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The controlled creation and manipulation of defects in 2D materials has become increasingly popular as a means to design and tune new material functionalities. However, defect characterization by direct atomic-scale imaging is often severely limited by surface contamination due to a blanket of hydrocarbons. Thus, analysis techniques that can characterize atomic-scale defects despite the contamination layer are advantageous. In this work, we take inspiration from X-ray absorption spectroscopy and use broad-beam electron energy loss spectroscopy (EELS) to characterize defect structures in 2D hexagonal boron nitride (hBN) based on averaged fine structure in the boron K-edge. Since EELS is performed in a transmission electron microscope (TEM), imaging can be performed in-situ to assess contamination levels and other factors such as tears in the fragile 2D sheets, which can affect the spectroscopic analysis. We demonstrate the TEM-EELS technique for 2D hBN samples irradiated with different ion types and doses, finding spectral signatures indicative of boron-oxygen bonding that can be used as a measure of sample defectiveness depending on the ion beam treatment. We propose that even in cases where surface contamination has been mitigated, the averaging-based TEM-EELS technique can be useful for efficient sample surveys to support atomically resolved EELS experiments.

We present a study directly measuring the electron‐beam‐induced plasticity of amorphous Al2O3 coatings. Core–shell nanostructures are employed as small‐scale model systems for two‐dimensional coatings made by atomic layer deposition (ALD). Copper nanowires (NWs) are used as substrates for ALD deposition, representing a model system for interconnects commonly found in integrated circuits. Experiments are performed in situ in a transmission electron microscope (TEM) and further analyzed with electron energy loss spectroscopy (EELS). Our in situ TEM tensile experiments reveal the highly plastic behavior of the ALD shell, which withstands a maximum strain of 188%. Comparable samples under beam‐off conditions show a brittle fracture, which underlines the effect of electron irradiation. The electron‐beam‐activated bond switching within the amorphous network enables compensation of the applied tensile strain, leading to viscous flow. By incorporating an intermediate nanocrystalline layer within the Al2O3 shell, the plasticity is suppressed and brittle fracture occurs. This work directly demonstrates the tuning of mechanical properties in amorphous ALD structures through electron irradiation.

Oxygen redox enhances the specific energy of sodium cathodes, but the other performance remains unsatisfactory. By introducing Cu into P2 lattice to replace Li cations, P3‐type Na0.75Li0.2Cu0.05Mn0.75O2 with high Na concentration is achieved. This modification induces notable alteration in the lattice structure, specifically increasing the interplanar spacing of NaO6 from 3.6 Å to 3.8 Å. The resultant P3‐type cathode delivers a remarkable capacity of 253 ± 1.3 mAh g−1 with energy density of 680 mWh g−1, setting a benchmark for P3‐type sodium cathodes. The high capacity can be attributed to the activation of Mn3+/ Mn4+ redox pair following Cu substitution. Further investigations confirm that Mn3+/ Mn4+, Cu2+/ Cu3+ and O2−/On− redox pairs all contribute to the high performance. The absence of O vacancy and the reduction in phase transitions enhance the cyclic performance with capacity retention of 86.3% at 0.5C. Additionally, the small diffusion energy barrier (34.6 KJ mol−1) results in a high Na diffusion coefficient (1.332 × 10−9 cm2 s−1), thereby promoting superior rate behavior with a capacity of 200.8± 2.1 mAh g−1 at 5C. These results demonstrate the advantages of the P3‐type Na0.75Li0.2Cu0.05Mn0.75O2 cathode over the other Na cathodes, suggesting high potential for application in high‐energy storage fields. [ABSTRACT FROM AUTHOR]

In East Asia, anguillid eels are commercially important. However, unlike other species, they have not been successfully cultivated throughout their lifecycle. Facing population decline due to overharvesting and environmental pressures, the industry is turning to alternatives, such as Anguilla bicolor pacifica (short-finned eel). However, genomic data for short-finned eels are unavailable. Here, we present in-depth whole-genome sequencing results for short-finned eel obtained using two sequencing platforms (PacBio Revio, and Illumina). In this study, we achieved a highly contiguous genome assembly of the short-finned eel, comprising 19 pseudochromosomes encompassing 99.76% of the 1.087 Gb genome sequence with an N50 of 16.88 and 61.07 Mb from contig and scaffold, respectively. Transcripts from four different tissues led to the annotation of 23,095 protein-coding genes in the eel genome, 98.66% of which were functionally annotated. This high-quality genome assembly, along with the annotation data, provides a foundation for future functional genomic studies of short-finned eels. [ABSTRACT FROM AUTHOR]

Solar energy has emerged as a key solution in the global transition to renewable energy sources, driven by environmental concerns and climate change. This is largely due to its cleanliness, availability, and cost-effectiveness. The precise assessment of hidden factors within photovoltaic (PV) models is critical for effectively exploiting the potential of these systems. This study employs a novel approach to parameter estimation, utilizing the electric eel foraging optimizer (EEFO), recently documented in the literature, to address such engineering issues. The EEFO emerges as a competitive metaheuristic methodology that plays a crucial role in enabling precise parameter extraction. In order to maintain scientific integrity and fairness, the study utilizes the RTC France solar cell as a benchmark case. We incorporate the EEFO approach, together with Newton-Raphson method, into the parameter tuning process for three PV models: single-diode, double-diode, and three-diode models, using a common experimental framework. We selected the RTC France solar cell for the single-diode, double-diode, and three-diode models because of its significant role in the field. It serves as a reliable evaluation platform for the EEFO approach. We conduct a thorough evaluation using statistical, convergence, and elapsed time studies, demonstrating that EEFO consistently achieves low RMSE values. This indicates that EEFO is capable of accurately estimating the current-voltage characteristics. The system's smooth convergence behavior further reinforces its efficacy. Comparing the EEFO with competing methodologies reinforces its competitive advantage in optimizing solar PV model parameters, showcasing its potential to greatly enhance the usage of solar energy. [ABSTRACT FROM AUTHOR]

Electron energy loss spectra collected from fresh and corroded silver nanoparticles are compared with those from a number of reference materials, focusing on the M4,5 edge. Chemical shifts and changes in the energy loss near edge structure (ELNES) are described and found to be sufficient to distinguish metallic silver from chemically oxidised silver. The measurements, in conjunction with electron energy loss spectrum imaging, are used to assess the mechanisms for atmospheric corrosion of silver nanoparticles. We unambiguously assign the corrosion product under atmospheric conditions to be silver sulphide, but show the reaction process to be distinctly inhomogeneous, producing a variety of types of corroded particles.LAY DESCRIPTION: >Here, we use analytical electron microscopy to track the corrosion of silver nanoparticles and present chemical maps of the corrosion products. We show clear spectroscopic differences between metallic and corroded silver using the M4,5 electron energy loss spectral feature, which is not commonly studied. Our study shows that corrosion is due to interactions with sulphur in the atmosphere; and the corrosion is not uniform, but appears to develop from specific points on the surface of the nanoparticles. [ABSTRACT FROM AUTHOR]

In fisheries management, accurate stock assessment is pivotal to determine sustainable harvest levels or the scope of conservation measures. When assessment is decentralized and methods differ regionally, adopted approaches must be subjected to rigorous quality-checking, as biased assessments may mislead management decisions. To enable recovery of the critically endangered European eel, EU countries must fulfill a biomass target of potential spawner ("silver eel") escapement, while local eel stock assessment approaches vary widely. We summarize local approaches and results of ground-truthing studies based on direct silver eel monitoring, to evaluate the accuracy of eel stock assessments in retrospect and identify bias sources. A substantial fraction of eel habitat is currently unassessed or assessed by unvalidated approaches. Across assessment models for which validation exists, demographic models frequently overestimated actual escapement, while misestimations of extrapolation ("spatial") models were more balanced, slightly underestimating escapement. Stock size overestimation may lead to overexploitation or insufficient conservation measures, increasing the risk of stock collapse or slow recovery in coordinated frameworks. Underestimations may imply inefficient allocation of conservation efforts or negatively affect socioeconomy. Our work highlights the risks of regionalizing assessment responsibilities along with management decisions, calling for a common assessment toolbox and centralized quality-checking routines for eel. [ABSTRACT FROM AUTHOR]

The use of Pop‐up Satellite Archival Tags (PSATs) has provided considerable new information about the behaviour of migrating (silver) eels (Anguilla spp.) at sea, with 9 of 19 recognised species or subspecies tagged to date. However, such studies often reported premature tag detachment and relatively high rates of predation. Since 2000, several PSAT‐tagged New Zealand longfin eels, Anguilla dieffenbachii, were released to understand migratory behaviour and location of potential spawning grounds. Of 20 PSAT‐tagged eels released in 2019, all tags detached prematurely, but 7 (58%) were likely eaten or injured by predators 1–81 days after release. Two eels were probably eaten by sperm whales, whereas other tagged eels were likely eaten by lamniform and non‐lamniform sharks, and southern bluefin tuna. Because of the high rate of predation, we recommend that future releases should be from smaller catchments or offshore. [ABSTRACT FROM AUTHOR]

Objective: Visible implant elastomer (VIE) tags are commonly used as a cost‐effective tool for marking small fish, making them valuable in mark–recapture studies. It is crucial to quantify the impact of tagging procedures on fish survival to address inferential bias in mark–recapture studies. We assessed marking‐related mortality and growth in American Eel Anguilla rostrata elvers in a 40‐day laboratory experiment, following VIE tag application. Methods: There were 500 elvers (80–149 mm) that were divided into four treatment groups and one control group. Treatment groups were tagged with two tags in three body locations (anterior, central, posterior on left bilateral side) or with two tags in all three locations, while the control group remained untagged. Eels were retained in experimental tanks, and mortality rates were compared. Result: The VIE tagging did not significantly affect survival, which was 90.9% across all treatment groups and 92% for the untagged control group; nor did it affect growth. Conclusion: The application of VIE tags on various body parts should be a safe and effective method for marking American Eel elvers. Impact statementThe effect of visible implant elastomer tags on juvenile eel survival has only been assessed for European Eel, and tagging was restricted to tail fins. By testing novel tag locations on American Eel elvers, we demonstrated that this species can be tagged multiple times with visible implant elastomer tags without affecting short‐term survival and growth. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the impacts of wild and breeding juvenile rice field eel under conditions of ammonia and heat stress. The growth performance (FBW, WGR, SGR, and FCR) of 360 wild (24.22 ± 0.30 g) and 360 breeding (24.16 ± 0.27 g) strains was significantly hindered by ammonia and heat stress. The inhibitory effects were more obvious when the two stresses were combined. The growth performance and survival rates of the breeding strains outperformed that of the wild strains under identical stress conditions, this was explained by the expression of the growth-related gene (gh). They have increased the enzyme activity (CAT and GSH-Px) and expression of immune-related genes (cat, gpx3, and hsp90a) in response to oxidative stress. However, the results of certain indicator enzymes indicate the presence of oxidative damage in their tissues. The presence of an inflammatory response in the tissues was suggested by the up-regulation of genes associated with pro-inflammatory cytokines (il-1b and il-8) and the downregulation of genes related to anti-inflammatory cytokines (il-10). Additionally, the presence of tissue damage was shown by the up-regulation of genes connected to apoptosis (cas2, cas8, and cas9) and the down-regulation of genes connected to tight junctions (zo-1). Nevertheless, it is noteworthy that breeding strains exhibited superior adaptability to ammonia and heat stress in comparison to wild strains. [ABSTRACT FROM AUTHOR]

In rearing systems for the Japanese eel Anguilla japonica, although it is assumed that microorganisms influence larval survival and mortality, particularly during the early stages of growth, the effects of bacterial communities on larval survival have yet to be sufficiently determined. In this study, we compared the bacterial communities associated with larval survival at three stages of eel growth. To artificially alter bacterial communities and assess larval survival, eel larvae were treated with 11 types of antibiotic, and larval survival and bacterial characteristics were compared between the antibiotic-treated and antibiotic-free control groups. Throughout the three growth stages, eels treated with four antibiotics (polymyxin B, tetracycline, novobiocin, and erythromycin) had survival rates higher than those in the control groups. The bacterial communities of surviving larvae in the control and antibiotic groups and dead larvae in the control groups were subsequently analyzed using 16S rRNA gene amplicon sequencing. PERMANOVA analysis indicated that these three larval groups were characterized by significantly different bacterial communities. We identified 14 biomarker amplicon sequence variants (ASVs) of bacterial genera such as Oceanobacter, Alcanivorax, Marinobacter, Roseibium, and Sneathiella that were enriched in surviving larvae in the antibiotic treatment groups. In contrast, all four biomarker ASVs enriched in dead larvae of the control groups were from bacteria in the genus Vibrio. Moreover, 52 bacterial strains corresponding to nine biomarkers were isolated using a culture method. To the best of our knowledge, this is the first study to evaluate the bacterial communities associated with the survival and mortality of larvae in during the early stages of Japanese eel growth and to isolate biomarker bacterial strains. These findings will provide valuable insights for enhancing larval survival in the eel larval rearing systems from a microbiological perspective. [ABSTRACT FROM AUTHOR]

This study describes Lipogenys hyalinumvelum, a new species of the genus Lipogenys found on the Portuguese coast on the northeastern Atlantic during a crustacean survey. Information on the classification history and known distribution of the genus Lipogenys is provided. Dichotomous keys to the genera of Notacanthidae and the species of Lipogenys, based on morphology, are provided. The specimens were analysed using both morphological and molecular methods, including DNA sequencing of the COI and 16S genes. The distinct genetic characteristics support the recognition of the present specimens as a new species. The hyaline color of the flap at the posterior edge of the operculum is a characteristic that differentiates L. hyalinumvelum from Lipogenys gillii and provides the etymology of the species name. [ABSTRACT FROM AUTHOR]

This study aimed to produce single-chain recombinant Anguillid eel follicle-stimulating hormone (rec-eel FSH) analogs with high activity in Cricetulus griseus ovary DG44 (CHO DG44) cells. We recently reported that an O-linked glycosylated carboxyl-terminal peptide (CTP) of the equine chorionic gonadotropin (eCG) β-subunit contributes to high activity and time-dependent secretion in mammalian cells. We constructed a mutant (FSH-M), in which a linker including the eCG β-subunit CTP region (amino acids 115–149) was inserted between the β-subunit and α-subunit of wild-type single-chain eel FSH (FSH-wt). Plasmids containing eel FSH-wt and eel FSH-M were transfected into CHO DG44 cells, and single cells expressing each protein were isolated from 10 and 7 clones. Secretion increased gradually during the cultivation period and peaked at 4000–5000 ng/mL on day 9. The molecular weight of eel FSH-wt was 34–40 kDa, whereas that of eel FSH-M increased substantially, with two bands at 39–46 kDa. Treatment with PNGase F to remove the N glycosylation sites decreased the molecular weight remarkably to approximately 8 kDa. The EC50 value and maximal responsiveness of eel FSH-M were approximately 1.23- and 1.06-fold higher than those of eel FSH-wt, indicating that the mutant showed slightly higher biological activity. Phosphorylated extracellular-regulated kinase (pERK1/2) activation exhibited a sharp peak at 5 min, followed by a rapid decline. These findings indicate that the new rec-eel FSH molecule with the eCG β-subunit CTP linker shows potent activity and could be produced in massive quantities using the stable CHO DG44 cell system. [ABSTRACT FROM AUTHOR]

Context. The Indo-Pacific eel (Anguilla marmorata) is a widely distributed and commercially valuable species across ecological regions worldwide. Overfishing and habitat loss are leaving the Indo-Pacific eel in a risky situation and raising a high demand for conservation. Previous research has found relationships between the Indo-Pacific eel's migration patterns and environmental factors. However, there is still a need to advance the discovery of its spatial distribution by using diverse environmental and ecological datasets and modelling its growth in terms of different environmental characterizations. Aims & Methods. Here, we compared machine learning (ML) CatBoost (CB) and the multivariate linear model to investigate the relationship between spatial distribution, Indo-Pacific eel development stages, and environmental factors in central Vietnam. Key results. Our results show that CB detected the Indo-Pacific eel at high accuracy (Overall Accuracy (OA) = 0.9, F1 = 0.88, AUC = 0.97) and estimated the total length at different confidence levels (R2 ranging from 0.51 to 0.70), demonstrating superior performance to the multivariate linear model. Conclusions & implications. This study highlights the potential use of ML models in species distribution mapping and modelling growth patterns to support conservation efforts of Indo-Pacific eels in their natural habitats. [ABSTRACT FROM AUTHOR]

This document is a compilation of research articles that focus on the gut microbiota of fish. The articles cover a range of topics, including the impact of sampling season and catching site on gut microbiota composition, the effects of diet on the microbiota and health of fish, the role of gut microbiota in fish disease and immunity, and the interactions between the gut microbiome and the aquatic environment in fisheries and aquaculture. These articles provide valuable insights into the diversity and functions of fish gut microbiota and its implications for fish health and aquaculture practices. [Extracted from the article]

Electric eel is an excellent example to harness ion-concentration gradients for sustainable power generation. However, current strategies to create electric-eel-inspired power sources commonly involve manual stacking of multiple salinity-gradient power source units, resulting in low efficiency, unstable contact, and poor flexibility. Here we propose a consecutive multimaterial printing strategy to efficiently fabricate biomimetic ionic hydrogel power sources with a maximum stretchability of 137%. The consecutively-printed ionic hydrogel power source filaments showed seamless bonding interface and can maintain stable voltage outputs for 1000 stretching cycles at 100% strain. With arrayed multi-channel printhead, power sources with a maximum voltage of 208 V can be automatically printed and assembled in parallel within 30 min. The as-printed flexible power source filaments can be woven into a wristband to power a digital wristwatch. The presented strategy provides a tool to efficiently produce electric-eel-inspired ionic hydrogel power sources with great stretchability for various flexible power source applications. Electric eels are an excellent example of harnessing ion-concentration gradient for power generation. Here, authors demonstrate an automatic and high-throughput consecutive multi-material printing strategy to fabricate electric-eel-inspired ionic hydrogel power sources with high stretchability. [ABSTRACT FROM AUTHOR]

Anguillid eel populations are under threat globally. A particularly vulnerable life‐cycle stage is the migration of mature adult eels downstream from freshwater habitats through estuaries into the sea to spawn. This study investigated the factors associated with downstream migration of the short‐finned eel Anguilla australis (Richardson 1841) from a coastal wetland (Lake Condah) in south‐east Australia, using acoustic telemetry. Migration was associated with time of the year, higher water level and river flows, decreasing water temperature, and darker moon phases. Larger individuals and those in better condition were more likely to migrate from the wetland. Downstream migration peaked in spring, in contrast to the typical autumn migration period for other temperate anguillids. Variable responses, in comparison to other studies, highlight how migration cues may not be universal. In south‐east Australia, short‐finned eels may have evolved to migrate in multiple phases by first migrating to the estuary during typical seasonal spring flow pulses (e.g., to avoid being stranded in upland reaches during dry summer periods) and then migrating into the ocean in autumn. More research is needed to unravel these processes and causes, especially considering that the relationship between migration and hydrology may be complex and confounded (e.g., by human‐induced disruptions to migratory pathways). [ABSTRACT FROM AUTHOR]

The present paper is the first document on heavy metal levels in the European eel (Anguilla anguilla) collected from the Gediz Delta in the Eastern Aegean (Türkiye). In this study, concentrations of Cd, Cu, Zn and Pb were determined in the liver, gills, and muscle tissues of A. anguilla eels. Sixty dead eels were obtained between June 2015 and January 2016, and their total size and weight were measured. Heavy metal accumulation levels in edible muscle tissue of the eels were compared with national and international standards, and Estimated Weekly Intake (EWI), Target Hazard Quotient (THQ), and Total Target Hazard Quotient (Σ THQ) were calculated. It was determined that metal concentration levels in A. anguilla follow the sequence of Zn > Cu > Pb > Cd. Zn has the highest concentration in all sampling periods and in all tissue types. It was found that Σ THQ was below 1 and amounted to 0.41. This result shows that there is no carcinogenic risk associated with the consumption of A. anguilla in adults. [ABSTRACT FROM AUTHOR]

Dysomma anguillare is a demersal eel widespread distributing in tropical waters of the Indo-West Pacific and Atlantic. As an important component of the coastal fishery and marine ecosystem, the lack of genomic information for this species severely restricts the progress of relevant researches. In this study, the abecedarian genome-wide characteristics and phylogenetic relationships analyses were carried out based on next-generation sequencing (NGS) platform. The revised genome size was approximately 1 310 Mb, with the largest scaffold length reaching 23 878 bp through K-mer (K = 17) method. The heterozygosity, repetitive rate and average GC content were about 0.94%, 51.93% and 42.23%, respectively. A total of 1 160 104 microsatellite motifs were identified from the de novo assembled genome of D. anguillare, in which dinucleotide repeats accounted for the largest proportion (592 234, 51.05%), the highest occurrence frequency (14.58%) as well as the largest relative abundance (379.27/Mb). The high-polymorphic and moderate-polymorphic loci composed around 73% of the total single sequence repeats (SSRs), showing a latent capacity for subsequent population genetic structure and genetic diversity appraisal researches. Another byproduct of whole-genome sequencing, the double-stranded and circular mitogenome (16 690 bp) was assembled to investigate the evolutionary relationships of D. anguillare. The phylogenic tree constructed with maximum likelihood (ML) method showed that D. anguillare was closely related to Synaphobranchidae species, and the molecular systematic results further supported classical taxonomy status of D. anguillare. [ABSTRACT FROM AUTHOR]

In this study, the thickness of a thin film (tc) at a low primary electron energy of less than or equal to 10 keV was calculated using electron energy-loss spectroscopy. This method uses the ratio of the intensity of the transmitted background spectrum to the intensity of the transmission electrons with zero-loss energy (elastic) in the presence of an accurate average inelastic free path length (λ). The Monte Carlo model was used to simulate the interaction between the electron beam and the tested thin films. The total background of the transmitted electrons is considered to be the electron transmitting the film with an energy above 50 eV to eliminate the effect of the secondary electrons. The method was used at low primary electron energy to measure the thickness (t) of C, Si, Cr, Cu, Ag, and Au films below 12 nm. For the C and Si films, the accuracy of the thickness calculation increased as the energy of the primary electrons and thickness of the film increased. However, for heavy elements, the accuracy of the film thickness calculations increased as the primary electron energy increased and the film thickness decreased. High accuracy (with 2% uncertainty) in the measurement of C and Si thin films was observed at large thicknesses and 10 keV, where t λ ≈ 1 . However, in the case of heavy-element films, the highest accuracy (with an uncertainty below 8%) was found for thin thicknesses and 10 keV, where t λ ≤ 0.29 . The present results show that an accurate film thickness measurement can be obtained at primary electron energy equal to or less than 10 keV and a ratio of t λ ≤ 2 . This method demonstrates the potential of low-loss electron energy-loss spectroscopy in transmission electron microscopy as a fast and straightforward method for determining the thin-film thickness of the material under investigation at low primary electron energies. [ABSTRACT FROM AUTHOR]

This study examined the presence of two heavy metals (Cd and Pb) in the sediments and Asian swamp eels (Monopterus albus) in the downstream area of Cisadane River. The average concentrations of Cd and Pb in the sediments from all sampling locations were 0.594 ± 0.230 mg/kg and 34.677 ± 24.406 mg/kg, respectively. These concentrations were above the natural background concentration and the recommended value of interim sediment quality guidelines (ISQG), suggesting an enrichment process and potential ecological risk of studied metals to the ecosystem of Cisadane River. The increase in contamination within this region may be attributed to point sources such as landfill areas, as well as the industrial and agricultural land activities in surrounding area, and experienced an increasing level leading towards the estuary of Cisadane River. Meanwhile, the average concentrations of Cd and Pb in the eels from all sampling locations were 0.775 ± 0.528 μg/g and 28.940 ± 12.921 μg/g, respectively. This study also discovered that gill tissues contained higher levels of Cd and Pb than the digestive organ and flesh of Asian swamp eels. These concentrations were higher than Indonesian and international standards, suggesting a potential human health risk and therefore the needs of limitations in the consumption of the eels. Based on the human health risk assessment, the eels from the downstream of Cisadane River are still considered safe to be consumed as long as they comply with the specified maximum consumption limits. [ABSTRACT FROM AUTHOR]

Compound plant extracts (CPE) are beneficial for aquatic animals on growth performance and antioxidant capacity. A 56‐day experiment was conducted to investigate its positive effect on rice field eel. The fish were fed a commercial diet and supplementing CPE (mainly containing eucommia polysaccharides, reducing sugar) at 0, 0.8, 1.6, 2.4, and 3.2 g/kg. Results showed that dietary CPE significantly increased weight gain and specific growth rate (p < 0.05). Liver lipid content in 1.6 and 3.2 g/kg groups was significantly lower than in 0.8 and 2.4 g/kg groups (p < 0.05). Muscle lipid content in 0.8, 2.4, and 3.2 g/kg CPE groups was significantly lower than in control (p < 0.05). Meanwhile, intestinal digestive enzymatic activities in the 3.2 g/kg CPE group were the highest in comparison to all other groups (p < 0.05). Dietary CPE enhanced the antioxidant activities of serum and intestine (p < 0.05). Compared with the control, intestinal fold thickness in CPE groups was significantly increased (p < 0.05). Furthermore, dietary CPE reduced the degree of liver steatosis and the number of lipid droplet vacuoles. This study indicated that dietary CPE was beneficial to growth performance, antioxidant capacity, liver, and intestinal histology. Supplementation with 1.6–3.2 g/kg CPE is optimal for this eel species. [ABSTRACT FROM AUTHOR]

Anisakis can cause Anisakiasis in humans if raw or undercooked fish is consumed. Symptoms of infection may include vomiting, acute abdominal symptoms, or allergies. In this study, we collected 187 commercially available marine fish from the Yellow Sea, East China Sea, and South China Sea. Among them, 79 were found positive containing 520 Anisakis worms. The average prevalence rate was found 42% in this investigation. Ninety-two worms from different sea areas were selected and analyzed for identification, revealing the presence of five different species, which are Anisakis pegreffii, Hysterothylacium aduncum, Hysterothylacium zhoushanense, Hysterothylacium amoyense, and Hysterothylacium sp. In the meta-analysis, three databases: PubMed, CNKI, and BaiduXueshu were searched for surveys on the prevalence of Anisakis in Chinese waters from January 2000 to December 2023. A total of 26 studies were included in this analysis of which 25 publications were retrieved from different databases and one being the present study. The pooled prevalence of Anisakis was 45% among commercially available marine fish. Variances in the prevalence of Anisakis were noted among the four seas, with the highest rates in the East China Sea and the Bohai Sea, reaching 53% [0.38; 0.68] and 49% [0.36; 0.62], respectively. The Prevalence of Anisakis infection was significantly higher in astern parts such as Liaoning, Shanghai, and Zhejiang. Analysis of the host fish subgroups revealed that the orders of Anguilliformes, Scombriformes, and Gadiformes had high rates of infection. These findings suggest a significant prevalence of Anisakis, posing an increasing risk of infection for individuals. This study provides impactful information for implementing preventative measures against Anisakis. [ABSTRACT FROM AUTHOR]

In a laboratory experiment, we quantified microhabitat use of small yellow-phase American eels (Anguilla rostrata, n = 130, 224–338 mm TL) conditional on five benthic substrate types common to rivers within their geographic range. During nine, 4-day trials replicated with three aquaria, American eels were given a choice to burrow into five equally available benthic substrates: cobble (90–256 mm), gravel (4–16 mm), sand (0.125–1 mm), silt/clay (< 0.0625 mm), and leaf pack. Five American eels were used per aquarium for each trial, and individuals were used one time only. All eels were injected with PIT tags prior to the study, which allowed for determination of lengths and otolith-based ages of each individual following each trial. Leaf pack was selected with a significantly higher probability than other substrates (63 of 130 individuals). However, other substrates were also used (cobble, 21 of 130; silt/clay, 18 of 130; gravel, 16 of 130; and sand, 12 of 130). Length and age covariates were not associated with substrate selection. Selection of leaf pack habitat supports the importance of forested riparian zones and terrestrial organic material to yellow-phase American eels in riverine systems. [ABSTRACT FROM AUTHOR]

Two new cutthroat eel species are described from Vietnam. Dysomma intermediumsp. nov. has a relatively long trunk, being about half of head length and anal‐fin origin more than twice pectoral‐fin length behind the pectoral‐fin tip; pectoral fin well developed; dorsal‐fin origin over or slightly in front of base of pectoral fin; two intermaxillary teeth; four or five compound teeth on ethmovomer; single row of seven or eight teeth on lower jaw; total lateral‐line pores 70–76; and 21 pre‐anal and 118–124 total vertebrae. Dysommina brevissp. nov. differs from congeners by having a trunk shorter than head length, its length 11.1%–11.8% TL; a short pre‐anal length 24.6%–25.6% TL, eye diameter 11.8%–12.3% head length; three large and one or two small teeth on ethmovomer; and fewer teeth on the upper and lower jaws. In addition, a specimen representing the first record of Dysommina orientalis in Vietnamese water is documented. [ABSTRACT FROM AUTHOR]

It is well established that non‐native fish can become invasive and outcompete and displace native fish populations. However, little research has explored the potential benefits that non‐native fish may provide to native fish populations. To address this information gap, we examined how the availability of non‐native perch (Perca fluviatilis) as prey could benefit populations of the endemic longfin eel (Anguilla dieffenbachii) and the native shortfin eel (Anguilla australis) in two neighbouring open‐water wetlands in the Rakatu‐Redcliff wetland complex in the Southland region of Aotearoa New Zealand. The Redcliff wetland fish community comprised native fish only, while the Rakatu wetland comprised native fish and non‐native perch. We compared the size, condition, population density, population size structure and diet of eels in these wetlands. While eels were not necessarily larger or better conditioned in Rakatu wetland, their population density was three times higher than the Redcliff wetland, with young‐of‐the‐year perch comprising ca. 40% of their diet. Furthermore, juvenile eel density was four times lower in Redcliff wetland, suggesting that cannibalism may occur at this site to support the existing eel population. Based on our findings, we suggest that freshwater managers consider the predator–prey dynamics of both native and non‐native fish before removing non‐native species, to avoid unintended negative consequences for native predatory fish species. [ABSTRACT FROM AUTHOR]

Eel (Anguilla sp.) is an important freshwater‐cultured species with high economic value in China. Anguillid herpesvirus 1 (AngHV‐1) has been proven to be the pathogen of "mucus sloughing and haemorrhagic septicaemia disease" in eels, resulting in significant mortality and substantial losses to the eel industry. Current diagnostic methods for detecting AngHV‐1 are limited to laboratory‐based tests, for example, conventional end‐point PCR and qPCR. Therefore, there is an urgent need to develop an accurate, rapid, and simple detection method for on‐site diagnosis of AngHV‐1. In this study, we developed a recombinase‐aided amplification combined lateral flow dipstick (RAA‐LFD) assay for the detection of AngHV‐1. The RAA‐LFD assay can be performed within a temperature range of 18–45°C, with a reaction time of just 10 min for amplification. Importantly, the established RAA‐LFD assay exhibited no reactivity with other common aquatic viral pathogens, indicating its high specificity. The limit of detection for this method is 102 copies of AngHV‐1, which is more sensitive than the established conventional end‐point PCR method similarly targeting ORF95. Clinical detection of the diseased samples demonstrated that the accuracy of RAA‐LFD was significantly higher than that of the conventional end‐point PCR. In conclusion, the developed RAA‐LFD assay has proven to be a convenient, rapid, sensitive, and reliable tool for on‐site diagnosis of AngHV‐1. This advancement will be invaluable for the prevention and control of AngHV‐1 in the eel farming industry. [ABSTRACT FROM AUTHOR]

A new species of deep-water snake eel, Ophichthus nigroventralis sp. nov. is described based on five specimens collected from deep-sea trawl landings at Kalamukku fish landing Centre, off Kochi, Arabian Sea, southwest coast of India. The new species is distinguished from its deep-water congeners by the following combination of characters viz., origin of dorsal fin slightly behind pectoral-fin tip; pectoral fin lanceolate, slightly shorter than upper jaw in length; head length 6.7–7.5 in TL; supraorbital (SO) pores 1 + 3; intermaxillary with a rosette of 10 pointed teeth; vomer with 6 anterior teeth in irregular biserial rows, 11 posterior teeth in a uniserial row; maxillary with 24–25 uniserial teeth; abdomen with numerous minute black pigmentation extends up to tail; pectoral fin whitish with brown base; vertebral count (pre-dorsal/pre-anal/total): 17–18/53–54/131–134. The genetic analysis reveals that the species Ophichthus urolophus is the closest congener for the new species with a genetic divergence of 4.2%. [ABSTRACT FROM AUTHOR]

The composition and microstructure of phyllosilicates are prone to transformation due to their great sensitivity to surrounding physicochemical changes. Berthierine [(R2+,R3+,□)6(Si,Al)4O10(OH)8] (□ represents octahedral vacancy) is a typical ferromagnesian phyllosilicate that commonly occurs in ferruginous rocks of shallow-marine habitats and has been used as an indicator of local depositional and/or hydrothermal activity in marine environments. However, little is known about the formation and mineralogy of non-marine berthierine, particularly in volcanic systems. Using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), we have identified a berthierine twin structure within weakly altered biotite in a rhyolite from Long Valley, California, U.S.A. The presence of nanoscale Fe-rich layers in the host biotite is revealed by energy-dispersive spectroscopy and electron energy loss spectroscopy (EELS). The HAADF-STEM pictures with atomic resolution demonstrate that the Fe-rich layers are composed of twinning berthierine layers rather than a single chlorite layer. The transformation of biotite to berthierine requires the dissolution of a tetrahedral (T) layer and the introduction of a new TO (O represents octahedral sheet) structure into the biotite stacking sequence, resulting in substituting one biotite layer (i.e., TOT) with two twinning berthierine layers (i.e., TO-OT). Observations based on morphology indicate that the transformation began at biotite defect locations (such as screw dislocation, edge dislocation, and microcleavage fracture), concurrent with the rearrangement of metal cations. During the fluid alteration of biotite, berthierine was produced via an interface-coupled dissolution-reprecipitation process. The EELS analyses further demonstrate that the Fe-rich biotite promotes the production of berthierine as the principal alteration product in low-temperature environments. Additionally, this study suggests that the combination of HAADF-STEM and EELS is effective for identifying nanominerals and elucidating their formation and alteration mechanisms. [ABSTRACT FROM AUTHOR]

Asian swamp eels (Monopterus albus/javanensis) were first reported as introduced to Florida waterbodies in 1997 near Tampa and Miami; a third population was recorded by 1999 in Homestead. Initial assessments, published soon after swamp eels in southern Florida were first recorded in wetlands beyond canals and ponds (in 2007), concluded there was little threat to Florida’s aquatic ecosystems. Long-term data now suggest they precipitated population crashes of crayfishes and small fishes in the eastern Everglades. We used records from continuous long-term monitoring programs, sporadic monitoring studies, and online databases to reconstruct swamp eel presence across Florida. Monitoring studies provided wetland hydrologic variables to assess limits for swamp eels. From 1997–2007, populations in southern Florida remained restricted to canals; initial spread from 2007–2017 across southern Everglades National Park proceeded slowly and the two populations covered ~1500 km² of southern Florida. From 2017–2022, the rate of spread increased as they spread west and north (~5800 km² range). Through 2014, the Tampa population occurred only along southern/eastern Tampa Bay (~60 km²) but has since spread south along the Gulf Coast, east into central Florida, and south along the Lake Wales Ridge (~11,000 km²). We found evidence of two potentially new introductions, in Palm Beach County and Orlando. There was no clear evidence of limitation of wetland drying on swamp eel occurrence in the Everglades; they were captured in marshes that dried for 1–5 months during the previous dry season, but short-hydroperiod wetlands may have slowed spread. In the Everglades, evidence suggests swamp eels may have been inadvertently spread into marshes from canals used to deliver water for flood control and hydrologic restoration. Swamp eels are currently spreading unchecked across Florida, and there should be great concern about continued spread in this region and their establishment and spread elsewhere. [ABSTRACT FROM AUTHOR]

Nanoporous metals are a class of nanostructured materials finding extensive applications in multiple fields thanks to their unique properties attributed to their high surface area and interconnected nanoscale ligaments. They can be prepared following different strategies, but the deposition of an arbitrary pure porous metal is still challenging. Recently, a dry synthesis of nanoporous films based on the plasma treatment of metal thin layers deposited by physical vapour deposition has been demonstrated, as a general route to form pure nanoporous films from a large set of metals. An interesting aspect related to this approach is the possibility to apply the same methodology to deposit the porous films as a multilayer. In this way, it is possible to explore the properties of different porous metals in close contact. As demonstrated in this paper, interesting plasmonic properties emerge in a nanoporous Au–Ag bi-layer. The versatility of the method coupled with the possibility to include many different metals, provides an opportunity to tailor their optical resonances and to exploit the chemical and mechanical properties of components, which is of great interest to applications ranging from sensing, to photochemistry and photocatalysis.

The population decline of American Eels (Anguilla rostrata) in North America represents multiple crises: ecosystem destruction, industrial impact, forced relocation, cultural disenfranchisement, water degradation, and biodiversity loss. Once a key component of Indigenous societies, trade routes, economies, and ceremonial cycles, today Eels experience migration barriers and habitat degradation stemming from waterway abuse and land use alteration. The development of agricultural and industrial social norms has led to dramatic reductions in Eel populations across North America. Fishery agencies familiar with Eel life cycles often list species as depleted, and disappearance of Eels is well-accepted in all sectors. Related species of Anguillid Eels are in decline globally. Yet, in some areas, American Eels continue to migrate, grow, and even thrive. This article proposes Eel continuity as powerful survivorship in troubled times, a counter-narrative to overwhelming stories of environmental pessimism. Although Eels are often discredited, reviled, and disrespected by Americans and Canadians alike, their contributions to marine and aquatic zones are underestimated and poorly understood. This article employs a reflexive method of dialogue and commentary from two Eel advocates with interdisciplinary training and backgrounds, who envision relational, wisdom-based practices that meaningfully integrate Indigenous, community, academic, and other forms of knowledge about Eels and about water. [ABSTRACT FROM AUTHOR]

A new species of the ophichthid eel of the family Ophichthidae is described based on five specimens collected from the Mudasalodai fish landing center, off Cuddalore coast, southeast coast of India, Bay of Bengal. Ophichthus naevius sp. nov. is distinguished from its congeners by having a unique color pattern: dorsal body with numerous dense dark spots or patches, ventral body pale yellowish green, dorsal‐fin origin just before pectoral‐fin tip, vertebral formula: 12–14/52–53/134–138, and teeth on jaw uniserial and pointed. The study also reports the range extension and molecular evidence of Ophichthus chilkensis from South India. Molecular analyses were performed for both species, and their phylogenetic relationship suggests that the new species exhibits 10.2% genetic divergence with its congener Ophichthus sangjuensis, followed by Ophichthus brevicaudatus (10.4%), and Ophichthus sp. 1 (11.8%) also forms the closest clade in both Bayesian inference and maximum likelihood (ML) tree. Similarly, according to the topology of the ML tree, the species O. chilkensis forms a clade with Ophichthus sp. 5, Ophichthus remiger, Ophichthus frontalis, Ophichthus sp. 6, and Ophichthus rex, suggesting that it would be the genetically closest congener. [ABSTRACT FROM AUTHOR]

Environmental stories, apart from benefiting from the positive aspects associated with narratives such as facilitating learning and connecting with emotions, allow content to be transmitted and foster values and attitudes of respect towards the natural environment. In order to show the life cycle of the eel and talk about the main problems that threaten river ecosystems, the design and implementation of an activity consisting of telling an environmental story next to the Besós River is described. Six sessions were held in which the story was explained in different ways: in the first variant it was explained using only the illustrations of the story, in the second the observation of live eels was added, and in the third images were distributed among the participants that should be used at different times of the story. The effect of each variant on attention and on the degree of participation of the audience from Primary education was evaluated. For the second variant it was also possible to analyze this effect on Preschool children and Secondary education participants. The results show that the age group that maintained higher levels of attention and participation were primary school children. Contact with live eels was associated with a greater understanding of their characteristics and the use of interactive images markedly increased participation. Based on experience, ideas are given of what dynamics can contribute to making the environmental story more effective. [ABSTRACT FROM AUTHOR]

Defects in semiconductor materials significantly impact their inherent properties, making the evaluation of local defects and their energy levels crucial for controlling device performance. With advancements in monochromators, electron energy loss spectroscopy (EELS) combined with scanning transmission electron microscopy (STEM) has emerged as a promising approach for assessing crystal and band structures of semiconductor materials at the nanoscale. However, there is limited experimental research investigating the relationship between actual defective structures in local regions and mid-gap states. In this study, we conducted high-energy resolution EELS (HR-EELS) measurements with an energy resolution of less than 100 meV to detect the mid-gap states of GaN. Various defects were intentionally induced through Ga-ion implantation, and the defect concentration varied in the depth direction. To understand the origin of the mid-gap states, we performed 4D-STEM analysis and atomic-resolution STEM observations. The HR-EELS measurements provided insights into the depth-dependent valence-loss spectra, revealing that the intensities corresponding to mid-gap states gradually increased toward the surface, whereas the slope at the onsets corresponding to interband transition decreased. Furthermore, local structural analysis unveiled the presence of structural disorder and defective structures, indicating the existence of extended defects such as stacking faults and domain boundaries. Observably, these defective structures were abundant near the surface and less pronounced in deeper regions. Based on these experimental findings, we concluded that the variations in valence-loss spectra can be utilized to qualitatively evaluate the crystal imperfections at the nanoscale. [ABSTRACT FROM AUTHOR]

American Eel (Anguilla rostrata) population characteristics and distribution remain drastically understudied in the Caribbean region. We conducted the first island‐wide study to evaluate the distribution of density, length, and sex in relation to distance from the mouth of 23 stream reaches in five rivers in Puerto Rico. We found 287 American Eel at a mean density of 156.7 fish/ha. Sex ratios favored females (52:3) but most of the eel sampled were undifferentiated or undetermined. Generalized linear modeling indicated that upstream habitats with low eel density were optimal environments for production of large and female eel. Our findings indicate that Puerto Rico could significantly contribute to the spawning population and strengthen knowledge of American Eel in the Caribbean. Our findings could be used to guide local and range‐wide conservation efforts to ensure stream connectivity and access to optimal upstream habitat for survival of the population. [ABSTRACT FROM AUTHOR]

Zoogeography and ecology of 3 widespread anguillid species (Anguilla marmorata, A. megastoma, A. obscura) in the western South Pacific are reviewed in relation to the freshwater habitats and communities of the many islands of Oceania (island geological ages, from > 40 Ma to < 1 Ma. Anguillid eels show habitat segregation among A. obscura (lower reaches-brackish water), A. marmorata (habitat generalist) and A. megastoma (upper reaches), where they feed on amphidromous snails, Macrobrachium shrimp and gobies, and freshwater insect larvae. Some information has been obtained about possible anguillid spawning areas in the region near New Caledonia and Fiji from larval surveys and satellite transmitting tagging studies. Larval drift simulations suggest separate spawning areas occur in the eastern region of French Polynesia. Little is known about how geography might influence the spawning ecologies and population structures of South Pacific anguillid eels that live on the many tropical islands that are spread across a wide region of ocean in the western Indo-Pacific. [ABSTRACT FROM AUTHOR]

The chemical composition of muscles from Japanese eels cultured in hot-spring water was determined and compared with that of eels cultured in well water. The proximate composition did not differ significantly between the culture conditions, but the hepatosomatic indices of the hot-spring water eels were significantly higher than those of the well water eels. Amino acid levels were higher in the hot-spring water eels, and the carnosine content of the hot-spring eels was lower than that of the controls. Our results suggest that hot-spring water is a promising medium for eel culture, and its use may bring energy cost savings. [ABSTRACT FROM AUTHOR]

Two post-metamorphic adult females of the sphyriid copepod Lophoura cornuta (C. B. Wilson, 1919) were collected from Kaup's arrowtooth eel Synaphobranchus kaupii Johnson, 1862 (Anguilliformes: Synaphobranchidae) at two deep-sea sites in the western North Pacific off the south coast of Hokkaido, northern Japan. This paper reports on the morphology of L. cornuta based on the adult female specimens collected as the second record of the species from Japan. One of the collection sites is near the type locality of the parasite, and the infected fish were captured at depths of 550 and 620 m on the continental slope. Although the type host of L. cornuta was reported as "Synaphobranchus affinis Günther, 1877", this fish may be S. kaupii because the latter species predominates among synaphobranchid eels in the western North Pacific off Hokkaido. An identification key to the four nominal species of the genus Lophoura Klliker in Gegenbaur, Klliker, and Müller, 1853 reported from Japan is also provided. [ABSTRACT FROM AUTHOR]

This work provides a new record that extends the western limit of the geographic distribution of Synbranchus marmoratus towards the Central Andes of Argentina, in the Department of Calingasta, Province of San Juan. In addition, an update of the geographical distribution map of the species in the country is provided based on this record and a complete literature review. We collected a specimen of this species on 12 September 2016 during an ichthyofaunal survey of high Andean rivers. This record corresponds to the westernmost distribution in the country. This finding is interesting since this species is considered an indicator of the ichthyofauna of the Biogeographic Provinces Greats Rivers and Pampean, while the ichthyofauna of the study area of this new record belongs to the Andean Cuyo Province. [ABSTRACT FROM AUTHOR]

Introduction and Objectives: To date, there are no known supplement products made from a combination of eel and tempe. The development of concentrate from eels in combination with tempe (ETF) aims to create supplements containing the essential amino acid L-arginine, which has many proven health benefits. Methods: The community empowerment was held from June to July 2023 at Cangkringan, Sleman, Yogyakarta. The main agendas consisted of ETF training production and the cooking creation of ETF-based food. Aside from that, there were several secondary agendas such as food halal socialization, accessories design training, patchwork utilization training, computer and Microsoft Office training, English language education, public speaking class, Al-Qur’an and miscellaneous education for children, community service, mutual cinema, and competitions for the community. Results: The community development program in the production of high-amino acid concentrated ETF flour has succeeded in achieving the three main objectives of the program, namely functional product innovation, empowerment of micro, small, and medium enterprises and local communities, as well as increasing demand for local commodities, showing the importance of collaboration between the government, community, and private sector in supporting the development of local products that are economically and health-beneficial and can be used as examples to share similar initiatives in other areas. [ABSTRACT FROM AUTHOR]

The present work reports a comparative study on CuO and 3.0% Mn-doped CuO nanofibers (NFs) produced by the electrospinning method. State-of-the-art characterization techniques such as Electron Energy Loss Spectroscopy (EELS) and X-Ray photoelectron Spectroscopy (XPS) have been employed to determine the multivalent states and elucidate their electronic structure at the Cu-L3,2 (2p) edge. The CASTEP code has been used to model CuO (P1) and Mn-doped (C 2/c) with the GGA-PBE functional on the supercomputing system with the Xeon10 module (10 nuclei). Structural characterization was done by using a CM 200 Philips Transmission Electron Microscope (TEM) and the chemical state of surfaces with ESCALAB 250Xi XPS Thermoscientific TM. The NFs present an indirect energy bandgap, Eg = 2.03 eV and 2.85 eV, respectively. The results show that the Cu-L3,2 edge presents degenerate states associated with Cu 2p - O and Cu 3d - O hybridization, indicated as Cu3+.