Lake Tahoe Invasive Species Research - Oris Lab, Miami University by Molly Mehling

Amanda (Gevertz) Kovach (graduate student) and Matt Kovach (field assistant) search for Lahontan Redside minnows in a nearshore gravel bed, which the minnows prefer for spawning.

Amanda's research examined two fish species, a Lake Tahoe native (Lahontan Redside minnows) and a Lake Tahoe non-native (Bluegill). She designed experiments to determine if the Redsides and Bluegill larvae (babies) differ in their ability to survive various combinations of water clarity and pollutants.

The research clearly shows that the native Lahontan Redside have capabilities to withstand the very clear water of Lake Tahoe while the Bluegill larvae aren't so tough. Bluegill sunfish have established populations in areas of Lake Tahoe that have locally degraded conditions with a loss of clarity that permits their survival.

Gevertz's research, in combination with other studies, will help maintain desirable conditions in Lake Tahoe in the face of multiple stressors.

LAKE TAHOE RESEARCH
Known for it's clear turquoise water, Lake Tahoe is a prized gem located on the border of California and Nevada in the Sierra Nevada mountain range. Thanks to Dr. Charles Goldman, the lake has been the focus of limnological research for over 40 years and boasts a unique data set.

CULTURAL EUTROPHICATION
Lake Tahoe and its surrounding mountains attract a constant stream of tourists though out the year as well as an increasing number of residents. Although significant effort has been made to minimize the effects of tourism and development in the Lake Tahoe watershed, the lake has lost 1/3 of its famed clarity in the past 30 years.

AN INVASIVE PROBLEM
People are not the only crowd to move in and take root in the Lake Tahoe area. Numerous non-native species have been introduced, intentionally and unintentionally, to Lake Tahoe. The widespread invasive Asian clam, Corbicula fluminea, has set up residence in Lake Tahoe; the consequences of its establishment are currently under investigation. (terc.ucdavis.edu/research/aquaticinvasives.html ).
Another non-native, the Bluegill sunfish (Lepomis macrochirus), has also caused quite a stir. Currently, present in only portions of the Lake Tahoe shoreline, there is fear that changing lake conditions could facilitate widespread take over of native fish, such as the Lahontan Redside dace, by the unwelcome Bluegill.

Ongoing research by scientists at Miami University (Oxford, Ohio) has examined interactions among lake clarity, contaminants and non-natives in Lake Tahoe. Using both field and laboratory techniques, results are in agreement that maintaining Lake Tahoe's clarity is key in keeping these unwanted fish at bay (www.tahoedailytribune.com/article/20100514/NEWS/100519904 ).
AN INVISIBLE PROBLEM
It now known that half of the clarity problem is due to very, very small particles (unable to be seen without a powerful microscope) that have entered the lake as a result of activity in its watershed. Proposed cuts to the amount of fine particles entering the lake may halt the loss of clarity (www.laketahoenews.net/2010/06/quest-to-increase-tahoes-clarity-begins-with-tmdl-document /). Better yet, the plan may send Lake Tahoe on a reversed path to its condition of 40 years past.

For more information:

UC Davis Tahoe Environmental Research Center (TERC): terc.ucdavis.edu /
Global Change Limnology Laboratory
www.users.muohio.edu/willia85 /
Global Warming Could Radically Change Lake Tahoe In Ten Years - Science Daily, May 26, 2008
www.sciencedaily.com/releases/2008/03/080325141202.htm 
Explore other Lake Tahoe GigaPans:

Sand Harbor
gigapan.org/gigapans/10756/
Emerald Bay
gigapan1.gc.cs.cmu.edu/gigapans/11042 /
gigapan5.gc.cs.cmu.edu/gigapans/22339 /