Characterizing fish assemblages and habitat attributes on an intermittent stream

 Droughts are naturally occurring phenomena in Mediterranean climate regions, resulting in fragmented and intermittent stream habitat. As a result, fishes seek refuge in isolated pools during the summer low flow season. The availability of this  pool habitat is of concern because fish are sensitive to habitat changes like temperature and surface area. Being able to understand the influence of specific habitat variables on native fish during drought seasons can be used as a foundation for effective conservation strategies. We are focusing on Oncohynchus mykiss (rainbow trout), an economic and culturally important species. We sampled twelve pools in San Antonio Creek, a relatively undisturbed intermittent stream in the Alameda Creek Watershed, California. We examined rainbow trout abundance and related it to habitat attributes (e.g., pool volume, depth, undercut bank, and temperature). To quantify fish, we surveyed pools by seining and electrofishing. We surveyed pools during both a dry year (2012) and a wet year (2011) to compare fish distributions under different conditions. Previous research suggests that, rainbow trout are found in pools that have lower maximum temperatures with high riparian canopy. We hypothesize that there is a positive correlation with rainbow trout distribution and local stream habitat attributes such as pool depth, undercut banks, and lower average temperatures. We also predict that lower pool volume and higher water temperature will have decreased trout populations this summer, when comparing from last years data.  By having a better understanding of species distribution and habitat associations, we can improve our conservation and restoration efforts.