Temperature blob in Pacific Ocean gives a glimpse of climate impact on humpback whales

March 20, 2019 by Bob Yirka, Phys.org report

A team of researchers with the Keiki Kohola Project and California State University reports that a recent "blob" of warm water in the Pacific gives marine scientists a preview of the impact of climate change on humpback whales. In their paper published in the journal Royal Society Open Science, the group describes their study of the whales and what they found.

Humpback whales were once hunted to the point that they became endangered, but several decades ago, international laws were enacted to protect them, and they rebounded—these measures were so successful that the U.S. National Marine Fisheries Service took the whales off the endangered species list back in 2016. But now, it appears the whales face a new threat—climate change.

In a new effort, the researchers studied the reproductive habits of humpback whales that migrate between the waters off the Alaskan coast and those that surround the Hawaiian Islands. They had noted that in 2013, a giant mass or "blob" of warm water had formed in the Gulf of Alaska, and over the course of the next six years, slowly made its way south. Prior research had shown that temperatures in the blob were up to 3 degrees C warmer than surrounding water—high enough to kill krill and other sea creatures that serve as food for humpback whales. This led the researchers to embark on a study of the impact of the blob on the humpback whales.

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Humpback whales' songs at subarctic feeding areas are complex, progressive

January 23, 2019, Public Library of Science

Humpback whales overwintering in feeding areas may sing complex, progressive songs which closely resemble those associated with breeding grounds, according to a study published January 23, 2019 in the open-access journal PLOS ONE by Edda E. Magnúsdóttir and Rangyn Lim from the University of Iceland.

Humpback whales (Megaptera noveangliae) migrate annually between summer subarctic feeding areas to winter tropical breeding grounds, where males are known to sing characteristic songs which are linked to mating. However, recent studies indicate some humpback pods may overwinter in their feeding grounds rather than migrating, raising the question of whether and how males sing in these circumstances. The authors of the present study used acoustic recorders in the feeding grounds of Skjálfandi Bay in northeast Iceland between January and March of 2011, recording the songs of male humpback whales which were overwintering here. Whale songs were recorded on 42 of the 46 recording days, producing a total of 70 ten-minute song files used for analysis.

The authors identified 15 distinct phrases and themes within the whale songs. They noted that the songs they recorded may represent a characteristic song type with a sophisticated structure and order of themes—and closely resemble the songs associated with breeding grounds. Song themes also appeared to evolve gradually over the recording period, possibly indicating the existence of song exchange and cultural transmission in these feeding grounds.

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Giant singers from neighboring oceans share song parts over time

January 9, 2019, Wildlife Conservation Society

Singing humpback whales from different ocean basins seem to be picking up musical ideas from afar, and incorporating these new phrases and themes into the latest song, according to a newly published study in Royal Society Open Science that's helping scientists better understand how whales learn and change their musical compositions.

The new research shows that two humpback whale populations in different ocean basins (the South Atlantic and Indian Oceans) in the Southern Hemisphere sing similar song types, but the amount of similarity differs across years. This suggests that males from these two populations come into contact at some point in the year to hear and learn songs from each other.

The study titled "Culturally transmitted song exchange between humpback whales (Megaptera novaeangliae) in the southeast Atlantic and southwest Indian Ocean basins" appears in the latest edition of the Royal Society Open Science journal. The authors are: Melinda L. Rekdahl, Carissa D. King, Tim Collins, and Howard Rosenbaum of WCS (Wildlife Conservation Society); Ellen C. Garland of the University of St. Andrews; Gabriella A. Carvajal of WCS and Stony Brook University; and Yvette Razafindrakoto of COSAP and Madagascar National Parks.

"Song sharing between populations tends to happen more in the Northern Hemisphere where there are fewer physical barriers to movement of individuals between populations on the breeding grounds, where they do the majority of their singing. In some populations in the Southern Hemisphere song sharing appears to be more complex, with little song similarity within years but entire songs can spread to neighboring populations leading to song similarity across years," said Dr. Melinda Rekdahl, marine conservation scientist for WCS's Ocean Giants Program and lead author of the study. "Our study shows that this is not always the case in Southern Hemisphere populations, with similarities between both ocean basin songs occurring within years to different degrees over a 5-year period."

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Humpback whales come to the Mediterranean to feed themselves

Experts predict that sightings of this species could increase in the Mediterranean in the coming years

Date:  November 15, 2018

Source:  University of Seville

Although the presence of humpback whales in the Mediterranean has been considered unusual, it is known that their visits have increased in the last 150 years. Until now, there had been no clear reason to justify this fact, with various options being considered, such as disorientation, following the migratory routes of other species, etc. However, a recently published study by experts from the University of Seville and from the Biological Research Area from the Seville Aquarium indicates that what motivates these cetacean mammals to enter these waters is the search for food.

This species travels long migration routes from the poles (both North and South), where the feeding areas are found, to the Equator to reproduced in the 15 DPS reproduction areas detected by the scientific community until now.

"In spring of 2016, a single young humpback whale was detected alongside a boat used from sighting cetacean mammals in the area. For almost a month, it was possible to follow the animal within the bay of Algeciras, taking exhaustive data, accompanied by photographs for photo-identification and future tracking of the animal, as well as for checking that the animal did not have any kind of problem," informs José Carlos García-Gómez, direct of the Marine Biology Laboratory at the University of Seville.

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First study of humpback whale survivors of orca attacks in the Southeastern Pacific

Date:  November 6, 2018

Source:  Smithsonian Tropical Research Institute

Humpback whales bear stark battle scars from violent encounters with orcas, also known as killer whales. Analysis of rake marks on more than 3000 humpback whale tails or flukes suggest that attacks on these undersea giants may be on the rise, according to a new study in Endangered Species Research.

"We set out to discover where, when and at what age humpback whales in the Southeastern Pacific are attacked by orcas," said Hector M. Guzman, marine ecologist at the Smithsonian Tropical Research Institute.

Orcas, Orcinus orca, like humans, are apex predators. Although they can feed on more than 20 different species of cetaceans, they usually prefer sea lions, fur seals, fish and sea birds. "Because the chances of observing rake marks on young, vulnerable whales increased in the last 20 years, we think that killer whale attacks on humpback whales may be more common now than they were in the past, perhaps due to the recovery of whale breeding stocks in the Southeast Pacific after hunting was prohibited," said Juan Capella, lead author and marine biologist from Whalesound Ltd. in Chile.

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Watching whales from space

Date: November 1, 2018

Source: British Antarctic Survey

Scientists have used detailed high-resolution satellite images provided by Maxar Technologies' DigitalGlobe, to detect, count and describe four different species of whales. Reported this week in the journal Marine Mammal Science, this study is a big step towards developing a cost-effective method to study whales in remote and inaccessible places, that will help scientists to monitor population changes and understand their behaviour.

Each species was observed in one of their known aggregation areas, where individuals come together to congregate: southern right whales off Argentina, humpback whales off Hawaii, fin whales in the Pelagos Sanctuary in the Mediterranean and grey whales off the coast of Mexico. Already it has helped whale conservation bodies to identify 10 key inaccessible whale populations that would benefit most from the application of satellite imagery in studies.

Lead author Hannah Cubaynes, a whale ecologist at British Antarctic Survey (BAS) and University of Cambridge explains:

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Are these humpback whales too close for comfort?

September 3, 2018 by Emily Arntsen, Northeastern University

As many as six humpback whales were spotted in Boston Harbor on Wednesday, a rare sight in the congested shipping port. But the whales probably weren't lost, according to Joseph Ayers, a professor at Northeastern's Marine Science Center in Nahant, Massachusetts. They were probably just looking for a snack.

"There appear to be a lot of bait fish in the area right now, like pogies, and that seems to be attracting the whales," he said. Ayers, who specializes in marine science and neurophysiology, said that whales are usually feeding whenever people see them close to shore.

Ayers said that in the past, he has seen humpbacks as close as "50 yards off the wharf in Nahant." But while it might be normal for these whales to come close to shore, it's not common for them to swim into Boston Harbor. In fact, Ayers said it could be quite dangerous.

"Boats are the biggest problem for whales. If a whale swims into the propeller of a boat, especially something as big as a shipping vessel, it could be deadly," he said. Since the whale sightings earlier this week, the U.S. Coast Guard in Boston has warned boaters to be aware of the animals.

Boaters might be able to avoid whales by steering clear of large flocks of birds because, according to Ayers, "Whenever you see a flock of birds, it means there are fish around." And where there are fish, there could be humpback whales.

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Baby Humpback Whales May Soon Fill Antarctic Seas

By Yasemin Saplakoglu, Staff Writer | May 2, 2018 11:14am ET

Lots of baby humpback whales may be on their way, if recent years are any indication.

An unusually high number of female humpbacks living in the Southern Ocean around the Western Antarctic Peninsula have gotten pregnant in recent years, according to a study published today (May 2) in the journal Royal Society Open Science. Researchers are hopeful that the population is recovering from years of commercial whaling that nearly wiped them out in the area in the 20th century.

Humpback whales usually give birth every couple of years and have pregnancies that last for around 11 months, according to the National Oceanic and Atmospheric Administration. Once the baby is born, the mother is very "protective" and "affectionate" toward its young, according to NOAA.

Pregnant or not, humpback whales were easy targets for whalers because of their abundance in bays and their tendency to float when killed, according to the study. With treaties put in place in the late 20th century, whaling stopped, and populations slowly began to recover. Now, humpback whales in the Southern Ocean around Antarctica are not considered endangered, according to The New York Times.

The researchers collected skin and blubber samples between 2010 and 2016 from 268 unsuspecting females. They tested the samples for progesterone — a hormone that regulates the reproductive system and pregnancy in most mammals, including humans. If the progesterone levels matched those found previously in pregnant female humpbacks, the researchers could indicate if these giants were "expecting."

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Monitoring bacteria on whale skin

Humpback microbiome linked to seasonal, environmental changes

Date:  February 14, 2018
Source:  Woods Hole Oceanographic Institution

Summary:
Just like with humans, the skin on marine mammals serves as an important line of defense against pathogens in their environment. A new study sheds light on the skin microbiome -- a group of microorganisms that live on skin -- in healthy humpback whales, which could aid in future efforts to monitor their health.

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Unexpected flipper flapping in humpback whales observed

Date:  July 10, 2017

Source:  Stanford University

Summary:  Humpback whales flap their foreflippers like penguins or sea lions, researchers have discovered. This unexpected observation helps explain whale maneuvering and could improve designs inspired by their movement.

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Humpback whales: Calving ground loyalty drives population differences, study finds

Largest study of its kind helps illuminate unseen connections between whale populations

Date:  July 6, 2017

Source:  Wildlife Conservation Society

Summary:  Scientists conducting the first circum-global assessment of mitochondrial DNA variation in the Southern Hemisphere's humpback whales (Megaptera novaeangliae) have found that whales faithfully returning to calving grounds year after year play a major role in how populations form.

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Baby whales 'whisper' to mothers to avoid predators: study

April 26, 2017 by Valerie Dekimpe

Newborn humpback whales and their mothers whisper to each other to escape potential predators, scientists reported Wednesday, revealing the existence of a previously unknown survival technique.

"They don't want any unwanted listeners," researcher Simone Videsen, lead author of a study published in Functional Ecology, told AFP.

"Potential predators such as killer whales could listen to their conversations and use that as a cue to locate the calf and predate on it."

Whales are known for their loud calls, congregating fellow members of the pod. Male humpback whales also emit reverberating sounds to attract females during the mating season.

But this is the first time scientists have observed a unique, intimate form of communication between humpback mothers and calves.

Researchers from Denmark and Australia tracked each of eight calves and two mothers for 24 hours in Exmouth Gulf, Western Australia, a breeding ground for Antarctic humpback whales seeking warmer waters to mate and give birth.

Using tags attached to the animals, the team of scientists recorded their faint squeaks and grunts.

"These signals between mother and calf are more quiet than those of normal adult humpback whales," Videsen said, noting they were 40 dB lower than the singing of males in the area.

While a male's cry can resound over an area covering several kilometres, the pairs in the study could only hear each others' calls within a distance of less than 100 metres (330 feet), she added.

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Humpback whales are gathering in huge groups, and nobody knows why

March 15, 2017

by Chuck Bednar

Although humpback whales are not typically known to be social creatures, preferring to swim alone or in small groups most of the time, experts have spotted so-called “super-groups” of the aquatic mammals during three recent research cruises, according to a new study.

Writing in the journal PLOS One, Ken Findlay of the Cape Peninsula University of Technology (CPUT) and his colleagues said that they had found 22 separate instances of between 20 and 200 whales gathering off the coast of South Africa during voyages in 2011, 2014 and 2015.

As Gizmodo and ScienceAlert reported this week, such large gatherings of humpbacks are rare. The creatures tend to prefer traveling in groups of seven or less. There had previously been only one recorded instance of a gathering of more than 20 whales, and that was thought to be multiple smaller groups traveling close together.

“I've never seen anything like this,” Findlay, a zoologist and marine biologist at CPUT, told New Scientist during an interview on Friday. “It’s possible that the behavior was occurring but just not where it was visible. Because there were so few of them, we may not have seen it.”

Odd behavior may actually be good news, say experts

In their study, he and his fellow researchers called the behavior “novel and intense,” adding that it is “a relatively recent behavior exhibited by these whales” and that no such large groups have been spotted “elsewhere in low or mid-latitudes during Southern Hemisphere... migrations.”

Findlay’s team believes that the whales may be adapting in response to the changing availability of prey, New Scientist said– and it isn’t just the size of their hunting groups that have gotten the attention of scientists. These “super-groups” were found far beyond the whales’ normal hunting grounds in the southern polar region of Antarctica, thousands of kilometers to the south.

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Massive genetic study of humpback whales to inform conservation assessments

Study confirms need to protect unique humpback whales in Arabian Sea

Date: January 9, 2017

Source: Wildlife Conservation Society

Scientists have published one of the largest genetic studies ever conducted on the humpback whale (Megaptera novaeangliae) for the purpose of clarifying management decisions in the Southern Hemisphere and supporting calls to protect unique and threatened populations, according to WCS (Wildlife Conservation Society), the American Museum of Natural History, Columbia University, and other organizations.

Using data generated from more than 3,000 skin samples from individual whales ranging from the South Atlantic to the Indian Oceans, the research team has uncovered previously unknown degrees of relatedness between different whale populations. The study will also help inform ongoing conservation reassessments of humpback whale populations, and reaffirms the highly distinct nature of a small, non-migratory population of humpback whales living in the Arabian Sea in need on continued protection.

The study titled "Multiple processes drive genetic structure of humpback whale (Megaptera novaeangliae) populations across spatial scales" appears in the the journal Molecular Ecology.

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