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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Transient orcas visiting northwest waters in record number

May 18, 2016

Transient off Morsby Island, BC. Photo by Capt. and Naturalist Heather MacIntyre, Maya's Legacy Whale Watching, Friday Harbor, WA.

Now deemed “resident transients,” mammal-eating orcas are becoming familiar visitors to northwest waters.

“I remember Dr. John Ford (head of the Cetacean Research Program at the Pacific Biological Station) telling me at least 10 years ago that by this time we’d start seeing an influx of transient killer whales in the Salish Sea, and he was right,” explained Capt. Mark Malleson, of Prince of Whales Whale Watching.

Scientists and whale watchers report that a boom in the pinniped population — seals and sea lions –means a set table for the orcas.

And it’s not just pinnipeds they prey on.

In early April, a Pacific Whale Watching Association crew even reported a young transient killer whale attacking two 40-ton gray whales in Puget Sound.

PWWA reports the orcas, also called Bigg’s killer whale T60D, are all business at mealtime, coming onto the scene swiftly, in small groups and without a sound.

About 320 individually identified transient killer whales swim along the West Coast of North America.

The seeming increase of prey resources for the “resident transient” orcas are a contrast to 84 endangered wild Southern Resident orcas, who face declining salmon supplies as they rebuild their ranks.

“As we say, if you’ve got fish, you’ve got blackfish — the rezzies (Southern Resident orcas) — and since we’ve got lots of seals and sea lions now, we’ve got the Bigg’s,” Harris said.

“And even though the transient killer whales carry the highest load of toxins of any marine mammal on the planet, even higher than the resident orcas, they seem to be doing pretty well.  Fat whales, lots of babies, no gender imbalance in the calves, behavior that indicates the population is thriving. It’s proof that if we get food in the water for these orcas, we can buy some time to deal with these other threats.”

Source: Kiro7.com

Strait of Gibraltar’s killer whales are ‘unique’

February 17, 2016

Strait’s killer whales are ‘unique’

Killer whales in the Strait of Gibraltar are socially, genetically and ecologically distinct from other groups in the north Atlantic and Canaries, according to a new scientific study.

Until now, orcas in the strait had been regarded as belonging to the same social group as those around the Canary Islands.

But the new research has established that none of the strait’s resident orcas has been spotted in the Canaries, or vice versa, meaning there is no interaction between the groups.

Based on detailed study of skin and fat samples, the scientists have also established that orcas in the Strait of Gibraltar do not share the same genes or even diet as other groups in Spain or Europe.

“The orcas in the Strait of Gibraltar are unique, they are isolated and bear different characteristics to orcas in the rest of Spain and the European continent,” said Spanish cetacean conservation group CIRCE.

Source: chronicle.gi