Dan Worth

Dan joined the lab in the spring of 2007.

Research: Lake Davis trout

Research: Growth and Dispersal of Recently Stocked Trout in the Lake Davis Watershed

Abstract:

In recent times, Lake Davis has been one of California's most controversial restoration projects. The California Department of Fish and Game had been trying to rid the lake of Northern Pike (Esox lucius), which were illegally introduced in the early 1990s. In the aftermath of a second attempt to remove pike from the watershed, a unique opportunity arose to study the re-introduction of trout into the watershed. I am proposing to study the growth and dispersal of recently stocked, and individually marked trout in the Lake Davis Watershed. The objectives of the proposed study are to learn how trout are utilizing the tributaries of Lake Davis, and to assess how growth and dispersal of trout are related. In addition, the growth of tagged fish and non-tagged fish will be compared, to determine the effects that tags have on fish under natural conditions. I have tagged 800 Eagle Lake rainbow trout, Oncorhynchus mykiss aquilarum, and spread them throughout the tributaries of Lake Davis. The tags used were Floy T-bar anchor tags that each has a unique number to identify individual fish. The location and size of each stocked fish were recorded at the time of planting. A week after the tagged fish were stocked into the creeks, 1200 non-tagged fish were stocked into similar locations within the creeks. Since the fish were stocked in May of 2008, the tributaries have been sampled for fish approximately once per month. Each time a tagged fish is caught, the GPS location and size of the fish is recorded. This data will be used to evaluate growth and dispersal patterns of trout in the Lake Davis Watershed. First, I will use regression analysis to compare growth rates of fish that were planted into different creeks. Second, this study will evaluate differences in growth rates of tagged fish versus non-tagged fish using regression analysis. Third, I will use regression analysis to compare the size of individual fish at stocking to the distance that they moved during the first sampling interval. In addition to the tagged creek fish, another 500 fish were tagged and stocked into the lake. These tags will be used to determine if and when lake fish move into the creeks. The data collection portion of this project will end in the fall of 2008.

 

CSUS BIO SCI