UNR biologists worried 'giant' goldfish could hurt Tahoe ecosystem

Christine Ngai wasn’t sure if it was an orange soda can or a plastic cup. It certainly wasn’t a largemouth bass, the fish Ngai was researching at Lake Tahoe in 2006 as part of her master’s thesis.

During her survey at the Tahoe Keys, Ngai first spotted a giant goldfish, and dozens more have been seen since, with some weighing in at 4 pounds.

“As it approaches you realize it is some sort of fish,” said Ngai, who studies fish for the University of Nevada, Reno. “And you scoop it up, remove the vegetation and there it is — a goldfish that is the size of your head.”

Research in the mid-2000s prompted funding for a warm-water fish control program to remove invasive, nonnative fish from locations along Lake Tahoe, mainly in the Tahoe Keys.

The project, which began in 2011, has removed thousands of fish, including about 90 giant goldfish.

It’s not entirely known why the goldfish are populating near-shore regions in Tahoe, but some suspect it is most likely form aquarium dumping.

“It is a big deal because it is not just in Nevada — this is something that has gone on throughout the country,” Nevada Department of Wildlife spokeswoman Teresa Moiola said.

The Nevada Legislature in 2011 passed a law to make it illegal to dump invasive fish, Moiola said.

What’s the problem with the giant orange guppies?

They eat native minnows, one of the main sources of food for naturalized species such as Mackinaw and trout.

But the goldfish is not the only minnow predator.

Since 2011, about 35,000 warm-water fish have been removed from water near the shore in Lake Tahoe through the program, the vast majority of them large-mouth bass and bluegill.

The minnow population declined 58 percent from 1988 to 2009, according to a University of Nevada, Reno study.

Large-mouthed bass numbers spiked at Tahoe in the 1980s, Ngai said. Their numbers, and the numbers of several other warm-water fish in Lake Tahoe, have thrived in the region partly because of climate change, she said.

But the goldfish, even with its population well below that of its other warm-water brothers, might pose another threat...

http://www.rgj.com/article/20130221/NEWS/302210056/UNR-biologists-worried-giant-goldfish-could-hurt-Tahoe-ecosystem-see-video-