Ultraviolet rays don't just bronze sunseekers on the beach. Underwater, they can give hammerhead sharks a suntan. And worse—give fish skin cancer. So says a study in the journal PLOS ONE. [Michael Sweet et al., Evidence of Melanoma in Wild Marine Fish Populations]

Researchers caught 136 coral trout in the southern Great Barrier Reef. Fifteen percent of them had black lesions on their skin: melanoma. Pathogens, toxic chemicals or UV rays can all cause melanoma. But DNA tests ruled out the presence of pathogens. And the fish were caught in the pristine waters of a marine sanctuary, so pollution wasn't to blame.

Turns out, the trout's cancer cells looked just like those of fish who'd been hit with UV radiation in the lab. So the researchers concluded that sunshine was the culprit. Makes sense, they say, because these trout live near the world's biggest hole in the ozone layer—meaning more exposure to UV rays.

Another recent study, this one in the journal Science, says the severe storms delivered by climate change could punch new holes in the ozone layer, upping our dose of radiation on land and at sea. And that's no fish story.

—Christopher Intagliata

[The above text is a transcript of this podcast.]