SFS Annual Meeting

6/06/2024  |   15:30 - 15:45   |  Independence Ballroom A

Predicting grass carp spawning conditions to improve removal and detection across Great Lakes tributaries Management agencies are removing invasive grass carp (Ctenopharyngodon idella) from Lake Erie because they consume vegetation, which could impact native communities and water quality. One important removal approach is targeting spawning aggregations in rivers using boat electrofishing. Grass carp are dispersed and difficult to find, further there are multiple Great Lakes tributaries that could host spawning. Therefore, quantifying conditions that trigger spawning could increase removal. Spawning is associated with rising discharge and water temperatures above 18 °C. Spawning has been documented in three Lake Erie tributaries, the Sandusky, Maumee, and Huron rivers. Jaffe et al. (2024) modeled spawning probability in the Sandusky River based on the presence or absence of eggs in relation to discretized bins of discharge and water temperature. They showed that spawning probability peaks between 19–22 °C and potentially peaks for discharges larger than 130 m3/s. However, discretized discharge is specific to the Sandusky River. Therefore, we generalized the Sandusky model by converting water temperature and discharge to continuous predictors described using the Gaussian distribution. We then converted continuous discharge to velocity, which is river-independent, by developing a log-log regression between discharge and velocity using HEC-RAS hydraulic model outputs for the known Sandusky River spawning area. This generalized model can now be used to evaluate probable spawning conditions for other tributaries. Consequently, pinpointing likely spawning times across tributaries will improve efficiency of crews removing adults and sampling eggs to document spawning locations.

Sabrina Jaffe (Primary Presenter/Author), University of Toledo, sabrina.jaffe@rockets.utoledo.edu;

Song Qian (Co-Presenter/Co-Author), The University of Toledo, song.qian@utoledo.edu;

Christine Mayer (Co-Presenter/Co-Author), The University of Toledo, christine.mayer@utoledo.edu;

Corbin Hilling (Co-Presenter/Co-Author), U.S. Geological Survey, chilling@usgs.gov;

P. Ryan Jackson (Co-Presenter/Co-Author), U.S. Geological Survey, pjackson@usgs.gov;

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6/06/2024  |   15:45 - 16:00   |  Independence Ballroom A

OUT OF REACH: HOW GRASS CARP USE RIVER HABITAT OUTSIDE OF AN ACOUSTIC ARRAY CAN INFORM REMOVAL EFFORTS IN THE SANDUSKY RIVER The expansion of reproductively viable Grass Carp (Ctenopharyngodon idella) in Lake Erie poses ecological and economic threats through habitat modification. The multi-jurisdictional effort to prevent and mitigate the negative effects of invasive Grass Carp has largely relied on adult removals since 2017. Dedicated removal crews have targeted the Sandusky River, a tributary to Lake Erie, because it hosts Grass Carp aggregation and spawning and yields relatively high capture rates. Our objective was to identify spatiotemporal patterns to be exploited by removal crews. We deployed an acoustic array that produces two-dimensional position data on fish implanted with telemetry tags. We paired Grass Carp location data from 2022 with environmental data to identify large scale movement patterns and the extent of backwater habitat use. Thirteen unique telemetered Grass Carp were detected by the positioning array. Detections of Grass Carp exiting the array for at least 10 minutes accounted for 2% of the detections but 38% of the time during the sampling period. Forty-two percent of these absences from the array were in or near (within 40 m) backwaters suggesting frequent use of this habitat. Fish exiting the array near backwaters peaked at sunrise as did absence length. Identified movement patterns may be exploited by field crews to capture grass carp attempting to enter backwaters in the early morning, particularly where backwater entrances are narrow. The ability to target fish when they are moving into backwaters, which are not accessible to capture boats, could help meet removal goals for this invasive species.

Sophia Bonjour (Primary Presenter/Author), U.S. Geological Survey, Columbia Environmental Research Center, sbonjour@usgs.gov;

James J. Roberts (Co-Presenter/Co-Author), U.S. Geological Survey, Ann Arbor, MI 48105, jroberts@usgs.gov;

Travis Brenden (Co-Presenter/Co-Author), Michigan State University, brenden@msu.edu;

Scott Colborne (Co-Presenter/Co-Author), Michigan State University, colborne@msu.edu;

Lucas Nathan (Co-Presenter/Co-Author), Michigan Department of Natural Resources, nathanl@michigan.gov;

Christine Mayer (Co-Presenter/Co-Author), The University of Toledo, christine.mayer@utoledo.edu;

Robert Hunter (Co-Presenter/Co-Author), U.S. Geological Survey, Huron Lake Erie Biological Station, rhunter@usgs.gov;

Richard Kraus (Co-Presenter/Co-Author), U.S. Geological Survey, Huron Lake Erie Biological Station, rkraus@usgs.gov;

Robin Calfee (Co-Presenter/Co-Author), U.S. Geological Survey, Columbia Environmental Research Center, rcalfee@usgs.gov;

Matthew Acre (Co-Presenter/Co-Author), U.S. Geological Survey, Columbia Environmental Research Center, macre@usgs.gov;

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6/06/2024  |   16:00 - 16:15   |  Independence Ballroom A

Ecological Hypothesis Testing Using Bayesian Hierarchical Modeling; Drivers of Grass Carp Density

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6/06/2024  |   16:15 - 16:30   |  Independence Ballroom A

Collection of an uncommon mayfly taxon (Neoephemera bicolor) from the Little Kanawha River An uncommon taxon, Neoephemera bicolor (Ephemeroptera: Neoephemeridae), was collected from the Little Kanawha River at approximately river mile 46.9 and 50.1. The WVDEP Watershed Assessment Branch database contains 28 previous records of Neoephemera out of nearly 12,000 total benthic samples; only one of which was collected from the Little Kanawha River watershed. Limited information exists documenting the range of N. bicolor. Populations of N. bicolor have been recorded from Wisconsin (Schmude, 2012), Michigan (Berner, 1956) and Missouri (Morse et al., 2017), but are suspected to have a broader range throughout the southeast. A newly described species of Neoephemera from Virginia and North Carolina—N. eatoni, has been documented to occur exclusively in association with Podostemum ceratophyllum (Holland et al., 2016). Our collection of N. bicolor amongst P. ceratophyllum-dominated benthic habitat suggests this association may also extend to populations of N. bicolor as well.

Garrett Hoover (Primary Presenter/Author), West Virginia Department of Environmental Protection, garrett.w.hoover@wv.gov;

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6/06/2024  |   16:30 - 16:45   |  Independence Ballroom A

Beneficial and detrimental contributions of alien freshwater megafauna to people: A global assessment Freshwater megafauna (i.e., freshwater animals with a maximum reported weight ? 30 kg) have been intentionally introduced globally due to their charisma and economic value. Despite their well-documented interactions with human communities, a comprehensive assessment of their socio-economic impacts has yet to be conducted at a global scale. We systematically collected evidence regarding the interactions between alien freshwater megafauna and humans. We adapted the framework of nature's contributions to people (NCP) and developed a semi-quantitative approach to assess their beneficial and detrimental socio-economic impacts. We identified 584 records that documented NCP associated with 59 species. In total, 430 records reported various beneficial NCP categories provided by alien freshwater megafauna, including habitat maintenance, regulation of water quality, regulation of detrimental organisms, provision of food, materials and companionship, enhanced physical and psychological experiences, and supporting identities. Provision of food is the most frequently reported category (58%), followed by enhanced physical and psychological experiences (20%), and materials and companionship (12%). Geographically, Asia, Europe, and North America covered most of the beneficial NCP records. Meanwhile, we identified much fewer records showing detrimental NCP associated with alien freshwater megafauna (154), with risk to health and safety being the most frequently reported category (68%). This study demonstrates the intricate relationships between humans and alien freshwater megafauna, advocating for a holistic approach in assessing environmental and socio-economic impacts. Proposed introductions should adhere to strict biosecurity measures, mandatory risk assessments, and management plans to ensure the preservation of native freshwater biodiversity and associated ecosystem functions and services.

Xing Chen (Primary Presenter/Author), Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany, chenxingjhdx@163.com;

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6/06/2024  |   16:45 - 17:00   |  Independence Ballroom A

Species richness estimation revisited – An effective computation method Species richness, a key biodiversity metric in ecology, is commonly assessed in assemblages for various aquatic taxa as an indicator of stream ecological health. This is often approximated by the observed species count, yet the actual richness exceeds observations due to imperfect sampling methods. Estimating the "true" species richness and identifying missing species has intrigued researchers across disciplines. In ecological studies, R.A. Fisher proposed a mixed model statistical method (Fisher et al., 1943) to estimate the number of "new" butterfly species with replicated sampling. This model, originally applied to biology, found applications in diverse fields, such as estimating Shakespeare's true vocabulary (Efron and Thisted, 1976). Various adaptations of Fisher's model, employing distinct numerical approximation strategies, have been published in statistical and ecological journals. Our contribution introduces a Bayesian hierarchical modeling approach to address the same problem. This method offers a straightforward setup and enables direct sampling of the posterior distribution of the richness parameter. The hierarchical structure facilitates embedding richness estimation in broader studies, such as assessing climate change impacts on aquatic biodiversity with long-term species sampling data. To validate our approach, we tested it on two historical datasets (Shakespeare’s true vocabulary and Fisher’s butterfly data) and applied it to USGS' long-term Lake Erie trawl survey data, evaluating changes in fish species richness over the past 11 years.

Song Qian (Primary Presenter/Author), The University of Toledo, song.qian@utoledo.edu;

Mark DuFour (Co-Presenter/Co-Author), USGS, mdufour@usgs.gov;

Sabrina Jaffe (Co-Presenter/Co-Author), University of Toledo, sabrina.jaffe@rockets.utoledo.edu;

Corbin Hilling (Co-Presenter/Co-Author), U.S. Geological Survey, chilling@usgs.gov;

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