Posted on: Tuesday, May 27, 2003

UH student discovers fish wear sunscreen

By Robbie Dingeman
Advertiser Health Writer

Ever wonder why fish don't get sunburned? Turns out many of them make their own sunscreen.

University of Hawai'i doctoral candidate Jill Zamzow was studying coral reef fishes in 1999 when she made the award-winning discovery that many species produce their own sunscreen in a mucus that coats their bodies and helps protect them from the sun's damaging rays.

Zamzow, 31, a graduate student in the UH-Manoa Department of Zoology, is finishing her dissertation and preparing to be awarded her doctorate in August.

She noticed that a Hawai'i white-spotted toby lost its distinctive markings when viewed through an ultraviolet-sensitive video camera.

Wondering why that happened, Zamzow "wiped the side of the fish down and the spots came back" when viewed through the same camera.

For that work, Zamzow was honored in the fall as "scholar of the year" by the Achievement Rewards for College Scientists Foundation's Honolulu Chapter.

She said the initial discovery made her want to learn more.

"Is this some weird mutant fish or are all the fish out there wearing sunscreen?" she said.

She's studied more than 200 species of fish in Hawai'i, Australia, Johnston Atoll, the Marshall Islands and on the Mainland West Coast and found that more than 85 percent of them have sunscreen compounds equivalent to or exceeding SPF 15 sunscreen for humans.

She has heard that some folks in Australia are looking into the commercial possibilities of using the fish mucus to produce skin protection for humans. Researchers there had found the sunscreen compounds in coral, she said. She wonders how they will address the fact that the fish mucus washes off in water because the fish is constantly producing more.

Zamzow did most of her research at the Hawai'i Institute of Marine Biology at Coconut Island in Kane'ohe Bay. She said sunscreen-producing fish include parrotfish, saddleback wrasse and butterfly fish.

When people hear what she studies, they often ask the same question: If you're out in the water and short on sunscreen, "they want to know if you can pick up a fish and rub it on yourself.

"I've never tried it myself, but I think the water-solubility issue would probably be a problem," she said.