Killer whales are passing on chemicals which end up in the ocean to their young, scientists have found for the first time.
A study has discovered that high levels of brominated flame retardants – used in furniture such as sofas – build up in the bodies of killer whales and may be passed on to their offspring as their mothers feed them.
The chemicals were found in the body of a newborn orca analysed in Norway, in low levels indicating they had been passed on by its mother.
Investigators, from the University of Oslo, also found banned manmade chemicals called polychlorinated biphenyls (PCBs) in the blubber of seven out of eight killer whales studied.
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The chemicals were found in the body of a newborn orca analysed in Norway, in low levels indicating they had been passed on by its mother
These chemicals were recorded at levels beyond the threshold for toxic effect in marine mammals, and could harm reproduction, the researchers warned.
The study, published in the journal Environmental Toxicology and Chemistry, reads: ‘Little is known about the movement or presence of unregulated, emerging contaminants in top predators.
‘The aim of the present study was to conduct the first screening of legacy and emerging contaminants in multiple tissues of killer whales from Norway.’
They were able to study tissue samples from seven whales which had washed ashore, and one which had been caught in a fishing net, between 2015 and 2017.
Carrying out autopsies allowed them to measure the chemical contents in their bodily tissues.
Most of the chemicals had been deposited in the whales’ blubber, and in milk within the calf’s stomach.
They said the discovery of chemicals in the newborn orca, which was only 10 days old, ‘is the first evidence of maternal transfer of these unregulated contaminants in marine mammals.’
The discovery of chemicals in the newborn orca, which was only 10 days old, ‘is the first evidence of maternal transfer of these unregulated contaminants in marine mammals’
‘Levels near to or exceeding health effect thresholds in such a young animal are worrying, considering that the endocrine and immune systems are still developing, thereby increasing the risk of developmental deficiencies and calf mortality,’ they wrote.
It is thought that the adult orcas ingested the chemicals through other, smaller animals in their diet.
‘Polychlorinated biphenyls, which have long been banned, pose a potential risk to population growth for the majority of known killer whale populations around the world,’ the scientists concluded.
‘The presence of unregulated emerging contaminants in their tissues, in addition to the legacy compounds, give cause for concern.
‘Our results are relevant for the continued environmental monitoring of contaminants in the Arctic.’
Polychlorinated biphenyls (PCBs) were used as dielectric filler liquids in some types of electrical equipment such as transformers, switchgear, capacitors and in the starter units of fluorescent lights and fractional horsepower motors.
However, they have been banned in the UK since 1981 due to their toxicity.
HOW WAS WIKIE THE KILLER WHALE TAUGHT TO SPEAK AND WHAT WORDS CAN SHE SAY?
A killer whale has been taught to speak human words through her blowhole.
Wikie, a 16-year-old female orca living in a French marine theme park, is able to copy words such as ‘hello’, ‘bye bye’ and ‘Amy’, as well as count to three.
Researchers tested multiple sounds in three situations. In one the whale was instructed to produce a sound to copy using gestures.
In another the sound was played through a loudspeaker and in the third a human produced the desired sound.
Each time the killer whale was able to accurately reproduce sounds.
Five sounds where orca noises that Wikie had not heard before. They were described by researchers as ‘breathy raspberry’, ‘strong raspberry’, ‘elephant’, ‘wolf’ and ‘creaking door’.
Three sounds were already familiar to Wikie – described by researchers as ‘song’, ‘blow’ and ‘birdy’.
She was also exposed to six human sounds – ‘hello’, ‘Amy’, ‘ah ha’, ‘one, two’ ‘one, two, three’ and ‘bye bye’.
In each trial, the killer whale was given a ‘do that’ hand signal by a researcher, but offered no food reward.
The recordings were rated by Wikie’s trainer and the researcher, as well as six independent observers.
Speech recognition software was also used to test how well she performed, which showed three words came close to the ‘high-quality match’ achieved by humans copying each other.
The recordings were rated by Wikie’s trainer and the researcher, as well as six independent observers. Pictured is Wikie with her calf
Wikie was able to copy all the sounds she was presented with. She managed to copy all the human produced orca sounds on her first go.
‘We found that the subject made recognisable copies of all familiar and novel conspecific and human sounds tested and did so relatively quickly (most during the first 10 trials and three in the first attempt)’, researchers wrote in the paper published in Proceedings of the Royal Society B.
‘The subject’s matching accuracy is all the more remarkable as she was able to accomplish it in response to sounds presented in-air and not in-water, the species’ usual medium for acoustic communication.
‘It is conceivable that our data represent a conservative estimate of the killer whale’s capacity for vocal imitation.’
The sounds emerge from her blowhole as parrot-like squawks, shrill whistles or raspberries, but most are easily understandable as words.
She ‘spoke’ while partially immersed in water with her blowhole exposed to the air.
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