A huge gathering of sharks obliterates a shoal of anchovies by herding the tiny fish into a tight ball before snapping and striking from every direction.

These incredible hunting abilities – filmed as part of a new BBC / Discovery coproduction television series – have contributed to a deadly reputation that has made sharks famous the world over.

Yet the ancient family – made up of 510 species and inhabiting every ocean – remains largely mysterious, leaving publicity surrounding shark attacks on humans and various Hollywood films to fill in the blanks.

Now scientists are beginning to take on the mantle of providing a fuller appreciation of sharks' incredible lives, and their global importance.

BBC Earth spoke with three experts who are among those leading the way to a better understanding of these epic fish.

Dr Alison Kock: great white shark (Carcharodon carcharias)

The majority of people are now against culling methods

Dr Kock studies the most iconic species of shark, long depicted as man-eating monsters. She is the research manager for Shark Spotters which operates a warning system for swimmers and surfers in Cape Town, South Africa, where one of the world’s largest concentrations of great whites can be found.

Great white sharks are a threatened species. They are also responsible for most of the reported attacks on humans and, although rare, such incidents have led to sharks being killed or kept out of inshore areas, as well as to a loss of compassion from the public.

The spotting scheme has alerted people to more than 1,700 sharks since it was introduced in 2004, and has also made new discoveries about shark hunting behaviour.

Dr Kock says this unique approach to preventing attacks has succeeded in transforming attitudes towards white sharks.

“The majority of people are now against culling methods and support non-lethal and environmentally friendly solutions to keep them safer,” she says.

“The city of Cape Town has truly been a pioneer in showing that it is possible to support shark conservation and keep people safer at the same time.”

Dr Kock tags and tracks white sharks in False Bay and has discovered that they gather in different areas of the bay depending on the season. In autumn and winter they prefer to be around an offshore island which is home to a fur seal colony, but in spring and summer they change location and come inshore.

She has also determined that sharks are more likely to enter bathing areas at higher water temperatures and during a new moon.

“To date I have identified the ‘where’ and the ‘when’ and I am working on the 'why',” she says.

“My focus is on identifying the drivers of shark occurrence and movement to predict levels of shark presence in different areas and times, and to better understand the role of this apex predator in a coastal ecosystem.”

Dr Andrea Marshall: manta ray (Manta alfredi and Manta birostris)

Dr Marshall is director of the Marine Megafauna Foundation and has begun to uncover the secrets of some of the shark's closest relatives, including confirming the existence of a second species of manta ray in 2009, and currently working to describe a third.

Possessing the largest brain of any fish, manta rays have much to show us about their intelligence, curiosity and sociability according to Dr Marshall, who has overcome the problems of monitoring a shy, wide-ranging and highly migratory species.

She has pioneered a global online database of manta rays, which she describes as a cross between Facebook and the FBI’s fingerprint database, allowing anyone who photographs a manta ray to create a profile using unique spot markings on the rays' undersides and cross-referencing it against existing entries.

The database, called Manta Matcher, can be used to track things like life-cycle, population size and structure, movement and speed. With numbers of manta rays declining and both species now listed as vulnerable to extinction, Dr Marshall says the project also helped towards manta rays gaining vital protection in international waters.

“When we first started we were seeing really important information like the fact these animals were making international migrations between countries, into high seas, into parts of the ocean that don’t belong to any country,” she explains.

They are becoming ambassadors for fish

“Governments were then able to start including the species in the Convention of Migratory Species of Wild Animals (CMS), ensuring that they would get better and more comprehensive conservation globally.”

In 2014, reef manta rays joined giant manta rays in being afforded the highest level of protection by CMS. This came hot on the heels of a study, using data from Manta Matcher, that showed reef manta rays were making long, dangerous migrations between sanctuaries in Indonesia, one of the largest manta ray fisheries in the world at the time.

Dr Marshall is also hoping it will be a way to prove her belief that manta rays have complex social lives – her team is currently investigating the make-up of their groups - and even individual personalities.

During her regular dives with the huge animals she has seen first-hand their inquisitive nature and playfulness with humans, a rare discovery in a fish and something she thinks could help raise their profile among the public.

“They are becoming ambassadors for fish, making people recognise for the first time that maybe they’re not just these cold, dumb animals that we just eat, maybe there’s more to them,” she says.

Dr Gillian Renshaw: epaulette shark (Hemiscyllium ocellatum)

Dr Renshaw, from Griffith University in Australia, works with one of the smaller species of shark and has discovered that they have evolved a remarkable strategy for surviving long periods with little or no oxygen.

Epaulette sharks are found in shallow tropical waters which are regularly cut off from the sea at low tide. When this happens the sharks are either left in rock pools with very low levels of oxygen, or they can also find themselves on the exposed reef where there is almost no oxygen.

These important ancestral vertebrates may hold the keys to the survival of fish species as the oceans of the world become more hypoxic

The sharks cope by slowing their breathing and heart rate and switching off all non-essential brain functions, as well as the energy-producing parts of their cells (mitochondria). In doing this they not only reduce their need for oxygen but also keep the production of tissue-damaging free radicals to a minimum.

Despite being able to achieve a death-like state, an epaulette shark can still hunt, feed and even “walk” between rock pools using its fins, and once the oxygenated waters return it simply snaps back into normal behaviour, completely unharmed by the whole process.

Most animals with this ability can only do it at cold temperatures, so finding one capable of doing it near to human body temperature means Dr Renshaw can apply her studies to the treatment of stroke and heart attack patients, who also experience a dangerous lack of oxygen.

Shark behaviour is complex and is as diverse as the sharks themselves

“An understanding of how the epaulette shark protects vulnerable tissues such as the heart and brain could be expected to give rise to novel interventions that could be employed in a clinical setting for victims of heart attack and stroke, to diminish the extent of damage that results from insufficient oxygen,” she says.

“Similarly, protecting the heart and brain of aquatic species that are being transported would assist with conservation by maximizing survival.”

Dr Renshaw has also found that because epaulettes have to make do without oxygen so often they get better at doing it. She has been working to see if similar “pre-conditioning” to low oxygen levels can help people at risk of developing cardiovascular disease, which she says is showing some positive results.

Mystery still surrounds how epaulettes sense a drop in oxygen, meaning that this timid shark will remain a fascination for scientists like Dr Renshaw, especially as their hardiness could prove vital in the future.

“These important ancestral vertebrates may hold the keys to the survival of fish species as the oceans of the world become more hypoxic,” she says.

With many sharks and ray populations under threat, and many more listed as Data Deficient on the IUCN Relist of threatened species – meaning there is not enough information to determine the health of their populations – all of the scientists would like to see much more research carried out to help find effective ways of protecting them.

“There are many species which have no current research on them,” says Dr Kock.

“This is a major gap, shark behaviour is complex and is as diverse as the sharks themselves – one cannot apply behaviour across species or across the same sharks in different areas or even sometimes on an individual basis. Therefore, we still have a lot to learn.”

'Shark' begins in the UK on Thursday 7th May at 20:55 BST, on BBC One. It will be broadcast at a later date in other countries.

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