Seals

[ramonmercado]

Elephant seals dive for science
By Jonathan Amos
BBC News science reporter



Elephant seals on South Georgia have been recruited to the cause of science. Equipped with computerised tags stuck to their heads, the animals have been collecting remarkable new information on conditions in the Southern Ocean.

As the animals swim for thousands of km and dive down to 2,000m, their tags record details of temperature, depth and the salinity of the water. When the seals pop up to breathe, the computers transmit the information to scientists in Scotland via satellite.

"These animals are opening an interesting new window on the ocean," said Mike Fedak, from the Sea Mammal Research Unit (SMRU), Gatty Marine Laboratory, University of St Andrews.

"They can go to places in the ocean that we very often can't go to, and can sample parts of the ocean where we can't afford to or logistically are not able to."

Climate understanding

SMRU has been running its Southern Elephant Seals as Oceanographic Samplers (SEaOS) project for just over two years. It is a collaborative effort with researchers from France, Australia, and the US; the British Antarctic Survey is involved, too.


They wake up down at 1,500m and hope there is squid there for them to eat
Martin Biuw, SMRU

And it is being run in parallel with other projects using sea lions, tuna, and even sharks to gather ocean data.
The elephant seals' information has enabled researchers to study how changes in salinity and temperature affect the movement of water at different depths.

This has provided new insights into the habits and habitat both of the elephant seal and its prey species, squid.


But it has also significantly improved our understanding of the processes of heat exchange within the Southern Ocean and between this region and the rest of the world.
The region plays a critical role in the Great Ocean Conveyor - the mass movement of water around the globe that helps redistribute the energy in our climate system.

New dynamic

The South Georgia seals have helped trace the positions of ocean "fronts" in unprecedented detail.

"These are like the weather fronts you have in meteorology only they are in the ocean," explained SMRU's Lars Boehme.


SOUTHERN ELEPHANT SEAL
So named because of their size and trunk-like snout
Scientific name: Mirounga leonina ; three sub-species
Dominant males control harems of up to 50 females
Will feed on squid and fish; males can weigh 4 tonnes

"These fronts show you where warm water is upwelled from the deeper ocean, bringing heat and nutrients to the shallower levels," he told the BBC News website.
"Knowing where these fronts are helps us to understand what happens to the global conveyor in this part of the Southern Ocean."

Sampling from ships using towed sensors had given a snapshot of the fronts' positions on a 10-year timeframe. Now, thanks to the seals and the 21,000 "profiles" they have collected over two years, the SMRU team has improved the resolution dramatically.

"Now, we are able to use just half a year of data to produce a snapshot of where these fronts are," Boehme said. "We also show the high dynamics of these fronts within half a year - they move around."

Ocean partnership

But what about the "giant oceanographers" themselves; what's in it for the elephant seals?

It is a good deal, says marine biologist Martin Biuw; it is one which could aid the animals' conservation.


POPULATION CENTRES
M. leonine population totals about 740,000 individuals
Breed in Sub-Antarctic; range widely over Southern Ocean
Largest groups on Macquarie, Kerguelen, and South Georgia
Enjoyed protection since end of industrial hunting in late 1950s

"On the biological side of the project, we want to see from the physical oceanography and the environment something that might help us explain why elephant seal populations have gone through such different trends," the SMRU researcher said.
South Georgia's population at 400,000 is the biggest group and has been relatively stable since the end of large-scale hunting in the 1950s.

But the groups centred on the islands of Macquarie and Kerguelen have not fared so well; and in the case of Macquarie may still be in decline.

Why this is so may emerge from an analysis of the data gathered by the seals.

Their tracked journeys have thrown new light on their wandering, where they go to feed and, amazingly, how they appear to use the frontal systems to navigate and find resources.

Fur fall

Much of this is speculative at the moment but what is not in doubt is the seals' diving prowess.

Adults will spend perhaps less than 10% of their time at the surface, preferring instead to swim below water for 30 minutes to an hour.


SEALS AND 'FRONTS'
Map shows four-month journey taken by one tagged seal
Traces fronts in the eastward flowing ocean current
Seals go down to 2km; experience 200 bar of pressure
Data dump at surface goes via ARGOS satellites

"They must have some way to reduce their metabolic rate when they are diving, shutting down most of their systems and resting as they go," said Biuw.
"So, they would go to sleep in transit and then they wake up down at 1,500m and hope there is squid there for them to eat."

The scientists stress the animals are not bothered by the data loggers carried on their heads. The boxes are attached with an epoxy glue and simply fall off after about a year during the moulting season.

The SMRU team has been explaining the results of its project this week at the 2006 Ocean Sciences Meeting of the American Geophysical Union in Honolulu, Hawaii.

[email protected].

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/s ... 736196.stm

Published: 2006/02/21 14:51:46 GMT
© BBC MMVI

 

[ramonmercado]

Gray seals may be becoming the great white sharks of Dutch beaches

The bodies kept washing ashore—dozens of mutilated harbor porpoises stranded on the Dutch beaches every year, their bloody remains discovered by screaming vacationers. Now, after 10 years of crime scene investigation–style work—complete with autopsies and DNA testing—biologists and veterinary pathologists have finally cracked the identity of the murderers: big-eyed, chubby-faced gray seals. The finding could lead conservationists to rethink gray seal rehabilitation, and it even raises the specter of a new “great white” in the North Sea.

When harbor porpoises with missing bellies first appeared on Dutch coastlines in 2006, local biologists thought someone was deliberately hurting the animals. But the numbers soon rose to dozens a year—impossible to attribute to a single person. So the scientists looked elsewhere: Perhaps it was ducted propellers that sucked the porpoises in? Or fishermen cutting up unintentionally trapped porpoises?

Then in 2012, a group of Belgian researchers noticed that some of the wounds on dead porpoises found on Belgium beaches bore the canine teeth marks of gray seals. “We thought, ‘Of course, how silly,’ ” says biologist Mardik Leopold of the Wageningen University and Research Centre in the Netherlands. “You think seals are nice, cuddly animals—they are not. They are predators.” ...

http://news.sciencemag.org/biology/2014 ... ch-beaches

 

[Kondoru]

I went to see the seals at Godrevy point yesterday; they were fast asleep.

But to my mind its terribly exciting; seals to my lubberly mind are exotic creatures, that they should be 40 minutes away is amazing.

 

[EnolaGaia]

Researchers have only now realized that Antarctic Weddell seals generate and use an array of ultrasonic sounds in addition to the sounds audible to humans. At the extreme, one recorded sound was too high-pitched to be heard by cats, dogs or even some bats.

Seals are making 'Star Wars' noises at each other underwater, and we have no idea why

They chirp, whistle and trill like droids — and scientists are hearing it now for the first time.

Above water, they sound like bellowing Wookies. Below the ice, they sound like chirping, chattering robots. Either way, the Weddell seals of Antarctica should have no trouble finding work in an upcoming "Star Wars" project.

"The Weddell seals' calls create an almost unbelievable, otherworldly soundscape under the ice," Paul Cziko, a visiting professor at the University of Oregon and lead author of a new study describing the bizarre seal sounds, said in a statement. "It really sounds like you're in the middle of a space battle in 'Star Wars,' laser beams and all."

The catch: You'd have to be an alien (or droid) to hear them; all of those sci-fi sounds are totally inaudible to human ears. Cziko and his colleagues were able to detect the otherworldly noises after two years of listening to Weddell seals (Leptonychotes weddellii) with a special hydrophone (an underwater microphone) installed in Antarctica's McMurdo Sound in 2017. ...

Before the researchers started recording, scientists knew about the 34 seal calls audible to human ears. Now, the team's research — published online Dec. 18 in The Journal of the Acoustical Society of America — adds nine new types of ultrasonic calls to the seals' repertoire. Those sounds include trills, whistles and alien-sounding chirps, sometimes composed of multiple harmonized tones. ...

FULL STORY (With Video):
https://www.livescience.com/weddell-seal-ultrasonic-star-wars-noises.html

PUBLISHED RESEARCH ARTICLE:
Weddell seals produce ultrasonic vocalizations
https://asa.scitation.org/doi/10.1121/10.0002867

 

[IbisNibs]

"Seals are making 'Star Wars' noises at each other underwater, and we have no idea why"
Honestly, do you think that seals would make Star Wars noises at each other while on land?

This is completely off topic, but I find the ending of this headline infinitely adaptable and inspiring. It inspires potential headlines, such as:
"People often act like idiots, and we have no idea why"
"On any given day, 36.6 percent of adults eat fast food, and we have no idea why"
"Americans are afraid of driving in roundabouts, and we have no idea why"

 

[ramonmercado]

Her doom was unsealed.

A seal has been freed after a week stuck on a white water rafting course.

The female seal spent days in the Tees Barrage course in Stockton after it is believed it chased fish through underwater gates which then closed. The RSPCA said the seal appeared distressed but uninjured. Water was drained and divers opened the gate to open the way for the animal. A spokeswoman said another seal was seen waiting for it in the river and the pair swam off together.

RSPCA inspector Krissy Raine said: "She is a very big seal and I think she must have followed some fish into this area through the gates. This does happen quite a lot in this location but usually the seals can get out. In this case her large body probably clattered on the gates and they shut behind her so she was unable to get back into the free-flowing river."

Ms Raine said the Canal and River Trust decided to drain water to allow divers in to open the gates for the seal.

https://www.bbc.com/news/uk-england-tees-58086090

 

[maximus otter]

California man stranded off the coast helped to safety by harbor seal, he says

A California man had a brush with death after falling from his boat into the Pacific Ocean, at night last month, but survived after a harbor seal assisted his five-hour swim back to safety, according to reports on Wednesday.

Scott Thompson, a sea urchin diver, was stranded in the Santa Barbara Channel in the middle of the night after he fell from his boat while its motor was still running, [a newspaper] reported.

With no sight of the shore, which was miles away, and only wearing a T-shirt and shorts in the chilly coastal waters, Thompson faced a despairing situation.

As Thompson attempted to catch the boat, he soon realized it was outpacing him, he told the outlet.

He planned to swim to an oil platform, which was closer than the shore, and soon received help from the marine mammal, he explained.

“I wasn't thinking about sharks or anything like that, until I hear this splash. It was a medium-sized harbor seal," Thompson said. "The seal would go underwater and he came up and nudged me. like a dog comes up and nudges your leg."

"Did it know, like hey, this human is in trouble, hey keep going dude?" he added.

Crew members aboard the oil platform treated Thompson, who was then taken to a hospital.

https://www.foxnews.com/us/california-man-stranded-coast-safety-harbor-seal

maximus otter

 

[Floyd]

Brilliant!
BBC's 'Patagonia- Earth's Secret Paradise' had lion and elephant seals on last night. Well worth a look on I-player if anyone missed it.

 

[escargot]

Honestly, do you think that seals would make Star Wars noises at each other while on land?

They might. I mean, listen to Chewbacca. He's no nightingale, know what I mean?

 

[escargot]

Rescued ill or injured seal pups are treated at the RSPCA Wildlife Centre in Cheshire.

Techy and I watched some being released from huge cat-carriers on the beach at Colwyn Bay on the Welsh coast. It was a wonderful sight.

 

[hunck]

Seal pup rides surfers boards in California

Drone video at link