By freedivinguae

Into the depths with free diver Brady Bradshaw

Into the depths with free diver Brady Bradshaw

Free diver Brady Bradshaw swims in the Carlsbad Lagoon. Photo by Shana Thompson

 

ENCINITAS — What could you do in one breath?

In the span of a single inhale and exhale, free diver Brady Bradshaw descended 51 meters (about the height of a 17-story building) below the surface of the water and then resurfaced two minutes and five seconds later. That was his deepest dive to date.

Bradshaw’s longest free dive was two minutes and 40 seconds, and on land he has demonstrated that he can hold his breath for five minutes and 50 seconds.

Free divers like to say that they dive to look within, while scuba divers dive to look around.

Photo by Carey Blakely

Like Bradshaw, those who rely on the physiology-defying ability to hold the breath and surrender to the ocean’s pressure find a zen state that keeps compelling them back to the depths.

To understand the sensation of free diving, Bradshaw explained how the lungs compress during the descent and that around a depth of 15 meters, the buoyancy of his body gives way to increased atmospheric pressure, allowing him to sink rapidly. This is called the free fall. At the same time, blood moves from the extremities to the core, and the heart rate slows in a process called bradycardia — a name that makes Brady smile.

Around 30 meters below the ocean’s surface in the San Diego area, the water becomes dark. Sometimes the only thing Bradshaw can see is the dive line, and the only sound — as he descends faster and faster — is his hand running down that line.

Bradshaw said the dark, quiet state of the water “melds” with a relaxed, meditative state of the mind and body for what he described as the “best feeling in the world” and the “perfect opportunity for total surrender.”

Courtesy photo

Bradshaw lives in Encinitas, works for the environmental nonprofit Oceana and free dives twice a week off La Jolla Shores. About one-quarter mile from the shore there is a canyon about 50 meters deep, providing the perfect spot for diving. Sea lions occasionally swim underwater alongside Bradshaw and his friends.

But like other extreme sports, such as big-wave surfing or climbing daunting peaks, free diving comes with risks. Bradshaw, for instance, is currently recovering from a tear in his trachea brought on by what’s called a “squeeze,” which results from the pressure of going too deep too fast without first being adapted to that depth. He’s refraining from diving for four weeks until his trachea heals.

Bradshaw once blacked out — a common risk brought on by a lack of oxygen — during a free diving competition in a pool. In those competitions, participants swim as far underwater as they can in one breath. Bradshaw attributes his blackout to being too competitive that day and not relaxed or in sync with his body.

At the extreme end, people have died from free diving, including the female phenom Natalia Molchanova, who was hailed as the greatest free diver in the history of the sport. In 2015 off the coast of Spain, Molchanova went down for a dive of her own after giving lessons to a wealthy Russian. She never surfaced. It’s possible that if Molchanova had been with another experienced diver that she might have been saved.

“Free diving is not dangerous if it’s done in the right way,” Bradshaw said. One of the top safety rules is to always dive with an experienced partner who functions as a safety.

Photo by Shana Thompson

“We can get obsessed with the depth” and about setting records, Bradshaw noted. He said it’s important to rein in the ego and realize that “it takes a long time for the body to adapt to a new depth.”

As a trained and frequent practitioner of yoga — with the om symbol tattooed on his right palm — Bradshaw explained how a person doing yoga can increase his or her range of motion over time as the muscles stretch and strengthen. He compared that process to free diving and said the nervous and circulatory systems require proper training, too. Bradshaw also stressed that “the body’s limits change day to day,” which is important to stay attuned to.

Before diving, Bradshaw likes to float on his back and look at the sky to get into a calm state. “If I’m too competitive with myself, it doesn’t work,” he said. He likes to keep his diving style as natural as possible, using fins only and no weights.

During dives, he’ll have fears that he pushes from his mind. Bradshaw laughed, recalling how he’s occasionally wondered if a shark was swimming nearby in the dark. “I also felt panicked the first time I dove to 51 meters. I looked up at the blackness, saw only the line in front of me, and wondered what have I done? Did I do something I can’t get out of?” That feeling reminded him of times he’d been mid-air on his skateboard and doubted whether he could land the jump safely.

But as Bradshaw sees it, “Panic is not an option. It’s physiologically discouraged because you need the oxygen.” He has worked to untrain the panic response and sees free diving as a “sanctuary and total reset. I come up and everything’s all good.”

One could call Bradshaw a free diving devotee. In 2015, he withdrew from graduate school in Australia to pursue his newfound and rapidly escalating passion for free driving, brought on initially by reading the book “Deep” by James Nestor and diving in the Great Barrier Reef.

Nestor describes the marine mammal diving reflex that relies, in part, on bradycardia and the blood shift from the extremities to the heart, lungs and brain. Free divers utilize those same mechanisms, which, it turns out, are also inherent to humans.

In fact, newborn babies up until about 6 months of age exhibit the diving reflex. Put them under water and they’ll naturally hold their breath and open their eyes. Their heart rate will slow to conserve oxygen, and blood will primarily circulate to the vital organs, where it is most needed. According to an article in Live Science, that “instinct may be a vestige of our ancient marine origins.”

For someone who was studying marine mammals at the time, this connection between humans and marine mammals was fascinating and pulled Bradshaw away from the textbook and into the water.

While Bradshaw says his ego wants to win a competition and set a record, “which might be in reach in a pool,” his ultimate goal is to teach people to free dive. “I want to show people the capability of their own bodies,” which he compared to “magic.”

Bradshaw also hopes that anyone who experienced the beauty of silence while deep in the sea would want to protect and preserve our marine environments.

source: http://www.thecoastnews.com/into-the-depths-with-free-diver-brady-bradshaw/

By freedivinguae

Reasons Why Whale Sharks Gather

File 20180618 85830 qai2nq.jpg?ixlib=rb 1.1

A whale shark basking in the Maldivian shallows

The whale shark is the largest fish in the world, but much of its lifecycle remains shrouded in mystery. These 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. A better understanding of whale shark movements could help prevent further population loss in a species that has already experienced a 63 per cent population decline over the past 75 years.

When swimming solo, the whale shark, which can grow up to 18.8m in length and 34 tonnes 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.

Face to face with the world’s largest fish. Jil KühneAuthor 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 much deeper water (usually between 200m  and 1,000m).

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 (1,928m to be precise) to feed on zooplankton and squid.

A group of whale sharks feeding near Indonesia

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℃.

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.

Whale sharks are imposing, but feed on krill and other plankton. MWSRPAuthor 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 per cent 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.

source: http://divemagazine.co.uk/eco/8144-mystery-of-whale-shark-aggragations-solved

By freedivinguae

Can We Create Sunscreen That Protects Both Humans and Coral Reefs?

Sunscreen is vital for skin protection. But researchers are finding that even ‘reef-friendly’ versions may pose serious environmental threats

The link between sunscreen and skin protection is watertight. Unfortunately, many common sunscreens may be devastating for the health of coral reefs. (RuslanDashinsky / iStock)

 

Earlier this month, Hawaii banned sunscreen. Not all sunscreen—just the kind containing the active ingredients oxybenzone and octinoxate—but that encompassed most of the major brands, from Banana Boat to Coppertone. The reason for this seemingly perverse law, which goes into effect in 2021, was recent research confirming that the lotion we slather on to protect our skin can also do grave harm to the world’s coral reefs.

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The Hawaiian ban was based on a 2016 study by Craig Downs and colleagues at the Haereticus Environmental Laboratory, which showed that these two chemicals were to blame for slowing coral growth and increasing the rate of coral bleaching. (Bleaching happens when conditions like temperature change so dramatically that corals turn completely white and the symbiotic algae living in their tissues flee their homes.) In February, Downs told The New York Times that sunscreen and other chemical wash-off through showering and swimming plays a bigger role than climate change in damaging coral reefs.

But just how conclusive the evidence on sunscreen’s impact on coral reefs—and whether consumers should switch to “reef-friendly” sunscreens—remains disputed. According to marine ecology researcher Cinzia Corinaldesi, who has studied the impact of sunscreens on coral reefs since 2003, the problem is that “unfortunately, oxybenzone is not the only harmful ingredient of sunscreens.” Other UV filters, including zinc oxide, are proving to have an impact on coral bleaching—and the ban does nothing to prevent these.

There are two kinds of sunscreen ingredients on the market, which work in different ways. Physical sunscreens, also called mineral or inorganic, block or reflect both UVA and UVB rays; zinc oxide and titanium dioxide are the two most common physical sunscreen ingredients. On the other hand, chemical, or organic, sunscreens, which typically include oxybenzone, octinoxate, avobenzone and PABA as ingredients, absorb and reduce UV rays’ ability to penetrate the skin. Some sunscreen formulas include both kinds of sunscreen actives.

The mounting research on the impact of sunscreen on coral reefs and marine environments is more important than ever, says analytical environmental chemist Felix R. Roman-Velazquez, a professor at the University of Puerto Rico at Mayaguez and one of the researchers behind a new experiment to remove oxybezone from bodies of water. “By 2020, over one billion people around the world will be visiting oceans for recreation and tourism,” he says. “We’re talking about lots of sunscreen that is going to be dumped into the ocean.”

While it’s unclear to what extent exactly bleaching actually affected by sunscreen compared to other factors, an estimated 6,000 to 14,000 tons of sunscreen go into coral reef areas each year. And this is enough, says Corinaldesi, to make an impact.

She would know. In 2008, Corinaldesi and her colleagues the Polytechnic University of Marche in Ancona, Italy, found that three individual chemical, or organic, sunscreen ingredients—oxybenzone, butylparaben and octinoxate—can bleach coral reefs. Considered the first scientific evidence on the impact of sunscreens on coral reefs, the study confirmed what some scientists and locals had witnessed: that swimmers, surfers and divers in popular beach destinations were affecting marine ecosystems. On the Yucatan coast in Mexico, for example, resort managers had noticed living species were dying off in enclosed pools known as cenotes where people regularly swam.

 

“Up to 40 percent of coral reefs are being bleached,” says Roman-Velazquez. “In the Caribbean, it’s near 60 percent. In Puerto Rico, there’s a lot of bleaching in this area, near our island.” (Seaphotoart / Alamy)

Since the 2008 study, the evidence suggesting chemical, or organic, sunscreen negatively impacts coral reefs has only gotten stronger. And yet organic filters like oxybenzone still dominate the sunscreen market. That’s largely because the alternative—mineral or physical sunscreens containing ingredients like zinc oxide and titanium dioxide—leave behind a heavy white cast that can look ghostly on people with darker skin, and they’re often greasier and tougher to blend in.

But given the evidence, there has been a push in recent years for “reef-friendly” alternatives. While these options, typically in the form of mineral sunscreens, have been considered safer, more environmentally friendly in the media, some new research has suggested that’s not the case. Since 2009, Corinaldesi has been putting these “reef-friendly” ingredients to the test. She has proved, along with other researchers, that some mineral sunscreens and those marketed as “eco-friendly” are no safer for coral reefs than chemical ones.

Confirming previous research, Corinaldesi and her team found in a newly published study that zinc oxide causes severe coral bleaching, damaging hard corals and their symbiotic algae. “Our studies indicate that zinc oxide nanoparticles are very harmful for marine organisms, whereas titanium dioxide with surface coatings and metal doping, have a much lower impact,” she says. “Unfortunately, despite several cosmetic products and sunscreens available in the market are defined ‘reef-safe’ or ‘eco-friendly’ or ‘biodegradable,’ they are not so, and indeed lack specific tests on marine organisms.”

But not everyone believes the evidence is so clear-cut. Seemal R. Desai, a clinical assistant professor of dermatology at the University of Texas Southwestern Medical Center, says there aren’t enough large-scale trials to suggest that the connection between sunscreen and coral reef damage is absolute. “There are some small studies that have shown potentially some association with chemical sunscreen [to damage to coral reefs],” he says. “However, we don’t have enough data to say that for sure. So I’m very cautious to buy into the argument about sunscreen causing environmental damage.”

review of research on studies related to sunscreen and coral reefs by the International Coral Reef Institute suggests that further research is needed. “To date, experiments have largely been undertaken exsitu and there are concerns that they may not properly reflect conditions on the reef, where pollutants could be rapidly dispersed and diluted,” the report states. For example, the report states, concentrations of sunscreen chemicals used in some research work have been higher than those in real coral reef environments. This may skew the perceived impact of reef damage.

Desai is concerned that Hawaii’s ban “may be sending the wrong message that sunscreens aren’t [safe] for use, and I think that’s really dangerous.” A trade association for sunscreen companies also warned in a statement that the ban is putting people at risk of skin cancer. Any environmental damage caused by sunscreen is no excuse to skimp on the sunscreen, given the alternative, Desai warns: “There is no denying the link between UV rays and skin cancer, so not wearing sunscreen would certainly be harmful to the individual patient.”

A review of sunscreen research published this month in the Journal of the American Academy of Dermatology also concludes there’s not enough evidence to suggest certain sunscreen ingredients are harmful to the environment.

Dermatologists suggest people should wear sunscreen on a daily basis because UVA rays (which penetrate deep into the skin) and UVB rays (which burn the superficial layers) can wreak havoc on our skin, and they can both directly contribute to skin cancer. In fact, one in five Americans will develop skin cancer by the age of 70, according to the Skin Cancer Foundation. Most skin cancers are caused by the sun, and some are deadly.

For consumers both interested in protecting their skin from sun damage and protect the environment, what’s the right choice?

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Unfortunately, right now there aren’t many alternatives on the market. One of the reasons is that, since it claims to prevent skin cancer, sunscreen is considered a drug by the Food and Drug Administration, meaning the process for approving sunscreens is more rigorous than other cosmetics. There are only 16 FDA-approved active sunscreen ingredients, and only a handful of those are commonly used, so the choices are limited.

The last time the FDA approved a new sunscreen active ingredient was in the 1990s, and currently, eight new ingredients are pending approval. By contrast, the European Union allows nearly 30 active sunscreen ingredients.

Sandy Walsh, a spokesperson for the FDA, says the agency is working on reviewing additional sunscreen active ingredients as required by the Sunscreen Innovation Act, a 2014 law that was supposed to expedite up the process of over-the-counter sunscreen approvals. “[We’re] doing our part to provide consumers with safe and effective sunscreen formulations,” says Walsh. “To be successful, we need industry’s help, and they need ours. That’s why we’ve also been meeting with manufacturers to discuss sunscreen data recommendations and why we have issued relevant guidance to assist them.”

An effort called the Public Access to SunScreens Coalition has also been working to improve and accelerate the FDA process for new ingredient approval since 2012. But for the time being, the group says Hawaii’s ban is detrimental without viable replacements. “A ban on these ingredients without adequate, FDA-approved alternatives and without extensive research demonstrating that this action is needed to properly balance environmental impact with the risk to public health from inadequate UV protection is premature,” the group said in a letter to Hawaii governor David Y. Ige before the legislation was signed into law.

This sentiment has also been echoed by the Skin Cancer Foundation, which said in a press release that “the legislation in Hawaii emphasizes the need for new sunscreen ingredients and should send a message to the FDA.”

Especially given the most recent study on zinc oxide, Sachleben points out that there aren’t any sunscreens proven to be safe to coral. “The most safe [option] is UV-protective clothing for use in the water. Right now that’s the only thing that has a good sun-blocking capability and minimal impact on coral.”

But you can’t rely only on sun-protective clothing, Desai notes. “Sun-protective clothing does not replace sunscreens,” he says. After all, some skin cancers, like basal and squamous cell, happen most often on the face, arms and necks—areas exposed to the sun and which are not always easy to cover up with clothing, especially on the beach.

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In the meantime, scientists are working on a few possible solutions. One research team from the College of Pharmacy at the University of Florida is working on creating a “natural sunscreen” from shinorine, a UV-absorbing ingredient harvested from algae.

Another team in Puerto Rico is working to create biodegradable beads that could soak up oxybenzone from oceans, as highlighted in Popular Science. The moment you step into the ocean, the oxybenzone you’ve slathered on your skin begins to seep into the waters around you. It doesn’t take long for it to build up to dangerous levels, the researchers reported last summer at the American Chemical Society national meeting.

The absorbent beads Roman-Velazquez and his team have created are a bit bigger than poppy seeds. Made from materials derived from algae and chitin, the beads would take about a month to completely disintegrate. In testing the beads for oxybenzone, they were able to remove 95 percent of the contamination within one hour. In theory, the beads could be used in conjunction with other efforts in high-tourism areas. “After people bathe in the beach all day, we can probably develop a process where we have a boat and drag these beads around [within a net] before [the chemicals] wash toward the corals,” Roman-Velazquez says.

Corinaldesi says any efforts to reduce the impact of sunscreen on coral reefs are a move in the right direction. “I appreciate the work done by these scientists to develop new systems to clean up marine water from the oxybenzone for the conservation of tropical reefs,” she says. “This is a first and important step forward to reduce the impact of oxybenzone in marine systems.”

And while their research—which they hope to publish as early as this year—has focused on oxybenzone, Roman-Velazquez says his team is hoping to test other sunscreen ingredients for future studies. He adds that while neither his team’s beads nor Hawaii’s ban offers a simple solution to clear the corals of damage, it’s an important measure. “Tourism is so big in Hawaii, so they should be concerned about protecting those resources,” he says.

source: https://www.smithsonianmag.com/science/scientists-are-unraveling-new-dangers-sunscreen-coral-reefs-180969627/

By freedivinguae

Entangled whale shark seen off Maui

An entangled whale shark swims near Molokini on Thursday. — JENNIFER MEYER photo

An entangled juvenile whale shark reported on the backside of Molokini, off of Maui’s south shore, was spotted Thursday for the second time last week, state Department of Land and Natural Resources officials reported Saturday morning.

Witnesses saw the whale shark ensnared by heavy gauge line wrapped around its midsection, officials said. Initial reports put the whale shark last week Sunday off of Olowalu and on Thursday several commercial snorkel and whale tour companies reported the shark near Molokini.

ProDivers provided photos that showed the entanglement as a tight wrap around the whale shark’s body, forward of its pectoral fins, officials said.

“The wrap is cutting into the animal, which is somewhat emaciated,” officials reported. Fisheries experts believe the entanglement to be life threatening.

Whale sharks are listed as endangered worldwide, with an estimated decline of more than 50 percent since 1975. Like many marine animals, they are at risk to threats like entanglement.

Officials asked anyone who sees the entangled whale to report its location by calling (888) 256-9840.

If conditions and resources allow, responders trained in disentangling large whales may attempt to remove the gear, officials said, adding that the responders are with the National Oceanic and Atmospheric Administration’s Marine Mammal Health and Stranding Response Program.

“While obviously not a whale, if the whale shark was to remain at or near the surface, the team would attempt to use a hooked knife deployed from a long pole (and from a boat) to cut the wrap of line entangling the animal,” officials said.

 

 

SOURCE: http://www.mauinews.com/news/local-news/2018/07/entangled-whale-shark-seen-off-maui/

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.

whale-shark-shallows_2018-07-11.JPG

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.

whale-shark-face-to-face_2018-07-11.JPG

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.

whale-sharks-Indonesia_small_2018-07-11.jpg

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.

swimming-with-whale-shark_2018-07-11.JPG

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.