Trends of Native & Non-Native Fish Communities in an Urban Creek (Marsh Creek, California)

Marsh Creek in Oakley, CA was once a naturally, intermittent creek that ran from the foothills of Mt. Diablo to Dutch Slough and into the San Francisco Estuary (Contra Costa Resource Conservation District, n.d.). It contained several native fish species, whose ranges were dispersed across varying aquatic habitats. Over time, the creek has been dammed and diverted for agricultural and recreational purposes. Today, only a few sections of intermittent and small, perennial streams remain in the foothills. The lower section of the creek has become channelized, receives perennial flow from a wastewater treatment plant, and the Marsh Creek Reservoir. These anthropogenic modifications have facilitated the creation of a novel ecosystem, where the remaining native aquatic community assembly blends with introduced, non-native species. 

 

Despite being modified, we detected regional species of concern such as Sacramento Hitch (Lavinia exilicauda) and Chinook Salmon (Oncorhynchus tshawytscha) using Marsh Creek as habitat. To determine how Marsh Creek serves as habitat for these native fish, we plan to utilize GoPro video surveys and clover/minnow traps to assess species abundance and habitat heterogeneity at sample sites. Macroinvertebrate and YSI samples will be collected to characterize water quality and identify invertebrate community assemblage. Visual observations are planned to be used to observe breeding behavior and abundances of chinook salmon and Sacramento hitch adults. This study seeks to provide insight into the persistence of native fish in novel ecosystems and the influence stream modification can have on aquatic communities in Central California.