Orca ‘apocalypse’: half of killer whales doomed to die from pollution

September 27, 2018

At least half of the world’s killer whale populations are doomed to extinction due to toxic and persistent pollution of the oceans, according to a major new study.

Although the poisonous chemicals, PCBs, have been banned for decades, they are still leaking into the seas. They become concentrated up the food chain; as a result, killer whales, the top predators, are the most contaminated animals on the planet. Worse, their fat-rich milk passes on very high doses to their newborn calves.

PCB concentrations found in killer whales can be 100 times safe levels and severely damage reproductive organs, cause cancer and damage the immune system. The new research analysed the prospects for killer whale populations over the next century and found those offshore from industrialised nations could vanish as soon as 30-50 years.

Among those most at risk are the UK’s last pod, where a recent death revealed one of the highest PCB levels ever recorded. Others off Gibraltar, Japan and Brazil and in the north-east Pacific are also in great danger. Killer whales are one of the most widespread mammals on earth but have already been lost in the North Sea, around Spain and many other places.

“It is like a killer whale apocalypse,” said Paul Jepson at the Zoological Society of London, part of the international research team behind the new study. “Even in a pristine condition they are very slow to reproduce.” Healthy killer whales take 20 years to reach peak sexual maturity and 18 months to gestate a calf.

PCBs were used around the world since the 1930s in electrical components, plastics and paints but their toxicity has been known for 50 years. They were banned by nations in the 1970s and 1980s but 80% of the 1m tonnes produced have yet to be destroyed and are still leaking into the seas from landfills and other sources.

The international Stockholm Convention on Persistent Organic Pollutants came into force in 2004 to tackle the issue, but Jepson said the clean-up is way behind schedule. “I think the Stockholm Convention is failing,” he said. “The only area where I am optimistic is the US. They alone produced 50% of all PCBs, but they have been getting PCB levels down consistently for decades. All we have done in Europe is ban them and then hope they go away.”

The researchers said PCBs are just one pollutant found in killer whales, with “a long list of additional known and as yet unmeasured contaminants present”. Further problems for killer whales include the loss of key prey species such as tuna and sharks to overfishing and also growing underwater noise pollution.

The new research, published in the journal Science, examined PCB contamination in 351 killer whales, the largest analysis yet. The scientists then took existing data on how PCBs affect calf survival and immune systems in whales and used this to model how populations will fare in the future. “Populations of Japan, Brazil, Northeast Pacific, Strait of Gibraltar, and the United Kingdom are all tending toward complete collapse,” they concluded.

Lucy Babey, deputy director at conservation group Orca, said: “Our abysmal failures to control chemical pollution ending up in our oceans has caused a killer whale catastrophe on an epic scale. It is essential that requirements to dispose safely of PCBs under the Stockholm Convention are made legally binding at the next meeting in May 2019 to help stop this scandal.” Scientists have previously found “extraordinary” levels of toxic pollution even in the 10km-deep Mariana trench in the Pacific Ocean.

“This new study is a global red alert on the state of our oceans,” said Jennifer Lonsdale, chair of the Wildlife and Countryside Link’s whales group. “If the UK government wants its [proposed] Environment Act to be world-leading, it must set ambitious targets on PCB disposal and protect against further chemical pollution of our waters.”

The research shows that killer whale populations in the high north, off Norway, Iceland, Canada and the Faroes, are far less contaminated due to their distance from major PCB sources. ”The only thing that gives me hope about killer whales in the longer term is, yes, we are going to lose populations all over the industrialised areas, but there are populations that are doing reasonably well in the Arctic,” said Jepson.

If a global clean-up, which would take decades, can be achieved, these populations could eventually repopulate empty regions, he said, noting that killer whales are very intelligent, have strong family bonds and hunt in packs. “It is an incredibly adaptive species – they have been able to [live] from the Arctic to the Antarctic and everywhere in between.”

He praised the billion-dollar “superfund” clean-ups in the US, such as in the Hudson River and Puget Sound, where the polluter has paid most of the costs: “The US is going way beyond the Stockholm Convention because they know how toxic PCBs are.”

Source: The Guardian.com

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Menopause Mystery: Why Do Female Killer Whales Experience The Change Of Life?

January 12, 2017

Menopause is a mystery to evolutionary biologists, but new insights could come from a long-term study of killer whales.

In these whales, the explanation may lie in a combination of conflict and cooperation between older and younger females, according to a report published Thursday in the journal Current Biology.

Killer whales are one of only three species known to have menopause — the others are pilot whales and humans. Researchers have long wondered why it was that these few species evolved to have females that spend so much of their lives unable to have babies.

Killer whales start reproducing around age 15, but stop having calves in their 30s or 40s, even though they can live for around a century.

A team led by behavioral ecologist Darren Croft of the University of Exeter decided to search for answers with the help of an unusual long-term study of killer whales in the Pacific Northwest. There, since the 1970s, researchers have carefully collected information on the births and deaths of individual whales that live in family groups.

Contained within the data is an intriguing clue about why female whales may stop reproducing later in life.

When older females reproduce at the same time as their daughters, who live alongside them, the calves of the older mothers are nearly twice as likely to die in the first 15 years of life. But when older mothers had calves in the absence of a reproducing daughter, their calves did just fine.

“It’s not that older mothers are bad mothers, that they’re not able to raise their calves as younger mothers,” says Croft. “It’s that when they enter into this competition with their daughters, they lose out and their calves are more likely to die.”

The competition may center on access to food, says Croft, because there’s good reason to believe older females feel more pressure to share their precious fish with the others around them.

That’s because, in killer whales, females mate with males from other groups but then rejoin their families. That means when a new calf is born, its father is not around, and females start their lives in a situation where their relatedness to the group is rather low.

As a female grows older and starts having calves that stay with her, however, she develops more kinship ties to those around her. “It may be that older females are more likely to share, and younger females are less likely to share food,” says Croft. That would mean younger females would have more resources to lavish on their own calves.

It’s clear that in these whales, older females play an important role in the survival of not just their own calves, but all of the family members they live with. “If an old female dies, her son’s risk of dying in the year following her death is over eight times higher than if his mother was still alive,” says Croft, “and these are adult sons, these are not juveniles, these are 30-year-old, fully grown males.”

The idea that older females safeguard and enhance their genetic legacy by protecting and providing for their children and grandchildren has been an influential explanation for why menopause evolved. It’s known as the Grandmother hypothesis, and was developed by anthropologists who studied hunter-gatherer cultures.

But Croft thinks that alone isn’t enough to account for menopause, because other long-lived, social species, like elephants, have older females that help their group but continue to bear young until the end of life. “Just the fact that these old females can store information and share that with the group and increase their survival doesn’t explain why they stop reproducing,” says Croft.

Proponents of the Grandmother hypothesis, however, may not be so convinced that intrafamilial conflict plays an important role.

Anthropologist Kristen Hawkes, at the University of Utah, says the killer whales are fascinating, but that they’re hard to study. “They’re doing all kinds of stuff where you can’t see it, and even to get demographic data is just so tricky, because they’re all underwater and they’re long-lived,” she says.

She points to one recent study on food-sharing in killer whales that found older females share fish with their older adult sons, perhaps to maximize the males’ ability to sire more babies.

If that’s the case, she says, “it’s not the older females and younger females in competition, it’s the older females contributing to the enormous success of their sons, and then those baby whales are all born somewhere else. They’re not competing, because their moms are elsewhere.”

Source: npr.org

Rare video of orcas in the Gulf of Mexico

May 26, 2016

SOUTH PASS, LA. — A group of friends out fishing, just 50 miles South of South Pass, Saturday, saw something extremely rare.

Mark Hawley, Nick Trist, IV, Jared Averill, Matt Teen, Ashley Joplin, and Jessica Piglia were tuna fishing in the Gulf of Mexico, when they caught an unusual sight on camera.

A pod of orcas, better known as killer whales, were swimming not far from their boat.

Orcas live in cold deep waters and rarely come that close to land.

Dr. Moby Solangi at the Institute for Marine Mammal Studies (IMMS) in Gulfport, says this could be a first warning sign that there is an environmental problem. The scientists at the IMMS got the GPS  location from the group and plan to investigate the sighting.

Watch raw video from the fishing trip.

Source: wwltv.com

Young killer whale calf spotted off Caithness coast

May 19, 2016

Adult orcas and calf

A group of killer whales have arrived in Scottish waters from Iceland to raise a young calf and to hunt.

The pod is known in Scotland as the Northern Isles community and moves between Iceland and Scotland.

Six of the group were spotted off Duncansby Head in Caithness on Monday afternoon and were photographed by wildlife watcher Karen Munro.

Scotland also has the West Coast community, a pod of older animals and the UK’s only resident orcas.

The killer whales from Iceland include a calf thought to be only three months old.

Scientists and wildlife watchers in Iceland and Scotland are able to identify individual orca from markings on their bodies and the shape of their dorsal fins.

Ms Munro told the BBC News Scotland website: “I knew straight away as I was looking through the lens taking photos who one of the whales was as she has a very distinct notch in her dorsal, I could also tell she had a very young calf with her due its orangey colouring and size.

“The adult is known as Number 19, or Mousa to some. She spends winter in Iceland feeding on herring and was photographed there this March with her newborn calf by Marie Mrusczok in Iceland, so it is only around three months old.”

Ms Mrusczok and another Icelandic scientist, Filipa Samarra, were also able help Ms Munro and other Scottish orca watchers to identify three of the others in the group.

They included 19’s older calf who is about four-years-old.

Earlier this year, it was found that the West Coast community killer whales had lost one of their number.

A killer whale known as Lulu was discovered dead on Tiree in the Inner Hebrides on 3 January. Only eight orca are now thought to survive in the pod.

Source: www.BBC.com