Perilous Times
UV Radiation: Whales suffer effects of sunburn
By Victoria Gill
Science and nature reporter, BBC News
Blue whale fluke (Image: Diane Gendron)
The researchers say that UV radiation poses a threat to whales' health
The Sun's rays can "burn" whales' skin, just like they can damage human
skin, according to a team of researchers.
The scientists studied more than 150 whales in the Gulf of California.
By taking photographs and skin samples, the US and Mexico-based team
found the whales had blisters that were caused by sun damage.
The report in the Royal Society journal, Proceedings B, concluded that
darker skinned whales showed fewer signs of sun damage.
The team was interested in the effects of increasing levels of
ultraviolet (UV) radiation on wildlife.
Laura Martinez-Levasseur, from the Zoological Society of London (ZSL)
and Queen Mary, University of London, led the study.
I hope this will also open the door for other researchers to look into
the effects of sun damage on wildlife
Laura Martinez-Levasseur, ZSL
More about whales, dolphins and porpoises on BBC Wildlife Finder
She explained that whales were a good model for this because "they need
to come to the surface to breathe air, to socialise and to feed their
young, meaning that they are frequently exposed to the full force of
the sun".
Ms Martinez-Levasseur and her colleagues from the marine research
centre CICMAR, in Mexico, studied blue whales, sperm whales and fin
whales over a period of three years.
They examined high resolution photographs of the whales' skin and took
skin samples from areas that appeared to be blistered.
Examining the samples under the microscope revealed that the blisters
were caused by sunburn.
Close-up on a whale with blistered skin
The researchers examined blisters on the whales' skin
The scientists also found that signs of sun damage were more severe in
the paler-skinned blue whales, compared with the darker-skinned fin
whales.
Like in humans, darker skinned whales have more cells that produce of a
dark brown pigment called melanin.
In humans, this is produced when DNA is damaged by UV radiation; a
similar response appeared to be occurring in the whales.
'First evidence'
In blue whales the symptoms of sunburn seemed to be worsening during
the period the study took place.
"This is the first evidence that the Sun's rays can cause skin lesions
in whales," said Ms Martinez-Levasseur.
"The increase in skin damage seen in blue whales is a matter of
concern, but at this stage it is not clear what is causing this
increase. A likely candidate is rising ultraviolet radiation as a
result of either ozone depletion, or a change in the level of cloud
cover."
Professor Edel O'Toole, from Queen Mary, University of London, a skin
specialist who took part in the study, said: "As we would expect to see
in humans, the whale species that spent more time in the sun suffered
greater sun damage.Fin whale (image: Diane Gendron)
Darker skinned fin whales suffer few skin lesions than paler skinned
whales
"We predict that whales will experience more severe sun damage if
ultraviolet radiation continues to increase."
This study showed no signs of skin cancer in the whales, but the team
are going on to find out how the whales respond to sun damage at a
genetic level.
This could provide clues about the longer term effects.
Ms Martinez-Levasseur said that other species were likely to be
affected by UV damage, especially hairless creatures, including
amphibians or sea mammals that live at the poles - where ozone decline
is most pronounced.
She said: "I hope this will also open the door for other researchers to
look into the effects of sun damage on wildlife."