Beluga whales’ hearing, new research


This 2017 video is called Things You Should Know About Beluga Whales.

From Woods Hole Oceanographic Institution in the USA:

Beluga whales have sensitive hearing, little age-related loss

June 20, 2018

Scientists published the first hearing tests on a wild population of healthy marine mammals. The tests on beluga whales in Bristol Bay, Alaska, revealed that the whales have sensitive hearing abilities and the number of animals that experienced extensive hearing losses was far less than what scientists had anticipated.

The latter findings contrasted with expectations from previous studies of humans and bottlenose dolphins, which showed more hearing loss as they aged, says Aran Mooney, a biologist at Woods Hole Oceanographic Institution (WHOI) and lead author of two new studies on beluga whales. “But unlike the wild beluga population, the dolphins that were studied lived in a very noisy environment, as most humans do.”

At a time when noise in the ocean is increasing from human activities, such as oil and gas exploration and ship traffic, understanding the natural hearing abilities of whales and other endangered marine mammals is crucial to assessing potential noise impacts on animals and to management efforts to mitigate sound-induced hearing loss.

In the two related studies, WHOI researchers and their colleagues measured the hearing sensitivity of 26 wild belugas and then compared the audiograms to acoustic measurements made within their summer habitat in Bristol Bay to study how natural soundscapes-all sounds within their environment-may influence hearing sensitivity. The soundscape also reveals sound clues that the belugas may use to navigate. The first study was published May 8, 2018, in the Journal of Experimental Biology. Results from the soundscape study were published June 20, 2018, in the Journal of Ecoacoustics. “In the first paper, we characterized the beluga population’s hearing ability, which had not been done before in a healthy, wild population”, says Mooney. “And in the second paper, we put that into context to see how they might use acoustic differences in their habitat and how their hearing is influenced by the natural ambient noise in their environment.”

How do you test a beluga whale‘s hearing? Researchers applied the same screening method that doctors use to test the hearing of newborn babies who can’t yet vocally respond to whether or not they hear sounds: automated auditory brainstem response.

A suction cup sensor is gently placed on the whales’ head, just behind the blowhole, and another is placed on the back for reference. A series of quiet tones are played, and the sensors help measure the brain’s response to the sounds from the surface of the skin.

“It’s fairly straightforward,” Mooney says. “We just had to make a portable system that we could bring out into an extreme environment in order to perform the hearing tests.”

The test itself goes quickly, taking only about five minutes to measure each frequency. The most challenging part, says Mooney, is catching the participants.

For that, the researchers relied on the expertise of Alaskan Natives who hunt belugas. From small aluminum boats, the team would approach an individual adult whale-no calves were included in the study-in shallow waters of the bay. Taking care not to stress or injure the whale, they would catch it in a soft net. Marine mammal handlers, including teams from Georgia Aquarium, Shedd Aquarium, and Mystic Aquarium, would then get in the water to help secure the animal’s tail with a rope before moving it to a belly band (like a small stretcher) in the water next to a soft inflatable boat where the hearing tests took place.

“The belugas stayed relatively relaxed during the tests, seemingly employing a resting behavior that they may use to avoid killer whales“, Mooney explains. “When a killer whale is hunting them, belugas will often move to very shallow water and quietly stay there until they can safely return to deeper waters.”

In addition to the auditory testing, the researchers also performed a physical exam to assess the overall health, sex, and estimated age of each animal and obtained skin, breath, and blood samples to collect information on the whales’ hormone levels, microbiome bacteria, and other health-related data. The assessments were part of a beluga population health assessment program coordinated by the NOAA Fisheries Alaska Fisheries Science Center, the Alaska Department of Fish and Game, and Alaska SeaLife Center. Satellite transmitters were attached to some of the whales before release to study the whales’ movements.

The hearing tests revealed little hearing loss in the seemingly older members of the population, which could be because the estuary where the belugas reside is fairly quiet compared to more urban areas.

“Because there haven’t been any other studies of the hearing of wild marine mammals, we compared the results to previous studies of captive dolphins in San Diego and in Russia”, Mooney says. “The dolphins showed clear hearing loss as they aged, but the San Diego group lives in a very noisy environment, as most humans do.”

Mooney and colleagues also compared the wild belugas tests to those of belugas living in human care facilities. Both groups heard similarly well, and the authors suggest that it is likely due to the quiet environments in which they live.

“Sensitive hearing within a quiet soundscape could allow belugas to detect predators, navigate, and communicate with their young via low-amplitude signals,” Mooney explains. “This hearing sensitivity could be compromised in a noisier environment. It also suggests management concerns for animals that inhabit noisy areas, where they may already be showing greater proportions of hearing loss.”

The two studies are important to efforts to evaluate the effects of underwater noise on endangered Cook Inlet beluga whales, whose numbers have dwindled to an estimated 328. The species lives in habitats close to Anchorage, AK, and is exposed to noise from shipping, pile driving, construction, and explosive noise from nearby military bases.

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Over 100 bowhead whales seen in Arctic ocean


This January 2018 video is called Ice Giants [Bowhead Whale Documentary].

From Wageningen University in the Netherlands:

At least 100 Bowhead whales sighted in the East Greenland Sea

June 12, 2018

Scientists of Wageningen Marine Research have just returned from the Arctic after a successful expedition organised by Oceanwide Expeditions, Inezia Tours & Natuurpunt. During the spring, whilst working in the Greenland Sea to the Southwest of Spitsbergen, the scientists discovered a group of at least 100 foraging bowhead whales (Balaena mysticetus). This is a rare and endangered whale which is believed to be almost extinct and is consequently classed as ‘Critically Endangered’ according to the IUCN.

For some years scientists from Wageningen Marine Research have worked as expedition guides on board the expedition vessel Plancius from Oceanwide Expeditions. Since 2015, increasing numbers of bowhead whales have been observed on the edge of the pack-ice off East Greenland during these expeditions, but this year all previous numbers were exceeded. On the 1st June 2018, during almost 7 hours steaming along the pack ice, a total of 104-114 bowhead whales were systematically counted.

The bowhead whale is well adapted to live in the Arctic and is therefore the only large whale that can survive year-round in this extreme climate and specifically along the pack-ice. The sub-population of bowhead whales in the area of Spitsbergen/Greenland Sea has been greatly reduced since the whaling operations from the 16th century [on] and consequently this subpopulation, which is estimated to number ‘several hundreds of whales’ is now listed as Critically Endangered on the Red List of the IUCN.

In 2015, during a similar expedition, a total of 90 bowhead whales were recorded. It became immediately clear to the scientists that this type of data has an important scientific value as so little is currently known about this species that occurs in the Greenland Sea. The data indicate that the bowhead whales gather along the pack-ice during May/June. Old whaling data from the 16th century onwards highlight that the whales were hunted in the waters to the northwest of Spitsbergen (in April/May) and migrated south-westward by late spring (adult males and females without calves), while others moved north from Spitsbergen into the receding pack ice. Acoustic data has recently shown that during the winter months the bowhead whales occur further north off West Spitsbergen.

The bowhead whales were intensively hunted from the 16th century onwards for several hundred years and the various subpopulations that occur in the Arctic have yet to recover. Added to this the species’ very survival is now under threat from climate change. Even though it appears that the Spitsbergen sub-population may be larger than previously assumed, continued international research is still very necessary. In spite of the exceptional numbers of Bowhead whales encountered by the scientists this spring it is clear that this long-lived whale continues to be on the brink of extinction.

Narwhal sounds, new study


This video says about itself:

Listening to the aquatic sounds of narwhals, bowheads and seals in Arctic Canada

27 November 2013

Out of this world sounds while listening to this underwater mic hanging in the cold Arctic Ocean around Baffin Island. See the full story here.

From PLOS:

Narwhals’ acoustic behavior described using audio tagging

Recordings provide new insight into when and where elusive whales click, buzz and call

June 13, 2018

The clicking, buzzing and calling behavioral patterns of elusive East Greenland narwhals have been described thanks to in-depth recordings, in a study published June 13, 2018 in the open-access journal PLOS ONE by Susanna Blackwell from Greeneridge Sciences, Incorporated, United States of America, and colleagues.

Climate change is predicted to increase human activity in the Arctic, including remote areas of Greenland where narwhals live. However, little is known about the whales’ acoustic behavior or their reactions to anthropogenic sounds. Previous studies have mostly relied upon underwater microphones, which are limited in their ability to record spatial and temporal variations.

The author of the present study captured six narwhals in East Greenland and tagged them with acoustic and satellite instruments. The researchers were able to record 533 hours of audio and analyzed their recordings to describe how the whales’ acoustic behavior varied by location and time.

The researchers found that the narwhals produced three types of sounds: clicks, buzzes and calls. Clicks and buzzes were produced during echolocation for feeding, while the authors presume that calls served communication purposes. Calls were typically produced at depths of less than 100 meters, with over half being produced less than 7m from the surface. However, buzzes were produced at much greater depths of between 350 and 650 meters. The authors even used their recordings to identify a likely preferred feeding area: a particular fjord which had especially high buzzing rates. They also noted a possible stress response to capture and tagging: the narwhals were silent afterwards for around a day, reinforcing the need to record over larger timespans.

While much remains unknown about narwhal acoustics, this work provides new insights into where and when these elusive whales produce sound and could establish a baseline to help assess future impacts of climate and anthropogenic changes on narwhals.

Susanna Blackwell says: “Wide-scale changes are taking place in the Arctic, with warmer temperatures leading to shrinking summer ice coverage. More ice-free water means easier access for vessels and industrial operations, such as exploration for oil and gas. The inhospitable pack-ice environment that is narwhals’ home for much of the year has for millennia kept them in relative isolation — even from biologists. Now new amazing tools allow us to take a multi-day, virtual ride on the back of a narwhal!”

See also here.

New Zealand blue whales research


This 2017 video says about itself:

See Blue Whales Lunge For Dinner in Beautiful Drone Footage | National Geographic

Scientists filming in the South Ocean off the coast of New Zealand captured this stunning footage of a blue whale eating a mass of krill. The whales can grow up to the length of three school buses and require a lot of energy to accelerate in the water. They speed up to about 6.7 miles just before consuming the krill, and the act of opening their mouth slows them down to about 1.1 miles per hour. They then have to expend even more energy to get back up to speed. All of this energy spent may lead the whales to be picky eaters, if the mass of krill is too small they may swim through without opening their mouth to feed.

From Oregon State University in the USA:

New Zealand has its own population of blue whales

May 17, 2018

A group of blue whales that frequent the South Taranaki Bight (STB) between the North and South islands of New Zealand appears to be part of a local population that is genetically distinct from other blue whales in the Pacific Ocean and Southern Ocean, a new study has found.

The whales show a high level of residency, researchers say, as hydrophones deployed in the region recorded blue whale calls on 99.7 percent of the days between January and December in 2016.

The study, led by Oregon State University’s Marine Mammal Institute, is important because the South Taranaki Bight has several oil and gas extraction rigs and the New Zealand government recently issued its first permit for mining the seafloor there for iron sands.

Results of the study are being published this week in the journal Endangered Species Research.

“We had five hydrophones deployed for two years in the STB and we never heard any Australian blue whale calls — just the local New Zealand population”, said Leigh Torres, a principal investigator with OSU’s Marine Mammal Institute and co-author on the study. “When we conducted biopsies of individual whales, we also discovered that they are genetically distinct from other blue whale populations.”

This journey of discovery began in 2011 when a colleague told Torres that observers aboard seismic survey vessels had spotted nine blue whales. Torres thought it was unusual, and began looking at whaling records, which suggested the South Taranaki Bight region historically was a minor “hotspot” for blue whale activity.

She then assessed oceanographic patterns and found documentation of local upwelling that “supports aggregation of a certain krill species that blue whales like to eat.”

In 2013, Torres wrote a paper hypothesizing that blue whales may use this region because of a steady food supply. She said she received pushback from industry, resource managers and even other scientists because the blue whale is listed as a “migrant” by the New Zealand Threat Classification System.

So in 2014 she led a 10-day research expedition looking for blue whales to see if they were foraging in the area and during that study she and her colleagues identified roughly 50 blue whales. That led to more questions, including whether the whales were part of a migratory population from, say, Australia, or were potentially a distinct New Zealand population.

Torres and her graduate student, Dawn Barlow, led longer surveys in the summers of 2016 and 2017, trying to determine the abundance, distribution patterns and population structure of the New Zealand blue whales. They used biopsy darts to determine the genetics of the whales, compared sightings with photo IDs of whales from other regions, and listened to the hydrophones deployed in the region for two years.

They were able to identify 151 individual New Zealand blue whales between 2004 and 2017 by examining various photographic evidence and then used that and other data to estimate their overall abundance.

“There is no doubt that New Zealand blue whales are genetically distinct, but we’re still not certain about how many of them there are”, Barlow said. “We have generated a minimum abundance estimate of 718, and we also were able to document eight individuals that we re-sighted in multiple years in New Zealand waters, including one whale seen in three of the four years with a different calf each time, and many others we saw at least once.”

Torres said the OSU researchers are “working closely with resource managers in New Zealand to help them understand what we do and don’t know about this New Zealand blue whale population so they can apply best management practices to minimize impacts from industry.”

“While we have gained a great amount of information about blue whales in New Zealand over the past few years, we continue to analyze our data and do more research to address other knowledge gaps.”

The blue whales found off New Zealand, Australia and Chile are not quite as large as Antarctic blue whales, which scientists believe to be the largest animals to have ever lived on Earth. Antarctic blues, when they reach adulthood, can range from 28 to 30 meters in length (nearly 100 feet). The other blue whales, though slightly smaller, are still formidable at about 22 meters in length (or 72 feet).

The Oregon State researchers will return to New Zealand in July and meet with government and political leaders, as well as industry representatives. They also are presenting their data to the International Whaling Commission.

Marine animals discoveries in Atlantic ocean


This video from the USA says about itself:

25 October 2017

Join NRDC senior oceans scientist Lisa Suatoni on an animated submersible tour of the weird, wonderful, and imperiled underwater world of the Northeast Canyons and Seamounts National Monument. The ocean floor off the east coast of the United States is carved with canyons deeper than the Grand Canyon, and, beyond those, extinct volcanoes. President Obama made almost 5,000 miles of this unique area a national monument, but the Trump administration is interested in revoking its monument status to open this pristine area with 4,000-year-old corals to industrial fishing, mining, and drilling. Not many people get to explore these incredible depths—but once you see what’s down there, you’ll never be the same!

Take action: here.

From the New England Aquarium in the USA:

Diverse and abundant megafauna documented at new Atlantic US Marine National Monument

Rare aerial survey of Northeast canyons and seamounts

May 16, 2018

Airborne marine biologists were dazzled by the diversity and abundance of large, unusual and sometimes endangered marine wildlife on a recent trip to the Northeast Canyons and Seamounts National Marine Monument, about 150 miles southeast of Cape Cod. Scientists with the Anderson Cabot Center for Ocean Life at the New England Aquarium observed dozens of dolphins mixing with schools of pilot whales plus more than a dozen of the very rarely seen and mysterious Sowerby’s beaked whales. The researchers, aboard a twin engine airplane, also spotted endangered, Moby Dick-like sperm whales as well as the second largest species of sharks in the world and the bizarre-looking giant ocean sunfish or Mola mola.

The Northeast Canyons marine monument is a critical hotspot of biodiversity on the edge of the continental shelf where the shallow seas off of New England drop sharply into the deep waters of the northwestern Atlantic. In 2016, President Obama designated three underwater canyons that are deeper than the Grand Canyon, and four seamounts as tall as the Rockies, as the first American marine national monument in Atlantic waters. However in 2017, Secretary of the Interior Ryan Zinke recommended to President Trump that the Northeast Canyons and Seamounts either be downsized or eliminated. The exact nature of the recommendation has yet to be specified.

Given the great distance offshore, documenting the marine life there is a challenge. During the 4.5-hour aerial survey, the team spotted 169 bottlenose dolphins, 57 pilot whales, 44 Risso’s dolphins, 13 rare Sowerby’s beaked whales, four sperm whales, and 44 other dolphins of various species. In two sightings, they saw a mixed group of up to 50 bottlenose dolphins and 30 pilot whales, but what intrigued the researchers most was that three groups of Sowerby’s beaked whales were spotted at the water’s surface, a rare occurrence given their marathon dive times.

This is “extraordinary for such a small area,” said Dr. Ester Quintana, the lead scientist on the Anderson Cabot Center aerial team, adding that they also observed basking sharks, the second largest species of shark in the world, and the strange, large, plankton-feeding Mola mola, or ocean sunfish.

The aerial sightings help researchers understand how the species are using the richly biodiverse monument waters and deep coral canyons at different times of year and for different purposes. “One of the reasons we do this work is that we are just discovering what’s going on out there,” said Dr. Scott Kraus of the Anderson Cabot Center. “This is an opportunity to see how animals use this habitat. No one has ever done this before.”

This was the third in a series of aerial surveys of the monument that began in summer 2017, and the number of sightings by the scientists during this survey was higher than any other, nearly double the number of animals observed last fall.

“These surveys continue to show the incredible abundance of marine life in the Northeast Canyons and Seamounts Marine National Monument,” said Kraus. “These sightings support the idea that this area is worthy of complete protection.”

“This area was declared protected because it is a fragile ecosystem with a wide diversity of corals, deep water fishes, and invertebrates around these pristine canyons and seamounts that support a vast array of whales, dolphins, and large fish”, Dr. Quintana said. “As new policies recommend opening more waters off the US coast to offshore drilling, it is incredibly important to have areas that remain protected.”

She said the Northeast Canyons monument area is about one-tenth of one percent of all US ocean territorial waters. “Yet, the wildlife diversity we are seeing out there highlights the importance of preserving its ecological value,” Dr. Quintana said.

‘A BETRAYAL OF THE AMERICAN PEOPLE’ EPA chief Scott Pruitt was lambasted by the Senate appropriations committee Wednesday for the myriad ethical scandals plaguing him, with Sen. Patrick Leahy (D-Vt.) accusing him of turning the department into “a laughingstock.” [HuffPost]

Cute marine animals video


This video from the USA says about itself:

5 Sea Creatures Cuter than Cats! | BLUE WORLD ACADEMY

23 February 2018

Jonathan explains why there should be less cat videos and more beluga videos in this goofy short video about the cutest creatures in the sea.

BLUE WORLD ACADEMY is a studio-based spin-off of the underwater YouTube program JONATHAN BIRD‘S BLUE WORLD featuring host Jonathan Bird.