Search Results (56)

Recent advances in passive acoustic monitoring (PAM) have markedly improved the ability to study marine soundscapes by enabling long-term, non-invasive monitoring of biological sounds across large spatial and temporal scales. Among aquatic organisms, fish are primary contributors to biophony, producing sounds associated with feeding, reproduction, and social behavior. However, the majority of previous research has focused on individual vocalizations, with limited attention to collective acoustic phenomena such as fish choruses. This study quantitatively analyzes choruses produced by the small yellow croaker (Larimichthys polyactis), an ecologically and commercially important species in the Northwest Pacific Ocean. Using power spectral density (PSD) analysis, we examined long-term underwater recordings from a sea cage containing approximately 2000 adult small yellow croakers. The choruses were centered around ~600 Hz and exhibited sound pressure levels 15–20 dB higher at night than during the day. These findings highlight the ecological relevance of fish choruses and support their potential use as indicators of biological activity. This study lays the foundation for incorporating fish choruses into soundscape-based PAM frameworks to enhance biodiversity and habitat monitoring. Full article

DNA metabarcoding is a powerful biodiversity monitoring tool, enabling simultaneous assessments of diverse biological communities. However, its accuracy depends on the reliability of reference databases that assign taxonomic identities to obtained sequences. Here we provide a DNA barcode dataset for aquatic fauna of the Panama Canal, a region that connects the Western Atlantic and Eastern Pacific oceans. This unique setting creates opportunities for trans-oceanic dispersal while acting as a modern physical dispersal barrier for some terrestrial organisms. We sequenced 852 specimens from a diverse array of taxa (e.g., fishes, zooplankton, mollusks, arthropods, reptiles, birds, and mammals) using COI, and in some cases, 12S and 16S barcodes. These data were collected for a variety of studies, many of which have sought to understand recent changes in aquatic communities in the Panama Canal. The DNA barcodes presented here are all from captured specimens, which confirms their presence in Panama and, in many cases, inside the Panama Canal. Both native and introduced taxa are included. This dataset represents a valuable resource for environmental DNA (eDNA) work in the Panama Canal region and across the Neotropics aimed at monitoring ecosystem health, tracking non-native and potentially invasive species, and understanding the ecology and distribution of these freshwater and euryhaline taxa. Full article

Danionella, a transparent freshwater species belonging to the Cyprinidae family, has emerged as a valuable model organism in biological and medical research due to its optical transparency. The cardiovascular system of Danionella larvae provides a unique opportunity for non-invasive heart rate monitoring in aquatic animals. Traditional approaches for evaluating larval heart rate often require manual or semi-automated definition of the cardiac region in video recordings. In this study, we developed a simplified heart rate monitoring system that estimates heartbeat activity by analyzing interframe luminance differences in video sequences of Danionella larvae. Our system successfully measured heart rates in the range of 150–155 beats per minute (bpm), consistent with previous findings reporting rates between 140 and 200 bpm. The non-invasive nature of this method offers significant advantages for high-throughput screening and long-term physiological monitoring. Furthermore, this system has potential applications in evaluating environmental stressors, supporting survival and health assessments, and guiding habitat management strategies to ensure stable populations of adult fish in both natural and laboratory settings. Full article

Invasive species often defy theoretical expectations, successfully establishing and spreading despite reduced propagule pressure and limited genetic diversity. What genomic mechanisms underpin this paradox? How do adaptive processes and host–pathogen interactions shape invasion outcomes? And which genes drive resistance and modulate pathogen virulence? Here, we address these questions using a model of co-invasion: the Asian topmouth gudgeon (Pseudorasbora parva) and its fungal parasite the Rosette agent (Sphaerothecum destruens), a system with profound ecological and economic consequences. Here by (1) mapping the reads obtained by Illumina sequencing on a previously deposited P. parva genome from Germany, (2) identifying SNPs and (3) creating a consensus sequence, we generated the first whole genome of an invasive P. parva population in France and compared it to a German population to explore patterns of genetic diversity, local adaptation, and potential signatures of pathogen resistance. Despite historical bottlenecks, our results reveal unexpectedly high levels of genomic diversity between these invasive populations. We identify candidate loci linked to immune function and provide insights into the evolutionary dynamics of co-introduction. These findings offer a rare window into how invasive species maintain adaptability and how pathogens may co-evolve during range expansion. Beyond advancing our understanding of invasion biology, the genomic resources generated here pave the way for translational approaches, including the development of genome-editing strategies aimed at mitigating the impact of invasive species and their associated pathogens. This work marks a critical step toward unraveling the complex interplay between genetics, ecology, and evolution in biological invasions. Full article

Biological invasions are one of the main causes of biodiversity loss globally, affecting the quality of ecosystem services, the economy, and public health. Research on the presence, distribution, impacts, and introduction pathways of invasive alien species is essential for understanding and tackling the invasion process. Continental, coastal, and marine aquatic ecosystems of the Yucatan Peninsula concentrate a high number of native species; however, the states that are in the region (Campeche, Yucatan, and Quintana Roo) also have the largest loss of natural capital at the national level. The presence of aquatic invasive species has contributed to this downward trend, mainly in protected areas. For this research, an analysis of the national biodiversity information system, the global biodiversity information facility, and the specialized scientific literature was carried out to determine the presence of aquatic invasive species within the protected areas of the Yucatan Peninsula and adjacent marine zone. The results indicated that there are 22 documented aquatic invasive species in 25 protected areas, which were classified into the following taxonomic groups: marine macroalgae (3 species), plants (2), inland and marine fish (11), crustaceans (2), mollusks (2), and hydrozoans (2). A total of 15 of these species had a very high invasiveness score, 6 had a high score, and 1 had a medium score. This research will be useful in strengthening regional public policy and guiding decision makers on the management of aquatic invasive species, mainly for those that are seriously affecting aquatic ecosystems, such as Pterygoplichthys disjunctivus and P. pardalis in freshwater protected areas and Pterois volitans in marine protected areas. Efficient management strategies will be a key element in the protection of biodiversity and ecosystem services, and for sustainable regional development. Full article

Submerged macrophytes can profoundly influence interactions between aquatic predators and their prey due to changes in foraging efficiencies, pursuit time and swimming behaviors of predator–prey participants. Water hyacinth, Eichhornia crassipes (Mart.) Solms-Laub. (Pontederiaceae), is the most widely distributed of the aquatic invasive weeds in South Africa. This invasive weed contributes to changes in physicochemical (turbidity, temperature and water column stratification) and biological (total chlorophyll-a (Chl-a) concentrations and species composition and distribution of vertebrates and invertebrates) variables within freshwater systems of the region. The current study assessed the influence of varying levels of water hyacinth cover (0, 25, 50 and 100% treatments) on the total Chl-a concentration, size structure of the phytoplankton community and the strength of the interaction between a predatory notonectid, Enithares sobria, and zooplankton using a short-term 10-day long mesocosm study. There were no significant differences in selected physicochemical (temperature, dissolved oxygen, total nitrogen and total phosphate) variables in these different treatments over the duration of this study (ANOVA; p > 0.05 in all cases). Results of this study indicate that treatment had a significant effect on total Chl-a concentrations and total zooplankton abundances. The increased surface cover of water hyacinth contributed to a significant reduction in total Chl-a concentrations and a significant increase in total zooplankton abundances (ANCOVA; p < 0.05 in both cases). The increased habitat complexity conferred by the water hyacinth root system provided refugia for zooplankton. The decline in total Chl-a concentration and the size structure of the phytoplankton community under elevated levels of water hyacinth cover can therefore probably be related to both the unfavorable light environment conferred by the plant cover and the increased grazing activity of zooplankton. The presence of the water hyacinth thus suppressed a predator–prey cascade at the base of the food web. Water hyacinth may, therefore, have important implications for the plankton food web dynamics of freshwater systems by reducing food availability (Chl-a), changing energy flow and alternating the strength of interactions between predators and their prey. Full article

Environmental DNA (eDNA) technology is a method for identifying specific biological species by monitoring the presence of DNA fragments in the environment. This technology has the capacity to detect a wide range of species, including elusive and cryptic organisms, by analyzing the genetic material in the environment. The advantages of high sensitivity, wide spatial coverage and non-invasiveness provide many opportunities for its application in identifying and monitoring aquatic organisms, improving our ability to detect and quantify biodiversity. Furthermore, eDNA technology can provide an accurate, convenient and standardizable solution for regularly monitoring aquatic ecosystems. The utilization of eDNA in ecology and conservation has witnessed substantial growth in recent years. However, eDNA still faces numerous challenges, including DNA degradation, risk of contamination and the absence of standardized protocols. Nonetheless, the application of eDNA in aquatic ecosystem monitoring holds considerable promise, particularly in light of technological advancements. As technology evolves, the accuracy, scalability and applicability of eDNA in diverse ecosystems are steadily improving. This paper aims to provide a comprehensive review of the application of eDNA technology in aquatic ecosystem monitoring, addressing its technical limitations and potential future developments. Full article

The monitoring of species in a habitat is important to ensure biological diversity. Environmental DNA (eDNA) can infer the presence–absence of species and enable rapid action to avoid threatening factors in ecosystems in the case of non-indigenous species. Loop-mediated isothermal amplification (LAMP) assays for molecular amplification are rapidly gaining popularity in species detection, but LAMP remains an underutilized method for eDNA-based monitoring practices. The most effective combination for successful species monitoring may be the collection of eDNA or biological traces collected by nanofiltration followed by LAMP-based species detection initiatives. Here, we used LAMP analysis to detect the eDNA of Esox lucius (Northern Pike), Anguilla anguilla (European Eel), and Salmo salar (Atlantic Salmon) in Borre Lake and in the Drammen River. The selection of species is based on the categories of regionally invasive species, endangered species, and species of least concern. Two target genes were considered for each species and LAMP primers were designed. Our study showed that LAMP is an effective tool for discovering specific fish eDNA (analysis) to maintain aquatic ecosystems. Full article

Climate change has amplified the threat posed by aquatic invasive species as potential disruptors of biodiversity and ecosystem functioning. Species Distribution Models (MaxEnt) based on original data and ecological variables have identified contemporary seven global centers of the oriental rivel prawn Macrobrachium nipponense distribution: the native range in East Asia, Northern, Western and Eastern Europe, the Irano-Turanian region, and North and South America. By 2050, further expansion in Europe is expected, likely due to climate change, particularly temperature changes (Bio1) and rain precipitation during the warmest quarter (Bio18). However, the species may see a range reduction in southern Europe due to lower precipitation and increased droughts related to climate change. Therefore, a northward shift in the range of the species is also predicted. In the context of global change, and especially biological invasions, this study highlights the risks of introducing aquaculture based on M. nipponense and recommends controlling such economic activities, which are associated with a high risk for native species and ecosystems. Further, long-term monitoring is needed to assess impacts and to efficiently manage M. nipponense populations that are already present in their non-native habitats, for mitigating their negative effects on native species and ecosystems worldwide. Full article

Biological invasions have been identified as the fifth cause of biodiversity loss, and their subsequent dispersal represents a major ecological challenge. The aquatic invasive species Ludwigia grandiflora subsp. hexapetala (Lgh) and Ludwigia peploides subsp. montevidensis (Lpm) are largely distributed in aquatic environments in North America and in Europe. However, they also present worrying terrestrial forms that are able to colonize wet meadows. To comprehend the mechanisms of the terrestrial adaptation of Lgh and Lpm, it is necessary to develop their genomic resources, which are currently poorly documented. We performed de novo assembly of the mitogenomes of Lgh and Lpm through hybrid assemblies, combining short reads (SR) and/or long reads (LR) before annotating both mitogenomes. We successfully assembled the mitogenomes of Lgh and Lpm into two circular molecules each, resulting in a combined total length of 711,578 bp and 722,518 bp, respectively. Notably, both the Lgh and Lpm molecules contained plastome-origin sequences, comprising 7.8% of the mitochondrial genome length. Additionally, we identified recombinations that were mediated by large repeats, suggesting the presence of multiple alternative conformations. In conclusion, our study presents the first high-quality mitogenomes of Lpm and Lgh, which are the only ones in the Myrtales order found as two circular molecules. Full article

Biological invasions are of special conservation concern in the Iberian Peninsula and other regions with high levels of endemism. Environmental variability, such as the seasonal fluctuations of Mediterranean streams, is a key factor that affects the spread of aquatic species in novel habitats. Fish parasites have a great potential to reflect such changes in the habitat features of freshwater ecosystems. The aim of this study consisted of seasonally analysing the health status and parasitological traits of non-native fish in Iberian waters. In particular, a strongly invasive population of Languedoc minnow Phoxinus septimaniae (leuciscid species native to south-east France) was assessed in Tordera Stream (north-eastern Iberian Peninsula, Mediterranean conditions). Fish were sampled in April, July, and October 2023 by electrofishing. Health status (external/internal organs) was significantly better in autumn (HAI = 28.8) than spring (HAI = 35.6). Life-cycle complexity was higher in spring (LCI = 1.98), whereas parasite abundance and Shannon diversity were significantly lower in autumn (TA = 19.6 and H’ = 2.15, respectively). In October (more ‘benign’ environmental conditions in Iberian streams), minnows could display elevated foraging activity, with fish increasing their health condition and level of parasite resistance/tolerance. Overall results showed a particular seasonal profile of health and parasite infra-communities that allow this minnow species to thrive under highly fluctuating habitat conditions. This information could help environmental managers to control non-native fish in Mediterranean streams. Full article

Coal mining activity contributes to energy security and employment occupation, but is associated with environmental deterioration. Coal combustion leads to GHG emissions, while coal mining results in the generation of saline effluents. These effluents are discharged in inland surface waters, applying significant pressure on their quality, with a negative impact on aquatic life and the economy of a region. This study includes water samples that were analyzed in order to investigate the organic compounds, heavy metals, and other physicochemical parameters. Biological monitoring was done according to the Water Framework Directive methodology. The results from an aquatic area in Southern Poland, which indirectly receives coal mine effluents, indicate elevated salinity with excessive chlorides, sulfates, and sodium ions. The water quality of another non-polluted aquatic area was also assessed to examine the impact of indirect coal mine wastewater discharge on this area. The high salinity levels hinder the use of river water for drinking, agricultural, or industrial purposes. The results obtained show high pressure on the ecological status of streams and rivers that receive mine effluents, and on the density and diversity of aquatic invertebrates. This pressure is clearly visible in the structure of benthic communities and in invertebrate diversity. It also contributes to the appearance of invasive species and increasing water salinity. Limiting discharges of mine water transporting large loads of saline substances would reduce the negative impact on the quality of river waters and biological life. Full article

Aquatic weeds, including invasive species, are a worldwide problem. The presence of aquatic weeds poses several critical issues, such as hindering the continuous flow of water in irrigation channels and preventing the proper distribution of adequate water quantities. Therefore, effective control measures are vital for agriculture and numerous downstream industries. Numerous methods for controlling aquatic weeds have emerged over time, with herbicide application being a widely used established method of weed management, although it imposes significant environmental risks. Therefore, it is important to explore nonchemical alternative methods to control existing and emerging aquatic weeds, potentially posing fewer environmental hazards compared with conventional chemical methods. In this review, we focus on nonchemical methods, encompassing mechanical, physical, biological, and other alternative approaches. We primarily evaluated the different nonchemical control methods discussed in this review based on two main criteria: (1) efficiency in alleviating aquatic weed problems in location-specified scenarios and (2) impacts on the environment, as well as potential health and safety risks. We compared the nonchemical treatments with the UV-C-radiation-mediated aquatic weed control method, which is considered a potential novel technique. Since there is limited published literature available on the application of UV-C radiation used exclusively for aquatic weed control, our review is based on previous reports of UV-C radiation used to successfully control terrestrial weeds and algal populations. In order to compare the mechanisms involved with nonchemical weed control methods, we reviewed respective pathways leading to plant cell death, plant growth inhibition, and diminishing reemergence to justify the potential use of UV-C treatment in aquatic habitats as a viable novel source for aquatic weed control. Full article

The ecosystem structure of a Mediterranean high-altitude artificial lake (Aoos Springs, Northwest Greece) was assessed and quantified using the Ecopath with Ecosim model. The artificial lake was created in 1990 for hydroelectric production and the fish fauna has been enriched across years due to deliberate or accidental fish stockings, as well as the introduction of the invasive pumpkinseed (Lepomis gibbosus), which may cause adverse effects on aquatic ecosystems and their biota. The model considered 20 species/taxa groups with biological data gathered during 2021–2022 from field surveys, interviews with recreational anglers and literature. The results revealed that the artificial lake of Aoos is a resilient ecosystem to unexpected events with low intensity of fisheries exploitation. The biomass of the introduced invasive species Lepomis gibbosus is low, due to the low biomass level of its diet, Chironomidae and zoobenthic organisms as well as other fish species. Full article

Triops longicaudatus is a crustacean typically inhabiting temporary freshwater bodies in regions with a Mediterranean climate. These crustaceans are easily maintained in the laboratory and show a set of biological features that make them good candidates for diagnosing environmental quality and health. However, information about their responses to environmental contamination is scarce. This study characterised the locomotor responses of juvenile and adult/mature T. longicaudatus to low concentrations of five model toxicants upon a very short 1.5 h exposure: tributyltin, mercury, lindane, sodium hypochlorite and formaldehyde. A video-tracking system was used to record the locomotor behaviour. The data were analysed with an artificial neural network to identify distinct behaviours, followed by Chi-square and Correspondence analysis to characterise the response to each toxicant. The results showed that T. longicaudatus is sensitive to aquatic contamination, particularly sodium hypochlorite. Six behaviour types were defined, which allowed for the characterisation and discrimination of the test toxicants. The results support the need for more investigation into this species and its behaviour types as an alternative to animal testing and the more apical and often invasive endpoints commonly recommended in standard guidelines. Full article