By freedivinguae

These giant sharks are 3 times as tall as a giraffe – and can lurk for 130 years, research finds

 

In this  May, 30, 2010 photo, a whale shark swims in the Georgia Aquarium in Atlanta. Inside a few small vials at the world's largest aquarium is the key to unlocking the mysteries of the planet's biggest fish. Scientists at the Georgia Aquarium and Emory University are teaming up to produce the first genome of the whale shark, bidding to catalog the DNA of a fish that long has puzzled researchers. (AP Photo/John Bazemore)

The largest fish in the sea can be found off the coast of the Carolinas — an enormous shark.

Whale sharks are the largest known fish species in existence today, but new research suggests the sharks can grow even larger than previously thought and can live more than a century.

Scientists observed whale sharks 18 feet to 40 feet or longer, and calculated that they lived to be about 70 years old on average, according to National Geographic. They can weigh more than 20 tons.

New research in the Maldives, published in the Marine and Freshwater Research journal this week shows whale sharks can grow even larger and live much longer than previously thought.

Whale sharks are an endangered species whose growth and reproduction are poorly understood, according to the research.

Traditionally, the size of whale sharks had been determined using vertebral samples from dead animals, but that was limiting for research purposes.

So the group of researchers used noninvasive techniques to investigate the growth of whale sharks in the South Ari Atoll, Maldives, an area that may be a nursery ground for the sharks.

Scientists analyzed repeat measurements of free swimming whale sharks over a 10-year period.

Total lengths of the sharks were estimated using three methods: visual estimates (which often underestimated the size of the sharks), and laser and tape measurements, which yielded similar results to each other.

After hundreds of shark encounters, researchers estimated that the sharks can live to be 100 to 130 years old and can grow between 50 and 62 feet long at those ages.

“This study suggests that, like some other shark species, we may have been underestimating age by quite a bit,” said Alistair Dove, a marine biologist and conservationist at the Georgia Aquarium. “We used to think whale sharks lived to be 75 to 100.”

But these numbers only show that more research about whale sharks is needed to better understand them.

By freedivinguae

Whale sharks gather at a few specific locations around the world – now we know why

The whale shark is the largest fish in the world, but much of its lifecycle remains shrouded in mystery. These gentle giants gather in just a handful of places around the globe – something which has long baffled scientists – but our new research has started to explain why. Better understanding of whale shark movements could help prevent further population loss in a species that has already experienced a 63% population decline over the past 75 years.

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A whale shark basking in the Maldivian shallows. Melody Sky, Author provided

When swimming solo, the whale shark, which can grow up to 18.8 metres in length and 34 tons in weight, travels all over the world. Recently, a group of scientists tracked the remarkable journey of one whale shark across the Pacific from Panama to the Philippines. At more than 12,000 miles it proved to be one of the longest migrations ever recorded.

Yet whale sharks are known to come together at just a few specific locations around the world. Anything from ten to 500 whale sharks may gather at any one time in areas off the coasts of Australia, Belize, the Maldives, Mexico and more.

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Face to face with the world’s largest fish. Jil Kühne, Author provided

Approximately 20 hotspots have been identified – mere pinpricks in the vastness of the world’s oceans – but we don’t know what exactly attracts the whale sharks to them. In some cases the sites are linked to a specific biological phenomenon – such as the spawning of land crabs at Christmas Island in the Indian Ocean, which provides whale sharks with the seasonal equivalent of a Christmas feast. Our new research aimed to discover whether there was something else that united the places where these giants of the ocean hang out.

It’s all about bathymetry

The physical features of these spots – known as their bathymetry – have been shown to influence gathering points in other marine species. So in collaboration with the Maldives Whale Shark Research Programme, we decided to investigate whether it drives whale shark gatherings in the same way.

Our new global study shows that whale sharks congregate in specific areas of shallow water, next to steep slopes that quickly give way to areas of much deeper water (usually between 200 metres and 1,000 metres).

We identified three main reasons. First, the deep water is used by whale sharks for feeding. Studies have shown the sharks diving to depths of almost 2 kilometres (1,928 metres to be precise) to feed on zooplankton and squid.

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A group of whale sharks feeding near Indonesia. Shutterstock

Second, the steep slopes are known to bring nutrients up to the surface from the deep, which in turn increases the abundance of plankton and attracts large numbers of filter-feeding species. And finally, in shallow water, as well as feeding on coral and fish spawn, the sharks are able to thermoregulate, warming themselves back up after their dives into deep water which gets as cold as 4℃ (39°F).

Valuable but vulnerable

If you’ve ever seen or swum with a whale shark, it was most likely in one of these relatively shallow aggregation areas. Knowing where these hotspots are has provided local communities with a windfall from ecotourism. In the Maldives alone, economic benefits from whale shark-related activities were estimated at US$9.4m per year. Whale sharks are worth a lot more alive than dead – and with many of these meeting points in developing countries, the income is invaluable.

But with the increasing pressures of tourism comes new dangers for the sharks. Crowds of snorkelers and tourist vessels are increasingly disturbing the whale shark’s waters, and – more worryingly – risk potentially fatal strikes by boats. To protect these beautiful creatures and continue to reap the rewards of ecotourism, we recommend that marine protected areas should be set up around whale shark gatherings and codes of practice be followed when interacting with them.

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Whale sharks are imposing, but feed on krill and other plankton. MWSRP, Author provided

Deep mysteries remain

These discoveries have narrowed down some of the key reasons why whale sharks congregate where they do, but many mysteries remain. Do individuals travel between these hotspots? Coastal gatherings are predominately made up of immature male sharks, usually still just four or five metres long. So where are all the girls? And where do whale sharks mate and give birth? Mating and pupping have never been seen in the wild – but, intriguingly, up to 90% of the whale sharks passing through the Galapagos marine reserve are female and thought to be pregnant.

The ConversationCould this be a key labour ward for the world’s whale sharks? Last year a BBC film crew at the Galapagos attempted to follow a pregnant female in a submersible to watch it give birth, but to no avail. That’s one secret that the depths are keeping for now.

Joshua Copping, PhD Candidate in Environmental Sciences, University of Salford and Bryce Stewart, Lecturer in Marine Ecosystem Management, University of York

This article was originally published on The Conversation. Read the original article.

Header image: Shutterstock

 

source: https://www.earthtouchnews.com/oceans/sharks/whale-sharks-gather-at-a-few-specific-locations-around-the-world-now-we-know-why/

By freedivinguae

Dolphin sanctuary gains steam thanks to ‘The Cove’ director push

Photo by Jorge Sanz/Pacific Press/LightRocket via Getty Images

This month, along the misty coastlines of Cascadia, a place where the Pacific Northwest blurs into the green Canadian wilderness, Louie Psihoyos—the director of the Academy Award-winning documentary The Cove—will be scouting out locations. It won’t be for a new film, however.

Since the release of his 2009 documentary, and with the help of Blackfish in 2013, Psihoyos says many Americans—and millions of people around the world, for that matter—have become increasingly sympathetic to the idea of retiring captive dolphins from their lives in the limelight. Indeed, in recent years protests against oceanariums have swelled in numbers and size—demonstrators routinely cite the films.

“[Dolphins] deserve respect and certainly don’t thrive in a sterile concrete tank any more than a prisoner would thrive in a jail,” Psihoyos tells Big Think. “These animals didn’t sign up to do tricks for food—a dolphin show is a grotesque spectacle of dominance.” This said, Psihoyos, who is currently the executive director of the Colorado-based Oceanic Preservation Society, has lent his support to The Whale Sanctuary Project’s endeavor to build a seaside asylum for captive marine mammals. It is poised to be the first North American whale sanctuary.

The project, which is currently in the phase of narrowing down potential sites—a location in Nova Scotia is still on the table—calls for what animal rights activists believe is the righting of the wrongs from yester-decades. Among them, for example, was the capture of nearly an entire generation of Southern Resident killer whales during the ’60s and ’70s for exhibition purposes. The roundup, according to NOAA Fisheries, had a long-lasting effect on the now endangered pod.

“To create a generation of humans that respects these animals, we need to make amends by creating a sanctuary so they can at least live out their lives in a more natural ocean habitat,” Psihoyos says, then describing one impetus for why his organization, and others, are supporting The Whale Sanctuary Project’s big idea. “The [entertainment] industry claims they would release some dolphins back to the wild but there isn’t an adequate facility. By creating a sanctuary we remove this excuse.”

With the expensive seaside sanctuary poised to be built, is it fair to say dolphins have a privileged status among some activists? Yes, in a way. Dr. Naomi Rose, a marine mammal scientist at the Animal Welfare Institute, and a board member of the Whale Sanctuary Project, believes the reason for this fondness for the marine mammal—besides the recent documentaries advocating for their wellbeing—may be tied to their alien-like stature to humans.

“For those activists who do think cetaceans are special, I do think it has to do with their intelligence, but it’s not just that or else these folks would be equally focused on great apes or elephants,” she tells Big Think. “I think it has to do with their intelligence combined with their completely different ecology—being fully aquatic mammals. They are the closest thing humans have yet encountered to ‘extraterrestrials’ and that gives them a mystique that can lead to intense fascination.”

For years, this “fascination” helped marine mammal parks across the United States exist with glowing auras, no to mention steep profits. It also gave way to research the animals that have helped us better understand them. For instance, new studies suggest orcas not only live in complex social structures in the wild, but they are far-ranging animals that may be cramped in their current enclosures. In the wild killer whales can swim up to 100 miles each day. These are just two critiques activists have against capturing and keeping dolphins in captivity.

Despite the recent cultural changes, Psihoyos says some people in the dolphin exhibition business are still threatened by the construction of a sanctuary for captive dolphins to live, a place between captivity and complete rehabilitation back into the wild. “When we select a location we’re going to need all the help we can get, political, as well as social—the industry will push back because a sanctuary undermines captivity as their business model,” he says.

Although pushback is expected, it hasn’t served as an excuse to stop envisioning and preparing a site to retire captive dolphins. In the end, Dr. Rose alludes that if other animals appealed to the human sense of wonder as much as dolphins do, they may be better protected. Or perhaps people need to reexamine animals—pigs, cows, bugs, goats, etc.—until they begin to take on an otherworldly charm.

“If there are some activists who think cetaceans are special, that’s their prerogative, but from an ecological and evolutionary standpoint, no species is privileged, and that includes human beings,” she says. “Biodiversity is essential for evolution and ecological health—all species play their roles. No one species should be set above any other—I truly mean that.”

 

source: https://bigthink.com/jonathan-kendall/dolphin-sanctuary-gains-steam-thanks-to-blackfish-director-push

By freedivinguae

Free divers have long defied science – and we still don’t really understand how they go so deep

‘Under’, Martina Amati. © Martina Amati

Free divers swim to extreme depths underwater (the current record is 214m) without any breathing apparatus. Champions can hold their breath for extraordinary amounts of time – the record for women is nine minutes, and men 11.

I’m a doctor with a special interest in extreme environments, so was intrigued when I was asked to collaborate in an art project about free diving for the Wellcome Collection’s new exhibition Somewhere in Between. Scientists and those who practise free diving are in many ways utterly alien to one another. When you look at the stresses this sport places on our physiology, it initially looks almost impossible that anyone should be able to dive to such profound depths – and yet they do.

Unsupported, breathing only air, you could just about climb Everest without any additional support other than your protective clothing. That’s 9km or so above sea level. But when you go into the ocean actually things change much more quickly because of the rapid pressure differences.

If you descend only 10m into the ocean, you are subjected to another additional atmosphere of pressure: that’s twice as much pressure as you’ve been used to at the surface. And for every 10m beyond you get another atmosphere of pressure. That starts to manipulate your body, your anatomy and your physiology in quite profound ways, which actually make the endeavour of diving into the deep ocean uniquely difficult. Not only does it compress you and shrink the air-containing spaces in your body, but also it alters your physiology, alters the way the gases act within your blood stream and how they act on everything, including your nervous system.

Somewhere in Between installation shot. © Wellcome Collection

In the very early days of free-diving, physiologists were pretty convinced that people couldn’t go beyond about 30 or 40 metres. They’d drawn their graphs as scientists and they’d worked out what they saw. They worked out what they understood about the human body and the effects of pressure on it and they said: “Well, look, your lungs are going to be crushed and you’re going to be spitting blood by the time you’re at 30 or 40 metres. So there’s no way that you can do this on breath-hold diving. It just can’t be done.”

But of course, free divers decided to do it anyway – and they swam well past those theoretical limits. How? Martina Amati, the free diver and artist involved in the project, tried to explain the mind set that goes with this extreme sport:

There is an element of physicality but it’s mainly mental. That’s what is incredible about free diving. It’s not about your physical ability, but about your mental skills and mental training basically. You need to let go of everything that you know and everything that makes you feel good or bad. And so it’s a very liberating process. But equally you need to stay completely aware of your body and where you are, entirely in the moment.

At a depth of 10m we need more oxygen in our bloodstream than at 100m, because the pressure of the water all around makes the oxygen more potent. So the most tricky part of a deep dive is the last stage of the ascent, when there is the risk of a shallow water black-out as the pressure fades and the oxygen levels in our tissues suddenly drop.

Getting started is hard too. You are buoyant at the surface and for the first few metres of the dive. As you start to descend, the pressure of the water pushes you back towards the surface, until around 13m to 20m deep when the dynamic is reversed. Here, according to Amati:

Your body begins to sink a little bit like a stone. We call this part the free-fall, the moment when freedivers stop moving completely, and the most beautiful part of the dive. When you eventually come back from a dive and you take your first breath, every time it feels like your first breath ever. So for me, it feels like being born again. I think of the water a little like the womb.

Martina Amati swimming back to surfaced. Photograph by Daan Verhoeven. © Martina Amati

As a diver, what you experience is the changing chemistry of your blood stream as the increased pressure allows gases to dissolve more easily and exert their effects more readily. So the nitrogen, the larger amount of nitrogen that dissolves in your blood stream, behaves as a narcotic and actually makes you feel quite drunk and at only 30 or 40 metres. If you dive at those limits, the additional nitrogen can make you feel quite euphoric.

As a free diver, going deeper, you’re just squeezing those last dregs of oxygen out of your blood stream and trying to subsist on much lower levels than any human being normally ever does. And you go into this sort of strange balance between the pressures that exist at depth temporarily helping to support you while your breath-holding is threatening your life. It’s really a very, very precarious balance and it requires you to enact some very weird and very strange and not all that well understood physiological feats just to stay alive. The depth records for human free diving now are quite absurd: not tens but hundreds of metres.

‘Under’ film still. © Martina Amati

People have rough models of how that is achieved. It’s not a total mystery – but clearly there’s more going on than we fully understand. What I found really fascinating working on this project was that the free divers and non-scientists that participate in free diving talk about this sort of quite holistic experience of being at one with the ocean and this great feeling of well-being. To a physiologist, that’s the euphoria of oxygen starvation and hypoxia, which is not great, but for the free divers themselves this is part of the experience. It’s impossible for them to disentangle that from the diving itself.

There’s a grey area between life and death in which there is a chance and things can happen. In medicine we don’t explore this boundary for fun – but people who are involved in endeavours like free diving do it as a pastime.

And so the act of free diving, looked at by two different cultures – the free divers and the scientists – has very little real overlap. One looks on in fascinated horror and the other sort of sees it as a way of life. For me, then, this was much more than just an art-science collaboration. There was a real reason to bring those two spheres together here – each can learn an awful lot from the other.

SOURCE: http://theconversation.com/free-divers-have-long-defied-science-and-we-still-dont-really-understand-how-they-go-so-deep-92690

By freedivinguae

What Is Freediving? Everything You Need To Know

What is Freediving? Is it just to dive without oxygen? Well- in it’s simplest form – yes.

Freediving has exploded in popularity in the last few years. Once only the sport of accomplished divers and photographers, it’s now becoming a sought after hobby within general sports and activity.

In its simplest form, freediving is diving without the assistance of breathing apparatus and without leaving any effect on your surroundings. To accomplish this, freedivers learn breath hold techniques in order to do entire dives on one breath.

If you’ve ever swum underwater while holding your breath for any amount of time, you’ve experienced freediving.

The origins of freediving can be found in Ancient cultures that used to dive for sponges, using weights tied to their body, to reach the body of sea bed. Mentions of sponge by Plato suggest that freediving dates back as early as the Archaic Period.

One of the earliest recorded instances of freediving> is of the Ama pearl divers, found 2,000 years ago in Japan. The divers were almost always female and specialised in freediving 30ft into cold water wearing nothing more than a loincloth.

“The first competitions were the skandalopetra, which was based off the first sponge divers” says Ian Donald of Freedive UK. “They were the first who started competing against each other.”

“Popular freediving as we know it now was really kicked it off by people seeing The Big Blue, a documentary of freedivers doing competiitons.”

“It coincided with the formation of Aida International as an organisation. Before Aidaexisted there was no organised national or international competitions, they were the first ones who started properly tidying the whole thing up.”

Simultaneous dives are very commnon in freediving

DIFFERENT TYPES OF FREEDIVING

While the technique of freediving is the same in any environment, it does not look the same in every case.

There are eleven different freediving disciplines, each practicing the breath hold technique in different environments and circumstances.

During training most freedivers practice static apnea, in which a divers hold their breath in a still position in a swimming pool, while another person times them.

When practiced recreationally, freedives can be anything between deep dives on a line to very shallow dives around reefs and rocks and mid depth dives with sealife and bigger sea mammals.

The freediver returns to the surface from the deep dive in Blue Hole, Dahab. Egypt

Freediving Training

While giving freediving a try looks like a very simple thing that anyone can do, in reality, everyone should have a short course or tutorial before diving on their own.

“It’s one of those thing that’s incredibly easy thing to get into and a very tempting thing to get into it without instruction” says …..

“It’s not like scuba, where you have to have a certificate to hire a tank, so  So the temptation to do it without a course is really strong, if you want to freedive, you should definitely do a course to sty safe.”

The basic techniques that go into freediving are simply the practice of breath hold and building a tolerance to higher levels of carbon dioxide in the body.

A course teaches individuals to understand the bodies reaction to rising carbon dioxide levels, how to hold their breath beyond their usual comfort level and how to come back to the surface and regain normal breathing in a safe way.

Freedivers equalize pressure while moving down

What Gear Do You Need?

At the most basic level, you can freedive or practice breath hold without any specialist equipment, but different conditions require additional pieces of kit.

If you’re diving with Freedive UK, or another school in the UK, you will need a wetsuit as the temperature drops significantly at lower depths and deeper dives in the ocean requires a diver to wear a mask to safely map out their route to the surface.

There are two types of fins used by most freedivers, by fins, one separate fin on each foot and monofins, one large fin that hold both feet, to create a dolphin-like movement.

“By fins are more useful for recreational stuff” says Ian “You can still snorkel with them on the surface, they’re more maneuverable, they’re easy to pack.”

“Mono fins are technically more efficient for doing distance or depth, all of the records have been set with monofins.”

“They have the downside however of being massive and being very difficult to use on the surface and their very tight around the feet.”

Freediving Films

The Big Blue, a film about competitive freedivers, is the most well known film about the sport and inspired many people to give freediving a go.

Many divers point however, towards record holder Guillaume Nery’s videos, for true freediving inspiration.

 

source:

https://mpora.com/adventure/diving/what-is-freediving-everything-you-need-to-know/

 

By freedivinguae

Sea Turtles Getting Life Saving Treatment In North Texas

GRAPEVINE, Texas (CBSDFW.COM) – A new exhibit at Sea Life Aquarium in Grapevine aims to educate the public about the dangers threatening sea turtles as well as nursing sick ones back to good health.

“Pancake,” is the first sea turtle to be brought to the aquarium from South Texas for rehabilitation after having tumors removed.

Pancake the sea turtle (CBS11)

The Sea Turtle Hospital, as it’s called, was built into the exhibit and is visible through a glass window so visitors can see the work that goes into caring for the turtles.

Senior Aquarist Krista Huebner said, “Really the problems that they face are problems that all ocean animals face.”

She said the sea turtles are susceptible to environmental dangers and those created by humans.

“Any chance that we can give them to fight to live, to reproduce is great for the entire species,” said Huebner.

By freedivinguae

Record-breaking free-diver leads guests on ocean adventures

When Ms Hanli Prinsloo started diving 18 years ago, she was not interested in competitions, yet she went on to smash 11 national recordsin her home country of South Africa.

It was the experience of being underwater that got her hooked.

In 2012, the free-diver stopped competing to focus on teaching her craft to the world.

Ultimately, Ms Prinsloo’s life mission is to save oceans – she founded the non-profit I Am Water Ocean Conservation in 2010 – and free-diving is her tool to spread the message.

Ms Prinsloo, 39, previously collaborated with travel companies such as Extraordinary Journeys from the US and Steppes Travel from Britain.

For the first time, she is focusing her work in South-east Asia. Teaming up with luxury tour operator Jacada Travel – which is headquartered in London – on its new Departures To The Last Wilderness journeys, she hopes to get more travellers involved in ocean conservation.

By freedivinguae

Free diver urges Hong Kong to rethink shark fin soup to give hope to the oceans

Free diver Hanli Prinsloo holds her breath for several minutes at a time as she plunges into the deep blue sea. It may sound terrifying, but what distresses her more is the way Hong Kong consumes seafood.

The South African visited Hong Kong to display ocean photos in “The Last Wilderness” exhibition.

“I meet so many people who love our photographs and the stories we’re telling,” she said. “But it breaks my heart to know just downstairs from the hotel I’m staying in there are restaurants serving shark fin soup.”

Over the course of her free-diving career she has seen the ocean change.


Hanli Prinsloo feels a sense of freedom when she dives. Photo: The Last Wilderness

“In Hong Kong and into mainland China, an understanding of how we consume seafood can really influence the well being of our ocean,” Prinsloo said. “There are many places where I’ve seen the disappearance of sharks and I can see the devastation it can cause to the reef.”

It is not just Hong Kong, though, as she has seen bleached coral, plastic-strewn beaches that were once pristine, dolphins playing with plastic bags where they once played with puffer fish and over fishing devastating ecosystems all over the world.


Free diver Hanli Prinsloo at the opening of The Last Wilderness exhibition. Photo: The Last Wilderness

“It’s heartbreaking to see a place you’ve explored and loved for so long being destroyed because of our actions and because we haven’t thought about what our actions can do,” she said. “ But I believe in sharing a hopeful message – if we give up hope the ocean is hopeless.”

The photo exhibition, which is by former swimmer Peter Marshall, who held eight backstroke world records during his career, and features Prinsloo, is showing at 29th floor Wyndham Place on Wyndham Street until August 18.

Prinsloo’s path to free diving was not an obvious one, as it is for many who take up the sport after growing up on the shore or on islands.


When sharks disappear it can devastate ecosystems. Photo: Brian Skerry/Photographers Against Wildlife Crime/Wildscreen

She grew up on an inland farm near Johannesburg where her father raised horses. It was not until she moved to Sweden in the 1990s that she found a free-diving coach.

“The first time I free dived was in a fjord, in dark water, my wetsuit didn’t fit and my mask was fogged up but it felt like coming home,” Prinsloo said. “It was the freedom I’ve always been looking for, that total immersion and being part of nature.”

Since then, Prinsloo went on to break a number of South African free diving records and became the first South African to hold records in all competitive free-diving disciplines – such as diving to 126 metres with no fins, a dive known as dynamic apnoea.

Hanli Prinsloo descends into a school of fish. Photo: The Last Wilderness

“Free diving is a mental sport,” she said. “Mental prep is around being incredibly calm and centred. When I was competing for really deep dives, it wasn’t just in a couple of hours leading up. It was days leading up of calming down and almost being simplistic.”

“The breath really helps you connect with the mental side of the body. It becomes an anchor.”

She has gone on to set up I am Water travel and I am Water conservation, aimed at promoting sustainable habits for ocean conservation while giving people the chance to travel and interact with nature.

“Free diving is such an inclusive practise,” Prinsloo said. “You don’t need any equipment but because of the risks involved make sure you start with a teacher.

source:

http://www.scmp.com/sport/outdoor/extreme-sports/article/2152912/free-diver-urges-hong-kong-rethink-shark-fin-soup-give