Professor Stephanie Carlson

Department of Environmental Science, Policy, and Management

“The Influence of Stream Habitat on the Distribution of Rainbow Trout, Oncorhynchus mykiss, in a Mediterranean-Climate Stream”

Streams in Mediterranean climate regions are characterized by annual drying periods during summer months, where flows are reduced and streams become fragmented. This results in isolated pools. Such drought disturbances create stressful conditions for fishes trapped in the pools, which can lead to elevated mortality. However, some pools may persist during this period and individuals may seek refuge in these sites. OOur research focuses on understanding changes in the availability of this critical pool habitat across the summer low flow season in San Antonio Creek, a small stream situated upstream of a reservoir in Alameda County. Several fish species make annual breeding migrations from the reservoir to the upstream sites. Juveniles migrating downstream to the reservoir often become trapped in isolated pools as the stream fragments. This accounts for the presence of juvenile Oncorhynchus mykiss (rainbow trout) during the drying period in our study site. We are surveying twenty randomly selected pools on a weekly basis to monitor changes over time. Specifically, we are measuring connectivity among pools, pool depth, and water temperature. Additionally, we are using several methods of capturing fish to sample juvenile rainbow trout. We will use this data to ask whether a relationship exists between habitat conditions and native trout distribution along San Antonio Creek. Based on our preliminary results, we expect that individuals will persist in the deeper, colder pools situated further upstream from the reservoir but will suffer 100% mortality in pools that go dry. This research will contribute to our understanding of Mediterranean-climate streams and the impacts of drought disturbances in these systems, as well as habitat preferences for native rainbow trout in these ecosystems.

Esther attended Laney and Merritt Community Colleges and accumulated an overall GPA of 3.675.  She is a first generation college student and has received an Associates in Science Degree- High Honors, and a member of Phi Theta Kappa. Esther will attend UC Berkeley in Fall 2011 as a Conservation and Resources Studies major. Upon graduation would like to become an Environmental Scientist helping to find solutions that minimize the hazards we impose on the environment.