USGS Science⌕ Search

Geology topics

Robin D. Calfee

Publications and source records attributed to Robin D. Calfee.

At least 19 recordsLinked to original sources
USGS2026

Identifying overwintering habitat of silver and bighead carp in the lower Mississippi River: Implications for harvesting and population reduction

A total of 41 sites along a 58 mi reach of the Lower Mississippi River (LMR) were surveyed during winter 2022 for invasive carp aggregation.* Sites consisting of scallops closest to the dike-vegetated bank interface with deeper, slow-moving water and consistent access back to the main channel were preferred. Carp avoided strong currents, and there was no trend in depth selection other than avoiding shallow (less than 20 ft) water. In January 2023, recreation-grade sonar (e.g., side-scan and down-imaging) surveys were conducted in the same reach of the LMR to demonstrate the technology and evaluate carp population size at sites with high abundances based on previous surveys. Fish density was estimated to be 32 fish/10,000 yd 3 (95% confidence interval [CI; 31–34]) using down-imaging software, which is the first estimate of assumed bigheaded carp density in the LMR. Additional fish collections are needed to confirm species composition and size abundance provided by sonar technology. Resurveying sites with high carp abundance over a range of river stages would be necessary to fully characterize habitat conditions, evaluate influence of river stage on occupancy duration, and continue to evaluate species composition and mass removal techniques as a management option in the Lower Mississippi River.

Louisiana, Mississippi↗
USGS2025

Long-term surgery survival, body condition effects, and incision healing of Silver Carp and buffalo species comparing sedation methods across seasons

Objective Internal tagging for telemetry studies requires invasive surgery procedures, necessitating sufficient sedation to support animal welfare. Challenges with existing chemical sedatives have resulted in technological alternatives, including electrosedation, with these newer methods less extensively studied. Our primary objective was to understand long-term survival, body-condition effects, and incision healing after surgical implantation of an imitation telemetry transmitter under three different sedation techniques. Methods We collected Silver Carp Hypophthalmichthys molitrix and buffalo Ictiobus spp. from the Missouri River watershed in 2022 and 2023, during each of the four seasons. One of three sedation techniques was applied: electric fish handling gloves, tricaine methanesulfonate (MS-222), and eugenol. Additionally, we observed a group of fish that were unsedated but subjected to handling similar to that experienced during surgery. Fish were monitored to determine the effects of treatment, individual characteristics, surgery characteristics, and time-varying environmental factors on survival, body condition, and incision healing over 69- to 85-d holding periods. Results Long-term survival was higher for buffalo (86%) than Silver Carp (57%), with the fewest mortalities during the winter trial and most in summer, but sedation treatment did not affect survival. Smaller fish had a greater risk of mortality but better incision healing. Incision healing scores improved in warmer temperatures. Conclusions Difference in seasonal effects on survival and healing indicate a need to consider trade-offs when scheduling tagging for projects. However, a lack of difference in survival among treatments, including the group that was handled but did not undergo surgery, suggests no advantage of one sedative over another, but handling impacts may require more consideration.

Transactions of the American Fishery Society↗
USGS2025

Behavioral responses of Silver Carp to underwater acoustic deterrent sounds

Objective Invasive carps continue to spread across the Mississippi River basin, posing significant ecological risk. Identifying technologies to slow their dispersal is critical. The use of sound has been proposed as a method to modify the behavior of Silver Carp Hypophthalmichthys molitrix , offering a nonstructural deterrent strategy. Methods Silver Carp implanted with acoustic transmitters were released into earthen ponds equipped with telemetry arrays. The fish were exposed to a 30-min playback of three underwater sounds (chirp saw, chirp square, and 100-hp boat motor). Movement trajectories were analyzed using a two-state hidden Markov model to estimate the effects of environmental and experimental variables on fish behavior. Results The results of the hidden Markov model supported two behavioral states. State 1 was characterized by longer step lengths (distance between positions) and greater directional persistence in turning angle (change in direction between two intervals), indicative of heighted activity. State 2 was defined by shorter step lengths and less directional persistence, suggesting reduced activity. Silver Carp that were exposed to the chirp square sound had an increased likelihood of entering state 1, whereas the 100-hp boat motor sound promoted transitions to state 2. Conclusions Underwater sounds distinctly influenced the movement of Silver Carp in earthen ponds. The chirp square sound elicited heightened activity levels, demonstrating potential for use in acoustic deterrent applications. However, the response of Silver Carp to these sounds may be influenced by the size of the study environment or the absence of natural drivers of fish behavior, such as food or reproduction. This study contributes to the development of nonstructural, species-specific deterrent systems by identifying sounds that influence the behavior of invasive carps. The application of sound-based methods may play a critical role in integrated pest management strategies for invasive carps, potentially limiting their spread while minimizing effects on native species.

Transactions of the American Fisheries Society↗
USGS2025

Reproductive biology of invasive grass carp (Ctenopharyngodon idella) in two North American systems

Grass carp ( Ctenopharyngodon idella ) are nonnative, herbivorous freshwater fish that represent an ecological threat in North American waters. However, data are limited on reproductive biology specific to wild populations in midwestern North America, despite recent concern for grass carp establishment within the Great Lakes. Basic information on reproductive traits could be useful to determine reproductive potential, inform future population modelling and provide information to aid control efforts. Our objectives were to evaluate grass carp age-at-maturity, spawning season timing, fecundity type, developmental timing and spawning strategy. Additionally, we evaluated the reliability of the gonadosomatic index (GSI) as a proxy for identifying mature grass carp and compared body condition across study areas. We sampled grass carp in portions of the Mississippi River watershed within the state of Missouri and within the Lake Erie basin. Based on gonad histological samples ( n = 274), grass carp are batch spawners with indeterminate fecundity and asynchronous ovarian developmental timing. This allows flexibility in their spawning, exemplified by a protracted spawning season in Lake Erie (April to November) in temperatures ranging from 12.3 to 27.3°C. Minimum observed age-at-maturity for females in Missouri and for both males and females in the Lake Erie population was age-3 and age-2 for males in Missouri. Accuracy of GSI as a measure of maturity during the spawning season was 89.7% and 87.5%, for females and males, respectively. Compared to Missouri, grass carp in Lake Erie had a significantly higher body condition, and females ready to spawn had significantly higher GSI values, suggesting that the grass carp in Lake Erie are healthier and more fecund relative to Missouri and, if left uncontrolled, potentially have a high probability of establishment within the Great Lakes. The results of this study will allow managers to identify the reproductive status of grass carp in the field and more accurately estimate populations and reproductive potential.

Michigan, Missouri, Ohio↗
USGS2025

Fish-assemblage evaluation in the lower Sandusky River, Ohio, following dam removal

The Sandusky River, Ohio, USA, has experienced more than a century of alterations, including dam implementation and removal, causing a cascade of habitat changes. The physical changes in the river led to establishment of several invasive species. Ten hoop-net sampling sites, spaced about 500 m apart were established in the river to monitor fish assemblage and their habitat preferences. Four 10-d sampling events were completed from April through October 2021. Ordination analyses were used to assess fish-assemblage structure seasonably, species-habitat relationships, and life-history strategies of 31 species. Generalized linear mixed-effects models were used to assess temporal factors that may drive diversity and community assemblage. Models indicated increased species richness after removal of the dam. Presence and proportion of catch data were compared to Ohio Environmental Protection Agency 2009 pre-dam-removal data to further assess changes in fish assemblage. Several species, especially catostomids, have begun to use the habitat downstream of the former dam, altering fish assemblage throughout the river. We expect shifts in assemblage structure to persist, making continued monitoring essential for understanding how non-native and recreationally important species continue to respond to dam removal.

Ohio↗
USGS2025

Grass carp (Ctenopharyngodon idella) movement states and backwater use can inform removal efforts

Expansion of grass carp ( Ctenopharyngodon idella ) within the Laurentian Great Lakes poses significant ecological and economic risks. Suppression efforts to remove grass carp have increased to curtail population growth, but capture efficiency remains low. One management challenge is the lack of understanding how this invasive species is using its novel habitats in the Great Lakes. This study aimed to identify spatiotemporal patterns in grass carp behavior and backwater use that could be exploited by management efforts, including removal. We used acoustic telemetry to examine when grass carp occurred in areas vulnerable to removal by boat electrofishing in the Sandusky River, Ohio, USA. Hidden Markov models were used to categorize behavioral states and evaluate their relationships with environmental factors. Best performing 2-state and 3-state hidden Markov models included proximity to backwater as a factor in state-dependent step length and transition probability between states, with a higher probability of being in less mobile states during the middle of the day and in backwaters. For the 2-state model, this less mobile state was also more common during warmer temperatures. Distinct diel patterns and backwater use identified in this study provide critical insights for improving management. Model results suggest that current removal efforts, focused primarily on the mainstem of the river, may benefit from adjustments in both timing and removal gear. The findings raise further questions about unobserved behaviors contributing to state assignment and sufficiently flexible adaptive management strategies to account for individual variation in grass carp behavior.

Ohio↗
USGS2024

A novel tool to selectively deliver a control agent to filter-feeding silver and bighead carp

Invasive carp pose substantial economic and ecological damage when populations are widespread in freshwater systems within the United States. Resource managers in the United States have few chemical control tools to selectively remove nuisance fish. This study examined whether Antimycin–A (antimycin) wax encapsulated microparticles could cause selective lethality in invasive carps. The antimycin microparticles were selective toward bighead carp ( Hypophthalmichthys nobilis ) and silver carp ( Hypophthalmichthys molitrix ) across multiple experimental scales. Microparticles applied in experimental pond studies caused approximately 50 percent lethality in invasive carp. Effluent pond studies performed at Rathbun Fish Hatchery (Moravia, Iowa) caused silver carp lethality at a lower rate than previous pond or laboratory studies (approximately 1 percent); however, minimal effects on other fish species were observed. The antimycin microparticle formulation shows the ability to cause lethality in filter-feeding invasive carp relative to other fish species and demonstrated the plausibility for delivering a typically nonselective toxicant in a selective manner to specific species based on their physiological feeding traits.

Open-File Report↗
USGS2024

Side-scan sonar as a tool for measuring fish populations: Current state of the science and future directions

Side-scan sonar (SSS) is a powerful tool that can be used to address many key questions in fisheries science. In principle, SSS uses dual transducers to transmit a narrow-beam, wide-angle acoustic signal as the survey vessel transits an area. The intensity of reflected sound is recorded to generate an image mosaic comprised of benthic substrates and targets in the water column, including organisms such as fish. Although SSS has been around for decades, recent advancements have opened new opportunities to leverage this technology to directly measure fish populations. In this paper, we review the current state of the science and identify opportunities to further refine SSS for fisheries applications.

Fisheries↗
USGS2024

Capturing potential: Leveraging grass carp behavior Ctenopharyngodon idella for enhanced removal

Effective management of invasive species benefits from a comprehensive understanding of the species’ behavior and interactions with the invaded system. We investigated temporal dynamics of telemetry detections and the potential utility of a traitor approach for informing response efforts to the invasive grass carp ( Ctenopharyngodon idella ) population in the Sandusky River, a major tributary to Lake Erie. Telemetered grass carp exhibited heightened activity at night and early morning, suggesting that capture and removal be more effective during these time periods. Analysis of catch per unit effort (CPUE) across different removal methods, trammel nets, electrofishing, and hoop nets. suggested that incorporating the traitor approach could improve capture. Low catchability values (<0.026), based on the number of telemetered grass carp present in the river on a weekly basis and the number of those telemetered fish captured, suggest the species is difficult to capture. Optimizing response effort efficiency is important and refining catchability estimates will lessen errors in population models and improve interpretation of low CPUE data. Results from generalized additive models suggest capture could be improved using telemetry data, night removals, and by attempting exploratory removal efforts in fall and winter months. By incorporating telemetry data and acknowledging the complexities of grass carp behavior and ecology, we found that a multifaceted and data-driven approach to invasive species control could be beneficial, ultimately promoting conservation and sustainability in dynamic ecosystems like Lake Erie.

Ohio↗
USGS2023

Sound and sturgeon: Bioacoustics and anthropogenic sound

Sturgeons are basal bony fishes, most species of which are considered threatened and/or endangered. Like all fishes, sturgeons use hearing to learn about their environment and perhaps communicate with conspecifics, as in mating. Thus, anything that impacts the ability of sturgeon to hear biologically important sounds could impact fitness and survival of individuals and populations. There is growing concern that the sounds produced by human activities (anthropogenic sound), such as from shipping, commercial barge navigation on rivers, offshore windfarms, and oil and gas exploration, could impact hearing by aquatic organisms. Thus, it is critical to understand how sturgeon hear, what they hear, and how they use sound. Such data are needed to set regulatory criteria for anthropogenic sound to protect these animals. However, very little is known about sturgeon behavioral responses to sound and their use of sound. To help understand the issues related to sturgeon and anthropogenic sound, this review first examines what is known about sturgeon bioacoustics. It then considers the potential effects of anthropogenic sound on sturgeon and, finally identifies areas of research that could substantially improve knowledge of sturgeon bioacoustics and effects of anthropogenic sound. Filling these gaps will help regulators establish appropriate protection for sturgeon.

The Journal of the Acoustical Society of America↗
USGS2023

Silver carp herding: A telemetry evaluation of efficacy and implications for design and application

Removal of invasive Silver Carp Hypophthalmichthys molitrix is a primary control action in North America. Strong avoidance responses to underwater sound and electricity have been shown to facilitate herding and mass removal of these fish. We conducted a telemetry study on a closed population of Silver Carp (i.e., 10 telemetered fish) to assess fine-scale movement responses to herding stimuli. Two herding boats traveled along bank-to-bank transects through the study area (longitudinal progression rate = 0.37 m/s) emitting sound and electricity (“combination technique”) or no added stimuli (“control”). The combination technique was most effective in terms of increasing fish presence (2.2 x the control) in the refuge-zones when herding had concluded and effective range (i.e., fish reaction distance; 1.6 x the control) relative to the herding boats. Fish median (~1 m/s) and maximum (~2 m/s) swimming velocity was relatively stable across fixed effects, except for the negative influence of water depth on maximum velocity. Water depth also exhibited a negative effect on fish reaction distance. Our results suggest effective range of the combination technique was conservatively 200 m (~20 dB re 1 μPa > ambient level) when accounting for water depth in the study area. Herding deployments less than 1 m/s (longitudinal progression) could control fish passing and maintain fish movements towards an intended location. Information provided herein can serve to assist planning, design, and application of herding efforts used to manage, control, and remove these invasive fish.

Kentucky↗
USGS2023

Amino acid variation at the mitochondrial binding site of Antimycin A is proposed to reflect sensitivity and toxicity differences among fish species

To better understand differential sensitivities among fish species to the piscicidal compound Antimycin-A (ANT-A), we hypothesized that variations in amino acids at the ANT-A binding site may reflect toxicity differences. Protein sequences for six motifs comprising the ANT-A binding site were obtained and compared for invasive carp species ( N = 515) and seven non-target species ( N = 277); a consensus was delineated from each species. The carp species, Common Carp ( Cyprinus carpio ), Silver Carp ( Hypophthalmichthys molitrix ), Bighead Carp ( Hypophthalmichthys nobilis ), Grass Carp ( Ctenopharyngodon idella ), and Black Carp ( Mylopharyngodon piceus ) , showed the same amino acids at the site; thus, it was termed the carp consensus motif sequence (CCM). Channel Catfish ( Ictalurus punctatus ) showed the most amino acid polymorphisms, with three motifs 96–100% different from CCM. Within a species, Bluegill ( Lepomis macrochirus ) and Fathead Minnow ( Pimephales promelas ) variation per motif was most dissimilar (46.7% and 21.6%, respectively). Organismal mortality data from the literature indicated Yellow Perch ( Perca flavescens ) , Walleye ( Sander vitreus ) , and American Gizzard Shad ( Dorosoma cepedianum ) to be most sensitive to the piscicide, Catfish least sensitive, and all others intermediate. The protein sequence variations of the binding site appeared to be in accord with organismal sensitivity categories when they differed from the CCM; the motifs in Gizzard Shad and Walleye were the same as in CCM. The physical/chemical nature of ANT-A is important to consider in organismal response comparisons. This cellular approach of studying ANT-A binding at its target enzyme is a non-destructive way to predict piscicidal efficacy of ANT-A against fishes of interest, informs management decisions in control efforts for invasives, and can be used to forecast effects on sympatric species.

Fishes↗
USGS2023

Herbivorous grass carp (Ctenopharyngodon idella) exhibit greater olfactory response to amino acids than filter-feeding bighead (Hypophthalmichthysnobilis) and silver carp (Hypophthalmichthys molitrix)

Due to their invasiveness in North America, grass ( Ctenopharyngodon idella ), bighead ( Hypophthalmichthys nobilis ), and silver carp ( Hypophthalmichthys molitrix ) are management priorities. Comparing electrophysiological responses to olfactory cues, such as amino acids, could help identify stimuli to facilitate management efforts (i.e., repellants or baits). We assessed olfactory response magnitude to individual amino acids between fish species and amino acids using electro-olfactogram recording techniques (EOG). We measured EOG responses (peak EOG magnitude) of juvenile grass ( n = 21), bighead ( n = 21), and silver carp ( n = 22) to 10 −4 molar amino acid solutions containing one of L-alanine, L-arginine, L-aspartic acid, L-asparagine, L-glutamine, or L-glutamic acid. Amino acid EOG responses differed across species; grass carp had the greatest mean EOG response. Statistical analyses showed no inter- or intra-specific differences in EOG response among amino acids. The greater EOG response of grass carp matched their selective grazing habits compared to more passive, generalist-tending, filter-feeding bighead and silver carp. All amino acids elicited significant EOG responses in all species, meaning they are candidates for future behavioral research. Such research could explore the management potential of amino acids, testing if amino acids are attractants or deterrents that could facilitate the removal of these fish by congregating and/or directing movement.

Fishes↗
USGS2023

U.S. Geological Survey invasive carp strategic framework, 2023–27

U.S. Geological Survey (USGS) research has supported management of Hypophthalmichthys nobilis (bighead carp), Mylopharyngodon piceus (black carp), Ctenopharyngodon idella (grass carp), and H. molitrix (silver carp), hereafter referred to collectively as invasive carps, for over a decade. This strategic framework identifies thematic research areas to guide funding decisions for USGS invasive carp research during 2023–27. The USGS will use this framework and input from research and management agencies to identify leading-edge research to advance control of these highly damaging invasive species.

Circular↗
USGS2023

Application of electricity and underwater acoustics to clear fish from a navigation lock during maintenance

The presence of fish within navigation locks can introduce an environmental challenge for construction crews when maintenance is required. This study examined the effectiveness of a dual-deterrent fish herding technique using electricity and acoustic stimuli to reduce the abundance of fish within a navigation lock before a scheduled dewatering for maintenance. Fixed-location multi-beam imaging sonar was used to evaluate fish per minute (FPM) detections near the lock entrance before, during, and after the herding effort. Standardized mobile side-scan sonar surveys were also conducted before and after the herding to examine fish presence throughout the entire lock. Collectively, a 73% reduction in fish targets detected by side-scan sonar and a 43% reduction in FPM detected by imaging sonar were observed following the herding technique. Post-fish herding, 88% reduction in FPM >400mm and a 35% reduction in FPM <400mm were observed. Fish abundance within the lock chamber was reduced and did not result in construction delays, which was problematic and costly during previous dewatering events. Since data from this study are limited to a single lock dewatering and fish clearing event, caution should be taken with the extrapolation of these results. However, the applied methods show promise and may inform future fish clearing efforts to aid lock maintenance.

Illinois↗
USGS2022

Effects of shady environments on fish collective behavior

Despite significant efforts devoted to understanding the underlying complexity and emergence of collective movement in animal groups, the role of different external settings on this type of movement remains largely unexplored. Here, by combining time series analysis and complex network tools, we present an extensive investigation of the effects of shady environments on the behavior of a fish species (Silver Carp Hypophthalmichthys molitrix ) within earthen ponds. We find that shade encourages fish residence during daylight hours, but the degree of preference for shade varies substantially among trials and ponds. Silver Carp are much slower and exhibit lower persistence in their speeds when under shade than out of it during daytime and nighttime, with fish displaying the highest persistence degree and speeds at night. Furthermore, our research shows that shade affects fish schooling behavior by reducing their polarization, number of interactions among individuals, and the stability among local neighbors; however, fish keep a higher local degree of order when under shade compared to nighttime positions.

Scientific Reports↗
USGS2021

An assessment of fish herding techniques: Management implications for mass removal and control of silver carp

We assessed the effectiveness of herding techniques on adult Silver Carp Hypophthalmichthys molitrix in a tributary to the Missouri River. Sites (600 m) were contained using block nets and treated with one of five herding techniques: (1) a method commonly used by commercial fishers in the United States (commercial technique), (2) pulsed-DC electrofishing (electric technique), (3) broadband sound administered with underwater speakers (sound technique), (4) both sound and electric in combination (combination technique), and (5) solely the boat, with no added stimulus (control). Treatments were administered at sites with repeated 20-min runs (3×) in a slow, bank-to-bank pattern downstream through a 4.5-m opening between the block net and shoreline. Herding effectiveness was quantified by run category (cumulative for the second and third runs) using adaptive resolution imaging sonar. Mean herding effectiveness of the combination technique was three to four times greater than that of the other techniques regardless of the number of runs included. The effectiveness of the combination technique was significantly greater than the sound technique and control with inclusion of the second run and the commercial technique with inclusion of the third run. All herding techniques, excluding the combination technique, were statistically similar to the control. Inclusion of the second run was advantageous for all techniques, as herding effectiveness increased 54–103%, whereas inclusion of the third run was less beneficial (9–17% increase). Repeated runs allowed fish additional time to vacate the sample reach, but behavioral responses (i.e., acclimation or sensitization) were likely technique dependent. This study describes which techniques are most effective for herding Silver Carp and provides insight for improving mass removal efforts.

Missouri↗