Beluga whales from aquarium to sanctuary


This 22 June 2019 video says about itself:

Two beluga whales make epic journey from China to Iceland sanctuary

Two beluga whales from an aquarium in Shanghai have arrived in Iceland on June 19 to live out their days in a unique marine sanctuary that conservationists hope will become a model for rehoming some 3,000 of the creatures currently in captivity.

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Narwhals, belugas can interbreed, new research


This September 2018 video says about itself:

Belugas adopt wayward narwhal in Canadian waters

A lonely narwhal finds majestic company in Canadian waters. Having strayed far from its Arctic habitat, the juvenile managed to join a pod of belugas.

From the University of Copenhagen in Denmark:

Narwhals and belugas can interbreed

June 20, 2019

A team of University of Copenhagen researchers has compiled the first and only evidence that narwhals and beluga whales can breed successfully. DNA and stable isotope analysis of an anomalous skull from the Natural History Museum of Denmark has allowed researchers to confirm the existence of a narwhal-beluga hybrid.

For nearly thirty years, a strange-looking whale skull has gathered dust in the collections of the Natural History Museum of Denmark. Now, a team of researchers has determined the reason for the skull’s unique characteristics: it belongs to a narwhal-beluga hybrid.

A Greenlandic hunter shot the whale in the 1980’s and was puzzled by its odd appearance. He therefore kept the skull and placed it on the roof of his toolshed. Several years later, Professor Mads Peter Heide-Jørgensen of the Greenland Institute of Natural Resources visited the settlement and also immediately recognized the skull’s strange characteristics. He interviewed the hunter about the anomalous whale he had shot, and sent the skull to Copenhagen. Since then, it has been stored at the Zoological Museum, a part of the Natural History Museum of Denmark.

“As far as we know, this is the first and only evidence in the world that these two Arctic whale species can interbreed. Based on the intermediate shape of the skull and teeth, it was suggested that the specimen might be a narwhal-beluga hybrid, but this could not be confirmed. Now we provide the data that confirm that yes — it is indeed a hybrid,” says Eline Lorenzen, evolutionary biologist and curator at the University of Copenhagen’s Natural History Museum of Denmark. Lorenzen led the study, which was published today in Scientific Reports.

Using DNA and stable isotope analysis, the scientists determined that the skull belonged to a male, first-generation hybrid between a female narwhal and male beluga.

Bizarre set of chops

The hybrid’s skull was considerably larger than that of a typical narwhal or beluga. But the teeth were markedly different. Whereas narwhals have only one or rarely two long spiraling tusks, belugas have a set of uniform conical teeth that are aligned in straight rows. The hybrid skull has a set of long, spiraling and pointed teeth, that are angled horizontally.

“This whale has a bizarre set of teeth. The isotope analysis allowed us to determine that the animal’s diet was entirely different than that of a narwhal or beluga — and it is possible that its teeth influenced its foraging strategy. Whereas the other two species fed in the water column, the hybrid was a bottom dweller”, according to Mikkel Skovrind, a PhD student at the Natural History Museum and first author of the paper.

The researchers do not know what prompted the two species to mate, but it suggests a new phenomenon:

“We have analyzed the nuclear genomes of a narwhal and a beluga, but see no evidence of interbreeding for at least the past 1.25 million years of their evolutionary histories. So, interbreeding between the species appears to be either a very rare or a new occurrence. To my knowledge, it has not been observed or recorded before,” says Eline Lorenzen.

Gems among the museum collections

Lorenzen points out that she and her colleagues used novel analytical methods that have only recently been developed.

“There are some true gems in the world’s natural history collections that can provide us with key insights into the evolution and diversity of life on Earth. It is incredible when material — such as this skull, which has been stored in our collection for decades — can be revisited with new methodologies to gain novel biological insights” says Eline Lorenzen.

Mikkel Skovrind adds: “It would be interesting to find out if similar hybrid whales have been spotted elsewhere.”

FACTS:

  • By extracting DNA from the anomalous whale skull and comparing it to a genetic reference panel of narwhal and beluga, researchers established the whale’s genomic affiliation.
  • Researchers analyzed reference stocks of narwhal and beluga for stable isotopes and compared these with isotope values from the hybrid skull. By measuring bone carbon and nitrogen concentrations, researchers were able to discern whether the whale’s diet consisted of food from the water column or from the sea floor. The isotopes demonstrated that the hybrid whale’s dietary choices were very different than those of either narwhal or beluga.
  • Narwhals and belugas are the only toothed whales endemic to the Arctic region. While they are each other’s closest relatives and roughly equal in size, the two species differ in their morphology and behaviour. The narwhal is characterized by its long, spiraled tusk and has a greyish-brown, mottled pigmentation, whereas belugas have two rows of uniform teeth, and adults are completely white. Narwhals are specialists when it comes to dietary choice, and belugas are generalists.
  • The research is a collaboration between the Natural History Museum of Denmark at the University of Copenhagen, the Greenland Institute of Natural Resources and the Department of Anthropology, Trent University (CA).
  • The research is supported by the Carlsberg Foundation, the Villum Fonden Young Investigator programme and the Canada Research Chair programme.

Narwhal genome sequenced


This 2018 National Geographic video is called Narwhals: The Unicorns of the Sea.

From ScienceDaily:

Narwhals have endured a million years with low genetic diversity, and they’re thriving

May 1, 2019

Danish researchers have sequenced the genome of a narwhal, the Arctic whale famous for the horn-like tusk protruding from its forehead. Their work, appearing May 1 in the journal iScience, finds that compared to other Arctic marine mammals, narwhals have low genetic diversity, which typically indicates a species is struggling. However, narwhal populations number in the hundreds of thousands — but researchers warn they are still vulnerable to climate change and human activities in the Arctic.

Low genetic diversity has historically been viewed as a species’ death sentence because it was thought that when members of a species have less DNA variation for natural selection to act on, they would struggle to adapt to changes in their surroundings. But this research suggests it might be more complicated than that.

“There’s this notion that in order to survive and be resilient to changes, you need to have high genetic diversity, but then you have this species that for the past million years has had low genetic diversity and it’s still around — and is actually relatively abundant,” says Eline Lorenzen, an associate professor and curator at the Natural History Museum of Denmark. Currently, the population estimate of narwhals places them at around 170,000 individuals, enough to change their IUCN Red List status from “Near Threatened” to “Least Concern” last year.

“This shows us that just looking at the number of individuals isn’t indicative of the genomic diversity levels of a species, but also looking at the genomic diversity levels isn’t indicative of the number of individuals. Equating those two doesn’t seem to be quite as simple as previously thought,” Lorenzen says.

Interestingly, the low genetic diversity found in narwhals appears to be unique to the species; several other Arctic species, including their closest relative, the beluga, all have higher levels of genomic diversity.

Instances of low genetic diversity usually stem from inbreeding or bottleneck events, which is when a species’ population is dramatically reduced as a result of a die-off and the surviving individuals are left to rebuild their numbers from limited genetic stock. However, neither of these possibilities, which result in an accumulation of unfavorable gene variants within a species, appear to explain what is seen in the narwhals. Instead, the authors suggest that the onset of the last glacial period roughly 115,000 years ago might have created an ideal habitat in which narwhals, whose population was probably considerably smaller at that time, could have rapidly proliferate.

“Narwhals’ long-term low genetic diversity may have allowed them to evolve different mechanisms to cope with their limited genome,” says Michael Vincent Westbury, a postdoctoral researcher at the Natural History Museum of Denmark.

The authors caution that although most narwhal populations are currently doing well, their niche specialization and confinement to the Arctic — an area expected to be one of the most dramatically affected by climate change — means they are still vulnerable in the coming decades. “Our study can’t comment on whether narwhals will be able to adapt, or if they have the plasticity to be resilient in these rapid changes,” says Lorenzen. “But what we can say is that they have had this low genetic diversity for a really long time and they’re still around.”

Ideally, Lorenzen and Westbury would like their work to inform the conservation of this charismatic animal. “Narwhals are culturally important to Danish national history,” says Lorenzen. She notes that Danish waters aren’t actually inhabited by narwhals, but narwhal tusks were traded intensively as unicorn horns during the Viking period, and … ‘even the coronation chair of Danish King Frederik the 3rd from 1640 is made of narwhal tusks.”

Moving forward, the authors are interested in exploring whether this unexpected finding in narwhals is present in other species as well. To that end, future research plans include conducting genomic analyses and expanding their genetic understanding of a variety of Arctic species, both terrestrial and marine.

“This study shows that, as new data becomes available, we can question these commonly perceived notions that genetic diversity predicts the survivability of a species,” says Westbury. “Ultimately, this analysis is just one step of a lot of work to come.”

Great white sharks scared of killer whales


This video says about itself:

This Is The Biggest Great White Shark Ever Caught On Camera

Great white sharks are… big. Obviously. But a few years ago, divers met up with Deep Blue, probably the biggest great white shark ever caught on camera. So what do we know about the massive great white?

From the Monterey Bay Aquarium in the USA:

White sharks flee feeding areas when orcas present

Electronic tag data reveals white sharks do not return until following season; elephant seals benefit

April 16, 2019

Summary: New research challenges the notion that great white sharks are the most formidable predators in the ocean. The research team documented encounters between white sharks and orcas at Southeast Farallon Island off California. In every case examined by the researchers, white sharks fled the island when orcas arrived and didn’t return there until the following season. Elephant seal colonies in the Farallones also indirectly benefited from the interactions.

New research from Monterey Bay Aquarium and partner institutions published today in Nature Scientific Reports challenges the notion that great white sharks are the most formidable predators in the ocean. The study “Killer Whales Redistribute White Shark Foraging Pressure On Seals” shows how the great white hunter becomes the hunted, and the elephant seal, the common prey of sharks and orcas, emerges as the winner.

“When confronted by orcas, white sharks will immediately vacate their preferred hunting ground and will not return for up to a year, even though the orcas are only passing through,” said Dr. Salvador Jorgensen, senior research scientist at Monterey Bay Aquarium and lead author of the study.

The research team — which included Jorgensen and Monterey Bay Aquarium scientist Scot Anderson, and research partners from Stanford University, Point Blue Conservation Science and Montana State University — documented four encounters between the top predators at Southeast Farallon Island in the Greater Farallones National Marine Sanctuary, off San Francisco, California. The scientists analyzed the interactions using data from 165 white sharks tagged between 2006 and 2013, and compiled 27 years of seal, orca and shark surveys at the Farallones.

“The research in this paper combines two really robust data sources,” said Jim Tietz, co-author of the study and Farallon Program Biologist at Point Blue Conservation Science. “By supplementing the Aquarium’s new shark tagging data with Point Blue’s long-term monitoring of wildlife at the Farallon Islands National Wildlife Refuge, we were able to conclusively show how white sharks clear out of the area when the orcas show up.”

In every case examined by the researchers, white sharks fled the island when orcas arrived and didn’t return there until the following season.

Elephant seal colonies in the Farallones also indirectly benefited from the interactions. The data revealed four to seven times fewer predation events on elephant seals in the years white sharks left.

“On average we document around 40 elephant seal predation events by white sharks at Southeast Farallon Island each season,” Anderson said. “After orcas show up, we don’t see a single shark and there are no more kills.”

Each fall between September and December white sharks gather at the Farallones to hunt for young elephant seals, typically spending more than a month circling Southeast Farallon Island. Transient orcas also feed on elephant seals, but only show up occasionally at the island.

To determine when orcas and sharks co-occurred in the area, researchers compared data from the electronic shark tags with field observations of orca sightings. This made it possible to demonstrate the outcome on the rare instances when the predators encountered each other.

Electronic tags showed all white sharks began vacating the area within minutes following brief visits from orcas. Sometimes the orcas were only present for less than an hour. The tags then found the white sharks either crowded together at other elephant seal colonies farther along the coast or headed offshore.

“These are huge white sharks. Some are over 18 feet long (5.5 meters), and they usually rule the roost here,” Anderson said. “We’ve been observing some of these sharks for the past 15 to 20 years — and a few of them even longer than that.”

The study’s findings highlight the importance of interactions between top predators, which aren’t well-documented in the ocean.

“We don’t typically think about how fear and risk aversion might play a role in shaping where large predators hunt and how that influences ocean ecosystems,” Jorgensen said. “It turns out these risk effects are very strong even for large predators like white sharks — strong enough to redirect their hunting activity to less preferred but safer areas.”

The researchers drew no conclusions about whether orcas are targeting white sharks as prey or are bullying the competition for the calorie-rich elephant seals.

“I think this demonstrates how food chains are not always linear,” Jorgensen said. “So-called lateral interactions between top predators are fairly well known on land but are much harder to document in the ocean. And because this one happens so infrequently, it may take us a while longer to fully understand the dynamics.”

Ancient four-legged whale discovery in Peru


This 4 April 2019 video says about itself:

Four-legged whale ancestors reached South America in an otter-like swimming style

A four-legged whale from Peru indicates that early whales crossed the South Atlantic before 42.6 million years ago and may have propelled like otters: with a robust tail and webbed fingers on their long feet.

Production: Stéphane Van Israël, Royal Belgian Institute of Natural Sciences

From ScienceDaily:

Ancient, four-legged whale with otter-like features found along the coast of Peru

April 4, 2019

Cetaceans, the group including whales and dolphins, originated in south Asia more than 50 million years ago from a small, four-legged, hoofed ancestor. Now, researchers reporting the discovery of an ancient four-legged whale — found in 42.6-million-year-old marine sediments along the coast of Peru — have new insight into whales’ evolution and their dispersal to other parts of the world. The findings are reported in the journal Current Biology on April 4.

The presence of small hooves at the tip of the whale’s fingers and toes and its hip and limbs morphology all suggest that this whale could walk on land, according to the researchers. On the other hand, they say, anatomical features of the tail and feet, including long, likely webbed appendages, similar to an otter, indicate that it was a good swimmer too.

“This is the first indisputable record of a quadrupedal whale skeleton for the whole Pacific Ocean, probably the oldest for the Americas, and the most complete outside India and Pakistan”, says Olivier Lambert of the Royal Belgian Institute of Natural Sciences.

Some years ago, study co-author Mario Urbina of Museo de Historia Natural-UNMSM, Peru, discovered a promising area for digging fossils in the coastal desert of southern Peru, named Playa Media Luna. In 2011, an international team, including members from Peru, France, Italy, the Netherlands, and Belgium, organized a field expedition, during which they excavated the remains of an ancient whale they’ve since named Peregocetus pacificus. It means “the traveling whale that reached the Pacific.”

“When digging around the outcropping bones, we quickly realized that this was the skeleton of a quadrupedal whale, with both forelimbs and hind limbs,” Lambert says.

With the help of microfossils, the sediment layers where the skeleton was positioned were precisely dated to the middle Eocene, 42.6 million years ago. Anatomical details of the skeleton allowed them to infer that the animal was capable of maneuvering its large body (up to 4 meters long, tail included), both on land and in the water. For instance, features of the caudal vertebrae (in the tail) are reminiscent of those of beavers and otters, suggesting a significant contribution of the tail during swimming.

The geological age of the new four-limbed whale and its presence along the western coast of South America strongly support the hypothesis that early cetaceans reached the New World across the South Atlantic, from the western coast of Africa to South America, the researchers report. The whales would have been assisted in their travel by westward surface currents and by the fact that, at the time, the distance between the two continents was half what it is today. The researchers suggest that, only after having reached South America, the amphibious whales migrated northward, finally reaching North America.

The international team continues to study the remains of other whales and dolphins from Peru. “We will keep searching in localities with layers as ancient, and even more ancient, than the ones of Playa Media Luna, so older amphibious cetaceans may be discovered in the future,” Lambert says.

Sperm whale hunts squid, video


This video says about itself:

Rare Footage of a Sperm Whale Hunting a Squid

For decades, scientists and filmmakers have been trying to capture footage of the world’s largest active predator hunting 3,000 feet below the surface, deep in the dark depths of the ocean. Witness a sperm whale echolocate its prey with intense clicking and then successfully hunt down what is believed to be a squid.

New killer whale species discovery?


This 12 March 2019 video says about itself:

Mysterious Orcas Confirmed Alive in New Video | National Geographic

A team of NOAA scientists have, for the first time, found and studied the fabled Type D killer whale alive in the wild. They were first documented in 1955 when more than a dozen unidentified animals were found beached on the coast of New Zealand.

Compared with other types of orcas, these killer whales have a more rounded head, a narrower and more pointed dorsal fin, and a small white eyepatch. The orcas were seen off the tip of southern Chile in January 2019. Type D killer whales live in the subantarctic, home to some of the world’s stormiest waters. This inhospitable environment, and the fact that they aren’t usually found near shore, makes them nearly impossible to study. The scientists expect lab results to show that the Type D killer whale is a new species, and the largest undescribed animal left on the planet.