FISH HEALTH AND DIVERSITY - JUSTIFYING FLOWS FOR A CALIFORNIA STREAM

Efforts by a citizen's group, Putah Creek Council, to improve the flow regime of a California stream for ecosystem, aesthetic, recreational, educational, and research purposes led to a successful court trial in which fish conservation played a key role. A major issue around which the trial revolved was the proper interpretation of a section (5937) of the California Fish and Came Code, which states that fish must be m aintained in ''good condition'' below a dam. We defined good condition to mean there had to be healthy individual fish in healthy population s that were part of healthy biotic communities. This definition result ed in a conceptual model for instream flows for the creek that favored native resident and anadromous fishes. The stream flow recommendation s from this model had four components: living space flows for the enti re creek, resident native fish spawning and rearing flows, anadromous fish flows, and habitat maintenance flows. The trial judge, in attempt ing to balance competing demands for the water, ordered the implementa tion of only the first two recommendations. The order has been appeale d by the water interests, but regardless of the final outcome, the cou rt's decision reflects the growing public interest in protecting strea ms, the need for innovative use of existing legal tools to try to prot ect aquatic resources, and the importance of biological information in developing flow recommendations for complex fish assemblages.