An Analysis of the Nearshore Water Temperatures of Lake Tahoe

• Lake Tahoe is a large freshwater lake that has been studied extensively over the last 50 years, primarily for the factors that are changing offshore clarity • It is the nearshore waters that contain the greatest concentration of particles entering the lake, largely by increased anthropogenic activity around the lakeshore, making it the ideal place to analyze spatial and seasonal trends 5 • The nearshore environment is not only the area that most visitors to the lake spend their time, but also the area of the lake where many invasive species are establishing, such as warmwater fishes • Recent studies suggest that the establishment of these fishes may be partly due to increases in nearshore temperature due to climate change. The probability of these nonnative species increasing in numbers and spreading to the offshore areas increases if the temperatures continue to rise • A literature search on invasive species and their temperaturepreference relationships was also conducted to gain an understanding as to why such species occur around Lake Tahoe • Approximately 20 locations were chosen around Lake Tahoe for the deployment of thermochron iButtons, placed 1-2 meters deep into the water, taking periodic temperatures at 3-hour intervals • Data was used from the year 2006 to 2011 to determine summer average temperatures of the nearshore areas around Lake Tahoe • Points were chosen between marinas and open water • Large lakes can be great indicators of climate change so long as the long-term data exists, with a high heat capacity short-term temperature variability is limited 4 • Due to the short-term data collected for this study it was more accurate to differentiate between sites opposed to changes in temperature over time • The TKED marina and CB Marina were expected to exhibit higher temperatures over all, surprisingly CB was the coldest site for most of the June and July averages • With the Tahoe Keys exhibiting average summer temperatures between 15-25 C* the potential for invasion of warmwater fishes increases in the southern area of Lake Tahoe • One potential affect of climate change is the modification of the geographic distribution of fish species with a chance of increasing warmwater spp and decreasing coldwater spp as summer temps continue to rise 3 ; currently taking place in the Tahoe Keys