How blue whales help remoras


This 2017 video says about itself:

Amazing footage– A Whale Shark covered with Remora Fishes !! ( COMMENSALISM)

This awesome footage was shot at Koh Tao, Thailand courtesy of Underwater Videographer (Lara Dakers).

From the New Jersey Institute of Technology in the USA:

Secret surfing life of remoras hitchhiking on blue whales

October 28, 2020

Summary: A new study of blue whales off the coast of California has given researchers the first ocean recordings of their famous hitchhiking partner — the remora — revealing the suckerfish’s secret whale-surfing skills as well as their knack for grabbing the most flow-optimal spots while riding aboard the world’s largest vertebrate.

Sticking to the bodies of sharks and other larger marine life is a well-known specialty of remora fishes (Echeneidae) and their super-powered suction disks on their heads. But a new study has now fully documented the “suckerfish” in hitchhiking action below the ocean’s surface, uncovering a much more refined skillset that the fish uses for navigating intense hydrodynamics that come with trying to ride aboard a 100-ft. blue whale (Balaenoptera musculus).

In a study published Oct. 28 in the Journal of Experimental Biology, an international team of researchers studying the unique fluid environments of blue whales traveling off the coast of Palos Verdes and San Diego, CA has reported capturing the first-ever continuous recording of remora behavior on a host organism, using advanced biosensing tags with video recording capabilities.

The study shows the secrets behind the remora fish’s success in hitchhiking aboard baleen whales more than 30 times their size to safely traverse the ocean — they select the most flow-optimal regions on the whale’s body to stick to, such as behind the whale’s blowhole, where drag resistance for the fish is reduced by as much as 84%. The team’s findings also show that remoras can freely move around to feed and socialize on their ride even as their whale host hits burst speeds of more than 5 meters per second, by utilizing previously unknown surfing and skimming behaviors along special low-drag traveling lanes that exist just off the surface of the whale’s body.

Researchers say the study represents the highest-resolution whole-body fluid dynamic analysis of whales to date, the insights from which could potentially be used as a basis to better understand the behavior, energy use and overall ecological health of the species, as well as improve tagging and tracking of whales and other migratory animals in future studies.

“Whales are like their own floating island, basically like their own little ecosystems. …To get a look into the flow environment of blue whales within a millimeter resolution through this study is extremely exciting,” said Brooke Flammang, assistant professor of biology at New Jersey Institute of Technology and the study’s corresponding author. “Through lucky coincidence, our recordings captured how remoras interact in this environment and are able to use the distinct flow dynamics of these whales to their advantage. It is incredible because we’ve really known next to nothing about how remoras behave on their hosts in the wild over any prolonged period of time.”

Until now, scientists studying the symbiotic relationships between remoras and their hosts in their natural ocean habitat have predominantly relied on still images and anecdotal evidence, leaving much of how they go about their renown sticking behavior beneath the surface a mystery.

In their recent investigation, the researchers employed multi-sensor biologging tags with dual cameras that they attached to the whales via four 2-inch suction disks. The tags were able to calculate various measurements inside the whale’s ecosystem, such as surface pressure and complex fluid forces around the whales, as well as GPS location and traveling speeds through tag vibrations, all while video recording the remoras at 24 frames per second and 720p resolution.

“Fortunately, the drag on dimple-shaped airplane cockpits has been measured many times and we were able to apply this knowledge to help figure out the drag these remoras were experiencing,” said Erik Anderson, co-author, biofluid dynamics researcher at Grove City College and guest investigator at the Woods Hole Oceanographic Institution. “But our study still required calculating, for the first time ever, the flow over a blue whale using computational fluid dynamics … it took an international team of biologists, programmers, engineers and a supercomputer to do that.”

The team’s 211 minutes of video footage and whale tag data processed by researchers at the Barcelona Supercomputing Center captured a total of 27 remoras at 61 locations on the whales overall, finding that the remoras were most often podding and traveling between three of the most hydrodynamically beneficial spots where separating flow and wakes are caused by the whale’s distinct topographical features: directly behind the blowhole, next to and behind the dorsal fin, and the flank region above and behind the pectoral fin.

According to the team’s measurements, Anderson says that the sheer force experienced by an average-sized remora in the wake behind the blowhole of a whale swimming at the casual speed of 1.5 m/s can be as low as 0.02 Newtons, half the force of drag in the free stream above. However, Anderson notes that the average remora’s suction force of 11-17 Newtons is more than a match for even the most intense parking spot on the whale, its tail, where the remora experiences roughly 0.14 Newtons of shear force. And though the forces are greater, the same is true even for large remora riding on whales swimming at much higher speeds.

“We learned that the remora’s suction disk is so strong that they could stick anywhere, even the tail fluke where the drag was measured strongest, but they like to go for the easy ride,” said Erik Anderson. “This saves them energy and makes life less costly as they hitchhike on and skim over the whale surface like a NASA probe over an asteroid or some mini-world.”

Remoras Go Surf’s Up

The tags showed that to conserve energy while getting about on their floating island, the remoras take advantage of the whale’s physics by surfing inside a thin layer of fluid surrounding the whale’s body, known as a boundary layer, where the team found drag force is reduced by up to 72% compared to the much more forceful free stream just above. Flammang says the fishes can lift within 1cm from their host in this layer to feed or join their mates at other low-drag social spots on the whale, occasionally changing directions by skimming, or repeatedly attaching and releasing their suction disks on the whale’s body.

Flammang suspects that remoras are able to move freely without being completely peeled from their speedy hosts, which can move nearly seven times faster than the remora, through something called the Venturi effect.

“The skimming and surfing behavior is amazing for many reasons, especially because we think that by staying about a centimeter off the whale body, they are taking advantage of the Venturi effect and using suction forces to maintain their close proximity,” explained Flammang. “In this narrow space between the remora and whale, when fluid is funneled into a narrow space it moves at a higher velocity but has lower pressure, so it is not going to push the remora away but can actually suck it toward the host. They can swim up into the free stream to grab a bite of food and come back down into the boundary layer, but it takes a lot more energy to swim in the free stream flow.”

Along with uncovering new details of the remora’s hitchhiking prowess, the team says they will continue to explore both the flow environments around whales and the mechanisms by which specifically adapted organisms like remoras successfully attach to hosts in order to improve animal tag technologies and designs for extended periods of behavioral and ecological monitoring. The team is also using their new insights into the remora’s preferred low-drag attachment locations to better inform where they might tag whales in studies to come.

“It’s an extremely arduous process to study whales what with permitting, research regulations and the game of chance of finding animals, all for the tags to usually fall off within 48 hours,” said Flammang. “If we can come up with a better way to collect longer-term data through better tag placement or better technologies, it could really advance our learning of the species, and many other animals that remoras attach to.”

Triassic marine reptiles, new research


This video is called Newly discovered Triassic lizard could float underwater to pick off prey 2020 10 28.

From ScienceDaily:

Ancient marine predator had a built-in float

New 240 million-year-old species uncovered in China

October 28, 2020

About 240 million years ago, when reptiles ruled the ocean, a small lizard-like predator floated near the bottom of the edges in shallow water, picking off prey with fang-like teeth. A short and flat tail, used for balance, helps identify it as a new species, according to research published in the Journal of Vertebrate Paleontology.

Paleontologists at the Chinese Academy of Scientists and Canadian Museum of Nature have analysed two skeletons from a thin layer of limestone in two quarries in southwest China. They identified the skeletons as nothosaurs, Triassic marine reptiles with a small head, fangs, flipper-like limbs, a long neck, and normally an even longer tail, probably used for propulsion. However, in the new species, the tail is short and flat.

“Our analysis of two well-preserved skeletons reveals a reptile with a broad, pachyostotic body (denser boned) and a very short, flattened tail. A long tail can be used to flick through the water, generating thrust, but the new species we’ve identified was probably better suited to hanging out near the bottom in shallow sea, using its short, flattened tail for balance, like an underwater float, allowing it to preserve energy while searching for prey,” says Dr Qing-Hua Shang from the Chinese Academy of Sciences, in Beijing.

The scientists have named the new species Brevicaudosaurus jiyangshanensis, from the Latin ‘brevi’ for ‘short,’ ‘caudo’ for ‘tail,’ and the Greek ‘sauros’ for ‘lizard.’ The most complete skeleton of the two was found in Jiyangshan quarry, giving the specimen its species name. It’s just under 60cm long.

The skeleton gives further clues to its lifestyle. The forelimbs are more strongly developed than the hind limbs, suggesting they played a role in helping the reptile to swim. However, the bones in the front feet are short compared to other species, limiting the power with which it could pull through the water. Most of its bones, including the vertebrae and ribs, are thick and dense, further contributing to the stocky, stout appearance of the reptile, and limiting its ability to swim quickly but increasing stability underwater.

However, thick, high-mass bones act as ballast. What the reptile lost in speed, it gained in stability. Dense bones, known as pachyostosis, may have made it neutrally buoyant in shallow water. Together with the flat tail, this would have helped the predator to float motionless underwater, requiring little energy to stay horizontal. Neutral buoyancy should also have enabled it to walk on the seabed searching for slow-moving prey.

Highly dense ribs may also suggest the reptile had large lungs. As suggested by the lack of firm support of the body weight, nothosaurs were oceanic nut they needed to come to the water surface for oxygen. They have nostrils on the snout through which they breathed. Large lungs would have increased the time the species could spend underwater.

The new species features a bar-shaped bone in the middle ear called the stapes, used for sound transmission. The stapes was generally lost in other nothosaurs or marine reptiles during preservation. Scientists had predicted that if a stapes was found in a nothosaur, it would be thin and slender like in other species of this branch of the reptilian family tree. However, in B. jiyangshanensis it is thick and elongate, suggesting it had good hearing underwater.

“Perhaps this small, slow-swimming marine reptile had to be vigilant for large predators as it floated in the shallows, as well as being a predator itself,” says co-author Dr. Xiao-Chun Wu from the Canadian Museum of Nature.

Trump loses election, fight not over


This 8 November 2020 video from the USA says about itself:

Congresswoman Alexandria Ocasio-Cortez shut down [Republican party politician] John Kasich’s lies following Joe Biden’s victory. I also break down Kasich’s misinformation with a mountain of data proving him wrong.

By Ceren Sagir from Britain today:

Fight against Trump’s dangerous ideology is ‘not over,’ unions, campaigners and socialists warn

CAMPAIGNERS, trade unionists and politicians have welcomed the US election result — but warned that the threat of Donald Trump’s dangerous ideology is “not over”.

Democrat candidate Joe Biden clenched victory after winning the key battleground of Pennsylvania on Saturday, four days after the polls closed, pushing him over the 270 electoral college votes threshold.

Vice-President-elect Kamala Harris becomes the first woman in the role – and the first person of African and Asian heritage to hold it.

Mr Trump is refusing to concede to the results, having begun legal action alleging fraud, and was playing golf when Biden’s win was announced.

A White House official said Mr Trump will “accept the results of a free and fair election.”

Prime Minister Boris Johnson congratulated Mr Biden and Ms Harris on their win and said: “The US is our most important ally and I look forward to working together on our shared priorities from climate change to trade and security.”

Mr Johnson said he would get in touch with Mr Biden “shortly” to discuss an alliance with the new administration.

But the president-elect is anti-Brexit and has previously described Mr Johnson as a “physical and emotional clone” of Mr Trump.

Following Mr Johnson’s congratulatory tweet, an aide of former president Barack Obama labelled the PM a “shapeshifting creep.”

Referencing Mr Johnson previously suggesting Mr Obama’s “part-Kenyan heritage” was behind his “ancestral dislike of the British empire,” Tommy Vietor said: “We will never forget your racist comments about Obama and slavish devotion to Trump.”

Labour MP Ian Lavery tweeted a photo of Mr Johnson and Mr Trump and said: “The blond duo. They share the same right-wing populism. Can one survive without the other?”

Stand Up To Racism said Mr Trump’s loss is “a blow to the racist right across the world.

“But Biden is not the answer to tackling racism in the US,” the group tweeted. “Solidarity to Black Lives Matter and the movement that defeated Trump.”

Unite Against Fascism wrote that it was “great to see the back of” Mr Trump as far-right figures such as France’s Marine Le Pen, Hungary’s PM Viktor Orban and Brazil’s President Jair Bolsonaro had backed him,

They added: “‘Tommy Robinson’ even begged Trump for asylum.

“All solidarity to US anti-fascists who will face reaction from embittered bigots.”

Former Labour leader Jeremy Corbyn said it was “great news for progressives around the world that Joe Biden and Kamala Harris had defeated Trump.

“Let’s work together internationally to build a better, fairer, greener, peaceful and more equal world.”

Unite general secretary Len McCluskey said: “Congratulations to our sister trade unions for supporting Joe Biden.

“It’s so good to see the back of such a divisive figure as Trump. I hope Biden now repays the unions and doesn’t let them down. He owes the left coalition a lot.”

Britain’s Communist Party leader Robert Griffiths hailed “a setback for the far-right mobs, proto-fascists and dangerous conspiracy-mongers who have gathered around Trump” but warned that “when it comes to foreign and military policy, president-elect Biden is every bit as committed to the pro-Nato, anti-China and anti-liberation agenda in Latin America and the Middle East as Trump.”

Mr Biden said: “The people of this nation have spoken. They’ve delivered us a clear victory, a convincing victory, a victory for you the people.”

But the Democrats lost ground in congressional elections and the Republicans still control the Senate, giving them a veto on most legislation.

Ms Harris, who took the stage before Mr Biden, said she was thinking of her mother and “the generations of women, black women, Asian, white, Latina, Native American women who throughout our nation’s history have paved the way for this moment tonight.

“While I may be the first woman in this office, I won’t be the last,” she added.

Mr Trump’s supporters have followed his claims of election fraud by taking to the streets, some of them armed with rifles and handguns.

Hundreds of people rallied in Phoenix on Saturday, charging the media with conspiring to steal the election and calling the results a coup.

A self-proclaimed Proud Boys chairman stated on his social media page that Mr Trump’s previous “standby order” was no longer in effect, and the violent hate group was “rolling out.”

His supporters have also clashed with counterprotesters.

Huge crowds gathered across cities to celebrate Mr Biden’s win. A street party erupted in front of the White House with people cramped together, despite Covid warnings.

Meanwhile, Democrat Representative Alexandria Ocasio-Cortez warned the Biden administration that if leftwingers were not put in top positions, the party would lose big in the 2022 mid-term elections.

She told the New York Times that the internal truce in place while the Democrats worked to defeat Mr Trump was over.

The New York representative rejected notions by some party members that left messaging during the Black Lives Matter movement and the Green New Deal led to a loss of congressional seats in the election.

In Israel, several thousand people attended the weekly demonstration against Prime Minister Benjamin Netanyahu, with some holding banners reading: “Trump Down, BiBi to go” and “Nethanyahu, You’re Next.”

Iranian President Hassan Rouhani called on Mr Biden to “compensate for past mistakes” and return the US to Tehran’s 2015 nuclear deal with world powers.

And in India, groups gathered at street corners in the small village of Thulasendrapuram, where Ms Harris’s grandfather was from, setting off firecrackers in celebration of her election.