Rescue of a Humpbacked Whale and Research on Sunburned Whales

 

A blue whale’s head and tail fluke tend to be uniformly grey but their dorsal skin is usually mottled and can be quite pale.

The way that whales react to sunlight can shed new light on the human ageing process, say researchers. Some species react by getting darker with UV exposure in the same way as humans get a tan. Others though, protect from themselves from sun burn by turning genes on and off. The work, which is published in the journal Scientific Reports, could lead to new anti-ageing treatments in humans.

For several years now, marine biologists in Mexico have noticed an increasing number of whales in the region with blistered skin as a result of exposure to increasing, damaging UV rays. Over a three-year period researchers took skin samples from three different species of whales during their annual spring migration, when they move to the sunnier waters of the Gulf of California. The scientists found the different species reacted differently to the increase in sunlight.

Blue whales are the biggest creatures ever to have lived on Earth, and they respond to the Sun by increasing the amount of pigment in their skin, just like humans.

"When blue whales go on their holidays to the Gulf of California they get a tan the same way we do," Prof Mark Birch-Machin said. "And that tan protects blue whales from sunburnt DNA."

The scientists used crossbows and modified arrows to take skin biopsies from blue whales in the Gulf of California

According to Prof Birch-Machin, exposure to ultra violet light can damage not just skin but can harm DNA in mitochondria, the battery packs of cells. The ability of blue whales to tan in response to UV exposure may be connected to their historic migratory patterns as they move annually from higher to lower latitudes with a greater amount of sunlight.

Sperm whales have a different approach to the sun, says Prof Birch-Machin. They can spend up to six hours at a time on the surface of the ocean and have far greater exposure to UV light.

"They are akin to people going for the lobster approach - so changes in pigment aren't going to help them very much as the UV is overwhelming the system," he said. Instead of changes in their pigment, the sun triggers a stress response in the genes of these whales, which is similar to our own protective mechanism against sun damage.

"We saw for the first time evidence of genotoxic pathways being activated in the cells of the whales," said researcher Amy Bowman.

"This is similar to the damage response caused by free radicals in human skin which is our protective mechanism against sun damage," she added.

The third species the scientists examined were fin whales. These deeply pigmented animals were found to be more resistant to sun damage, with the lowest prevalence of sunburn lesions.  All species of whales are subject to sunburn lesions in varying degrees.  The researchers hope that by seeing both changes in pigment and changes in genes, the whales may shed some light on the ageing process in humans.

 

But can they help the poor whales who are getting blistered by the increasing intensity of the ultra-violet rays they are exposed to?? Unfortunately not. We can only hope they find a way to adapt quickly. In the mean time, these studies can help us to learn more about our own responses to sun damage and our own ageing mechanisms. And perhaps the plight of the whales will wake us up to the reality of global warming and the  danger of exposure to the growing concentration of ultra violet rays.