Sturgeon Occurrence and Behavior in the Outer Continental Shelf
A new study aims to collect information on sturgeon temporal and spatial distribution to inform offshore wind energy and sand leasing operations.
The Science Issue and Relevance: Atlantic sturgeon (Acipenser oxyrinchus) and Gulf sturgeon (Acipenser oxyrinchus desotoi), both protected under the Endangered Species Act (ESA), spawn in select rivers during spring and/or fall, and spend winters along the Outer Continental Shelf (OCS) in the Atlantic Ocean and Gulf of Mexico. Gulf sturgeon spend summers in the rivers where they'll sometimes spawn, while Atlantic sturgeon may return to the ocean after spawning. While on the OCS, sturgeon regularly occur on and near sand-lease borrow areas which puts them at risk of entrainment during dredging (direct uptake of aquatic organisms by the suction field generated during dredging). Relocation trawling is a common mitigation measure initially implemented to capture and relocate sea turtles to avoid dredge entrainment, but is also used to protect sturgeon. However, no information is available on how sturgeon respond to trawl capture. Additionally, sturgeon presence in OCS habitats puts them at risk of interacting with offshore energy activities including wind turbines. Increased boat traffic, electromagnetic energy, and noise from energy development represent potential impacts to these imperiled species. Distribution and density data on sturgeon use of the OCS habitats is needed by the Bureau of Ocean and Energy Management (BOEM) Office of Renewable Energy Program and Marine Minerals Program to meet obligations under the National Environmental Policy Act (NEPA), as well as the U.S. Fish and Wildlife Service as they make decisions related to the ESA.
The overarching goal of this study is to better understand how sturgeon use the OCS, with a particular focus on sand shoals that may support energy or mineral leases. This project aims to:
(1) Characterize Atlantic and Gulf sturgeon occurrence around sand shoals within and among years, as well as distribution before, during, and after dredging;
(2) Estimate sturgeon recovery following trawl relocation; and
(3) Document sturgeon distribution on the OCS in the Gulf of Mexico and Atlantic
This project is funded in collaboration among the USGS Ecosystems Mission Area and BOEM’s Environmental Studies Program
Methodology for Addressing the Issue: Vessel-based side-scan sonar will be used at select OCS habitats, including shoals, to document the density of sturgeon throughout sand lease areas. These surveys will be conducted before, during, and after dredging to document immediate changes in sturgeon occupancy and potential associations with bathymetric changes following dredging activities. Side-scan sonar will also be used at select periods throughout the year to monitor seasonal changes in sturgeon abundance.
Sturgeon movements will be monitored through a combination of acoustic telemetry and pop-off satellite archival tags. These two tagging technologies afford complimentary datasets that, when combined, can provide information about fine- and broad-scale movement patterns. Additionally, in the Gulf of Mexico, accelerometer tags will be deployed on sturgeon to document behavior on shoal habitat, and immediately following release post-capture via trawler. Accelerometer tags do not transmit data remotely therefore pop-off packages will be utilized which will allow recovery of the tags after they detach from the fish. Finally, a fin clip will be collected from all Atlantic and Gulf sturgeon and genotyped. Individual genotypes will be used to determine stock origin and identify which distinct population segments may be impacted most by anthropogenic activities in the OCS.
Future Steps: Development of energy resources and extraction of minerals in OCS areas of the Atlantic Ocean and Gulf of Mexico will require BOEM to produce information for a variety of NEPA-related decision documents, as well as maintain compliance with the ESA. This project will inform specific decisions regarding timing of dredging and implementation of relocation trawling, for example, whether sturgeon captured in relocation trawls may need to be released at a distance to prevent re-capture or do released sturgeon move out of the area post-capture. Results will also inform timing and location of offshore wind energy installation and other activities related to energy resources on the OCS. Expanding this study to include additional sand lease areas in the Atlantic and Gulf of Mexico (particularly in estuaries and river mouths), more detailed examinations of genetic connectivity among sturgeon using OCS habitats, and further examinations of the impacts of wind energy and dredging on the habitat and sturgeon prey base would be beneficial.
Supporting Interstate Conservation of Atlantic Sturgeon (Acipenser o. oxyrinchus) Using Genetics, Telemetry, and Side-scan Sonar
Gulf Sturgeon Ecological Investigations
A new study aims to collect information on sturgeon temporal and spatial distribution to inform offshore wind energy and sand leasing operations.
The Science Issue and Relevance: Atlantic sturgeon (Acipenser oxyrinchus) and Gulf sturgeon (Acipenser oxyrinchus desotoi), both protected under the Endangered Species Act (ESA), spawn in select rivers during spring and/or fall, and spend winters along the Outer Continental Shelf (OCS) in the Atlantic Ocean and Gulf of Mexico. Gulf sturgeon spend summers in the rivers where they'll sometimes spawn, while Atlantic sturgeon may return to the ocean after spawning. While on the OCS, sturgeon regularly occur on and near sand-lease borrow areas which puts them at risk of entrainment during dredging (direct uptake of aquatic organisms by the suction field generated during dredging). Relocation trawling is a common mitigation measure initially implemented to capture and relocate sea turtles to avoid dredge entrainment, but is also used to protect sturgeon. However, no information is available on how sturgeon respond to trawl capture. Additionally, sturgeon presence in OCS habitats puts them at risk of interacting with offshore energy activities including wind turbines. Increased boat traffic, electromagnetic energy, and noise from energy development represent potential impacts to these imperiled species. Distribution and density data on sturgeon use of the OCS habitats is needed by the Bureau of Ocean and Energy Management (BOEM) Office of Renewable Energy Program and Marine Minerals Program to meet obligations under the National Environmental Policy Act (NEPA), as well as the U.S. Fish and Wildlife Service as they make decisions related to the ESA.
The overarching goal of this study is to better understand how sturgeon use the OCS, with a particular focus on sand shoals that may support energy or mineral leases. This project aims to:
(1) Characterize Atlantic and Gulf sturgeon occurrence around sand shoals within and among years, as well as distribution before, during, and after dredging;
(2) Estimate sturgeon recovery following trawl relocation; and
(3) Document sturgeon distribution on the OCS in the Gulf of Mexico and Atlantic
This project is funded in collaboration among the USGS Ecosystems Mission Area and BOEM’s Environmental Studies Program
Methodology for Addressing the Issue: Vessel-based side-scan sonar will be used at select OCS habitats, including shoals, to document the density of sturgeon throughout sand lease areas. These surveys will be conducted before, during, and after dredging to document immediate changes in sturgeon occupancy and potential associations with bathymetric changes following dredging activities. Side-scan sonar will also be used at select periods throughout the year to monitor seasonal changes in sturgeon abundance.
Sturgeon movements will be monitored through a combination of acoustic telemetry and pop-off satellite archival tags. These two tagging technologies afford complimentary datasets that, when combined, can provide information about fine- and broad-scale movement patterns. Additionally, in the Gulf of Mexico, accelerometer tags will be deployed on sturgeon to document behavior on shoal habitat, and immediately following release post-capture via trawler. Accelerometer tags do not transmit data remotely therefore pop-off packages will be utilized which will allow recovery of the tags after they detach from the fish. Finally, a fin clip will be collected from all Atlantic and Gulf sturgeon and genotyped. Individual genotypes will be used to determine stock origin and identify which distinct population segments may be impacted most by anthropogenic activities in the OCS.
Future Steps: Development of energy resources and extraction of minerals in OCS areas of the Atlantic Ocean and Gulf of Mexico will require BOEM to produce information for a variety of NEPA-related decision documents, as well as maintain compliance with the ESA. This project will inform specific decisions regarding timing of dredging and implementation of relocation trawling, for example, whether sturgeon captured in relocation trawls may need to be released at a distance to prevent re-capture or do released sturgeon move out of the area post-capture. Results will also inform timing and location of offshore wind energy installation and other activities related to energy resources on the OCS. Expanding this study to include additional sand lease areas in the Atlantic and Gulf of Mexico (particularly in estuaries and river mouths), more detailed examinations of genetic connectivity among sturgeon using OCS habitats, and further examinations of the impacts of wind energy and dredging on the habitat and sturgeon prey base would be beneficial.