Spotlight on sharks – A multitude of fins

Elasmobranch. It may sound like a sylvan superhero from a mash-up of The Incredibles and The Lord of the Rings, but it’s the collective name for the cohort of cartilaginous (boneless) fish that includes sharks – along with rays, skates and sawfish. Literally meaning ‘gills of beaten metal’, this umbrella term covers a multitude of fins. 

There are well over 1,000 species of elasmobranch in our ocean, around half of which are sharks. Most people could name a handful of these, including the gargantuan whale shark – the world’s biggest fish – and the much-maligned great white shark, a frequent victim of vilification at the hands of the tabloid press. Many have marvelled at the facial distortions of the hammerhead, but that’s by no means the most bizarre of this extraordinary collective.

Whale sharks are harmless filter feeders, gulping down vast quantities of plankton and tiny shrimps. Credit: Amanda Cotton/Ocean Image Bank

Weird and wonderful sharks

If you think that the wide-set eyes of a hammerhead are bizarre, prepare to be floored by the cryptic camouflage of the tassled wobbegong, a bottom-dwelling carpet shark. The sawshark, meanwhile, looks like a fish that’s swallowed a hedge trimmer. Relative to its size, the cookiecutter has the largest teeth of any shark, and is named for its gruesome habit of biting perfectly round plugs of flesh from much larger species.

The tasselled wobbegong is a well-camouflaged ambush predator that preys on small fish and invertebrates on the sea floor. Credit: Fabrice Dudenhofer/Ocean Image Bank

Remarkable rays

Among an astounding array of rays, you’ll find everything from giant manta rays with their seven-metre wingspan to the evocatively named shovelnose guitarfish and the Atlantic torpedo – the largest known electric ray – which can generate a shocking 220 volts.

Manta rays have the largest brain-to-size ratio of any cold-blooded fish. Credit: Hannes Klostermann/Ocean Image Bank

Where have all the wobbegongs gone?

A cartilaginous skeleton is not the only thing that sharks and rays have in common. Make no bones about it, an alarming number of these fish are in deep trouble. A global study carried out in 2021 found that almost 36% of the 536 shark species assessed are at risk of extinction. We should also be seriously worried about rays. Over 40% of the 611 species assessed face some level of existential threat. What’s more, over three-quarters of shark and ray species in tropical and subtropical coastal waters are threatened with extinction.

Sharks and rays are disappearing from our oceans at an alarming rate. Credit: Gregory Piper/Ocean Image Bank

Why are sharks and rays endangered?

Sharks have reigned supreme over their marine domain for 450 million years. Until now. The inexorable rise of an even more voracious predator, Homo sapiens, poses a grave threat to the continued survival of this ancient lineage and to the future of the marine ecosystems in which sharks play such a vital role.

Despite the positive contribution of research and education in dispelling many of our misconceptions about sharks, western societies still tend to regard these formidable predators with a mixture of fear and morbid fascination. Isolated shark attacks continue to elicit a media feeding frenzy. In other cultures, however, particular among Indigenous peoples, sharks are respected and even revered. To Hawaiians, they symbolise all-consuming love.

Not all traditional practices benefit sharks, of course. Numbers are difficult to quantify, but upper estimates suggest that between 73 million and 275 million sharks may be slaughtered annually to satisfy the demand for shark’s fin soup, particularly in China. Our insatiable appetite for shark meat, liver oil and other products is also driving this unsustainable harvest.

Shark fins drying out in the sun in Myanmar. Credit: Saw Han Shein/Fauna & Flora

A century of unremitting abuse, facilitated by technological advances in fishing, has brought our ocean ecosystems to the brink of collapse. Sharks and other marine species are facing a perfect storm of overexploitation, pollution, inadequate regulation and other pressures.

Typical shark characteristics such as slow growth, late maturation and production of few offspring render them still more vulnerable, in that populations are slow to recover even after threats are removed.

This hapless hammerhead is just one among tens of millions of sharks that end up as by-catch each year in longlines, trawls and gillnets. Credit: Toby Matthews/Ocean Image Bank

The importance of sharks

As keystone species, sharks are crucially important for the health of the marine environment. The removal of these apex predators would upset the delicate equilibrium of ocean ecosystems. They keep prey populations healthy by culling the sick and weak, but also keep numbers in check to control the amount of ecological damage they inflict.

Sharks also represent a vital source of income in local and regional economies. By helping to maintain the dynamic equilibrium of our ocean, they help sustain fisheries that provide a source of food and livelihood to billions.

They also act as a powerful draw for tourists; an estimated half a million divers a year pay for the privilege of swimming with sharks, contributing millions of dollars to hard-pressed economies. One study in the Maldives found that a single grey reef shark is worth over US$3,000 annually in tourism revenue compared to a one-off value of US$30 to a fisherman.

Worth more alive: shark tourism attracts scuba divers and photographers from around the world. Credit: Jayne Jenkins/Ocean Image Bank

How Fauna & Flora is helping to protect sharks

A decade ago, as part of our expanding marine programme, Fauna & Flora put together an ambitious, comprehensive five-point plan to boost shark conservation and help reverse the dramatic decline in the world’s shark populations.

Working closely with our in-country partners, we have undertaken research to increase knowledge of the distribution, status and conservation needs of target shark species. Having identified critical shark habitat, we are working to safeguard these vital havens by paving the way for improved coastal zone management and the establishment of marine protected areas.

A solar-powered monitoring system being installed in Turkey, to monitor sandbar shark numbers and activity. Credit: Akdeniz Koruma Derneği

A crucial facet of our work has been to raise community awareness about the plight of sharks and their importance, and to encourage wider local participation in their conservation. We also aim to reduce the pressure exerted by direct fishery activity and accidental by-catch by helping to promote shark-friendly fishing techniques and strengthen law enforcement. Perhaps most importantly of all, we are devising and supporting alternative livelihood strategies that help reduce communities’ dependency on unsustainable and uneconomic fishing practices.

Find out more about how our work at key sites is benefiting sharks in this companion piece.

Snatching victory from the jaws of defeat

Of all the apex predators on the planet, none exerts a stronger hold on our imagination than the shark. And few can elicit such a passionate, atavistic response. Love them or loathe them, there is no denying that the ocean would be greatly impoverished without their iconic presence.

Sharks maintain balance within our marine ecosystems and are critical to the health of our oceans. Credit: Tom Vierus/Ocean Image Bank

It would be a tragedy if others were to go the way of the aptly named lost shark, which was formally described as recently as 2019, but is now presumed to be extinct, having not been seen for the best part of a century.

For many other shark species, extinction remains a very real threat, but we still have a window of opportunity – narrowing by the day – in which to turn around their fortunes and help ensure that these paragons of piscine durability continue to persist long into the future.