Since 2011, University of Nevada, Reno biologists are consistently finding large goldfish inhabiting Lake Tahoe, a species introduction biologists will investigate in May 2013. (Photo: courtesy of University of Nevada, Reno)
Emerson Marcus, Reno Gazette-Journal
RENO - Biologists are worried that Lake Tahoe's pristine blue water may be affected by a "giant" visitor.
Goldfish have inhabited the water of the Tahoe Keys since the 1990s, said Sudeep Chandra, a biologist at the University of Nevada, Reno.
But it wasn't until 2011 that biologists found a 14.2 inch, 3.4 pound goldfish in the lake. More "giant" goldfish have been found since, he said.
It is not entirely known how the goldfish are being introduced to Lake Tahoe. Chandra said he thinks people who have goldfish as pets are disposing of them in the lake.
According to the U.S. Forest Service's Lake Tahoe Basin Management Unit, warm-water fish, which include goldfish, have been seen in the lake over the last decade. The invasion of these warm species can be detrimental to the ecology within the lake.
Goldfish introduction is common in the Midwest where many people are populating the Great Lakes through aquarium trade and water gardens, Chandra said.
"What we forget is this introduction can have a large impact in the region," Chandra said.
Chandra said the waste from the goldfish creates a certain near-shore algae that can reduce the clarity of the lake. The introduction of goldfish also creates more competition for other species, he said.
According to the Lake Tahoe Basin Management Unit site, goldfish "strip waters of oxygen-producing plants which increases water temperatures and destroys habitat for native juvenile fish."
Lake Tahoe is not the only area affected by non-native species. The Florida Everglades has pythons and the Mississippi River basin has been affected by Asian carp.
Biologists at the University of Nevada, Reno, will conduct research in May to understand the extent of the goldfish population in Tahoe, the university said Thursday.