UW's albino ratfish is 1 in 7 million

Jon Reum was sick of ratfish.

The University of Washington doctoral student had spent five straight days hauling up nets loaded with the slimy bottom dwellers as part of a marine survey in Puget Sound. It was drizzling and cold.

"We brought up a deep tow, and I knew it was going to have hundreds, if not thousands, of ratfish," he recalls. "And then I saw it."

Gleaming like a pearl in the mass of brown was a pure white albino, a rare phenomenon in the aquatic world.

"This animal would just stand out like a beacon," says UW fisheries professor Ted Pietsch. "I don't know why it wasn't eaten long before."

In his 40-year-career, Pietsch had never seen an albino fish. "To my knowledge, there has never been another albino ratfish described."

In the marine environment, few albinos live long enough to pass on the mutant genes that block production of skin pigment.

Reum and his fellow students were stunned.

"Everyone just started chanting and clapping," he says. "It was the most exciting thing."

They rushed the foot-long female into a bucket to keep her alive.

The ratfish is a creature that normally doesn't inspire much concern for its well-being, even among fisheries biologists.

Its name probably derives from rodentlike front teeth, part of a grinding plate used to crush clams, crabs and worms scooped up from the sand and mud. The normal color for Puget Sound's white-spotted ratfish is a muddy gray, with light mottling to blend in with the bottom.

"They're pretty ugly," Reum says. "They've got this gnarly spine on their backs, they bite, and they're just a pain to work with."

But the cartilaginous cousins of skates and rays are the most abundant fish in Puget Sound.

"People think of Puget Sound and they think of these iconic animals like killer whales and salmon," Reum says. "But when you go by just the numbers, ratfish are by far the most important animal in the ecosystem — yet we know so little about them."

Even though ratfish can grow up to three feet in length, people rarely see them because they prefer very deep water, says Greg Bargmann, research scientist for the Washington Department of Fish and Wildlife. Ratfish will move into the shallows at night to feed but rarely strike a baited hook. Only net fishermen encounter them regularly.

Ratfish numbers seem to be on the upswing, Bargmann said.

Reum ran a saltwater hose into the bucket to keep the water clean and aerated, and laid boards on top to prevent the albino from jumping out.

"I thought it would be perfect for the Seattle Aquarium," he says.

The albino was probably two or three years old when she was netted earlier this summer on the west side of Whidbey Island, Pietsch estimates. That's the ratfish equivalent of a teenager. Mature females will produce an egg sac containing two embryos every two to four weeks.

Large nostrils positioned over the top lip help the fish sniff out delicacies. A special organ in the snout detects faint electrical signals from muscle contractions, allowing ratfish to nab prey hidden in the mud.

"They're really pretty fascinating," Reum says.

He and his colleagues retired for the night, leaving the female in her bucket on the UW research ship. In the morning, her body lay on the deck.

She had flipped out through a gap in the boards.

"It was a sad, sad thing," Reum says.

But the ratfish isn't lost to science. She's now floating in a jar of alcohol, the only pure albino among the 7.2 million specimens in the UW's fish collection.

Sandi Doughton: 206-464-2491

or sdoughton@seattletimes.com