Efficacy and fate of fluridone applications for control of invasive submersed aquatic vegetation in the estuarine environment of the Sacramento-San Joaquin Delta

We conducted a study in the Sacramento-San Joaquin Delta to determine efficacy of the widely used herbicide fluridone in an estuarine ecosystem. The primary goal of SAV removal was restoration of open water habitat for endangered Hypomesus transpacificus (Delta Smelt). Over 18 months and multiple sets of multi-week fluridone applications, we monitored concentrations of fluridone and responses by SAV across pairs of treated and reference sites. Fluridone concentrations in the water were generally below the 2-5 parts per billion required for SAV control. Monitoring demonstrated these low water concentrations were likely due to dissipation by tides, despite use of pelleted fluridone formulations marketed for flowing water environments. Fluridone did, however, accumulate in sediment at concentrations hundreds of times higher than those measured in the water. Nonetheless, we did not observe lasting reductions in SAV abundance or changes in SAV community composition. By demonstrating lack of efficacy of one of the few herbicides permitted for use in this estuary, this study highlights the need for development of SAV management tools tailored to the challenges of hydrologically complex environments like estuaries. ## About This Federated Record This CNRA Open Data Platform record is based on metadata federated from the Environmental Data Initiative (EDI) Data Portal. Its purpose is to improve the discoverability of the data package through the CNRA Open Data Platform. The EDI Data Portal is the repository of record for this data package. Metadata, resource links, and supporting information displayed here may not reflect the latest updates available in EDI. Resources shown here—including Full Metadata, Provenance, and Data Quality Report—are provided to help users understand and evaluate the data package and the supporting information available from EDI. For the current data package, citation, DOI, data files, metadata, provenance, data quality documentation, revision history, and other supporting information, refer to the EDI data package landing page: https://portal.edirepository.org/nis/metadataviewer?packageid=edi.1079.2&key=vqSpNwnbe91Bi8trB5RY25CoPD4 Access requirements, permissions, and authorization policies for resources hosted by EDI are established and managed independently of the CNRA Open Data Platform.