rays help the world, from fighting climate change to sharing food with their neighbours, to growing phytoplankton, and more.

Climate action advocates

 Tiger shark swimming over a seagrass meadow © Marion Kraschl / Shutterstock   Abundant seagrass © Lauren Simmonds / WWF-UK

 

Did you know that tiger sharks in Western Australia help to make oceans more resilient to climate change? How? Swimming around the shallow seagrass meadows, these sharks serve as crowd-controllers and prevent overgrazing by marine creatures such as turtles or dugongs. Less continuous grazing in the same spot means more abundant, denser seagrass. And you know what captures carbon from the atmosphere 35 times faster than tropical rainforests? Yes, that’s right – seagrass!

 

 

Good-hearted architects

Stingray and jacks in Belize © Antonio Busiello/WWF-US

 

Thanks to their unique way of feeding, large bottom-dwelling rays – such as stingrays, cownose rays, or whiptail rays – act as 'habitat engineers'. Hovering over sandy areas, they excavate the sand in search of food, while simultaneously creating micro-habitats for various tiny invertebrates. For these 'architects', sharing is caring! As they uncover tasty snacks for themselves, they also help many other marine species to feed, from small reef fishes to bigger predatory jacks, all the way to seabirds such as cormorants.

 

 

Underwater gardeners

Spinetail devil rays (Mobula mobular) © naturepl.com / Mark Carwardine / WWF Phytoplankton © NOAA MESA Project /Public Domain

 

Large, deep-diving sharks and rays help phytoplankton (microscopic marine plants) to grow, simply by cruising between ocean depths and the shallows. One species of open-ocean Mobula ray was found to dive to almost 2,000 metres – nearly 2.5 times further than the height of the tallest building in the world! These creatures dive down to feed and as they return to the surface, they defecate, bringing back crucial nutrients. Without those essential elements, phytoplankton – which forms the foundation of many oceanic food chains – couldn’t grow! And you know what's responsible for every second breath you take? Yes, phytoplankton, as it produces half of the Earth’s oxygen supply! So yes, some rays and sharks really are deep-diving gardeners that help us breathe.

 

 

Marine ecotourism stars

Whale shark (Rhincodon typus) with diver © Jürgen Freund / WWF  Juvenile blacktip reef shark in Maldives © Simon Lorenz / WWF-Hong Kong

 

Just as nature-loving tourists all around the world dream of seeing elephants, lions, or gorillas in the wild, many cannot imagine their lives without swimming with sharks and rays underwater! Every year around 600,000 shark divers travel the world to witness these magnificent creatures in their natural surroundings. In 2014 in Australia alone, shark tourism brought at least AU$47m to the national economy. The economy of Maldives – a small island nation in South Asia – is driven by tourism, with diving and snorkelling the country’s most popular tourist activity. Shark divers brought over US$65m to their local economy in 2016, contributing directly to the diving industry and many other business sectors. A tourism survey revealed that 74% of travellers came to Maldives because of diving and devoted shark divers said that they would not return if there were no live sharks to be seen!

 

 

Blue circle of life

Whale shark and mobulid ray carcasses © 2014 Higgs et al. Licensed under CC BY 4.0

 

Even after they die of natural causes, sharks and rays contribute so much to the marine ecosystems! Scientists analysing video footage from the seafloor off Angola’s coast discovered that carcasses of a dead whale shark and large rays resting peacefully at 1,200 metres supported entire communities of deep-sea scavengers. A real blue circle of life!

 

 

No longer the immortal superheroes…
Now you see how amazing sharks and rays really are! Sadly, up to 100 million are killed every single year, whether caught on purpose or by accident (as bycatch). Overfishing, deadly gill nets and lack of controls are driving declines of sharks and rays on a global scale. As a result, 30% of all 1,200+ species are currently threatened with extinction. Without urgent action and our help, some of these blue superheroes – which have been around for hundreds of millions of years, outliving the dinosaurs – might disappear for ever… Let’s not let that happen!


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Want to do more?

Purchase a pair of upcycled, limited edition, sustainable eyewear! ReefCycle sunnies are made started life as a deadly gill net. Every pair sold saves the lives of iconic sharks, dugongs, dolphins, turtles and countless other marine species.