Effectively managing a stream system requires knowing the conditions of many elements, such as fish and aquatic invertebrate populations, water quality, and physical conditions like bank stability. Such indicators provide insight into the health of a stream. FISHBIO uses a variety of sampling methods to assess the conditions in a number of California Central Valley streams. We make water quality measurements on site and also collect water samples for advanced laboratory analysis. In addition, we sample streams for macroinvertebrates, such as stoneflies, caddisflies and mayflies, conduct electrofishing surveys to estimate fish populations, and survey for vertebrates like snakes and salamanders. Our assessment also includes calculating the amount of sediment deposited in pools, profiling stream cross sections, estimating canopy cover, and counting large woody debris.