Aquatic Species Research Articles

Mathematical modelling and control approach for sustainable ecosystems in mitigating the impact of pollutants on aquatic species in rivers

This paper focuses on the urgent issue of minimising the impact of pollutants on aquatic life in river ecosystems. Our innovative approach involves the integration of mathematical modelling and strategic control methods to counteract the negative consequences of industrial and agricultural activities. The model, developed in a one-dimensional context, captures the complex dynamics of species population and pollutant concentration. Using an optimisation framework, we strive to achieve a harmonious balance that limits pollution, enhances species diversity and optimises control expenditure. Ultimately, we seek to harmonise industrial progress with ecological vitality, promoting the sustainability of river ecosystems for generations to come.

Contribution to the Knowledge of Two Endangered Fishes of the Jequitinhonha River Basin

Objective: Investigate the capture of Brycon devillei and Steindachneridion amblyurum in the Jequitinhonha River basin to contribute to the knowledge of these endemic and endangered species. Theoretical Framework: Based on concepts of ecology and conservation of aquatic species, highlighting the importance of preserving natural habitats for maintaining biodiversity. Theories on the relationship between climatic events and fish capture patterns are also explored. Method: Monthly collections of the species from 2011 to 2015, focusing on the months of October to February. Data collection included the capture of live specimens, which were sent for macro and microscopic analysis at the Machado Mineiro Environmental Station. The relationship between rainy days and reservoir levels with the number of species captured was statistically analyzed. Results and Discussion: Both Brycon devillei and Steindachneridion amblyurum were mainly captured during periods of rain and reservoir filling. There was a significant relationship between capture and rainy days for both species, with p<0.003 for Steindachneridion amblyurum and p<0.002 for Brycon devillei. The discussion contextualizes these findings in light of the theoretical framework, considering the ecological implications. Research Implications: Monitoring the reservoir during rainy days for the conservation of these species. Theoretically, the study highlights the importance of environmental factors in the capture of endangered aquatic species. Originality/Value: Contributes to the literature by providing unprecedented data on Brycon devillei and Steindachneridion amblyurum. The research offers valuable insights for the conservation of endemic fish in impacted habitats.

Evaluation of industrial and consumer 3-D resin printer fabrication of microdevices for quality management of genetic resources in aquatic species

Aquatic germplasm repositories can play a pivotal role in securing the genetic diversity of natural populations and agriculturally important aquatic species. However, existing technologies for repository development and operation face challenges in terms of accuracy, precision, efficiency, and cost-effectiveness, especially for microdevices used in gamete quality evaluation. Quality management is critical throughout genetic resource protection processes from sample collection to final usage. In this study, we examined the potential of using three-dimensional (3-D) stereolithography resin printing to address these challenges and evaluated the overall capabilities and limitations of a representative industrial 3-D resin printer with a price of US$18,000, a consumer-level printer with a price <US$700, and soft lithography, a conventional microfabrication method. A standardized test object, the Integrated Geometry Sampler (IGS), and a device with application in repository quality management, the Single-piece Sperm Counting Chamber (SSCC), were printed to determine capabilities and evaluate differences in targeted versus printed depths and heights. The IGS design had an array of negative and positive features with dimensions ranging from 1 mm to 0.02 mm in width and depth. The SSCC consisted of grid and wall features to facilitate cell counting. The SSCC was evaluated with polydimethylsiloxane (PDMS) devices cast from a typical photoresist and silicon mold. Fabrication quality was evaluated by optical profilometry for parameters such as dimensional accuracy, precision, and visual morphology. Fabrication time and cost were also evaluated. The precision, reliability, and surface quality of industrial-grade 3-D resin printing were satisfactory for operations requiring depths or heights larger than 0.1 mm due to a low discrepancy between targeted and measured dimensions across a range of 1 mm to 0.1 mm. Meanwhile, consumer-grade printers were suitable for microdevices with depths or heights larger than 0.2 mm. While the performance of either of these printers could be further optimized, their current capabilities, broad availability, low cost of operation, high throughput, and simplicity offer great promise for rapid development and widespread use of standardized microdevices for numerous applications, including gamete quality evaluation and “laboratory-on-a-chip” applications in support of aquatic germplasm repositories.

Influence of salinity and geographical locations of Mekong river estuaries on the abundance and biomass of rough river shrimp Macrobrachium equidens Dana, 1852 (Crustacea, Palaemonidae)

The Mekong river estuaries play a crucial role as a breeding ground for shrimp and various other valuable aquatic species. However, the scientific understanding of shrimp assemblages in this area remains limited. Therefore, the objective of this research is to investigate the density and biomass of the rough river shrimp Macrobrachium equidens, a highly valuable shrimp species in terms of nutrition and economy, in three Mekong river estuaries: Co Chien, Ham Luong, and Cua Dai. Additionally, environmental parameters were measured to assess their interactions with shrimp distributions. The results indicated that Cua Dai had the highest total density and biomass, followed by Ham Luong and Co Chien. However, the density and biomass of the rough river shrimp did not show significant variations among the estuaries but rather differed based on the salinity gradient. Salinity emerged as the primary factor influencing shrimp distribution. This study provides fundamental ecological data on the rough river shrimp, contributing to conservation efforts and sustainable exploitation in the future.

Phylogeny predicts sensitivity in aquatic animals for only a minority of chemicals

There are substantial gaps in our empirical knowledge of the effects of chemical exposure on aquatic life that are unlikely to be filled by traditional laboratory toxicity testing alone. One possible alternative of generating new toxicity data is cross-species extrapolation (CSE), a statistical approach in which existing data are used to predict the effect of a chemical on untested species. Some CSE models use relatedness as a predictor of chemical sensitivity, but relatively little is known about how strongly shared evolutionary history influences sensitivity across all chemicals. To address this question, we conducted a survey of phylogenetic signal in the toxicity data from aquatic animal species for a large set of chemicals using a phylogeny inferred from taxonomy. Strong phylogenetic signal was present in just nine of thirty-six toxicity datasets, and there were no clear shared properties among those datasets with strong signal. Strong signal was rare even among chemicals specifically developed to target insects, meaning that these chemicals may be equally lethal to non-target taxa, including chordates. When signal was strong, distinct patterns of sensitivity were evident in the data, which may be informative when assembling toxicity datasets for regulatory use. Although strong signal does not appear to manifest in aquatic toxicity data for most chemicals, we encourage additional phylogenetic evaluations of toxicity data in order to guide the selection of CSE tools and as a means to explore the patterns of chemical sensitivity across the broad diversity of life.

Pedigree reconstruction based on target sequencing in Pacific white shrimp Litopenaeus vannamei

Litopenaeus vannamei is one of the most economically productive species in aquaculture. It accounts for about 80% of the world's mariculture production of shrimp. Genetic selection of shrimp is mainly based on family selection. Therefore, accurate pedigree information is essential to ensure the reliability of estimated genetic parameters and the selection of the best broodstock. Recent advances in molecular breeding have facilitated molecular pedigree reconstruction based on SNPs and improved the accuracy of selection. However, breeding populations of aquatic species tend to be large. Therefore, a high-throughput and cost-effective method was needed for the commercial application of parentage assignment. In this study, we developed a low-density SNP panel based on target sequencing. A total of 200 amplicons, evenly distributed across the genome, were captured by multiplex PCR and sequenced by next-generation sequencing. Genotyping of 320 individuals in four ponds including multiple families identified 1,169 SNPs. Based on these SNPs, two softwares including Sequoia and PaternityT were used to reconstruct the sibling information. Consequently, a total of 39 families were accurately identified, and the results of the two software programs were highly consistent. Analysis based on different numbers of amplicons showed that at least 50 amplicons were required for accurate assignment. The identification result was also validated by principal component analysis and phylogenetic analysis. With the development of NGS technology, thousands of individuals could be genotyped with high throughput and low cost, making the method developed in this study affordable for parentage assignment in commercial breeding program. Meanwhile, the low-density SNP panel also has high value and prospects for application in shrimp genetic research.

Development of a Reference Transcriptome and Identification of Differentially Expressed Genes Linked to Salt Stress in Salt Marsh Grass (Sporobolus alterniflorus) along Delaware Coastal Regions.

Salt marsh grass (Sporobolus alterniflorus) plays a crucial role in Delaware coastal regions by serving as a physical barrier between land and water along the inland bays and beaches. This vegetation helps to stabilize the shoreline and prevent erosion, protecting the land from the powerful forces of the waves and tides. In addition to providing a physical barrier, salt marsh grass is responsible for filtering nutrients in the water, offering an environment for aquatic species and presenting a focal point of study for high salt tolerance in plants. As seawater concentrations vary along the Delaware coast from low to medium to high salinity, our study seeks to identify the impact of salt tolerance in marsh grass and to identify genes associated with salt tolerance levels. We developed more than 211,000 next-generation-sequencing (Illumina) transcriptomic reads to create a reference transcriptome from low-, medium-, and high-salinity marsh grass leaf samples collected from the Delaware coastline. Contiguous sequences were annotated based on a homology search using BLASTX against rice (Oryza sativa), foxtail millet (Setaria italica), and non-redundant species within the Viridiplantae database. Additionally, we identified differentially expressed genes related to salinity stress as candidates for salt stress qPCR analysis. The data generated from this study may help to elucidate the genetic signatures and physiological responses of plants to salinity stress, thereby offering valuable insight into the use of innovative approaches for gene expression studies in crops that are less salt tolerant.

Enhancing global maritime traffic network forecasting with gravity-inspired deep learning models

Aquatic non-indigenous species (NIS) pose significant threats to biodiversity, disrupting ecosystems and inflicting substantial economic damages across agriculture, forestry, and fisheries. Due to the fast growth of global trade and transportation networks, NIS has been introduced and spread unintentionally in new environments. This study develops a new physics-informed model to forecast maritime shipping traffic between port regions worldwide. The predicted information provided by these models, in turn, is used as input for risk assessment of NIS spread through transportation networks to evaluate the capability of our solution. Inspired by the gravity model for international trades, our model considers various factors that influence the likelihood and impact of vessel activities, such as shipping flux density, distance between ports, trade flow, and centrality measures of transportation hubs. Accordingly, this paper introduces transformers to gravity models to rebuild the short- and long-term dependencies that make the risk analysis feasible. Thus, we introduce a physics-inspired framework that achieves an 89% binary accuracy for existing and non-existing trajectories and an 84.8% accuracy for the number of vessels flowing between key port areas, representing more than 10% improvement over the traditional deep-gravity model. Along these lines, this research contributes to a better understanding of NIS risk assessment. It allows policymakers, conservationists, and stakeholders to prioritize management actions by identifying high-risk invasion pathways. Besides, our model is versatile and can include new data sources, making it suitable for assessing international vessel traffic flow in a changing global landscape.

Internal and external spatial analysis of trace elements in local crayfish

ABSTRACT Pollution in urban environments is a major health concern for humans as well as the local wildlife and aquatic species. Anthropogenic waste and discharge from storm drainage accumulate nutrients and environmental contaminants in local water systems. Locating contaminated sites using water samples over the vast landscape is a daunting task. Crayfish thrive in urban environments and have been used for biomonitoring pollutants. This study aimed to use crayfish as sentinels to monitor for elements in local environments. In this study, crayfish were used to measure metals and metalloids in lotic environments using ICP-OES analysis of abdominal and exoskeletal tissue. Using cluster analysis, geographical zones of trace element accumulation were determined. Eighteen total elements were analysed providing baseline data on local genera, biometric data, and element concentrations averaging 267.3 mg/kg Mn in the exoskeleton and with Zn averaging 6.88 mg/kg being significantly higher in the abdomen. Correlations of elements with biometric data allowed for internal analyses of elements. The elements As, Cr, Hg, Ni, and Tl demonstrated equivalent concentrations in both tissues. The crayfish locations with high abundance of elements allowed for the determination of contaminated areas with higher accumulations being areas of active urban development. These analyses gave measurable results of metal and metalloid to pinpoint potential sources of pollutants. Since crayfish are consumed globally as a food source, these methods can be used to determine the risk of toxic metals being passed through the food chain to the public.

Amphibious ethics and speculative immersions: laboratory aquariums as a site for developing a more inclusive animal geography

ABSTRACT Human capacity to sense and respond to the suffering of non-human animals is key to animal care and welfare. Intuitively these modes of relating seem best suited to interactions between humans and warm-blooded mammals who share human-like facial features and characteristics. Animal geographers and those working in animal welfare have noted the challenges that humans face in learning to care about fishes, and how this leads to welfare guidelines and regulations which are poorly suited to aquatic species. This paper draws on interviews with laboratory aquarists and biomedical researchers to explore how they have learnt to sense and respond to the needs of fishes in the laboratory. We offer two key observations. Firstly, despite significant bodily differences, humans find ways to empathise with fishes. Secondly, whilst observations of bodies and behaviours predominate in laboratory mammal welfare assessments, when working with fishes water quality serves as an important proxy for species health. We conclude that the laboratory aquarium signifies methodological and conceptual limits in contemporary animal geographies. We further argue that these barriers should be understood as cultural, and – as we demonstrate – that there is consequently scope and capacity to reach beyond them by engaging in amphibious ethics and speculative immersions.

Elucidating the reproductive toxicity mechanisms in female zebrafish: A transcriptomic study of lifetime tris(2-chloroethyl) phosphate exposure

Tris(2-chloroethyl) phosphate (TCEP), emerging as a predominant substitute for brominated flame retardants (BFRs), is now increasingly recognized as a prevalent contaminant in aquatic ecosystems. The extent of its reproductive toxicity in aquatic species, particularly in zebrafish (Danio rerio), remains insufficiently characterized. This study subjected zebrafish embryos to various concentrations of TCEP (0, 0.8, 4, 20, and 100 μg/L) over a period of 120 days, extending through sexual maturation, to assess its impact on female reproductive health. Notable reductions in body weight (0.59- and 0.76-fold) and length (0.71- and 0.77-fold) were observed at concentrations of 20 and 100 μg/L, with a concomitant decrease by 0.21- to 0.61-fold in the gonadal somatic index across all treatment groups. The reproductive output, as evidenced by egg production and hatchability, was adversely affected. Histopathological analysis suggested that TCEP exposure impedes ovarian development. Endocrine alterations were also evident, with testosterone and 11-ketotestosterone levels significantly diminished by 0.38- and 0.08-fold at the highest concentration tested, while 17β-estradiol was elevated by 0.09- to 0.14-fold in all exposed groups. Transcriptomic profiling illuminated numerous differentially expressed genes (DEGs) integral to reproductive processes, including hormone regulation, neuroactive ligand-receptor interactions, oocyte meiosis, and progesterone-mediated maturation pathways. Collectively, these findings indicate that lifelong exposure to TCEP disrupts ovarian development and maturation in female zebrafish, alters gene expression within the hypothalamic-pituitary-gonadal axis, and perturbs sex hormone synthesis, culminating in pronounced reproductive toxicity.

Eye morphology contributes to the ecology and evolution of the aquatic avifauna.

Aquatic birds are notable among the global avifauna for living in environments exposed to large amounts of light. Despite growing evidence that visual adaptations to light underly the ecology and evolution of the avian tree of life, no comprehensive comparative analysis of visual acuity as approximated by eyes size exists for the global aquatic avifauna. Here, I use Stanley Ritland's unpublished dataset of measurements for axial length collected from museum specimens to explore the ecology and evolution of eye size variation for half of the aquatic avifauna (N = 464 species). After correcting for body mass allometry and incorporating phylogenetic relationships, aquatic species had significantly smaller eyes compared to terrestrial species. Furthermore, species using hyperopic foraging manoeuvres, exhibiting carnivorous and insectivorous diets, and displaying nocturnal behaviour had larger eyes. Plunge-divers (e.g. boobies and tropic birds) and stalkers (e.g. herons) had the largest relative eye sizes, especially species identifying prey at higher altitudes or longer distances. Underwater pursuit-divers foraging at greater depths had larger eyes, likely due to the dramatic attenuation of light in the deep ocean. Overall, residual eye size was phylogenetically conserved (l = 0.94), with phylogeny alone explaining 62% of residual eye size variation. Collectively, these results suggest that the relatively bright environments found in aquatic ecosystems negate the adaptive benefits of costly metabolic investments associated with developing and maintaining larger eyes, while also reducing the potential occurrence of disability glare. Strong correlations between eye size and foraging ecology in different aquatic environments corroborate similar comparative studies of terrestrial birds and underscore the central role that vision has played in driving the ecology and evolution of the global avifauna.

Viral diversity and potential threats in residues and ballast water of ballast tanks at Shanghai port

Ballast water is one of the most important vectors for transferring and spreading marine aquatic species throughout the world. While technological advancements have led to an enhanced comprehension of ballast water viromes, the understanding of viral diversity in the residues after deballasting such as sediment and residual water remains predominantly unexplored. Our research conducted an initial exploration of viromes present in both residues (sediment and residual water) and ballast water of ballast tanks at Shanghai port, revealing distinct profiles between viromes in sediment and the water column (residual water and ballast water). The diversity, richness, and evenness of viral communities in sediment were lower than those in the water column. Our study underscores the existence of viral pathogens within residues and ballast water. Shrimp hemocyte iridescent virus (SHIV), a strain of decapod iridescent virus 1 (DIV1) listed as an aquatic animal disease by the World Organization for Animal Health (WOAH), was identified in all three types of samples. Our research expanded the understanding of viral diversity in sediments and residual water, highlighting the need for better management of residues after deballsting.

Emergence of lake conditions that exceed natural temperature variability

Lake surface temperatures are projected to increase under climate change, which could trigger shifts in the future distribution of thermally sensitive aquatic species. Of particular concern for lake ecosystems are when temperatures increase outside the range of natural variability, without analogue either today or in the past. However, our knowledge of when such no-analogue conditions will appear remains uncertain. Here, using daily outputs from a large ensemble of SSP3-7.0 Earth system model projections, we show that these conditions will emerge at the surface of many northern lakes under a global warming of 4.0 °C above pre-industrial conditions. No-analogue conditions will occur sooner, under 2.4 °C of warming, at lower latitudes, primarily due to a weaker range of natural variability, which increases the likelihood of the upper natural limit of lake temperature being exceeded. Similar patterns are also projected in subsurface water, with no-analogue conditions occurring first at low latitudes and occurring last, if at all, at higher latitudes. Our study suggests that global warming will induce changes across the water column, particularly at low latitudes, leading to the emergence of unparalleled climates with no modern counterparts, probably affecting their habitability and leading to rearrangements of freshwater habitats this century.

Occurrence and potential ecological risks of PFAS in Pampulha Lake, Brazil, a UNESCO world heritage site

Per- and polyfluoroalkyl substances (PFAS) comprise >4000 synthetic substances used in industrial applications and consumer products. PFAS used daily in households and manufacturing plants end up in domestic sewage, and industrial effluents can be discharged to surface water. Urban watersheds located in low and middle-income countries (LMIC), which lack sanitation infrastructure, are potential recipients of waste containing PFAS. Yet, only a few studies report PFAS occurrence in urban reservoirs and lakes, especially those located in the Global South due to resource limitations. This is the first study aimed to assess PFAS occurrence and ecological risks in Pampulha Lake, Brazil, a site which represents the reality of many other urban watersheds in LMIC as it is surrounded by densely populated areas and manufacturing plants. Surface water samples were collected monthly for 1 year from four sampling points at Pampulha Lake. Sample analysis was based on US Environmental Protection Agency Method 1633, which employs solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Species sensitivity distribution (SSD) curves were built to identify potentially susceptible species based on detected water concentrations. Bioaccumulation was estimated for fish tissue. Short-chain (perfluorobutanesulfonic acid, PFBS and perfluorohexanoic acid, PFHxA) and long-chain PFAS (perfluorodecanoic acid, PFDA; perfluorooctanoic acid, PFOA; perfluorododecanoic acid, PFDoA; and perfluorooctanesulfonic acid, PFOS) were detected at the μg L−1 range. Total PFAS concentrations in the wet season were generally higher than in the dry season, likely due to limited capacity of the treatment plant processing water from tributaries which receive raw sewage. More than 5 % of aquatic species are potentially susceptible to chronic effects of PFOS at detected concentrations (0.2–2.2 μg L−1). Predicted bioaccumulation of PFOS in fish was above advisory diet intake levels for humans. Results emphasize the need for studies related to PFAS occurrence in watersheds located in LMIC.

Towards an integrative understanding of British Columbia’s Nechako Watershed: Connecting knowledge systems to strengthen understanding of climate change, watershed security, health and well-being

Understanding of upstream and downstream dynamics of continental river basins demands attention to the influence of important tributaries and watersheds. This is exemplified by the 47,200 km2 Nechako Watershed, the second largest sub-watershed of British Columbia’s Fraser River Basin. Although the Nechako (derived from the Indigenous Dakelh word meaning “big river”) is recognised for its ecological, societal and cultural importance, attention to this sub-watershed has often been overshadowed by a focus on the iconic Fraser River. This paper examines insights from a purposeful response to this gap, whereby a team of researchers has worked together to strengthen understanding of cumulative stressors and changes in the Nechako, focusing on climate change and water security, sediment sources and quality, and health and well-being dynamics within the Nechako Watershed. Lessons learned from a decade of this collaboration are presented, reflecting on the Nechako Watershed’s past, present, and future through the lens of a unique case study of interdisciplinary research. Emerging research and knowledge exchange partnerships are highlighted along with growing concerns for the Nechako’s keystone aquatic species including three species of Pacific salmon and the endangered Nechako white sturgeon. Drawing on the natural, social and health sciences, we examine strengths and challenges of connecting research across interrelated watershed security issues ranging from climate change, landcover disturbances (e.g., wildfires, mountain pine beetle outbreaks and forest harvesting), land use changes (e.g., expansion of Vanderhoof’s agricultural belt), and the far-reaching impacts of the damming of the Nechako River mainstem in the 1950’s. Our paper brings necessary attention to these and other influences on waterways, landscapes and communities of the Nechako Watershed, highlighting new research opportunities arising among diverse knowledges and disciplines, and the ongoing collaborative effort required to address emerging challenges for the Nechako and wider Fraser River Basin, with consequences for current and future generations.

Forecasting ocean hypoxia in salmonid fish farms

IntroductionHypoxia is defined as a critically low-oxygen condition of water, which, if prolonged, can be harmful to fish and many other aquatic species. In the context of ocean salmon fish farming, early detection of hypoxia events is critical for farm managers to mitigate these events to reduce fish stress, however in complex natural systems accurate forecasting tools are limited. The goal of this research is to use a machine learning approach to forecast oxygen concentration and predict hypoxia events in marine net-pen salmon farms.MethodsThe developed model is based on gradient boosting and works in two stages. First, we apply auto-regression to build a forecasting model that predicts oxygen concentration levels within a cage. We take a global forecasting approach by building a model using the historical data provided by sensors at several marine fish farms located in eastern Canada. Then, the forecasts are transformed into binary probabilities that indicate the likelihood of a low-oxygen event. We leverage the cumulative distribution function to compute these probabilities.Results and discussionWe tested our model in a case study that included several cages across 14 fish farms. The experiments suggest that the model can detect future hypoxic events with a commercially acceptable false alarm rate. The resulting probabilistic predictions and oxygen concentration forecasts can help salmon farmers to prioritize resources, and reduce harm to crops.

Impact of Temperature on the Growth Performance, Survival Rate, Osmoregulation, Dissolved Oxygen and Physiological Changes of Freshwater Tilapia (Oreochromis mossambicus)

For many aquatic species, any changes in water temperature affect their survival. This study was performed to investigate the effect of rising temperature on the growth parameters, protein content, dissolved oxygen content, moisture content osmoregulation, and physiological activity of freshwater Tilapia (Oreochromis mossambicus). The experiments were set in plastic fish tanks, the experimental tank placed in direct sunlight and the control tank in shade, and measuring temperature and pH daily, with proper aeration and feed was provided. The study found that increasing water temperature led to higher mortality rates and low survivability percentages in fish, with a higher growth rate in the experimental group with a pH range of 5.7 to 8.2. High dissolved oxygen levels were recorded during the experimental period, with a mean difference of 26.56 compared to the control group, possibly causing restless movement in fish. The study revealed that the alkalinity of water decreases with increasing temperature. The study found that increased salinity led to a significant increase in growth performance, indicating an increase in metabolic rate, and a decrease in alkaline nature. The difference between the mean protein value in the experimental and control groups is 0.896mg/ml. Thermal limitations may negatively impact O. mossambicus physiological responses, impacting aquaculture production due to predicted global climate change-induced water temperature changes.

Angler knowledge of live bait regulations and invasive species: insights for invasive species prevention

The prevention of aquatic invasive species is one of the most cost-effective management strategies for reducing negative ecological, economic, and social impacts to freshwater ecosystems. The release of leftover baitfish via the live bait trade has been identified as a high-risk pathway for introducing invasive species beyond physical barriers (e.g., mountains, dams). To assess differences in behavior surrounding live bait use and angler knowledge of invasive species, we conducted in-person angler surveys at waterbody access sites (i.e. boat ramps with available shore fishing and a shore fishing location with no boat ramp) along the Missouri River, above and below Gavins Point Dam (Yankton, South Dakota, USA). We were primarily interested in whether angler behavior and knowledge differed among fishing locations over the course of a year because of potential variation in risk. Gavins Point Dam is impervious to fish passage and prevents the spread of invasive silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis (collectively known as bigheaded carp), but bigheaded carp could be transported above this dam by the use of live baitfish. Regardless of where respondents fished (above the dam/carp absent, below the dam/carp present, or both), 70% ± 11.12 of anglers used live baitfish and 57% ± 3.14 participated in ‘higher risk’ baitfish practices including release. Knowledge of bigheaded carp was limited, as only 2% ± 1.31 of respondents identified both bigheaded carp as invasive in an image collage, 51.82% ± 4.48 could not identify where invasive carp are present/absent, and 40% ± 3.34 of anglers had not received any information regarding bigheaded carp. These findings highlight limitations in angler knowledge, compliance, and identification of native and invasive species. Future implementable actions could include invasive species and baitfish release outreach via electronic media sources or additional signage that address these knowledge gaps.

Genetic diversity and connectivity of the invasive gastropod, Callinina georgiana (Caenogastropoda: Viviparidae) across a fragmented riverscape: A mitonuclear perspective

Abstract Aquatic invasive species are a significant threat to global freshwater biodiversity. This study focuses on the banded mystery snail, Callinina georgiana, an invasive species in the Adirondack region of northern New York—an important section of the New York Great Lakes Basin. This project aims to explore the genetic connectivity of C. georgiana within its invasive range using a combination of mitochondrial and nuclear markers. Sampling was conducted in the Raquette River and adjacent waterways, with a total of 229 snails collected from 16 distinct populations distributed across eight different waterbodies. Also included were two populations from the species' native range in the southern U.S.A. DNA was extracted, and a 710‐bp fragment of the mitochondrial DNA marker cytochrome c oxidase 1 and a 351‐bp fragment of nuclear marker histone‐3 were amplified. Population genetic analyses including haplotype patterning, AMOVA and genetic diversity estimates, neutrality tests and tests for isolation by distance were performed to assess connectivity patterns. Results showed moderate to high levels of genetic admixture within the snail's invasive range as indicated by the lack of geographic patterning of haplotypes and low to moderate levels of genetic differentiation across multiple sites. Demographic analyses combined with high numbers of private haplotypes indicate historic population expansion. Interestingly, a case of mitonuclear discordance was detected for native and invasive populations as evident by incongruent haplotype patterns for the cytochrome c oxidase 1 and histone‐3 markers. Callinina georgiana exhibits a high level of genetic connectivity in its invasive range. The presence of dams does not significantly affect apparent gene flow, indicating that anthropogenic activities, such as boat traffic might be key in dispersing the snails across this fragmented freshwater system. This study offers new insights into the dispersal and genetic structure of an invasive freshwater snail. It highlights the importance of considering anthropogenic factors when confronting complex patterns of genetic diversity. The findings are significant for biodiversity conservation and provide a basis for developing strategies to manage and contain the spread of aquatic invasive species such as C. georgiana, especially in regions with high human activity.