Role Nutrients Play in Fish Death Rates at Rodeo Lagoon
Scientists investigate excessive nutients levels in Rodeo Lagoon that are believed to be cause of dying fish
Hypoxia resulting from nutrient-enhanced eutrophication is believed to be the primary cause of fish kills and aesthetically unpleasing water quality conditions that have led to visitor complaints at Rodeo Lagoon, Golden Gate National Recreational Area. Fish kills have been documented in Rodeo Lagoon since 1993 and are an especially important management issue because they have included die-offs of two federally-listed fish species, the endangered tidewater goby (Eucyclogobius newberryi) and the threatened Central California Coast steelhead (Oncorhynchus mykiss). Immediate action is needed on this issue because visitor satisfaction is going down and imperiled fish species are dying. Fish kills have occurred as recently as 2014 and without proper remediation the continued poor water quality will perpetuate the likelihood of future hypoxia and fish kill events.
The fundamental problem being addressed by this project is to identify the sources of nutrients contributing to eutrophication, hypoxia and fish kills in Rodeo Lagoon. This project will identify measures that can reduce or eliminate the occurrence of the eutrophication, hypoxia, and fish kills in Rodeo Lagoon. The information being gathered will characterize energetic pathways and nutrient sources in the Rodeo Lagoon foodweb and quantify hypoxia exposure of imperiled fish species in Rodeo Lagoon. This information will enable park managers to determine the most effective measures for ameliorating the problem.
This study will utilize state-of-the-art isotopic methods for determining nutrient sources and hypoxia exposure in fish species. To our knowledge, this will be the first time this suite of tools has been used in a complimentary fashion to address problems in costal resource management. This study brings together an interdisciplinary team of scientists from multiple agencies. The team includes scientists from the USGS California Water Science Center and the USGS National Research Program, the NPS, and the National Marine Fisheries Service with combined expertise in coastal environments, fish biology and ecology, nutrient-algal linkages, and state-of-the-art isotopic and chemical tools for applications in isotopes and fish otoliths.
The results generated by this study are expected to provide, for the first time, a more complete understanding of the energetic pathways and nutrient sources in the Rodeo Lagoon foodweb that lead to eutrophication, hypoxia and fish kills. They will also quantify, for the first time, hypoxia exposure of imperiled fish species. This study will be the first such comprehensive characterization of a coastal ecosystem. Methods applied to this system, in particular use of phosphate isotopes and otolith chemistry, will be applicable to other aquatic systems in the NPS. For example, both Point Reyes National Seashore and Redwood National Park have coastal lagoon systems. The novel results expected from this study are likely to be of widespread interest to scientists and managers both locally and more broadly to those around the world addressing ecological problems in coastal ecosystems.
Scientists investigate excessive nutients levels in Rodeo Lagoon that are believed to be cause of dying fish
Hypoxia resulting from nutrient-enhanced eutrophication is believed to be the primary cause of fish kills and aesthetically unpleasing water quality conditions that have led to visitor complaints at Rodeo Lagoon, Golden Gate National Recreational Area. Fish kills have been documented in Rodeo Lagoon since 1993 and are an especially important management issue because they have included die-offs of two federally-listed fish species, the endangered tidewater goby (Eucyclogobius newberryi) and the threatened Central California Coast steelhead (Oncorhynchus mykiss). Immediate action is needed on this issue because visitor satisfaction is going down and imperiled fish species are dying. Fish kills have occurred as recently as 2014 and without proper remediation the continued poor water quality will perpetuate the likelihood of future hypoxia and fish kill events.
The fundamental problem being addressed by this project is to identify the sources of nutrients contributing to eutrophication, hypoxia and fish kills in Rodeo Lagoon. This project will identify measures that can reduce or eliminate the occurrence of the eutrophication, hypoxia, and fish kills in Rodeo Lagoon. The information being gathered will characterize energetic pathways and nutrient sources in the Rodeo Lagoon foodweb and quantify hypoxia exposure of imperiled fish species in Rodeo Lagoon. This information will enable park managers to determine the most effective measures for ameliorating the problem.
This study will utilize state-of-the-art isotopic methods for determining nutrient sources and hypoxia exposure in fish species. To our knowledge, this will be the first time this suite of tools has been used in a complimentary fashion to address problems in costal resource management. This study brings together an interdisciplinary team of scientists from multiple agencies. The team includes scientists from the USGS California Water Science Center and the USGS National Research Program, the NPS, and the National Marine Fisheries Service with combined expertise in coastal environments, fish biology and ecology, nutrient-algal linkages, and state-of-the-art isotopic and chemical tools for applications in isotopes and fish otoliths.
The results generated by this study are expected to provide, for the first time, a more complete understanding of the energetic pathways and nutrient sources in the Rodeo Lagoon foodweb that lead to eutrophication, hypoxia and fish kills. They will also quantify, for the first time, hypoxia exposure of imperiled fish species. This study will be the first such comprehensive characterization of a coastal ecosystem. Methods applied to this system, in particular use of phosphate isotopes and otolith chemistry, will be applicable to other aquatic systems in the NPS. For example, both Point Reyes National Seashore and Redwood National Park have coastal lagoon systems. The novel results expected from this study are likely to be of widespread interest to scientists and managers both locally and more broadly to those around the world addressing ecological problems in coastal ecosystems.