Welcome Guest [Log In] [Register]
Welcome to Carnivora. We hope you enjoy your visit.


You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are some features you can't use. If you join our community, you'll be able to access member-only sections, and use many member-only features such as customizing your profile and voting in polls. Registration is simple, fast, and completely free.


Join our community!


If you're already a member please log in to your account to access all of our features:

Username:   Password:
Add Reply
Gray whale - Eschrichtius robustus
Topic Started: Jan 9 2012, 12:31 PM (4,767 Views)
Taipan
Member Avatar
Administrator

Gray whale - Eschrichtius robustus

Posted Image

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Mysticeti
Family: Eschrichtiidae
Genus: Eschrichtius
Species: Eschrichtius robustus

PHYSICAL DESCRIPTION: Gray whales have a streamlined body, with a narrow, tapered head. The upper jaw is arched in profile, and slightly overlaps the lower jaw. The rostrum (upper jaw) is dimpled and each of the little depressions contains one stiff hair. There are 2-5 grooves on the ventral throat 5 feet (1.5 m) in length.

COLOR: The gray whale received its name from the gray patches and white mottling on its dark skin. On the skin are many scratches, scattered patches of white barnacles, and orange whale lice. Newborn calves are dark gray to black, although some may have distinctive white markings.

FINS AND FLUKE: The gray whale has no dorsal (top) fin. About 2/3 of the way back on its body is a prominent dorsal hump followed by a series of 6-12 knuckles along the dorsal ridge that extend to the flukes (tail lobes). Its flippers are paddle shaped and pointed at the tips. Its fluke is about 10-12 feet (3.7 m) across, pointed at the tips, and deeply notched in the center.

LENGTH & WEIGHT : Adult males measure 45-46 feet (13.7-14 m) and adult females measure slightly more. Both sexes weigh 30-40 tons (27,200-36,300 kg).

Posted Image

DISTRIBUTION & MIGRATION: Gray whales inhabit shallow coastal waters of the eastern North Pacific. The gray whale makes one of the longest of all mammalian migrations, averaging 10,000-14,000 miles (16,000-22,530 km) round trip. In October, the whales begin to leave their feeding grounds in the Bering and Chukchi Seas and head south for their mating and calving lagoons in Baja California, Mexico. The southward journey takes 2-3 months. The whales remain in the lagoons for 2-3 months, allowing the calves to build up a thick layer of blubber to sustain them during the northward migration and keep them warm in the colder waters. The return trip north takes another 2-3 months. Mothers and calves travel very near shore on the northbound migration. There are some individual gray whales that are found year round in the Straits of Juan de Fuca between the State of Washington and Vancouver Island, Canada, and some that are seen during the summer months off the northern California coast.

Posted Image

FEEDING: Gray whales feed on small crustaceans such as amphipods, and tube worms found in bottom sediments. They feed primarily during the summer months of long daylight hours in the cold Arctic waters of the Bering and Chukchi seas. As a baleen whale, it has a series of 130-180 fringed overlapping plates hanging from each side of the upper jaw, where teeth might otherwise be located. These plates consist of a fingernail-like material called keratin that frays out into fine hairs on the ends inside the mouth next to the tongue. The plates are off-white and about 2-10 inches (5-25 cm) in length. To feed, a whale dives to the bottom, rolls on its side and draws bottom sediments and water into its mouth. As it closes its mouth, water and sediments are expelled through the baleen plates, which trap the food on the inside near the tongue to be swallowed.

Posted Image

REPRODUCTION: Gray whales reach sexual maturity at 5-11 years of age, or when they reach 36-39 feet (11-12 m) in length. Gestation is 12-13 months. The calf weighs 1,100-1,500 pounds (500-680 kg) and is about 15 feet (4.5 m) at birth. Calves nurse 7-8 months on milk that is 53% fat (human milk is 2% fat). Females bear a single calf, at intervals of 2 or more years. Courtship and mating behavior are complex, and frequently involve 3 or more whales of mixed sexes. Mating and calving both occur primarily in the lagoons of Baja California, Mexico, although both have been observed during the migration.

NATURAL HISTORY: A migrating gray whale has a predictable breathing pattern, generally blowing 3-5 times in 15-30 second intervals before raising its fluke and submerging for 3-5 minutes. A gray whale can stay submerged up to 15 minutes, and travel at 3-6 miles per hour (4.8-9.6 km/hr). Mothers are very protective of their calves, and earned the name "Devilfish" from early whalers in the lagoons because of their violent defensive behaviors. Orcas (killer whales) are a cause of gray whale deaths, and many gray whales have orca teeth scars on their flukes.

Posted Image

STATUS: At one time there were three gray whale populations: a north Atlantic population, now extinct, possibly the victims of over-hunting; a Korean or western north Pacific stock now very depleted, also possibly from over-hunting; and the eastern north Pacific population, the largest surviving population. Hunted to the edge of extinction in the 1850's after the discovery of the calving lagoons, and again in the early 1900's with the introduction of floating factories, the gray whale was given partial protection in 1937 and full protection in 1947 by the International Whaling Commission (IWC). Since that time the eastern north Pacific gray whale population has made a remarkable recovery and now numbers between 19,000 and 23,000, probably close to their original population size.

http://www.acsonline.org/factpack/graywhl.htm

Posted Image

Edited by Taipan, Feb 11 2018, 01:18 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Gray Whales A Fraction Of Historic Levels, Genetic Research Shows

Posted Image
Gray whales (Eschrichtius robustus) return from Arctic feeding grounds to lagoons in Mexico each winter to give birth. New genetic results indicate that in the past, the number of whales returning to these lagoons may have been much larger.

Science Daily — Gray whales in the Pacific Ocean, long thought to have fully recovered from whaling, were once three to five times as plentiful as they are now, according to a new article.

Today's population of more than 22,000 gray whales has successfully been brought back from the threat of extinction and is now the most abundant whale on the North American west coast. But the new findings from researchers at Stanford University and the University of Washington suggest that the current population is actually far below the original number--estimated by genetic methods at 96,000 animals--that once roved the Pacific Ocean.

The report also weighs in about why large numbers of gray whales have recently been discovered suffering from starvation. Previously it was assumed that the thin and starving animals are a consequence of the gray whale population exceeding its historical ecological limits. But if the Pacific normally housed 96,000 gray whales, then starving whales may be suffering reduced food supply from changing climate conditions in their Arctic feeding grounds. This possibility parallels reports last year of major climate shifts in the Arctic ecosystems in which gray whales feed. The study also suggests that lowered numbers of gray whales no longer play their normal role in ocean ecology.

Gray whales were hunted extensively in the late 19th century. "The lagoons of Baja California were the primary killing fields for gray whales," recounted lead author S. Elizabeth Alter, a Stanford researcher. "But we don't know exactly how many there were before whaling took its toll." The new research measures the amount of genetic variation in current gray whales across ten different sections of their genome, and back calculates the long-term population size based on new measurement of the mutation rate of these gene segments.

Steve Palumbi, the Harold A. Miller Professor in Marine Sciences at Stanford's Hopkins Marine Station, explained, "Our survey uncovers too much variation for a population of 22,000. The overabundance of genetic variation suggests a much larger population in past centuries." The study uses computer-based genetic simulations to show that the level of genetic variation is instead more likely to be from a past population of 76,000 to 118,000 animals (with an average of 96,000).

Such a vastly reduced population of gray whales has likely exerted large changes in Pacific ocean ecosystems. Unique among whales, the gray bulldozes the oceans, digging troughs through the sea floor for food. In the process, they resuspend ocean sediments bring food to the surface. "A population of 96,000 gray whales would have resuspended 12 times more sediment each year than the biggest river in the Arctic, the Yukon," said Alter, "and would have played a critical role in the ecology of the Bering Sea."

Other species may have felt the loss of whales as well. "The feeding plumes of gray whales are foraging grounds for Arctic seabirds," Palumbi said. "96,000 gray whales would have helped feed over a million seabirds a year."

The research also raises questions about how many whales the current oceans can now support-- and whether the future of whales, even if whaling is limited, may be reduced by new problems in the guise of oceanic overfishing and global climate change. "Despite our best efforts," Palumbi said, "these genetic results suggest gray whales have not fully recovered from whaling. They might be telling us that whales now face a new threat - from changes to the oceans that are limiting their recovery."

"Decades ago, whales were the first creatures to tell us that we were overfishing the oceans," Palumbi concluded. "Maybe now they trying to tell us the oceans are in deeper trouble."

This research is to be published September 10 in the Proceedings of the National Academy of Sciences.

Note: This story has been adapted from a news release issued by SeaWeb.

http://www.sciencedaily.com/releases/2007/09/070910173819.htm
Edited by Taipan, Feb 11 2018, 01:19 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Gray Whale Shot with Machine Gun

By Associated Press

posted: 10 September 2007 09:38 am ET

NEAH BAY, Wash. (AP) -- An injured California gray whale was swimming out to sea Saturday after being shot with a machine gun off the western tip of Washington state, officials said.

Coast Guard Petty Officer Kelly Parker said five people believed to be members of the Makah Tribe shot and harpooned the whale Saturday morning. The extent of the whale's injuries were not immediately known.

Tribe members were being held by the Coast Guard but had not been charged, said Mark Oswell, a spokesman for the law enforcement arm of the National Marine Fisheries Service.

A preliminary report said the whale was shot with a .50-caliber machine gun, Oswell said.

Coast Guard officials created a 1,000-yard safety zone around the injured whale, which was shot about a mile east of Neah Bay in the Strait of Juan de Fuca. The whale had begun heading to sea Saturday afternoon, Oswell said.

Although the tribe has subsistence fishing rights to kill whales, Oswell said preliminary information indicates the whale may have been shot illegally.

"We allow native hunts for cultural purposes. However, this does not appear to be of that nature so far,'' he said.

The Makah Tribe has more than 1,000 members and is based in Neah Bay.

A call to tribal officials was not immediately returned on Saturday. Tribal Chairman Ben Johnson told The Seattle Times that the tribe has been seeking an exemption from the federal Marine Mammal Protection Act so that it could take up to five gray whales per year. However, Johnson said the tribe had not yet secured that exemption for a new hunt.

http://www.livescience.com/animals/070910_ap_whale_gun.html
Edited by Taipan, Feb 11 2018, 01:21 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Whale 'success story' questioned

By Richard Black
Environment correspondent, BBC News website

Last Updated: Monday, 10 September 2007, 21:47 GMT 22:47 UK

Posted Image
Gray whales have one of the most spectacular migrations known

A whale conservation success story, the recovery of the eastern Pacific gray whale, may not be quite what it seems.

Since the end of commercial whaling, numbers rose to about 20,000, thought to be the level they had been at before hunting began.

But a new study using genetic methods, reported in the journal PNAS, suggests pre-hunting numbers were much higher.

The scientists say climate change may be altering the whales' supply of food significantly.

Earlier this year, researchers noted signs that grays were showing distinct signs of malnutrition when they arrived at their winter breeding grounds along Mexico's Baja peninsula.

They raised the idea that this might be connected with climate change. But the prevalent theory was that numbers had risen beyond the maximum level which the ecosystem could support.

The new research challenges that idea.

"I think that when we see large-scale issues in the population, such as starving or malnourished whales, we should be looking to long-term climatic changes in their feeding grounds," said Liz Alter from Stanford University, US.

Stock take

A few hundred years ago, three separate populations of gray (or grey) whales lived in the oceans.

The Atlantic stock is thought to have perished in the 17th Century, perhaps despatched by a combination of environmental change and early hunting. Later, the eastern and western Pacific populations almost followed suit.

The western stock, which lives along the eastern coast of Russia, is now close to extinction once more.

Numbers may be as low as 120; development of oil and gas installation and entanglement in fishing nets are the principal threats.

But the eastern Pacific gray has supposedly seen rude health. It was taken off the US endangered species list in 1994, with numbers each year hovering about 20-25,000, which historical records from the whaling industry and computer models of population indicated was around the historical level.

The new genetic analysis, which Liz Alter's group has published in Proceedings of the National Academy of Sciences (PNAS), challenges this view.

By looking at variation in the animals' DNA, the team concludes there were once 76,000-118,000 grays in the Pacific.

Even if those numbers were split between the eastern and western stocks, this indicates that the population of the eastern gray today is well below the historical level.

However, Greg Donovan, head of science at the International Whaling Commission (IWC) and editor of the Journal of Cetacean Research and Management, suggested these estimates should be treated with some caution.

"Using genetic methods to estimate pre-whaling abundance is fascinating but still in its infancy, and IWC scientists believe there are a number of issues still to be resolved with it," he said.

The Stanford researchers acknowledge that further analysis should be done to confirm their findings. In particular, they would like to have samples from the critically endangered western stock, but given its parlous health, this would clearly be a sensitive issue.

Look west

Confirmation could have implications for traditional, or subsistence, whaling.

Aboriginal groups in Chukotka in the Russian northeast are permitted to hunt 124 eastern grays each year to provide meat for their communities.

The Makah tribe of Washington State near Seattle is allowed a further five. Its hunting is currently suspended pending a domestic US legal settlement, though one gray was killed just this weekend, apparently without permission of tribal elders.

If historical numbers were much higher, that could imply the grays are not as robust as believed, which could lower these hunting quotas still further.

However, Dr Donovan said current quotas are reliable.

"We have taken scientific uncertainties into account, including how many whales the environment can support, in our calculations of catch limits for the eastern gray whale," he said.

"We believe that conservation efforts should focus on the western population, which numbers only about 120 animals."

http://news.bbc.co.uk/2/hi/science/nature/6988339.stm

Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Mediterranean gray whale appears 'back from the dead'

By Matt Walker
Editor, Earth News

Posted Image
Gray whale sighted off Herzliya Marina

A gray whale has appeared off the coast of Israel, shocking conservationists.

Gray whales are thought to be extinct across the Atlantic Ocean, so the appearance of an individual within the Mediterranean Sea is a major surprise.

The whale may have inadvertently travelled a huge distance from its natural habitat thousands of kilometres away in the Pacific Ocean.

However, it raises the possibility that gray whales have returned to former haunts in the western hemisphere.

Photographic ID

Once, three major populations of gray (also spelt grey) whale existed: in the western and eastern North Pacific Ocean, and in the North Atlantic.

[blockquote]"This discovery is truly amazing. To find one in the North Atlantic, let alone the Mediterranean Sea, is bizarre in the extreme"
Nicola Hodgins of the Whale and Dolphin Conservation Society [/blockquote]

However, the North Atlantic population of gray whale became extinct sometime in the 17th or 18th Century, for reasons that are not clear.

No sightings of the species had been made in the Atlantic Ocean since.

That was until a single individual gray whale was sighted off the coast of Herzliya Marina, Israel.

On 9 May, researchers from the Israel Marine Mammal Research and Assistance Centre (IMMRAC) in Israel went to investigate.

They took photographs to identify the huge animal, which they have since confirmed is a gray whale.

"This discovery is truly amazing. Today, gray whales only inhabit the Pacific Ocean, so to find one in the North Atlantic, let alone the Mediterranean Sea, is bizarre in the extreme," says Nicola Hodgins of the Whale and Dolphin Conservation Society (WDCS), which has its headquarters in Wiltshire, UK.

Scientists baffled

The WDCS says that experts are baffled by the whale's appearance.

"Gray whales are well known for performing one of the world's longest migrations, making a yearly round trip of 15,000-20,000 km," says Ms Hodgins.

"Over a lifetime, a gray whale migrates the equivalent distance of a return trip to the moon.

"However, these new images show that this particular whale would have had to beat all previous distance records to end up where it has."

It would also have had to swim a circuitous route to reach the Mediterranean, perhaps taking the extremely unlikely course of swimming up a major swimming canal that links the Pacific and Atlantic.

That raises the possibility that the whale did not swim into the Mediterranean Sea alone, but is part of a population that has recolonised parts of the Atlantic Ocean, and the Mediterranean Sea that links to it.

"Its presence off the coast of Israel will certainly pose a lot of questions to the scientific community," says Ms Hodgins.

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8672000/8672970.stm
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Gray Whales Likely Survived the Ice Ages by Changing Their Diets

ScienceDaily (July 7, 2011) — If ancient gray whale populations migrated and fed the same as today's whales, what happened during the Ice Ages, when their major feeding grounds disappeared? UC Berkeley and Smithsonian paleontologists argue that gray whales utilized a range of food sources in the past, including herring and krill, in addition to the benthic organisms they consume today. As a result, pre-whaling populations were two to four times greater than today's population of around 22,000.

Gray whales survived many cycles of global cooling and warming over the past few million years, likely by exploiting a more varied diet than they do today, according to a new study by University of California, Berkeley, and Smithsonian Institution paleontologists.

The researchers, who analyzed California gray whale (Eschrichtius robustus) responses to climate change over the past 120,000 years, also found evidence to support the idea that the population of gray whales along the Pacific Coast before the arrival of humans was two to four times today's population, which stands at about 22,000. The whale is considered a conservation success story because protections instituted as early as the 1930s have allowed populations to rebound from fewer than 1,000 individuals in the early 20th century, after less than 75 years of systematic whaling.

"There almost certainly were higher gray whale populations in the past," said evolutionary biologist David Lindberg, a UC Berkeley professor of integrative biology who coauthored the paper with his former student, Nicholas D. Pyenson, now curator of fossil marine mammals at the Smithsonian in Washington, D.C. The paper appears on July 6 in the online, open-access journal PLoS ONE.

Lindberg and Pyenson suggest that higher populations in the past were possible because gray whales utilized a greater variety of food resources -- resources that today's whales are only now beginning to exploit. According to Lindberg, gray whales were once thought to feed only by suctioning seafloor sediment and filtering out worms and amphipods -- so-called benthic organisms. But some whales are now eating herring and krill as well, just like their baleen whale relatives, which include the humpback and the blue.

Some whales are even dropping out of the migratory rat race. One group hangs out year-round off Vancouver Island in Canada, where they chase herring and krill.

"We propose that gray whales survived the disappearance of their primary feeding ground by employing generalist filter-feeding modes, similar to the resident gray whales found between northern Washington State and Vancouver Island," the scientists wrote in their paper.

"A combination of low population numbers and a species migrating between places where humans didn't bother them gave us the impression that gray whales have a stereotypical migratory and feeding behavior that may not be historically correct," Lindberg said.

The new population numbers accord with a 2007 estimate that the California gray whale population was likely 76,000 to 120,000 before humans began hunting them. That estimate, by Stephen Palumbi of Stanford University and his collaborators, was based on an analysis of gray whale genetic diversity.

The numbers clash, however, with claims by some ecologists that populations of between 15,000 and 20,000 are likely the most that the Pacific Coast -- specifically along the whales' 11,000 kilometer (6,900 mile) migratory route from Baja California to the Bering Sea -- could support, today or in the past.

"Our data say that, if the higher estimates are right, gray whales would have made it through the Ice Ages in numbers sufficiently large to avoid bottlenecking," Pyenson said. "If gray whale populations were at the lower levels, they would only have squeaked through the ice ages with populations of hundreds or a few thousand. That would have left bottlenecking evidence in their DNA."

Bottlenecking is when populations drop so low that inbreeding becomes common, decreasing the genetic diversity in the species and making them less able to adapt to environmental change.

The new assessment is good news for gray whales, which appear to have "a lot more evolutionary plasticity than anyone imagined," Lindberg said. This could help them survive the climate change predicted within the next few centuries that is characterized by an expected sea level rise of several meters.

"I suspect the gray whales will be among the winners in the great climate change experiment," Pyenson said.

Lindberg and Pyenson initiated the study several years ago in the face of conflicting and contentious estimates for past gray whale populations. They thought that an understanding of how gray whales adapted to climate change over the past 3 million years, the period called the Pleistocene, might provide insight into how they will adapt to climate change today.

Since gray whales arose -- the oldest fossils date from 2.5 million years ago -- Earth has gone through more than 40 major cycles of warming and cooling, each of which significantly affected the world's flora and fauna. During the last glacial cold spell, between 50,000 and 10,000 years ago, most of the large terrestrial mammals disappeared through a combination of climate change and human depredation, Lindberg noted. The marine realm, however, experienced almost no extinctions and very few new originations during that same period.

The California, or eastern, gray whale, one of two surviving populations of gray whale, can be traced back about 150,000-200,000 years. Pyenson and Lindberg looked closely at only the past 120,000 years, during which Earth transitioned from a warm period to a glacial period and then to today's warmer climate.

During the glaciated period, ocean water became locked up in land-based glaciers, drawing down the sea level by about 120 meters, or nearly 400 feet. That drop eliminated nearly 60 percent of the Bering Sea Platform, a shallow area that is part of the continental shelf and the major summer feeding area for today's gray whales. Gray whales can engage in benthic feeding no deeper than about 75 meters (250 feet), Pyenson said, and during the glacial period, waters offshore of the Bering platform would have been much deeper than that.

"If gray whales were primarily feeding on the Bering Platform, it's hard to see how they could have avoided a population crash," Lindberg said.

By calculating the amount of food lost because of dropping sea levels, and combining this with estimates of the food needed to keep a whale alive, the two researchers calculated the impact of global cooling on gray whale populations and the populations that would have had to exist in order for the whales to survive.

They concluded that populations would have had to have alternative feeding modes sufficient to support a population of around 70,000 during warm periods so that population drops during glacial periods wouldn't be below 5,000-10,000 whales. Much lower numbers would have produced a genetic bottleneck obvious in the DNA of the whales, and such a signature has not yet been seen.

"We don't yet have the ability to look deep enough into the whale genome to see this type of bottleneck," Pyenson added, though genetic analysis that has been done shows no evidence of a bottleneck much shallower in time, just before humans targeted the mammals for whaling.

The carrying capacity of the North Pacific could have been as high as 170,000, "assuming modern day values for benthic productivity, food density, and gray whale energetics," the authors concluded. If gray whales also exploited non-benthic organisms, such as krill, the populations could have been even higher.

If gray whales do respond well to the rising temperatures and sea levels predicted for the future, that may not be true for the birds and other marine mammals that feed in the Bering Sea, one of the most productive marine ecosystems during the summer.

"If this environment disappears in glacial maxima, we really need to rethink what we know about the ecological history of all the other organisms that make a living in the Bering Sea," Pyenson said. He and Lindberg urge other scientists to focus on the historical ecology of species to fully understand their complex interactions with a changing environment.

"We really make a lot of conservation decisions without a lot of data," Lindberg said. "Integrating paleontological and geological data in the context of known ecological traits can help us address impending biological changes in marine ecosystems."

The work was supported by the National Science Foundation, the Natural Sciences and Engineering Research Council of Canada and the Smithsonian Institution.

Pyenson performed part of this research while a post-doctoral fellow at the University of British Columbia. Lindberg is also a member of the Center for Computational Biology and the Museum of Paleontology at UC Berkeley.

Posted Image
A grey whale mother and calf off the coast of Baja California. If ancient gray whale populations migrated and fed the same as today's whales, what happened during the Ice Ages, when their major feeding grounds disappeared?

--------------------------------------------------------------------------------

Journal Reference:

Nicholas D. Pyenson, David R. Lindberg. What Happened to Gray Whales during the Pleistocene? The Ecological Impact of Sea-Level Change on Benthic Feeding Areas in the North Pacific Ocean. PLoS ONE, 2011; 6 (7): e21295 DOI: [url]10.1371/journal.pone.0021295[/url]

http://www.sciencedaily.com/releases/2011/07/110706195758.htm
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Rare Russian Whale Tracked to Mexico, a First for Science

OurAmazingPlanet Staff
Date: 20 March 2012 Time: 02:55 PM ET

Posted Image
Varvara the gray whale.
CREDIT: Oregon State University.

Scientists have tracked a critically endangered western gray whale from its native habitat in the chilly Pacific Ocean off Russia for thousands of miles to balmy lagoons off the coast of Mexico — a first for the rare whales.

Now, the 9-year-old female — dubbed Varvara, the Russian equivalent of Barbara — is making her way back up the west coast of North America, and appears to be returning home.

On Friday (March 16), Varvara was near the Canadian border, and traveling about 100 miles (160 kilometers) a day.

The whale's incredible journey is generating great interest among researchers, who are able to track Varvara thanks to a satellite tracking tag attached to the massive mammal.

It's thought that only about 130 western gray whales remain on Earth, so scientists are closely monitoring Varvara's behavior. The young whale's trip to Mexico took her to an area frequented by eastern gray whales, cousin to western gray whales, yet far more plentiful. Western gray whales are thought to be a separate population in the western part of the Pacific Ocean, while eastern gray whales stick to the eastern half.

Like their western relatives, eastern gray whales once teetered on the brink of extinction, but have rebounded, their population swelling to about 18,000 animals. The whales travel from Arctic waters down the coast of North America to Mexican waters each year.

It's possible Varvara was breeding with eastern gray whales in the Mexican lagoons, said Bruce Mate, director of the Marine Mammal Institute at Oregon State University. The whale "spent time around three areas where that activity is commonly seen," he said in a statement.

Last year, OSU scientists tracked Flex, a 13-year-old male western gray whale, across the Bering Sea from Russia to North America, but the whale's tag stopped working near Oregon, and it's unknown whether the whale continued south to Mexico.

"Clearly the experience of Varvara, and Flex before her, demonstrates that western gray whales can and do come over to the eastern Pacific," Mate said. "Whether this suggests that they are not a distinct population or that we underestimated their range isn't yet clear."

The whale's tags typically survive for only about 120 days, yet Varvara's is still going strong. Mate said scientists are eagerly watching her progress in hopes they will be able to learn whether she retraces her journey to her home waters near Russia's Sakhalin Island, or takes a different route entirely.

http://www.livescience.com/19180-rare-russian-whale-tracked-mexico-science.html
Edited by Taipan, Feb 11 2018, 01:22 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Extinct Whale Fossil Found on Seafloor

Megan Gannon, News Editor
Date: 21 December 2012 Time: 02:16 PM ET

Posted Image
Scientists from UGA and the National Oceanic and Atmospheric Administration discovered and fully recovered a large fossilized whalebone near Gray's Reef National Marine Sanctuary approximately 20 miles off the Georgia coast in 2008.

Researchers diving off the coast of Georgia may have found the remains of an Atlantic gray whale, a relic of a population that was hunted to extinction by the 18th century.

But this particular specimen died long before whalers became a threat. Carbon dating showed that the fossil, a left jawbone, is about 36,000 years old.

The big bone was first discovered along with two badly eroded vertebrae near Gray's Reef National Marine Sanctuary about 20 miles (32 kilometers) off southeast Georgia in 2008. It took the researchers two years to pull out all the pieces of the fossil, which was embedded in layers of shell and sand 70 feet (21 meters) below the surface. The jawbone was recovered in sections and measures 5 feet (1.5 meters) in length.

The researchers say the bone is clearly from a baleen whale and looks very similar to that of the gray whale, Eschrichtius robustus. This species is only locally extinct. Gray whales can be found today in quite strong numbers, but only in the Pacific Ocean, and even these had once teetered on the brink of extinction during eras when the whaling industry reigned.

It was previously believed that the Atlantic gray whale had been a distinct species. But recent research has shown that these vanished whales and the living ones in the Pacific are actually one in the same.

"The California grays looked exactly like the bones that were dug up in Scandinavia back in the 19th century," Ervan Garrison, a geoarchaeology professor at the University of Georgia said in a statement, describing it as "one of the first instances where a living species was named based on the fossil evidence."

The new specimen's age of approximately 36,570 years old makes it one of the oldest fossil finds in the western Atlantic basin, the researchers say. And if the find indeed represents a Pleistocene age gray, its oldest counterpart is a specimen found on the southern North Sea dating to 42,800 years ago.

The research was detailed online last month in the journal Paleontologica Electronica.

http://www.livescience.com/25765-extinct-atlantic-gray-whale.html
Edited by Taipan, Feb 11 2018, 01:23 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Dolphins Get Free Ride from Gray Whale

By Megan Gannon, News Editor
Date: 01 July 2013 Time: 06:06 PM ET

Posted Image
A gray whale giving a boost to dolphins was spotted off the coast of Southern California during an aerial survey.

Scientists taking stock of cetaceans off California's coast captured an amazing sight from the air: a pod of dolphins enjoying a free ride from a migrating gray whale.

In the photo, a dozen long-beaked common dolphins cruise in front of the gray whale, pushed along by the bigger animal's bow wave. The image was taken from about 600 feet (182 meters) above the water near Catalina Island and published last week by the National Oceanic and Atmospheric Administration (NOAA).

This whale is just one of about 20,000 eastern North Pacific gray whales that migrate each year from feeding grounds in the Arctic to breeding and calving grounds off the coast of Mexico.

Scientists keep track of this subspecies in aerial surveys as part of NOAA's Cetacean Health and Life History Program. Photos from the air can reveal whether the animals are pregnant, well-nourished or accompanied by new calves during their annual journeys.

Indirectly, the images can serve as a barometer for the health of the Arctic ecosystem, since the whales' bodies during migration mirror the conditions in their feeding grounds.

"Gray whales integrate the impacts of climate change into their physical condition, then they swim right by our coast. So we can actually do Arctic research right here from San Diego," Wayne Perryman, a biologist with the whale-tracking program, said in a feature on NOAA's website.

As the Arctic warms, the food supply of the baleen whales is shifting north, meaning the big-bodied marine mammals may have to travel longer to chase their prey. Perryman and his colleagues are examining the relationship between the length of the migration and the rate of successful pregnancies, according to NOAA.

Eastern gray whales were once on brink of extinction but their population has rebounded in the past several decades, though their current numbers are likely still a fraction of the pre-whaling population.

http://www.livescience.com/37893-dolphins-get-free-ride-from-gray-whale.html
Edited by Taipan, Feb 11 2018, 01:25 PM.
Offline Profile Quote Post Goto Top
 
maker
Member Avatar
Apex Predator
[ *  *  *  *  *  *  *  * ]
NOAA
 
Scientists have combined infrared cameras with image recognition software to automatically detect and count migrating gray whales.

By Rich Press, NOAA Fisheries Science Writer | Posted: February 9, 2015
Follow Rich on Twitter: @Rich_NOAAFish


Posted Image
A gray whale mother and calf. Credit: NOAA

Posted Image
A set of three thermal imaging cameras are used to automatically detect migrating whales based on the difference in temperature between the whales' blow and the surrounding environment. Credit: NOAA

Every year, gray whales migrate from their summer feeding grounds in the Arctic to their wintering grounds off Baja California in Mexico. And roughly every other year, scientists with binoculars count them as they funnel past a point on the California coast a bit south of Monterey Bay. Scientists conduct this survey to keep track of how well the population is doing, and this year they have a new set of eyes to help with the job.

Three eyes, to be exact. Each one is a thermal imaging camera that captures the blow from a whale as it surfaces to breathe.

“A whale is this great big motor that takes in a breath of air and holds it inside for a long time,” said Wayne Perryman, a NOAA Fisheries scientist who helped develop the new system. “When it exhales, the air is much warmer than the background, and we can detect that difference very easily, both day and night.”

New Tech on the Job

The cameras themselves are nothing new—they’re similar to the infrared cameras that police use when searching for suspects from a helicopter. What is new is software that automatically analyzes the video to detect when a whale blows. To do that, it has to distinguish the blow of a whale from other signals that might confuse it, such as a bird diving into the water or a small boat passing by.

“The biggest challenge was getting the detector to be as accurate as possible without having it get fooled by false alarms,” said Dave Weller, the NOAA Fisheries scientist who leads the survey team.

In addition, every time the computer sees a blow, it predicts where and when that same whale will surface to blow again. That prediction algorithm, which is based on years of research into gray whale diving behavior, allows the computer to track individual whales. “If you don’t have a way of tracking who’s who, you can double-count some whales or miss them altogether,” Weller said.

Previously, two scientists would conduct the survey—one a spotter with high-powered binoculars and the other a record-keeper. For now, human observers are still working the survey to ensure that the automated system produces accurate results. However, human observers can only count whales during daylight, and limited budgets mean that they’re onsite only during the peak weeks of the migration. But the thermal imaging system works 24/7 throughout the entire migration—it was already counting when the earliest migrants made their way south, and it will still be counting when the stragglers take up the rear.

“The biggest advantage of the new system is that it vastly increases our sample size,” Weller said. “That means we can more accurately estimate the size of the population.”
Video: http://www.fisheries.noaa.gov/stories/2015/02/gray_whale_survey_thermal_imaging.html
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Gray Whale Breaks Mammal Migration Record

by Laura Geggel, Staff Writer | April 14, 2015 07:01pm ET

Posted Image
A female western gray whale (not pictured) swam all of the way from Russia to Mexico and back again in 172 days.

The western gray whale now holds the record as the mammal with the longest known migration, researchers say.

A female western gray whale swam from Russia to Mexico and back again — a total of 13,988 miles (22,511 kilometers) — in 172 days, according to a new report.

Until now, the title of the longest-migrating mammal belonged to the humpback whale (Megaptera novaeangliae), which migrates up to 10,190 miles (16,400 km) round trip as it travels between its breeding grounds near the equator and the food-rich waters of the Arctic and Antarctic, according to Guinness World Records.

But the new report shows that a female western gray whale (Eschrichtius robustus) named Vavara (the Russian equivalent of the name Barbara), has stolen the record. Researchers placed satellite-monitoring tags on seven western gray whales living off Russia's Sakhalin Island, where the mammals feed every year. Vavara was the only whale whose tag stayed intact throughout the entire journey, said the study's lead researcher, Bruce Mate, the director of the Marine Mammal Institute at Oregon State University. [Quest for Survival: Photos of Incredible Animal Migrations]

Western gray whales are critically endangered; they were once even thought to be extinct, Mate said. Before the new study, little was known about these animals' migratory paths, and many researchers suspected that the whales migrated in a loop from Russia to the South China Sea.

Instead, the tagging study shows that Vavara swam to Mexico.

"She crossed the Bering Sea, the Gulf of Alaska [and] the lengths of the North American continent to get down to the Baja breeding calf lagoons that are used by eastern North Pacific animals," Mate said.

Western or eastern?

Curiously, the western gray whale's cousin, the eastern gray whale, also swims off the coast of Baja California in Mexico. Eastern gray whales are not endangered, Mate said. It's entirely possible that Vavara and the six other whales that Mate and his team tracked are actually eastern gray whales that had migrated westward all the way to Russia, he said.

Posted Image
This map tracks the journeys of Vavara, Agent and Flex, three gray whales that swam from Russia to North America.

It's also possible what researchers have thought of as two whale groups, western and eastern, are actually a single whale species, although more research is needed to know for sure, Mate said.

Evidence from photographs of whales taken by whale researchers also suggests they are just one group. For example, 10 western gray whales spotted in Russia have been photographed near British Columbia and Baja California, Mexico, the researchers said in the study.

Research on the genes of two whales also supports the idea that these two whale groups are actually one.

What's more, two other western gray whales, Agent and Flex, tagged by Mate and his colleagues took migration routes similar to Vavara's. However, Agent's tag stopped working in the Gulf of Alaska, and Flex's tag conked out near Lincoln City, Oregon.

Perhaps the whales currently thought of as western gray whales came from the population of gray whales once thought to be extinct, Mate said. Or, maybe they are actually eastern gray whales that expanded their range once the western gray whales disappeared.

"It's a question that still needs to be addressed," Mate said. "It's still under investigation."

Vavara's journey

Several aspects of Vavara's journey caught the researchers' attention. For one thing, she didn't follow the same exact route on her way there and back. This suggests that she knew the general way, and didn't need to hug the coast to orient herself.

"My respect for navigational skills in gray whales has changed tremendously," Mate told Live Science.

It also appears that Vavara did not stop to feed during her 5.5-month migration. Like other baleen whales (whales that have baleen plates in their mouths that filter food), gray whales typically don't eat during migration, Mate said.

"These animals do well enough feeding in Russia to sustain a migration that's pretty extreme," Mate said.

The study is published in the April 15 (Wednesday) online edition of the journal Biology Letters.

http://www.livescience.com/50487-western-gray-whale-migration.html
Edited by Taipan, Feb 11 2018, 01:27 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Unmanned aerial vehicle used to study gray whales from above

Date: May 28, 2015
Source: NOAA National Marine Fisheries Service
Summary:
Scientists are using an unmanned aerial vehicle to take very precise overhead images of migrating gray whale mothers and calves. This research will help scientists understand how environmental conditions control the reproductive success of individual whales and ultimately of the population.

Posted Image
A gray whale and her calft migrate north along the California coast on their way to summer feeding grounds in the Arctic.

One recent spring day, John Durban, a NOAA Fisheries marine mammal biologist, stood on the California coast and launched an unmanned aerial vehicle into the air. The hexacopter--so called because it has six helicopter-type rotors--zipped over the ocean and hovered above a gray whale mother and her calf. The pair was migrating north from their calving grounds off Baja California, Mexico, to their summer feeding grounds in the Arctic.

NOAA Fisheries scientists have stood at this point of land each year for the past 22 years, binoculars in hand, to estimate the number of gray whale calves born each year. That's an important step in monitoring the ups and downs of the population. But scientists would like to understand more completely what causes those ups and downs, and this year, with the addition of the hexacopter, they hope to find out.

As the hubcap-sized hexacopter hovered high above the whales it shot straight-down photos from a digital camera mounted in its belly. In addition to a camera, the hexacopter also carried a very precise pressure altimeter, allowing scientists to know the exact altitude at which each image was taken. Later in the lab, they would analyze the images, measuring the length and girth of the whales to within a few centimeters.

"We can't put a gray whale on a scale, but we can use aerial images to analyze their body condition--basically, how fat or skinny they are," Durban said.

Durban and co-pilot Holly Fearnbach, also a NOAA Fisheries scientist, would ultimately capture images of more than 60 cow/calf pairs.

A Long and Difficult Journey

The amount of fat on a gray whale cow is critical to the survival of her calf. Gray whales don't feed during most of their months-long migration, and while the mothers are fasting, they're also nursing their fast-growing calves. Therefore they need a lot of blubber to fuel the journey to their Arctic feeding grounds.

How much blubber they're carrying depends in part on conditions in the Arctic the summer before. If the whales had access to plentiful prey, the cows will have sufficient fat on them, and most calves will likely survive the journey. But if conditions weren't favorable, fewer calves will be born, and fewer still will make it.

"By studying the body condition of females, we hope to connect the dots between conditions in the Arctic one year and calf production the next," Durban said. "Ultimately, we're trying to understand how environmental conditions affect the reproductive success of the population."

Throughout the study, scientists kept the hexacopter at least 120 feet above the whales. When used at this altitude by trained scientists, unmanned aerial vehicles offer a safe and non-invasive way to collect important data on marine mammals and other protected species.

A Recovery Success Story

Gray whales were hunted nearly to extinction during the whaling days. Thanks to legal protections, the U.S. population of gray whales recovered and was taken off the endangered species list in 1994 (though a second population of gray whales on the Russian side of the Pacific remains endangered).

This success presents scientists with a unique opportunity to study the ecology of large whales, including how environmental conditions put an upper limit on population growth. Because most other large whales are still threatened or endangered, scientists have had few opportunities to observe these dynamics in action.

"With gray whales, we're just beginning to understand what a recovered population of large whales looks like," Durban said.

This understanding will help scientists set recovery goals for other species. And once a species is recovered, it will help scientists distinguish between normal ups and downs in a population and signs of--should it happen--a more serious decline.

"We'll have to get used to seeing recovered populations have good years and bad years," Durban said. "That's what happens when you've recovered and you're hovering around a food ceiling."

As the sun descended toward the horizon, Durban brought the hexacopter in for the day's final landing. He still had a lot of work in front of him, minutely analyzing images on a computer screen. Though all the images from this study would be of gray whales, other species of large whale are also showing promising signs of recovery.

"Hopefully in the not-too-distant future," Durban said, "there will be many healthy populations of large whales to study."

http://www.sciencedaily.com/releases/2015/05/150528163133.htm
Edited by Taipan, Feb 11 2018, 01:28 PM.
Offline Profile Quote Post Goto Top
 
Taipan
Member Avatar
Administrator

Grey whales have a peculiar way of feeding

February 8, 2018 JAYMI HEIMBUCH

Posted Image
Grey whales are unique among their cetacean peers in many respects
Photo: Joe Morris 917/Shutterstock

You may be familiar with the spectacular lunge feeding strategies of humpback whales, or the amazingly advanced attacks orca pods coordinate. The range of feeding behaviors across cetacean species is fascinating, but one such strategy you might not be familiar with is that of the grey whale.

Gray whales are filter feeders, sifting their food through baleen plates. But unlike any other species of whale, grey whales strain the sediment of the sea floor for food. They swim along, sucking up mouthfuls of sediment and spitting out everything but their prey. What are they looking for? Tiny amphipods, shrimp-like animals that live inside that sediment. Along with the amphipods, grey whales will also consume cumaceans, isopods and mysids among other tiny animals scraped up from the floor.

But to get at these small sea creatures, grey whales put on a rather interesting feeding show.

Arkive describes the behavior:

"Individuals roll onto their sides after diving to the bottom and take large amounts of sediment into their mouth. As the whale rises to the surface, it strains the contents of the mouth through the baleen, leaving a trail of mud and sand behind it. The invertebrate prey consisting of bottom-dwelling crustaceans, worms and molluscs is isolated in this way and swallowed. A number of seabirds are attracted to feeding gray whales, and take advantage of invertebrates that escape the filtering process."

Here's an example of what this feeding strategy looks like when viewed from above. This grey whale was filmed feeding along the rocky shoreline near Yaquina Head Lighthouse in Newport, Oregon.



Next time you see grey whales rolling next to rocks or kicking up mud in a shallow cove, you'll know they’re probably just taking their next mouthful of food.

https://www.mnn.com/earth-matters/animals/blogs/grey-whales-peculiar-way-of-feeding-video
Offline Profile Quote Post Goto Top
 
Palaeoscincus
Member Avatar
Heterotrophic Organism
[ *  *  * ]
First archaeological evidence that gray whales lived and possibly gave birth to calves in the Mediterranean sea in historic times:
https://amp.livescience.com/63028-pliny-ancient-mediterranean-whales.html

Paper:
http://rspb.royalsocietypublishing.org/content/285/1882/20180961
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
DealsFor.me - The best sales, coupons, and discounts for you
« Previous Topic · Cetacean, Pinnipeds & Sirens · Next Topic »
Add Reply