Rearing Habitats of Longfin Smelt in the Low Salinity Zone of the San Francisco Estuary Active
Scientists study habitats occupied by longfin smelt larvae to better understand their ecology and to inform water management operations, species management, and habitat restoration efforts.
Protecting and managing special status fish species requires an understanding of their ecology and habitat. The longfin smelt (Spirinchus thaleichthys) is listed as threatened under the California Endangered Species Act. Understanding the ecology of longfin smelt is critical to the management of California's water supply. Longfin smelt has undergone a substantial long-term decline in abundance leading to its listing while water exported from the Bay-Delta supplies approximately 25 million people in California and a multi-billion dollar agricultural industry in California's Central Valley. Managing water operations while protecting longfin smelt is a key management goal in the estuary. Presently, there is a need to better understand the habitats occupied by longfin smelt. Long-term monitoring programs sample in open water pelagic habitat and it is believed that shallow tidal marsh habitats probably represent a key under-sampled component of critical habitat.
The goal of this study is to generate information on the habitats occupied by longfin smelt larvae to better understand its ecology and to inform water management operations, species management, and habitat restoration efforts. Specific objectives include determining the density and distribution of longfin smelt larvae (and the ichthyoplankton community overall) in shallow tidal marshes of the low salinity zone (salinity ranging from approximately 1 to 6), determining if the density of longfin smelt larvae in tidal marshes differs from adjacent open water habitat of similar depth, and if water quality factors are meaningful drivers.
Work will begin immediately. Field collections of fish larvae within tidal marshes and in nearby open water habitats will be conducted in April and May, including collection of ancillary water quality and biological information. Samples will be submitted for processing immediately after collection. The resulting data will be analyzed using various statistical techniques during the remainder of the 2014 fiscal year. At least one draft journal article will be prepared in fiscal year 2015.
This study will provide much needed information on the ecology of a threatened fish species. It will provide new information on the habitats occupied by longfin smelt larvae, which will be useful for resource agencies managing the species and for informing habitat restoration actions in the future. This proposal supports several elements of the USGS strategic plan and will contribute to multiple missions of the USGS: 1) describe and understand the Earth; 2) manage water and biological resources; and 3) enhance and protect our quality of life. The project will contribute to the Program thrust to strategically position the USGS as the provider of choice for assessments of real and anticipated changes in the environment and resources. More specifically, the project will showcase the unique capabilities of the USGS to further our understanding of environmental change.
- Overview
Scientists study habitats occupied by longfin smelt larvae to better understand their ecology and to inform water management operations, species management, and habitat restoration efforts.
Sources/Usage: Public Domain. View Media DetailsSampling locations within the upper San Francisco Estuary shaded in blue polygons. Base map is a screen shot from Google Maps obtained on 4/21/14 Protecting and managing special status fish species requires an understanding of their ecology and habitat. The longfin smelt (Spirinchus thaleichthys) is listed as threatened under the California Endangered Species Act. Understanding the ecology of longfin smelt is critical to the management of California's water supply. Longfin smelt has undergone a substantial long-term decline in abundance leading to its listing while water exported from the Bay-Delta supplies approximately 25 million people in California and a multi-billion dollar agricultural industry in California's Central Valley. Managing water operations while protecting longfin smelt is a key management goal in the estuary. Presently, there is a need to better understand the habitats occupied by longfin smelt. Long-term monitoring programs sample in open water pelagic habitat and it is believed that shallow tidal marsh habitats probably represent a key under-sampled component of critical habitat.
The goal of this study is to generate information on the habitats occupied by longfin smelt larvae to better understand its ecology and to inform water management operations, species management, and habitat restoration efforts. Specific objectives include determining the density and distribution of longfin smelt larvae (and the ichthyoplankton community overall) in shallow tidal marshes of the low salinity zone (salinity ranging from approximately 1 to 6), determining if the density of longfin smelt larvae in tidal marshes differs from adjacent open water habitat of similar depth, and if water quality factors are meaningful drivers.
Work will begin immediately. Field collections of fish larvae within tidal marshes and in nearby open water habitats will be conducted in April and May, including collection of ancillary water quality and biological information. Samples will be submitted for processing immediately after collection. The resulting data will be analyzed using various statistical techniques during the remainder of the 2014 fiscal year. At least one draft journal article will be prepared in fiscal year 2015.
This study will provide much needed information on the ecology of a threatened fish species. It will provide new information on the habitats occupied by longfin smelt larvae, which will be useful for resource agencies managing the species and for informing habitat restoration actions in the future. This proposal supports several elements of the USGS strategic plan and will contribute to multiple missions of the USGS: 1) describe and understand the Earth; 2) manage water and biological resources; and 3) enhance and protect our quality of life. The project will contribute to the Program thrust to strategically position the USGS as the provider of choice for assessments of real and anticipated changes in the environment and resources. More specifically, the project will showcase the unique capabilities of the USGS to further our understanding of environmental change.
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