By freedivinguae

MEASURING THE CONTINUED DESTRUCTION OF CORAL IN THE GREAT BARRIER REEF

As the global coral crisis continues to unfold, once shocking news has become commonplace: Case in point, Australian scientists now report that coral cover on the Great Barrier Reef has fallen sharply in all three sections of the reef for the first time in 35 years of continuous monitoring.

Their recently completed annual survey follows the back-to-back bleaching events of 2016–17 that killed off half of the Great Barrier Reef’s corals. After surveying 50 reefs in the Great Barrier Reef system between September of 2017 and May of 2018, researchers at the government-funded Australian Institute of Marine Science found that mean coral cover had fallen from 22 percent to 14 percent in the central section of the reef over the past year, and from 33 percent to 25 percent in the southern section. Reefs in the northern section were not surveyed, but reports from aerial surveys showed that mean coral cover had plunged to just 10 percent in 2017, according to the AIMS report.

Now scientists are questioning whether those reefs—which also face threats from cyclones, pollution, and predatory crown-of-thorns starfish—will be able to bounce back, given that bleaching events occur with increasing frequency as greenhouse gas emissions accelerate climate change. (When ocean temperatures exceed corals’ tolerance, the symbiotic algae that supply their food and color in exchange for shelter turn toxic and are expelled. Deprived of nutrition, corals turn white and can die unless waters cool.)

“The geographic scale of recent bleaching means that breeding populations of corals have been decimated over large areas, reducing the potential sources of larvae to recolonize reefs over the next years,” the AIMS scientists wrote in their report. “It is unprecedented in the 30+ year time series that all three regions of the [Great Barrier Reef] have declined and that many reefs have now very low coral cover.”

Separately, new research by coral scientist Terry Hughes and his team indicates that “recovery will be slow and painful and will likely be mostly local and it won’t go back to the same system,” as he told attendees at the annual meeting of the Australian Coral Reef Society in May.

“The barrier reef has just gone through one hell of a natural selection event,” he said. “To me, the bleaching is a game changer. It’s a new system.”

Hughes and his colleagues laid “recruitment panels” along the length of the Great Barrier Reef to collect coral larvae. They then retrieved the panels in January of 2018 to determine how many larvae had successfully spawned and settled on reefs where they would grow into new coral colonies, a process known as recruitment.

“The amount of recruitment this last season is a tiny, tiny percentage of the normal level of recruitment, which is directly related to the loss of adult brood stock,” Hughes, the director of the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University, told the gathering of coral scientists in Exmouth, Australia.

That means there are far fewer corals to recolonize devastated reefs. In the course of their fieldwork, the researchers also surveyed the number of juvenile corals. “The juveniles seemed to have survived better than adults,” he said. “In most places we’ve looked, the juvenile density is half what it used to be.”

Hugh Sweatman, a senior research scientist at AIMS and the leader of the organization’s Long-Term Monitoring Program, said in an email that healthy coral cover could be considered 75 percent or greater, though that is “quite rare in my 40 years’ experience.”

He noted that, over thousands of years, coral ecosystems have faced ongoing disturbance from cyclones, crown-of-thorns starfish infestations, and sediment runoff that blocks sunlight. “Thus a reef can be ‘healthy’ in terms of retaining ecosystem functions and capacity to recover, but if you survey it soon after a disturbance, the coral cover will be low,” Sweatman said. “The more revealing measure of reef health and ecosystem function is the rate at which coral cover returns.”

With some 3,300 individual reefs spread over 133,000 square miles of ocean along 1,400 miles of Australia’s northeast coast, the Great Barrier Reef, as Sweatman notes, “is a big place, and few disturbances affect the entire area.”

Yet the back-to-back bleaching events of 2016–17 struck two-thirds of the Great Barrier Reef. The southern third was spared extensive bleaching only by the propitious appearance of a cyclone that cooled waters during the first bleaching event. Storms, meanwhile, are increasingly intense and causing more damage to coral reefs. Then there are the outbreaks of crown-of-thorns starfish that eat corals.

All of which “means that the intervals between the acute disturbances decreases—less time for recovery to occur,” Sweatman said. “At the same time, coastal development often leads to more sediment and pollutants, which slow the process of recovery (plus there are coral diseases and sub-lethal temperatures, which may also slow recovery). So greater loss of coral must be made good in shorter times as recovery rates slow … they all point to lower coral cover.”

Hughes and other coral scientists have repeatedly said the only long-term hope for the world’s coral reefs is a dramatic reduction in greenhouse gas emissions driven by the burning of fossil fuels.

“Personally, I am not totally pessimistic,” Sweatman said. “In the short term, the north and central [Great Barrier Reef] reefs may substantially recover. But in the longer term the outlook is very poor unless there are dramatic changes.”

For Hughes’ part, “I’m scraping the barrel here looking for some sources of optimism,” he told his fellow coral scientists at the conference in May. “The glass is still half full. About 51 or 52 percent of the corals that were alive two years ago are still out there.”

“So my final take-home point is that we need to look after these billion survivors, and I don’t think there’s much we can do in terms of restoring them based on growing corals in aquariums,” he added.

 

 

source: https://psmag.com/environment/the-continued-decline-of-the-great-barrier-reef

 

By freedivinguae

Whale Sharks of Isla Mujeres

Swimming with a whale shark – the ocean’s largest fish is something that seems to be on many diver’s bucket lists. These animals can reach up to lengths of over forty feet/twelve meters, and weigh over 41,000 pounds, so getting up close and personal with just one of these gentle giants is something truly humbling. Imagine now, the ability to immerse yourself within not one, but hundreds of migrating whale sharks. Sounds too good to be true, right? If you’ve been looking for the opportunity to swim alongside feeding whale sharks, breaching mantas, and potential encounters of even more marine species, then the waters off Isla Mujeres are where you should be looking.

Freediver Sarah Barrett swimming beneath a whale shark. Image by Amanda Cotton
Freediver Sarah Barrett swimming beneath a whale shark. Image by Amanda Cotton

Every year the Yucatan Peninsula-specifically the waters surrounding the state of Quintana Roo become a feeding ground for hundreds of migrating whale sharks. The sharks are there to feed on a massive spawn of bonito (small Atlantic Tuna) eggs that are present from May through September. A Cotton Photo (ACP), founded by underwater photographer and Women Diver’s Hall of Fame member Amanda Cotton, has been heading down to Isla Mujeres for the last eleven years to partake in this incredible gathering.  As full disclosure, as well as being a writer and videographer for DeeperBlue.com, I’m also a team leader for ACP on this expedition.

Black/White up close image of a whale shark filter feeding
Black/White up close image of a whale shark filter feeding

ACP’s Whale Shark Expedition, strategically scheduled around the lunar cycle each year to maximize the chance of ideal encounters, is a total of six days-two for travel and four days on the water. Traveling to Isla is a breeze (see below for travel info.) There is a team briefing the night you arrive on the island to hear the rules/guidelines of the coming days, as well as meet the rest of the group. The mornings start with a 7:30am launch time from Playa Norte, where you wade out into the water to meet the boats. For this reason, I recommend bringing along a dry bag for your belongings you wish to keep dry. It’s about an hour ride out to the stomping grounds. As you get closer to where the whale sharks are feeding, you will hear the captains in the surrounding area staying in radio contact in order to let each other know where the sharks are.

You’ll know you’ve found the feeding grounds when you glance over the side of the boat and see nothing but countless dorsal fins breaching the surface. This is a truly spectacular sight to see. The only thing better is the first moment you enter the water and realize you must keep your head on a constant swivel as to avoid being bumped into by a whale shark. These guys are the size of a school bus, so they’re not stopping for anyone! I will admit some days are better than others out on the water, but any day where I lose track of the number of whale sharks is a good day in my eyes. I think at one point, with my Paralenz pointed in one direction, I counted 6-7 whale sharks in the frame. Another amazing occurrence is when you come upon a whale shark feeding in an upright or vertical position known as static feeding, or what the locals refer to as “Coke bottling.” A shark will sit in this position for anywhere from a few minutes to over twenty, constantly sucking water in and filtering out the eggs. Just remember to keep an eye out behind you as well, because more often than not, there’s another whale shark you don’t see swimming right behind you!

Manta Ray feeding alongside the whale sharks
Manta Ray feeding alongside the whale sharks

Rules & Regulations

In the past years, the Mexican government has put in place some rules in order to protect the migrating whale sharks, as well as keep the environment safe for tourists. The first of these rules is that there is no scuba with the sharks. Freediving/snorkeling is the only way to get into the water with these animals, which is more than suitable seeing as how they spend most of their time on the surface. You must wear some form of flotation device, which, when traveling with ACP, means either a wetsuit or a skin of some kind. There are of course life jackets on the boat if you feel more comfortable wearing one, but it is not required if you’re wearing a suit.

Up close view of the mouth of a whale shark
Up close view of the mouth of a whale shark

When it comes to photography, lights and strobes of any kind are not allowed. Again, the sharks spend most of their time on the surface on the water so there is more than enough ambient light for photos. As most other wildlife trips go, the touching of these animals at any time is prohibited. The captains do a pretty good job of making sure that everyone stays at least a meter away from the sharks at all times.

Later in the afternoon, you will start to notice the number of boats lessoning, and the whale sharks, after gorging themselves on eggs, will soon begin to dive down to the depths to digest the day’s haul. All boats must leave the area by 2 pm. Then all that’s left is to sit back, relax, and enjoy the boat ride back to Isla Mujeres.

ACP group after a day on the water
ACP group after a day on the water

Location

What You Need to Know

Transportation

You will be flying into Cancun International Airport. If arriving on the trip’s official start/end dates, ACP arranges a shuttle that will take you from the airport to the ferry terminal. The Ultramar ferry runs every half hour from 5am-midnight. Tickets can be purchased in front of the ferry terminal inside their shop. I recommend buying a round-trip ticket, as the ticket does not expire. The price of a round-trip ticket will cost you approximately 300 pesos, or roughly 17 USD/14 EUR, just remember to keep your return ticket if you purchase one! After the 20-25 minute ferry ride over to Isla Mujeres most hotels are within walking distance if you are staying anywhere between the terminal and Playa Norte, however, a taxi stand is conveniently located to the left once you exit the terminal.

Where to Stay

The great thing about ACP is the hassle of finding/dealing with a hotel is taken care of. Hotel arrangements are made ahead of time and details are sent to you on a series of multiple emails that let you know where you are staying as well as maps to help you visualize. As it gets closer to the trip dates, you will also receive emails with reminders, last minute details, transportation information, etc.

Currency

Another great thing about Mexico is their use of both the Mexican peso and the US Dollar. You can use whichever is more convenient for you, however since the exchange rate is currently 18.63 MXN/1 USD/.86 EUR, if you either convert your currency to pesos ahead of time (i.e. airport, banks, ferry terminal) or choose to be charged in pesos with your credit card you will end up saving money in the long run.

Where to Eat & Drink

There are many restaurant options available on Isla, especially on the main street Miguel Hidalgo, located near Playa Norte. This is the street you’ll find most other vacationers as there are shops, bars, convenience stores, and of course restaurants. You can choose from Mexican, Italian, American, and almost everything in between. There are countless little bars on this strip for drinks/dancing, but my favorite would have to be Kokonuts and Faynes. They have great people, 2 for 1 happy hour specials, and music and dancing at night!

Extras

If you’re feeling adventurous, there are golf cart rentals at some of the hotels on Isla, and since the island is so small it doesn’t take much time at all to get from one end to the other! There is an “Observation deck” called Mirador Océanico on the south side of the island which has incredible views, various sculptures for photos, and little shops and stores around that area. There are also restaurants along the south end as well. Check out Casa de los Sueños for great barbecue and an even better view!

For more information about this expedition, check out acottonphoto.com or shoot them an email at info@acottonphoto.com

View from La Casa de los Sueños, south side Isla Mujeres

 

SOURCE: https://www.deeperblue.com/whale-sharks-of-isla-mujeres/

By freedivinguae

Breakthrough as New Caledonia votes to protect coral reef

New Caledonia is home to thousands of marine species including dugongs and nesting green sea turtles.
 The coral reef in New Caledonia is home to thousands of marine species including dugongs and nesting green sea turtles. Photograph: Marc Le Chelard/AFP/Getty Images

New Caledonia has agreed to tougher protections around a huge swathe of some of the world’s last near-pristine coral reefs, in a move conservationists hailed as a major breakthrough.

The Pacific nation, a French overseas territory, is home to a rich array of wildlife including 2.5 million seabirds and more than 9,300 marine species such as dugongs and nesting green sea turtles, many of which thrive in and around remote zones off the island nation’s coast.

The archipelago boasts some of the world’s healthiest reefs, including Astrolabe, Petrie, Chesterfield and Bellona, which are considered exceptional examples of coral ecosystems.

After years of work, the New Caledonia government on Tuesday voted to set up marine protected areas (MPAs) surrounding the reefs, and to strengthen an existing one around Entrecasteaux, which is already a Unesco world heritage site.

The move will see 28,000 square kilometres (10,810 square miles) of waters safeguarded from commercial and industrial fishing and other exploitation, helping conserve habitats and allow marine life to feed and reproduce undisturbed.

Tourist activity around the reefs is also set to be more rigorously controlled.

According to the South Pacific Tourism Organisation, New Caledonia had 27,000 visits in the first three months of the year, making up about 6% of trips to the South Pacific region.

“This is the kind of leadership we need to see in coral reef conservation and we applaud it,” said John Tanzer, the head of oceans for WWF International.

“With good management, these marine protected areas will help maintain fish populations and ecosystem health that will build the reef’s resilience to the impacts of climate change in future.”

Christophe Chevillon, head of the Pew Bertarelli Ocean Legacy in New Caledonia, which helped draft the plans, said it would elevate the territory as a global leader in ocean protection, but more could still be done.

“Although we believe this to be a major breakthrough, we are convinced that New Caledonia can still go further and lead the way for other Pacific countries,” he said.

“In fact, the 28,000 square kilometres protected only represents 2% of the Coral Sea Natural Park.”

The MPAs fall within New Caledonia’s enormous 1.3 million-square kilometre Coral Sea Natural Park, which was established in 2014 and covers the country’s entire exclusive economic zone.

Protections here, such as limiting shipping and banning shark, turtle and whale fishing, are not as comprehensive as under an MPA.

Coral reefs, which only cover 0.1% of the ocean’s surface but support a quarter of known marine species, are on the decline globally, threatened by climate change, pollution and overfishing. WWF estimates the world has already lost about half of its shallow water coral reefs.

source: https://www.theguardian.com/environment/2018/aug/14/breakthrough-as-new-caledonia-votes-to-protect-coral-reef

By freedivinguae

85 meters: Freediving national record set by Santa Cruz native

The timer called out the seconds: “Plus 7, plus 8, plus 9, plus 10. … Plus 20.”

Shelby Eisenberg had just 10 seconds to let go of the gray tube bobbing off the coast of Grand Cayman and plunge into the depths of the Caribbean. Just 10 seconds to begin her attempt to go deeper than any American woman had ever dove while using only the oxygen in her lungs.

Shelby Eisenberg, a Santa Cruz native, uses a monofin to propel herself 85 meters down into the Carribean Sea off Grand Cayman on Sunday on her way to setting the women's United States constant weight freediving record. (Joakim Hjelm Photography/ contributed )
Shelby Eisenberg, a Santa Cruz native, uses a monofin to propel herself 85 meters down into the Caribbean off Grand Cayman on Sunday on her way to setting the women’s United States constant weight freediving record. (Joakim Hjelm Photography/ contributed ) 

Her window was closing, creating more pressure on her than she would feel at her target depth of 85 meters, under 22,400 gallons of water. Yet to go that far, it was imperative she remain calm.

“I knew it was my last chance, my last day. I had to take a couple of relaxed breaths,” Eisenberg, a Santa Cruz native, said. “I just had to tell myself — because I can stay there breathing all day long — I had to tell myself, ‘OK, you’re ready. One more breath won’t make you more ready.’”

Eisenberg put her hands up, then she dove down, a graceful mermaid leveraging her monofin through the clear, cobalt water. When she reached her target depth, she snatched a tag off a weight tethered to a rope, then sped her way back to the surface. As she emerged into the glorious, oxygen-rich air, the smile on her face said it all.

She had just set the national record for a controlled weight freedive, ending a six-year-plus monopoly on the mark held by Ashley Futral Chapman of North Carolina. Chapman held the record at various depths before setting her personal best, 84 meters, in September 2016.

After breaching the surface, Eisenberg still had to wait another 30 seconds to go through a brief series of tests and have the judges confirm her record, but she wasn’t worried.

“I knew I had it because I felt completely in control,” Eisenberg, 27, said. “I had a coach at the surface smiling back at me and judges smiling back at me, so I knew I was OK. It was just, ‘OK, don’t get too excited.’”

She stayed calm. The same couldn’t be said for the judges and safety personnel who witnessed the feat Sunday at the Deja Blue International Diving Festival. They circled around her and broke into whoops and splashes once the judges flashed the white cards that signaled the dive was legitimate.

Francesca Koe of San Francisco, who is well-acquainted with Eisenberg because of their Bay Area connection, was among the three judges in the water that day.

“Everyone has aspirations and dreams, we just didn’t realize she was training for weeks on end since January trying to do this,” Koe said. “We were all on pins and needles. She looked super strong and super clean.”

The record-setting dive came as a surprise to many. Eisenberg, who goes by the nickname “Shell,” has only been freediving for six years and competing for four.

A former Westside resident — her parents Sandy and Geoff still live there — she attended the University of Hawaii after graduating from Kirby School in 2009. There she began experimenting with freediving as a way to get a better look at reef and sealife. In 2012, she took her first freediving course (similar to SCUBA diving, participants must be certified) and she entered her first competition in 2014. Last year Eisenberg became a professional freediving instructor for Performance Freediving International, a company that trains and certifies people in the sport, including the cast of the upcoming “Avatar” sequel.

“It’s something that’s always been really difficult for me to describe and put words to,” Eisenberg said of the freediving experience. “You’re deep in the ocean, deep in nature. Even though there are a lot of people on the dive, there’s a feeling that it’s just you in the water, and it seems to get clearer as I go deeper.

“There’s not a lot of emotion down there, just peace.”

Though she had previously set two records for pool diving, which is measured by length, her personal-best ocean depth before arriving in the Grand Cayman last week was 74 meters, which many believed did not put her in striking distance of Chapman’s mark.

Over the course of the weeklong competition, she drew closer and closer. Then, in her last dive before setting the record, she missed an attempt. Knowing she had just one more dive before returning to her home in Hawaii, however, Eisenberg decided to go for the gusto.

“Shel’s 85-meter dive was incredible on so many levels,” John Hullverson, president of USA Freediving, said in a statement. “Not only was she able to withstand the nine atmospheres of pressure her body was under at that depth, but for her to endure the hypoxia, increased lactic acid buildup in her muscles and urge to breathe throughout the nearly three-minute dive — and then complete her surface protocol so cleanly — is a testament to what kind of shape she’s in.

“I don’t think we’ve seen the last national record for Shel.”

Eisenberg doesn’t think so either. She’d like to tack on another meter or two this year alone. But she has no intention of plateauing there.

While 104 meters is the women’s constant-weight world record, only a couple of U.S. men have reached 100 meters, and no U.S. women. Eisenberg would like to be the first, but she said she wouldn’t mind if someone else beat her to it.

“One hundred meters is the life goal, but I’m not in a rush,” she said. “It’s easy to get excited and that’s how people get hurt. Of course, it’s on my mind. I’ve got to get to 90 meters before I get to 100, and that’s a little more on my mind. … Then we’ll see where we go from there.”

Her motto now is the same as it was when time was running out on her record attempt: Take a breath, then take the plunge.

Contact Julie Jag at 831-706-3257.

For the Record: Freediving marks

Constant Weight

World: 129 meters, Alexey Molchanov, Russia, 2017

World women’s: 104 meters, Alessia Zecchini, Italy, 2017

U.S. men’s: 101 meters, Kurt Chambers, Hawaii, 2016

U.S. women’s: 85 meters, Shelby Eisenberg, Hawaii, 2018

By freedivinguae

Boaters urged to watch for sea turtles following fatal boat strikes

With two sea turtles killed in Long Island Sound by propellers in the last month, The Maritime Aquarium at Norwalk is asking boaters to slow down and be aware of these endangered animals.

A dead juvenile sea turtle — believed to be a loggerhead — was found Aug. 9 near Norwalk’s Sheffield Island by staff of the Norwalk Seaport Association. The turtle had three obvious propeller gouges up its approximately 20-inch-long shell.

On July 15, a loggerhead was found in Stratford, dead from a boat strike. And exactly one year since this most-recent death — on Aug. 9, 2017 – a loggerhead was found in Branford, also reportedly killed by an encounter with a boat propeller.

“Summer is the time of year that sea turtles visit Long Island Sound,” said Dr. David Hudson, research scientist for The Maritime Aquarium. “It’s also the height of boating season in the Sound, but that doesn’t have to mean a deadly overlap for the turtles – if boaters would just practice caution.”

Four species of sea turtles may visit the Sound in the summer: loggerhead and green, which are both listed as Threatened; and Kemp’s ridley (the smallest sea turtle) and leatherback (the largest), both Endangered.

Sea turtles are most vulnerable to boat collisions when they come to the surface to breathe and/or warm themselves in the sun. (They are cold-blooded.) At the surface, Hudson said, the turtles are least able to make avoidance maneuvers.

Hudson recommended that boaters reduce their speeds, especially in comparatively shallower waters and anywhere near sea grasses, where some turtles feed. He discouraged the use of autopilot, and encouraged assigning a passenger to serve as a spotter.

Turtles sometimes survive boat strikes, but with large scars or lost limbs.

 

source: https://www.stratfordstar.com/83878/boaters-urged-to-watch-for-sea-turtles-following-fatal-boat-strikes/

By freedivinguae

Effective method to control algae growth on Hawaiian coral reefs

Researchers with the State of Hawai’i Division of Aquatic Resources (DAR) and the Hawai’i Institute of Marine Biology (HIMB) at the University of Hawai’i at Mānoa found a management approach that combining manual removal and outplanting native urchin was effective at reducing invasive, reef smothering macroalgae by 85% on a coral reef off O’ahu, Hawai’i.

Globally, the health of coral reefs is threatened due to rising ocean temperatures and ocean acidification. However, local factors such as invasive macroalgae also pose a serious risk to coral reefs — monopolizing reef habitats, and overgrowing and smothering native species, such as corals.

Brian J. Neilson, Acting Administrator at DAR, and Chris Wall, doctoral candidate at HIMB in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), and others tested a novel approach to curbing the abundance of invasive macroalgae on the coral reefs of Kāne’ohe Bay, O’ahu. First, divers manually removed invasive macroalgae with the assistance of an underwater vacuum system, “The Super Sucker.” Then, hatchery-raised juvenile sea urchins (the Hawaiian native collector urchin, Tripneustes gratilla) were outplanted to graze on invasive algae to control regrowth.

In total, the team removed over 40,000 pounds of invasive macroalgae, outplanted 99,000 sea urchins, and treated nearly six acres of reef area over two years. During this period, invasive macroalgae declined in response to treatments, and importantly, there were no observed negative effects to important reef calcifiers such as corals and crustose coralline algae.

Unfortunately, there are often limited options for reducing invasive macroalgae without causing further environmental damage. Prior to this study, scientists at DAR, UH Mānoa and the Nature Conservancy showed the manual removal/urchin herbivory method worked at reducing invasive macroalgae in the laboratory and in small enclosures on the reef.

“This management approach is the first of its kind at the reef-scale,” said Wall. “Our research shows promise as an effective mean to reduce invasive macroalgae with minimal environmental impact, while also incorporating a native herbivore to regulate a noxious invasive species.”

“Coral reefs are an important part of the economy, culture, sustenance and recreation of Hawai’i,” said Neilson. “Local action is instrumental in supporting the resilience of coral reefs. This study provides an important tool that can assist in the management and conservation of coral reefs.”

“The surprise was just how effective this approach was at reducing invasive macroalgae over the two-year period,” said Wall. “We were able to successfully leverage the rigorous, detailed science of prior studies to assist in scaling the management plan from an aquarium to an entire reef. One of the lessons here is that a well-designed management plan can reap significant benefits and lead to the most effective path forward, both logistically and financially.”

DAR is continuing to monitor the reefs of Kāne’ohe Bay and the long-term effects of macroalgae removal and urchin herbivory on coral reefs. In addition, DAR and UH scientists are actively studying the influence of local weather and global climate phenomena, such as the 2014-2016 El Niño and global bleaching episodes, as drivers of changing coral and invasive macroalgae abundance through time.

Story Source:

Materials provided by University of Hawaii at ManoaNote: Content may be edited for style and length.

By freedivinguae

FREE-DIVING FAMILY SAVES WHALE SHARK STUCK IN A FISHING NET

While free-diving off the shore of Kaunolu on Hawaii’s island of Lanai, a Hawaiian family saw something they’d never seen before: A young whale shark.

Even for people who spend a lot of time in Hawaii’s crystalline waters, this endangered animal—the world’s largest fish—is a rare and joyous sight.

 

 

 

But the initial wonder faded as Kapua Kawelo and her husband Joby Rohrer, both of whom work on endangered species for the O‘ahu Army Natural Resources Program, noticed the creature had a thick, heavy rope wrapped around its neck.

“It looked really sore,” says Rohrer. “There were these three scars from where the rope rubbed into the ridges on her back. The rope had cut probably three inches into her pectoral fin.”

After filming the shark for a while, the family decided to try to cut the rope with a dive knife. Using only his experience as a free-diver and a small, serrated dive blade, Rohrer dove down again and again at depths of 50 to 60 feet for spans of up to two minutes at a time.

Finally, after about half an hour of careful work and a little bit of support from the couple’s son Kanehoalani and from Jon Sprague, a wildlife control manager for Pulama Lana?i, the shark was free.

Then the family’s 15-year-old daughter, Ho’ohila, swam the 150-pounds worth of rope to shore.

“It’s a family story,” says Kapua.

WILL IT SURVIVE?

Clearly, the whale shark is better off now that it’s without “an unbreakable rope lei,” as Kapua puts it. But will the whale shark be able to recover from the ordeal?

According to Brad Norman, a National Geographic Explorer and one of the world’s foremost experts on whale sharks, you can tell the rope had been strangling the animal for at least a few months because of all the barnacles that had colonized it. Hawaii’s Department of Land and Natural Resources had actually been alerted to the shark’s plight in mid-July by SCUBA divers and had since sent out a call for people to report any future sightings.

But Norman says that, all things considered, the shark appeared to be in pretty good condition. He also estimated that the animal was at least 20 years old, giving it excellent odds to survive.

“Although globally, all whale sharks are endangered and threatened with extinction,” says Norman. “If we don’t reverse the declining trend in their numbers, it’s dire for the species as a whole.”

What’s more, lost fishing gear doesn’t just harm whale sharks. According to a recent report by World Animal Protection, more than 700,000 tons of new gear enters earth’s oceans each year.

DID THE WHALE SHARK COME TO HUMANS FOR HELP?

Whale sharks typically swim away when they’re touched, says Norman, so the fact that the shark remained even after Rohrer began to saw at the rope is evidence that it was comfortable with the situation. Norman calls it “amazing to see.”

“The shark appears to allow the diver to assist,” says Norman, “seemingly knowing he’s helping.”

Kapua credits her husband’s zen-like demeanor and heroic free-diving ability for allowing him to be able to free the entangled shark.

“We all wanted to help but none of us could hold our breath that long,” she says.

But there was also something else about the experience, she says. In Hawaiian mythology, ancestors sometimes come back as guardian animals, called ?aumakua. These guardians are thought to protect families, who also must help protect them.

“And we’ve never seen a whale shark before but, just like native peoples around the world, you feel like you have a special connection to the resources that surround you and your family,” says Kapua.

“I like to think that we were there for a reason and that the least we could do for having that amazing experience, seeing that beautiful creature, was to help it survive.”

source: https://www.nationalgeographic.com.au/animals/free-diving-family-saves-whale-shark-stuck-in-a-fishing-net.aspx

By freedivinguae

Why the endangered green sea turtle is losing its male population

BOCA RATON, Fla. — The struggle to save the already endangered green sea turtle faces a new challenge. The turtles nearly vanished 40 years ago in Florida, but a coordinated effort by conservationists, government agencies and volunteers brought the animals back from the brink. Now, the males of the species seem to be disappearing, CBS News’ Mark Strassmann reports.

In a beachfront ritual that dates back more than 100 million years, CBS News came upon a 300-pound green sea turtle covering her beach nest, burying maybe 100 eggs or more.

Biologist Jeanette Wyneken directs Florida Atlantic University’s marine lab, and has studied Florida’s sea turtle population since 2002. She’s alarmed by what she doesn’t see in her tanks of hatchlings.

“We’re seeing fewer and fewer and fewer years where we find males, so seven out of the last ten years, we have not found any males,” she said. “Not a single one.”

          It’s not genetics that determine a sea turtle’s sex, it’s the temperature of the sand. The tipping point is roughly 85 degrees for a species that’s predominantly female.

“If it’s too warm you don’t get boys. If it’s too cool, you don’t get girls. So it’s the hot chicks and the cool dudes,” Wyneken said.

She says the nests are getting warmer because of the weather and climate change.

As Florida’s beaches get hotter, species are showing signs of shutting down — sea turtles, and possibly alligators, another reptile whose eggs skew female and whose sex is determined by nest temperatures.

On a rooftop at the University of North Florida, biologist Adam Rosenblatt has built 20 nests, of 20 alligator eggs each. Plastic will artificially warm the nests by five-point-five degrees, which is how much hotter north Florida’s expected to be by the end of the century.

“If it’s happening in sea turtles, my thought was it could be happening in alligators as well and it could throw off that balance between males and females,” Rosenblatt said.

Back in Wyneken’s lab, she uses a mini-camera to determine their sex after they reach six weeks old.

“So I have to wait until they’re big enough for me to sort of – look under their skirts,” Wyneken said.

Monday night, her team released hundreds of hatchlings into the sea, to the admiration of dozens of turtle fans. She knows the odds are already long for this prehistoric species, more so now that climate change is in play.

“There’s some resilience in there that we scientists may not have discovered and then there’s a part of us that says, ‘Things are changing so fast compared to what’s happened in the past, that resilience may not be enough,'” Wyneken said.

Sea turtles don’t reach sexual maturity until they’re at least 25 years old, so the impact of disappearing male hatchlings may not be known for another generation.

 

source; https://www.cbsnews.com/news/male-green-sea-turtles-climate-change-impacting-population/

By freedivinguae

The freediving champions of the dolphin world


Bottlenose dolphin populations are often found close to land in shallow coastal environments, making short, shallow dives of less than 10m for their prey.
Credit: Copyright Michele Hogan

For the first time, researchers have explored the physiological adaptations that enable different populations of the same species of dolphin to vary in diving ability by almost 1000m. The research, published in two complementary studies in Frontiers in Physiology, compared the lung mechanics and metabolic rates of bottlenose dolphin populations known for their different hunting depths. Using theoretical estimates of gas management, the results support a new hypothesis that lung architecture and the management of blood flow allow the dolphins to access oxygen in the lungs while preventing uptake of nitrogen, thereby avoiding decompression sickness.

Bottlenose dolphin populations are often found close to land in shallow coastal environments, making short, shallow dives of less than 10m for their prey. However, some populations — such as the Bermudian population in this study — frequently dive to depths of up to 400m, and as deep as 1000m on occasion, spending up to 13 minutes underwater in search of food on a single breath.

“How can a single species have such extremely different life styles?” This question motivated Dr Andreas Fahlman of the Fundación Oceanográfic in Valencia, Spain, who led both studies with his international team. “We wanted to measure what kind of differences are responsible for these huge variations. This allows us to determine how far the physiology can change within a single species and understand the threat that stressors may have on these deep diving dolphins.”

Anyone who has previously scuba-dived will know about decompression sickness, commonly known as ‘the bends’. This painful and potentially life-threatening condition is caused from surfacing too quickly at the end of a dive. The rapid expansion of nitrogen bubbles — which form in the bloodstream and tissues during the dive — are not given enough time to diffuse from the body naturally during the ascent.

Dolphins run the same risks when diving to great depths. The team measured the physiology of the lungs and energy consumption of several bottlenose dolphins known to make deep dives to understand how these problems are avoided.

In the first study, the authors compared their results with existing data on a short, shallow diving population of bottlenose dolphins in Florida. The deep diving dolphins had greater oxygen storage capacity, which would enable them to dive for longer durations. However, the authors found no differences in the lung mechanics or metabolic rates between the shallow and deep diving populations.

“This was unexpected, as past studies have suggested that compression of the lungs was the main adaptation to avoid taking up excessive nitrogen at depth and getting the bends,” says Fahlman. “The lack of differences in the lungs between the shallow and deep divers suggest that the dolphins may use other means to avoid diving related problems.”

This led the researchers to their second study, where they estimated how different populations may manage gas exchange during shallow and deep diving lifestyles. They constructed theoretical models using known species-specific parameters to determine what adaptations the deep diving dolphins would need to reach these depths without suffering negative health implications. The model suggested that, when comparing known parameters with how much oxygen storage would be required, the deep diving dolphins would exceed their calculated dive limits.

“The results indicated that the deep diving population would need to keep an elevated heart rate, not only during surface intervals, but also during shallow dives in-between deep dives to allow sufficient restoration of oxygen stores,” says Fahlman. “Keeping the blood flow elevated between deep foraging dives helps reduce time spent at the surface and enhances recovery time. On the other hand, during deep dives, the dolphins would need to direct blood flow through collapsed regions of the lung, allowing some exchange of oxygen and carbon, while preventing the exchange of nitrogen. Thus, the dolphins may have a way to manage the level of nitrogen they absorb and thereby preventing the bends.”

“This hypothesis provides new and exciting research opportunities to understand how mammals can dive to extreme breaths on a lung full of air without any of the related problems that humans experience,” says Fahlman. “However, our dataset is limited, and further studies should be done on other deep diving dolphin populations to determine if there are similar physiological requirements for deep diving.”

The results presented in these publications may provide vital information to better understand the risks associated with diving in marine mammals and the impact humans may have on their survival as a species.

Environmental changes may alter prey distribution and availability, causing the dolphins to search beyond their normal depth ranges for prey. Additionally, human-made stresses such as increasing ocean noise, sonar exposure or capture in fishing nets may cause disturbance to normal diving conditions. This could affect the physiological adaptations dolphins use to ensure safe surfacing after deep dives, increasing the risk of diving related problems such as decompression sickness.

“If we are able to better understand how our impact may affect these species, we may eventually be able to improve conservation efforts for these dolphins, and all marine mammals,” hopes Fahlman.

source: https://www.sciencedaily.com/releases/2018/07/180717094804.htm

By freedivinguae

Family diving trip becomes mission to rescue whale shark

A family diving off the coast of Kaunolu, Hawaii, saved a whale shark from a potentially life-threatening situation this week, by removing some heavy fishing line that had become wrapped around it.

Husband and wife Joby Rohrer and Kapua Kawelo, both biologists, decided to attempt to free the 20-foot whale shark after they spotted it. Footage filmed by their son, Kanehoalani Kawelo, shows Rohrer and a family friend diving down to free the shark.

Rohrer told Hawaii News Now that it took him five dives to cut through the five-inch-thick rope.

The shark, a juvenile, had been seen locally several times before it was finally cut free, Hawaii News Now said.