Automated eDNA sampling to detect Grass Carp spawning in Great Lakes tributaries
Researchers and managers have documented spawning by Grass Carp (Ctenopharyngodon idella) in three tributaries of Lake Erie, with additional rivers potentially providing suitable spawning habitat. Spawning events can be targeted by managers to disrupt reproduction and remove aggregating fish. Prior research has identified the temperature and streamflow conditions that can help predict spawning activity (Embke et al. 2016; Embke et al. 2019; Jackson and Doyle 2023), but there is still uncertainty as to the exact timing of spawning that would be needed to best capture Grass Carp. We would expect environmental DNA (eDNA) to increase as carp begin to aggregate and spawn, which requires regular eDNA sampling and rapid analysis to confirm activity. This project addresses the first aspect by using an eDNA robotic autosampler to filter water samples and investigate if eDNA detection increases during fish aggregations and spawning events.
This project represents a collaboration between USGS and the Monterey Bay Aquarium Research Institute (MBARI). MBARI has developed cutting-edge automatic water samplers (named ESPs) that can be deployed for long time periods with little or no maintenance. The ESP will draw water from the water body, run it through a filter to capture cells and genetic material, and store sample in a preservative that is stable at ambient temperature. We used the second generation (2G) ESP which allows us to collect over 120 samples in a single deployment. We can then collect the filters at the end of deployment and analyze them for the presence of eDNA. The sampler we used does not allow sample retrieval before the end of a full mission, but newer prototypes from MBARI will allow samples to be collected from the sampler at any point during deployment.
Our goal is to place the autosampler on rivers with known grass carp spawning to provide proof of concept to confirm increases in eDNA occur at the same time as spawning events or fish aggregations. Between April – June 2022 and May – July 2024 we placed an autosampler on the Sandusky River near Fremont, OH and in May-July 2024 on the Maumee River in Toledo, OH. We collected samples at least once daily, but increased sampling up to three times per day in either ideal spawning conditions (based on temperature and river discharge) or during late May through mid-June, when Grass Carp are most likely to be moving to the spawning site (Bopp et al. 2023). At the end of the autosampler deployment, we removed all filters and analyzed them for presence of grass carp eDNA at the UMESC laboratory in La Crosse, WI. We are currently analyzing all the data for the association of grass carp eDNA positives with 1) known spawning events based on egg collection, 2) likelihood of spawning based on environmental conditions, and 3) presence of Grass Carp based on telemetry data collected by USGS colleagues. If eDNA is reliable to identify spawning events, we can next optimize field-based eDNA analysis to pair with autosamplers to serve as true real time alerts to Grass Carp spawning that can help direct management agencies’ removal of this invasive species.
References:
Bopp, J.J., Brenden, T.O., Faust, M.D. et al. Drivers and timing of grass carp movement within the Sandusky River, Ohio: implications to potential spawning barrier response strategy. Biol Invasions 25, 2439–2459 (2023). https://doi.org/10.1007/s10530-023-03049-9
Embke, H.S., Kocovksy, P.M, Garcia, T., Mayer, C.M., and Qian, S.S., 2019, Modeling framework to estimate spawning and hatching locations of pelagically spawned eggs: Canadian Journal of Fisheries and Aquatic Sciences, v. 76, no. 4, p. 597–607. [Also available at https://doi.org/10.1139/cjfas-2018- 0047.]
Embke, H.S., Kocovsky, P.M., Richter, C.A., Pritt, J.J., Mayer, C.M., and Qian, S.S., 2016, First direct confirmation of grass carp spawning in a Great Lakes tributary: Journal of Great Lakes Research, v. 42, no. 4, p. 899–903. [Also available at https://doi.org/10.1016/j.jglr.2016.05.002.]
Jackson, P.R., and Doyle, H.F., 2023, Methods for Generating Grass Carp Spawning Forecasts in Select Tributaries to Lake Erie for USGS SpawnCast: U.S. Geological Survey SpawnCast web page, accessed [DATE], at https://il.water.usgs.gov/proj/spawncast/.
Researchers and managers have documented spawning by Grass Carp (Ctenopharyngodon idella) in three tributaries of Lake Erie, with additional rivers potentially providing suitable spawning habitat. Spawning events can be targeted by managers to disrupt reproduction and remove aggregating fish. Prior research has identified the temperature and streamflow conditions that can help predict spawning activity (Embke et al. 2016; Embke et al. 2019; Jackson and Doyle 2023), but there is still uncertainty as to the exact timing of spawning that would be needed to best capture Grass Carp. We would expect environmental DNA (eDNA) to increase as carp begin to aggregate and spawn, which requires regular eDNA sampling and rapid analysis to confirm activity. This project addresses the first aspect by using an eDNA robotic autosampler to filter water samples and investigate if eDNA detection increases during fish aggregations and spawning events.
This project represents a collaboration between USGS and the Monterey Bay Aquarium Research Institute (MBARI). MBARI has developed cutting-edge automatic water samplers (named ESPs) that can be deployed for long time periods with little or no maintenance. The ESP will draw water from the water body, run it through a filter to capture cells and genetic material, and store sample in a preservative that is stable at ambient temperature. We used the second generation (2G) ESP which allows us to collect over 120 samples in a single deployment. We can then collect the filters at the end of deployment and analyze them for the presence of eDNA. The sampler we used does not allow sample retrieval before the end of a full mission, but newer prototypes from MBARI will allow samples to be collected from the sampler at any point during deployment.
Our goal is to place the autosampler on rivers with known grass carp spawning to provide proof of concept to confirm increases in eDNA occur at the same time as spawning events or fish aggregations. Between April – June 2022 and May – July 2024 we placed an autosampler on the Sandusky River near Fremont, OH and in May-July 2024 on the Maumee River in Toledo, OH. We collected samples at least once daily, but increased sampling up to three times per day in either ideal spawning conditions (based on temperature and river discharge) or during late May through mid-June, when Grass Carp are most likely to be moving to the spawning site (Bopp et al. 2023). At the end of the autosampler deployment, we removed all filters and analyzed them for presence of grass carp eDNA at the UMESC laboratory in La Crosse, WI. We are currently analyzing all the data for the association of grass carp eDNA positives with 1) known spawning events based on egg collection, 2) likelihood of spawning based on environmental conditions, and 3) presence of Grass Carp based on telemetry data collected by USGS colleagues. If eDNA is reliable to identify spawning events, we can next optimize field-based eDNA analysis to pair with autosamplers to serve as true real time alerts to Grass Carp spawning that can help direct management agencies’ removal of this invasive species.
References:
Bopp, J.J., Brenden, T.O., Faust, M.D. et al. Drivers and timing of grass carp movement within the Sandusky River, Ohio: implications to potential spawning barrier response strategy. Biol Invasions 25, 2439–2459 (2023). https://doi.org/10.1007/s10530-023-03049-9
Embke, H.S., Kocovksy, P.M, Garcia, T., Mayer, C.M., and Qian, S.S., 2019, Modeling framework to estimate spawning and hatching locations of pelagically spawned eggs: Canadian Journal of Fisheries and Aquatic Sciences, v. 76, no. 4, p. 597–607. [Also available at https://doi.org/10.1139/cjfas-2018- 0047.]
Embke, H.S., Kocovsky, P.M., Richter, C.A., Pritt, J.J., Mayer, C.M., and Qian, S.S., 2016, First direct confirmation of grass carp spawning in a Great Lakes tributary: Journal of Great Lakes Research, v. 42, no. 4, p. 899–903. [Also available at https://doi.org/10.1016/j.jglr.2016.05.002.]
Jackson, P.R., and Doyle, H.F., 2023, Methods for Generating Grass Carp Spawning Forecasts in Select Tributaries to Lake Erie for USGS SpawnCast: U.S. Geological Survey SpawnCast web page, accessed [DATE], at https://il.water.usgs.gov/proj/spawncast/.