A whale shark has made the longest migration journey ever recorded travelling 12,000 miles across the Pacific Ocean.
The large fish, named Anne by scientists, was tracked making the mammoth migration from near Panama in the south eastern Pacific, to an area close to the Philippines in the Indo-Pacific.
Experts at the Smithsonian Tropical Research Institute followed her signal from Panamanian waters, past Clipperton Island and Costa Rica’s Cocos Island, en-route to Darwin Island in the Galapagos, a site known to attract groups of sharks.
After 266 days of tracking, Anne’s signal disappeared as she went into deep waters, before resurfacing again 235 days later south of Hawaii.
She then made her way to the Marianas Trench – a canyon in the ocean floor where movie director James Cameron located the deepest point on the Earth’s surface almost 11,000 metres below sea level.
The trip was the first recorded evidence of a trans-Pacific migration route for the species of the largest living fish.
Marine biologist Dr Héctor Guzmán, who first tagged Anne near Coiba Island in Panama, said: “We have very little information about why whale sharks migrate.
“Are they searching for food, seeking breeding opportunities or driven by some other impulse?”
Genetic studies show that whale sharks across the globe are closely related, suggesting they must travel long distances to mate. An adult female can travel around 40 miles per day and can dive more than 1,900 metres.
Whale sharks are filter feeders, eating plankton, fish eggs, krill, crab larvae as well as small squid and fish that enter their large mouths. They cannot digest plastic garbage.
Credit: Kevan Mantell
Little is known about the world’s largest living fish, gentle giants reaching 12 meters (40 feet) in length. Researchers from the Smithsonian Tropical Research Institute (STRI) and colleagues tracked a female whale shark from the eastern Pacific to the western Indo-Pacific for 20,142 kilometers (more than 12,000 miles), the longest whale shark migration route ever recorded.
STRI marine biologist Héctor M. Guzmán tagged a female whale shark (Rhincodon typus) near Coiba Island in Panama, the largest island off of the coast of Central America, a National Park, World Heritage Site and marine protected area. His team named the shark Anne for conservationist Anne McEnany, president and CEO of the International Community Foundation (ICF). The multi-year project also tagged 45 additional sharks in Panama with sponsorship from Christy Walton’s Candeo Fund at the ICF, along with STRI and Panama’s science and technology bureau (SENACYT).
Guzmán estimated Anne’s position based on signals from a Smart Position and Temperature (SPOT) tag tethered to the shark, received by the Advanced Research and Global Observation Satellite (ARGOS). The tag only communicates with the satellite when the shark swims near the surface. Anne remained in Panamanian waters for 116 days, then swam toward Clipperton Island (France), nearing Cocos Island (Costa Rica) en route to Darwin Island in the Galapagos (Ecuador), a site known to attract groups of sharks. 266 days after she was tagged, the signal disappeared, indicating that Anne was too deep to track. After 235 days of silence, transmissions began again, south of Hawaii. After a nine-day stay, she continued through the Marshall Islands until she arrived at the Marianas Trench, a canyon in the ocean floor near Guam in the Western Pacific where movie director James Cameron located the deepest point on the Earth’s surface almost 11,000 meters (36,000 feet) below sea level.
Whale sharks dive to more than 1900 meters (6000 feet). But it is unknown what the animal was doing in this area.
“We have very little information about why whale sharks migrate,” said Guzmán. “Are they searching for food, seeking breeding opportunities or driven by some other impulse?”
“Despite being the world’s largest fish, it’s amazing to me how little we know about this species,” said Scott Eckert, co-author and biology professor at Principia College. “When I first began working on them, their taxonomy was debated, and it still wasn’t clear how they reproduced.”
Found in warm, tropical and sub-tropical waters, it is thought that about a quarter of whale sharks live primarily in the Atlantic, whereas about three-fourths live in the Indo-Pacific. Tourists are drawn to sites where 500 or more whale sharks gather: in Oman, Australia, Galapagos, Mexico, Mozambique and the Seychelles. Large groups are also reported from Taiwan, Southern China and the Gujarat coast of India.
Genetic studies show that whale sharks across the globe are closely related, indicating that they must travel long distances to mate. Whale sharks have been tracked for shorter distances along similar routes, but this report is the longest-recorded migration to date and the first evidence of a potential trans-Pacific route. Like Anne, other whale sharks appear to follow the North Equatorial Current for most of the distance. Large females can swim an average of 67 kilometers (about 40 miles) per day.
The whale shark is one of only three known filter-feeding sharks, feeding on plankton, fish eggs, krill, crab larvae as well as small squid and fish (and, accidentally, plastic, which they cannot digest). As such, they are not considered to be particularly dangerous, and tourism companies that offer the opportunity to swim very close to whale sharks are common near areas where they aggregate in large numbers. But their size also attracts fishing boats. They are sought after for their fins and meat, for their teeth (used for crafts and sold to tourists) and for cartilage and oil with purported medicinal value. Juvenile whale sharks often end up as bycatch in tuna and other fisheries.
Whale sharks were classified as endangered in 2016. During the past 75 years, it is estimated that nearly half of the world’s whale sharks have disappeared. In many parts of the world, whale sharks have legal protection, but regulations are often not enforced. Guzman’s data were used to design and draft local and regional policies for the protection of the species. Fishing, capture and sale of whale sharks are prohibited in Panama by Executive Decree No. 9, signed in 2009. In 2014, Panama’s environmental authority passed an additional resolution regulating whale shark watching in Coiba National Park and the Isla Canales de Afuera marine reserve. The resolution includes a Whale Shark Watching Manual but unfortunately, tourism activities are not well organized and the authorities are not present to enforce the regulations.
“Whale sharks in Coiba have already changed their behavior to avoid the surface and tourists,” Guzman said. “These studies are critical as we design international policy to protect transboundary species like the whale sharks and other highly migratory marine species.”
How do you get inside a whale’s head? With a CT-scanner made for rocket bodies, that’s how.
Researchers from San Diego State University stuck an entire juvenile minke whale inside a computed tomography (CT) scanning machine to virtually slice and dice its anatomy with X-rays. Their goal was to get a look at the structures that allow whales to hear underwater and better understand a sense that’s vital for these underwater mammals.
Ears Over Eyes
In the ocean, sight can only get you so far. In dim, murky ocean waters, sound offers much better insights into the environment. Dolphins and toothed whales use a version of sonar to visualize their underwater environment, and baleen whales like the minke whale use sound to both communicate and possibly to keep an ear out for potential threats.
Unlike us, whales don’t really rely on their ear canals to pick up on sounds. When you’re surrounded by water, your whole skull becomes an antenna — it’s why we can’t tell where sounds are coming from underwater, and it’s how whales pick up sounds. Whales have ear canals, but they likely don’t use them. Their specialized inner and middle ears include bones that are entirely detached from the skull, which functions like the outer ear does in humans, and which help them determine where sounds are coming from.
Getting an accurate picture inside a whale’s head is difficult though, given their enormous size. The researchers caught a lucky break when they were able to obtain the body of a young minke whale that had beached itself and been euthanized. After a two-year wait in line at a CT-scanning facility usually used for solid-fuel rocket engines, the researchers were able to use the machine to get a full-body image of the 11-foot whale, and, crucially, its skull and ears.
What Do You Ear?
With the CT scan, the researchers were able to get a much better idea of what these structures looked like in minke whales. Analyzing the structure of hearing organs usually gives a fairly good estimate of what types of sounds they can pick up on. They did the same for fin whales in 2015, and the data in both cases is helping scientists narrow down what frequencies of sound the whales can hear and shedding more light onto how their ears work.
In the case of the minke whales, the researchers found that they were able to hear sounds of much higher frequency than was thought. While their hearing, as with most whales, is optimized for low the kind of low frequency sounds used to communicate across long distances in the ocean, they can also pick out higher frequency sounds, in the 10-40 kilohertz range, the researchers say.
The researchers presented their findings Monday at the American Association of Anatomists annual meeting during the 2018 Experimental Biology meeting in San Diego.
They think the sensitivity to higher frequencies serves a defensive purpose. Killer whales often prey on minke whales, and they communicate within this frequency range. Minke whales likely evolved the ability to hear these sounds in order to better avoid their predators. In addition, the ears’ structure indicates that the minke whales probably hear sounds best when they encounter them head-on, something the researchers suggest the whales could use to determine the direction a sound is coming from.
As the cacophony of human activities in the oceans increases, it’s becoming more important for researchers to understand how sea life will be affected. Whales are particularly vulnerable, as things like ship propellers and sonar fall within their hearing range and could potentially overwhelm the sounds they need to pay attention to in order to survive. Knowing exactly how, and in what range, whales can hear will help researchers better protect these massive mammals of the sea.
Scientists have uncovered the secrets of the Bajau people, long-famed for their ability to hold their breath for extraordinary lengths of time
The secret behind the ability of a group of “sea nomads” in Southeast Asia to hold their breath for extraordinary periods of time while freediving to hunt fish has finally been revealed – and it’s down to evolution.
The Bajau people are able to dive tens of metres underwater with no conventional diving aids. Instead they rely on weights, handmade wooden goggles – and a single breath of air.
But while the Bajau people’s talents have long been known, it was unclear whether the skill was the result of practice, as in the case of the excellent underwater vision of Thai “sea nomad” children, or the result of adaptations which have their roots in the Bajau people’s DNA
Now experts say they have the answer: over time the Bajau people have undergone natural selection, resulting in certain versions of genes becoming widespread – many of which are linked to biological changes, including having a larger spleen, that could help the Bajau to hold their breath underwater for many minutes at a time.
The team say the findings could eventually prove useful in medical settings, potentially allowing experts to identify patients that might be at greater risk of death if they experience a lack of oxygen, for example during surgery.
“There seems to be so much to learn from the Bajau and other diving populations about how the human body is able to react to oxygen deprivation, which is an important medical issue,” said Dr Melissa Ilardo, first author of the study who was at the University of Copenhagen at the time of the research.
Writing in the journal Cell, the scientists reveal how they unpicked the mystery following a clue from previous research: species of seals which can dive for longer have larger than expected spleens – an organ which, among its functions, can store oxygen-carrying red blood cells.
As a result the team used an ultrasound device to measure the spleen in 43 Bajau people and 33 people from a neighbouring group of farming people, the Saluan.
“The spleen size is about 50% larger in these sea nomads than it is in the [Saluan], so already it was like ‘Oh my God – it is really [an] extreme physiological characteristic,” said Prof Eske Willerslev, a co-author of the study from the University of Cambridge.
The team note the trend held regardless of whether the Bajau individual was themselves a diver, and even when factors such as age, sex and height were taken into account.
Genetic testing revealed that certain versions of genes are more commonly found in Bajau people than would be expected, with many apparently linked to biological changes that could help individuals cope with low-oxygen conditions.
Among them is a form of a gene linked to an increased spleen size – an effect the team reveal is likely down to an increase in thyroid hormone levels. Crucially, a contraction of the spleen is one of the features of the so called “diving reflex” – a set of responses in mammals that occur when the head is submerged. A large spleen means even more oxygen-carrying red blood cells can be pumped into the circulatory system when the organ contracts, allowing individuals to stay underwater for longer.
Another is a form of a gene linked to a different feature of the diving reflex: narrowing of the blood vessels to the extremities, aiding delivery of oxygenated blood to organs such as the brain, heart and lungs.
Further analysis by the team revealed that these genetic boons are not the result of chance, but evolutionary adaptations arising from natural selection.
Stephen Stearns, professor of ecology and evolutionary biology at Yale University who was not involved in the research, saidthe study adds to evidence for recent natural selection on certain genes in human populations – with previous examples including genes for lactose tolerance that cropped up with the advent of domestication of dairy animals, and genes for adaptation to high altitude in Tibetans and Native Americans in the Andes.
“What we lack at this point, and badly need, are samples large enough to allow us to infer when the selection [in the Bajau] started to happen,” he said. “We know that the Bajau have been leading this lifestyle for at least a thousand years, but we do not know when they started it – perhaps much earlier.”
A striking photo of a dolphin reflected in the sea off a rocky Inner Hebridean outcrop has won an annual photo competition to celebrate British mammals.
The image, captured by James West, from Hampshire, was among 350 wildlife pictures snapped in the British Isles for the annual Mammal Photographer of the Year competition.
James, who took the picture near the Cairns of Coll, off the northern end of the Island of Coll, said the reflection added a different dimension to the picture.
“The sea was very calm and like a mirror.
“As I examined the shots afterwards, I could see not only a sharp photograph of the dolphin but also its reflection in the water, revealing a beautiful creature in motion with tremendous power and grace,” said James, from Chandler’s Ford.
“The reflection adds a different dimension to the shot, bringing out details that a shot from above couldn’t have done by itself.”
Chief Judge Hilary Conlan, editor of Mammal News, said: “It is hard to photograph dolphins completely out of the water as well as capturing not only the reflection but also a sense of speed and purpose.”
The winner of the Best Mammal Society member photo was Graeme Hull, from Caithness, with a stunning picture of a grey seal “waving”.
Clearwater, Fla. (WOFL FOX 35) – Clearwater Marine Aquarium released three sea turtles today at Fred Howard Park.
The sea turtles included Echo and Papa, two endangered green sea turtles treated for the Fibropapilloma virus, and Marigold, a critically endangered Kemp’s ridley sea turtle treated for boat strike injuries.
Echo and Papa, named during the NATO phonetic alphabet theme, were rescued in January this year in Hudson Beach, FL. They were brought in with low body temperatures and tumors caused by the Fibropapilloma virus. Both sea turtles underwent successful tumor removal surgery and the Florida Fish and Wildlife Conservation Commission (FWC) cleared them for release.
Marigold was rescued in October 2017 during the flower naming theme. The critically endangered Kemp’s ridley sea turtle was found by a fisherman on the Cotee River, near New Port Richey, FL. Marigold’s left lung was partially exposed through an extensive wound on her top shell and had sustained additional wounds on her bottom shell. The injuries are believed to have been caused by a boat strike.
Marigold was also cleared for release by FWC and returned home along with Echo and Papa
Loggerhead sea turtles that nest on beaches with similar magnetic fields are genetically similar to one another, according to a new study.
“Loggerhead sea turtles are fascinating creatures that begin their lives by migrating alone across the Atlantic Ocean and back,” says Kenneth Lohmann, professor of biology at the University of North Carolina at Chapel Hill.
“Eventually they return to nest on the beach where they hatched—or else, as it turns out, on a beach with a very similar magnetic field.”
The research, that appears in Current Biology, provides valuable insight into the turtles’ navigation and nesting behaviors that could advance future conservation efforts.
Key takeaways include:
Magnetic fields are the strongest predictor of genetic similarity among nesting loggerhead sea turtles, regardless of the geographic proximity or environmental traits of nesting beaches.
The findings support previous research which indicated that adult loggerhead sea turtles use magnetic fields to find their way back to the beach where they themselves hatched. The new research implies that sometimes the turtles mistakenly nest at a different beach with a similar magnetic field, even if that beach is geographically far away from the beach on which they hatched—like on the opposite coast of Florida.
Conservation efforts should consider the importance of a beach’s magnetic field for attracting loggerhead sea turtles. Sea walls, power lines, and large beachfront buildings may alter the magnetic fields that turtles encounter.
“This is an important new insight into how sea turtles navigate during their long-distance migrations. It might have important applications for the conservation of sea turtles, as well as other migratory animals such as salmon, sharks, and certain birds,” Lohmann says.
WILLEMSTAD – Curacao is special to me because I received my Open Water certification there ten years years ago when my local dive shop referred me to The Dive Bus, one of the most popular local operators. In the intervening years I have widely traveled around the world, and the rest of the Caribbean. These experiences have given me the benefit of contrast and hindsight, and so I decided to return to Curacao last summer for a week of diving.
Why? Curacao has lots to do-above and below the water. For photographers like me that want some independence, you can enjoy unlimited shore diving. If you want to reach the more inaccessible sites then you have the option of boat diving. You can also relax with an easy dive, or challenge yourself at the more advanced sites. And you always have the option of a quick snorkel.
On surface intervals, I’ve visited the Nurse Sharks at the Curaçao Sea Aquarium, joined an awesome dune buggy tour through the desert interior, explored historic sites, and toured the colourful colonial architecture in the capital of Willemstad.
But here I want to focus on the diving. I believe that the secret to enjoying your stay, and getting the most out of your diving, is to stay close to activities, be mobile and carefully choose your dive sites. This way you can avoid long boat rides, enjoy some great diving, and avoid long car rides as the shore diving sites are not that close together.
We based our stay at the all-inclusive Sunscape Curaçao – Resort, Spa and Casino (formerly Breezes, Curaçao) in Willemstad, a beachfront hotel with five different cultural restaurants, four bars and three pools. You won’t be in want for anything, and you won’t waste time travelling anywhere for meals or snacks. You can ask for a room close to the dive shop which also helps.
The other real advantage to staying at Sunscape Curaçao is that the resort is partnered witha Ocean Encounters Diving Curaçao which is conveniently located right on the resort grounds. Within minutes you can be in the water enjoying a nice reef, quite often all to yourself! We did several days of diving with them, and found them to be friendly, knowledgeable, and helpful in all things. They even gave us a key to a storage room so that we could do our own night dives. They have covered bench seating, cold drinking water, fresh water showers, rinse tanks, and a dock that makes getting into and out of the water a breeze.
The House reef, Oswaldo’s Drop Off, is an easy and fun dive, but it gets better the deeper and further West you go. On your way through you will see numerous (rare and endangered) elegant Staghorn corals, and many re-planted Staghorn corals that have been out-planted by the Coral Restoration Foundation Curaçao. At this reef we were visited by Reef squid, a large Tarpon, a large Southern Stingray, a Chainlink Moray Eel, Blennies peeking out at us from their homes in Brain Corals, curious Spotted shrimps in anenomes, and all the other usual suspects that you’d expect in the Caribbean.
You have to pass through the House reef to get to the Car Pile site, which is a “must do” dive. It’s an artificial reef consisting of old cars, boats, and trucks and other construction materials that were sunk in the 1970’s. If you love to “poke around” and explore, then this site is for you. I got such a “kick” out of diving this reef that I spent half my week here. And again, most times we had it all to ourselves since the site is not moored for dive boats. It begins at 45’, and goes to more than 100’. It’s full of life. For the first time ever I saw numerous purple masses of eggs being guarded by Sergeant Majors on the Barge, the biggest wreck you will come to. Here you can expect to find massive tube sponges, loads of colourful fishes, and schools of Snappers and Jacks.
I can also recommend diving theWatamula! This at the extreme West end of the Island and we had the pleasure of boat diving this site with GO WEST Diving Curaçao. Part of the fun was the Sunday drive getting there through the peaceful, cactus- studded desert terrain. Watamula gets its name from the Dutch word for “Water Mill” because of the currents that flow there. These currents nourish a very healthy reef, mostly of hard corals, and attract schools of fishes. This is one dive that I could do over and over again. The slow drift felt like a continuation of the relaxing drive up, only through a lush reef exploding with life. Like its name-sake neighbour in the west, Mushroom Forest, you can expect to see large mounds of mushroom-shaped Star corals, huge Barrel Sponges, and fields of massive Sea Plumes almost 6’ tall. There’s so much here, you don’t know where to look.
We finished our last day with boat dives at the Lost Anchor (no, there’s no Anchor to see, as it’s lost!) and Saba Tugboat. Lost Anchor makes for a nice Wall dive, filled with lots of sponges and soft corals. Close to the boat mooring, my wife spotted a large moray eel in the process of swallowing prey! It was relaxed enough to allow us to watch and get an up-close pic.
The nearby Saba Tugboat was sunk intentionally as an artificial reef and as an alternative to their busy signature Tugboat site. It sits in about 20’ of water and is filled with lots of colorful small fishes that now call it home. It makes for a nice safety stop after doing the nearby wall dive. It was also encouraging to massive colonies of growing Staghorn coral here, which is a real success story for the Coral Restoration Foundation Curaçao. I would highly recommend learning more about this important coral reef restoration initiative and even adopting a coral fragment, because when you “Adopt A Coral” you contributing directly to the restoration of the Curaçao coral reefs. Since my visit, the Coral Restoration Foundation Curaçao has expanded their coral nurseries. Now, the Foundation’s coral nurseries include their initial site located on the Ocean Encounters house reef (Stella Maris) and now, the house reef of Atlantis Diving.
Curacao is a place that I will keep coming back to! It’s easy to get to, it’s safe, it has a great cultural mix and an amazing balance of everything you need. And, the diving is exceptional, rich with biodiversity at a very reasonable cost. The best part is that the Curaçao diving community is committed to sustainable dive tourism initiatives so that these beautiful reefs will be around for years to come!
As Florida manatees are dying at a record pace from the cold winter and algae blooms, an unlikely sea cow duo has surprised researchers for their persistence in braving frigid temperatures to survive.
A manatee dubbed Leesburg — after the Lake County city where she was first spotted in 2015 — was seen by researchers from the group Sea to Shore Alliance alongside her 6-month-old calf several times this year in the St. Johns River. Their survival comes as 166 manatees have died this year through March 2, according to the Public Employees for Environmental Responsibility.
“There’s several springs we monitor, and we’ve seen her multiple times,” said Sea to Shore researcher Monica Ross, who dispatches alongside colleagues on boats to observe the manatees every year.
Leesburg is one of the first manatees recorded on the Harris Chain of Lakes, about 35 miles west of Orlando. The first-time manatee mother, distinguished by a boat propeller scar on her back, has amazed observers by surviving the winter with her newborn.
Florida’s manatee counts have doubled in the past two decades to about 6,600, but the marine mammals are still dying by the hundreds every year. In 2017, 538 manatees died in Florida, a 13 percent increase from 472 deaths the year before.
The trademark Florida species is designated as endangered by the federal government. Jeff Ruch, Public Employees for Environmental Responsibility executive director, has said he fears for the manatees’ future.
“Manatees may join polar bears as one of the first iconic victims of extinction in the wild from climate change.”
When Leesburg was first spotted in the Harris Chain of Lakes by recreational boaters in 2015, officials were skeptical of eyewitness accounts until a photograph of the sea cow and another male manatee convinced them.
Her companion didn’t make it through the harsh winter leading in to 2016; he was found dead at the Moss Bluff Lock in the Ocklawaha River, north of Lake Griffin.
Leesburg was also found suffering from the cold temperatures and transported to Lowry Park Zoo in Tampa for rehab. Three months later and weighing a healthy 1,100 pounds, Leesburg was dropped off in the St. Johns River in Putnam County nearly 80 miles away.
But she insisted on being in Lake County. Astonished researchers tracked her by GPS as she bolted from Putnam back to the Harris Chain.
Since then, an alligator ripped off her tracking collar and a boat propeller slashed her back, scarring her but distinguishing her from the other manatees researchers count every year. It’s how Sea to Shore was able to identify her among other manatees in the St. Johns River this winter, Ross said.
After she has endured so many trials, no one is sure if Leesburg and her newborn will return to Lake as some of the only documented manatees to make it their home.
“When a female has her first calf, she tends to change her pattern,” Ross said. “So she might go back to the Lake County area, but if she does she might not stay the time she did there before.”
If freediving the South Pacific has been on your bucket list for a while, you might want to check out Australian-based Encounter Freediving.
Encounter Freediving is offering a trip for freedivers to Kimbe Bay, off the Papua New Guinea island of New Britain. The group will be led by Michael Bates, an Austrialian freediving instructor who holds a PhD in marine science. Bates says:
“I grew up in PNG, and worked in tourism. I know what an amazing place it is, and what it has to offer freedivers. I am truly excited to be able to showcase what is on offer to the world of freediving.”
The group will be lodged at Walindi Plantation Resort on the shore of Kimbe Bay, a place that Bates calls “an ideal spot for freediving”:
“You have areas with over 80 meters of depth inside a protected bay with almost no current or swell. There are a wide variety of coral reef environments for freedivers to explore and a couple of wrecks, including a reminder of the region’s pivotal role in World War II, in a Japanese fighter plane. Dolphin and shark encounters are also a regular occurrence in Kimbe Bay. On occasion, divers are lucky enough to encounter a pod of orcas!”
The group size will be limited to 12 freedivers, allowing Bates to give individualized feedback to help folks reach new depths. Aside from the freediving, you’ll also be able to do a village visit, take a hike, or go bird watching.
The trip runs from September 28th to October 5th, 2018. Prices start from AU$3595 (~US$2791/~2257 Euros) and include return airfares from Brisbane, Australia to Kimbe, accommodation at Walindi Plantation Resort, all meals at Walindi, five days of diving, airport transfers in Kimbe, and taxes.