Giant goldfish have been discovered in Lake Tahoe by researchers in the Department of Natural Resources and Environmental Science. Image: Univ. of Nevada, RenoIt may sound like a science-fiction plot, but, as Univ. of Nevada, Reno researchers have discovered, giant goldfish are among the non-native fish species living in Lake Tahoe, which straddles the Nevada-California state line.

Research conducted by university faculty and the California Department of Fish and Wildlife has shown the Tahoe Keys, on the lake's south shore, is the primary spawning area for non-native, warm-water fish. The environmental concern is that these invaders damage the habitat for native fish. For example, in the Tahoe Keys, the establishment of non-native fish has virtually eliminated the native minnow population.

According to Christine Ngai, a researcher in the university's Aquatic Ecosystems Analysis Laboratory, thousands of non-native, warm-water fish, mainly largemouth bass and bluegill, have been removed from the lake, and a surprising number of giant goldfish – some as large as 4 pounds and nearly 15 inches long – have been removed as well.

"In Lake Tahoe, since 1960, there has been a tenfold decline in native fishes, but what we also know is that these recent invaders could further depress the native population through competition and predation," says Sudeep Chandra, a freshwater scientist in the university's Department of Natural Resources and Environmental Science and director of the university's Aquatic Ecosystems Analysis Laboratory.

A "warm-water-fish pilot control project" began in 2011 and is one of many research-based, aquatic invasive-species prevention and control programs currently implemented in the Lake Tahoe Basin under the general Lake Tahoe Environmental Improvement Program. Through the project, researchers are studying the proliferation and migration of non-native, warm-water fishes and exploring the feasibility and effectiveness of mechanical-removal methods, such as electrofishing, as a means to manage their population.

Another component of the project is tagging the fish as a means to monitor them.

"We are trying to determine the extent to which these fish are moving into the main part of the lake and when and where they might be moving," says Chandra.

The giant, invading goldfish have sparked international interest and considerable media coverage around the country.

For Chandra and his team, the media coverage is welcome. It highlights attention on this important environmental issue and the capabilities and successes of the researchers and faculty in the Aquatic Ecosystems Analysis Lab; plus, Chandra hopes the increased awareness will inspire prospective and current students to consider environmental sciences as a career path.