Search Results (2,610)

In recent years, the recording of fish with vertebral malformations has attracted growing interest worldwide, as these malformations may be associated with exposure to xenobiotics. This study aimed to determine the presence and concentrations of pesticide residues (organochlorines and organophosphates) in coastal fish in Nayarit, Mexico, and to assess their potential association with vertebral malformations. From November 2013 to September 2021, 32 fish, with visible malformations were conveniently collected, an equal number of healthy specimens per species was selected for comparative analysis. The fish exhibited vertebral malformations of the following types: kyphosis, lordosis, and scoliosis in 9, 8 and 6 species, respectively, while the total number of malformations was higher across the sampled organisms. Furthermore, pesticide residues were detected in both healthy and malformed fish using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The samples analyzed contained at least one pesticide, with the group of healthy fish showing greater diversity of organochlorine compounds. The most frequent of these were p,p’-DDE, followed by p,p’-DDT (41%), p,p’-DDD (25%), and endrin (25%). The species C. raredonae and A. seemanni exhibited the greatest number of pesticides. The pesticides observed in malformed fish samples were p,p’-DDE (100%), p,p’-DDD (97%), p,p’-DDT (97%), endrin (50%), and BHC delta (31%). Chlorpyrifos was present (56% and 100% in healthy and malformed fish), with the highest frequency observed in A. seemanni and B. panamensis. The highest concentrations were observed in the DDT group. An association was also observed between vertebral malformations and concentrations of p,p’-DDE and chlorpyrifos in the species C. raredonae and A. guatemalensis. Multivariate analysis revealed a clear separation between malformed and healthy fish based on contaminant profiles. Full article

Environmental DNA metabarcoding has proven to be a powerful tool for monitoring fish diversity, and has been widely used in both freshwater and marine ecosystems. Fish diversity is a critical indicator to assess ecosystem function and its health. In this study, we took 12 samples from four areas (Area 1 (LS1) is the edge of the seagrass field adjacent to oyster reefs; Area 3 (LS3) is the edge of the seagrass field adjacent to coral reefs; Area 2 (LS2) is situated between LS1 and LS3 where there is dense seagrass distribution around the sampling sites; and Area 4 (LS4) is located between LS1 and LS3; we sample in the places at least 4 m by 4 m on the beach where no seaweed is present, each with three replicates) from Li’an Bay to detect fish diversity across multi-habitat seagrass areas based on the environmental DNA metabarcoding. A total of 312 Amplicon Sequence Variants (ASVs) were detected from 12 samples, and 58 fish species were annotated, representing 21 orders, 32 families and 48 generas. In general, the mean of Simpson and Pielou’s evenness indices followed the pattern LS1 > LS4 > LS2 > LS3, while the mean of Shannon–Wiener Diversity Index is LS4 > LS1 > LS2 > LS3. A total of 35 functional entities were observed among the four areas, with functional redundancy (FR) values of 0.800, 0.657, 0.542, and 0.7 for LS1, LS2, LS3, and LS4, respectively. All FR values were below 1.5, suggesting low ecological niche overlap among species within each area. These findings provide fundamental insights into the ecological health and stability of seagrass beds in Li’an Bay and offer a scientific basis for future ecological restoration efforts. Full article

Instant noodle fortification with fish-derived proteins enhances nutritional value; however, the effects of catfish powder (CFP) combined with different drying methods and barrier packaging on prolonged storage stability remain unknown. This study incorporated 10% (w/w) CFP into wheat flour-based instant noodles processed by tray drying or deep-fat frying, yielding four treatments: control tray-dried (CD), control fried (CF), CFP tray-dried (TD), and CFP fried (TF). Samples were packed in metallized low-density polyethylene (M-LDPE) and evaluated every 15 days over 180 days. CFP fortification increased protein and mineral content, which remained stable throughout storage. CFP incorporation and frying elevated lipid oxidation, whereas tray drying improved oxidative stability. Drying methods influenced moisture attributes, product structure, rehydration behavior, and color; tray-dried noodles retained higher lightness and hardness, whereas fried noodles showed faster water uptake. Cooking performance remained largely stable, with gradual shifts noticed in CF and TF samples over time. Microbiological quality remained acceptable, with no pathogens detected. Multivariate analysis identified the drying method as the primary driver of quality differentiation, with storage time intensifying oxidation and color divergence. Overall, tray drying with M-LDPE packaging is recommended to optimize the nutritional and storage stability of CFP-fortified instant noodles. Full article

The sea turtle is an indicator organism used in marine conservation to identify the health status of ecosystems in various marine regions. In the past, researchers had to review an 8 h underwater video every day to monitor and count sea turtle appearances. However, since sea turtles often appear for only short periods, traditional approaches of manual searching and counting require significant labor and time to ensure accurate periods of their appearance. To address this issue, we adopted the You Only Look Once (YOLO) model for object detection, utilizing real underwater videos captured from three different areas in the Taiwan Keelung City Chaojing Bay Aquatic Plants and Animals Conservation Area for training and testing. To overcome limitations, such as underwater blur, sediment interference, obstructions from other fish, and distant targets that are challenging to identify, we applied data augmentation techniques, including scaling, rotation, and depth blur, with labeled data of different fish species to improve generalization capability. The experimental results of this study showed that this method achieves a 99.4% accuracy in sea turtle detection. After 60 days of deployment across the three areas, the model reduced search time by over 99%, significantly improving efficiency and reducing workload. Full article

Schizothorax wangchiachii, as a cold-water fish, is a predominant or common species in high-altitude areas with large population sizes. It is among the main edible economic fish species in the production area. We used genotype sequencing (GBS) technology to analyze the genetic diversity and population structure of 10 wild populations in the Jinsha River and Yalong River basins of the upper Yangtze River. A total of 724,858 single-nucleotide polymorphisms (SNPs) were detected in these 10 wild populations. The population genetic diversity was low; however, the degree of genetic differentiation was not significant. The populations from the Jinsha River and Yalong River could not be clustered separately on the basis of the SNPs. The Panzhihua (PZH) and Wudongde (WDD) populations from the Jinsha River exhibited gene flow with the Yajiang (YJ) population from the Yalong River, and a secondary pulse of gene flow subsequently connected the PZH and WDD populations to the upper-Jinsha population Suwalong (SWL). The demographic history of S. wangchiachii, reflected in its effective population size (N_e), has been influenced by the uplift of the Qinghai–Tibet Plateau (QTP). Furthermore, the identified SNPs are functionally associated with key cellular processes, environmental adaptation, and metabolism. These findings provide critical genomic insights that can inform conservation strategies and support the sustainable utilization of wild S. wangchiachii resources. Full article

In recirculating aquaculture systems, fish detection is an essential component for maintaining effective farming operations. The availability of high-quality fish datasets is limited because of the richness of fish species, and the annotation of large-scale data, which is used to train models, is often labor-intensive and time-consuming. The presence of different fish species across batches introduces further challenges for consistent detection performance. This work introduces a few-shot learning approach for fish detection, utilizing a customized dataset as novel classes and the Fish4Knowledge dataset for base classes, thereby establishing a framework that enhances adaptability in data-scarce scenarios. Within the model architecture, multi-scale feature extraction is enhanced through an attention mechanism, which is integrated as a dedicated module to strengthen representation learning, thus enhancing the model’s capability to differentiate visually similar fish species. Two distinct customized fish datasets are employed to evaluate the robustness of the proposed method. Experimental results show that the proposed model performs competitively against TFA, Meta-RCNN, and VFA. In the base-training phase, it achieves a mAP of 0.775, slightly surpassing VFA, while in the 1-shot, 5-shot, and 10-shot fine-tuning settings, it obtains mAP values of 0.152, 0.247, and 0.265, respectively. A similar trend is observed on a subset of black fish, with mAP scores of 0.169, 0.253, and 0.286 in the corresponding few-shot settings. These results indicate that the proposed approach can maintain relatively stable detection accuracy and adaptability across different fish batches, offering a practical solution for fish detection tasks in aquaculture when annotated data is scarce. To further demonstrate the efficacy and practical utility of the proposed methodology, a case study in fish farming confirms that the enhanced model achieves consistent and precise detection across diverse fish species, even when trained with limited annotated data. Full article

Quinolone antibiotics (QNs) are widely used in animal production and may pose potential health risks through dietary exposure. A total of 1612 animal-derived food samples covering 10 food categories were collected in Guangzhou, China, from 2016 to 2023. Residues of six QNs were determined using ultra-performance liquid chromatography coupled with tandem mass spectrometry. Dietary exposure among different age groups was assessed using a probabilistic approach based on local food consumption data, and non-carcinogenic health risks were characterized using hazard quotient (HQ) and hazard index (HI) methods. QN residues were detected in 7.75% of samples, with an exceedance rate of 2.23%. Aquatic products, particularly fish and crustaceans, exhibited the highest detection frequencies and contributed most to overall dietary exposure. Enrofloxacin (ENR) was the most frequently detected compound, while sporadic samples showed extremely high residue concentrations (1003 unit/g in eggs). Children aged 3–6 years had the highest HI (mean is 1.94 × 10⁻²). All HQ and HI values were below 1, indicating low non-carcinogenic health risks under current exposure scenarios. Although dietary exposure to QNs among Guangzhou residents is unlikely to pose appreciable non-carcinogenic health risks, elevated exposure in children and sporadic high-residue events highlight the need for continued risk-based monitoring and targeted food safety management. Full article

The Esox lucius is a high-quality fish species endemic to northern Xinjiang, having developed into a regional specialty industry with significant market value. However, during storage, it is prone to microbial growth that elevates biogenic amine levels, posing potential food safety risks. Therefore, this study systematically evaluated the effects of protamine—extracted from Esox lucius byproducts and used as a natural preservative—on the succession of microbial communities and biogenic amine accumulation in fish muscle under storage conditions of 4 °C, −3 °C, and −18 °C. A detection method for biogenic amines was also established. Results revealed characteristic changes in fish muscle microbial community α-diversity over storage time. Protamine treatment significantly delayed increases in total colony counts and microbial succession processes without altering the final dominant microbial community composition. By optimizing ultrasonic-assisted extraction and derivatization steps, an analytical method suitable for detecting eight biogenic amines in fish muscle matrices was established. Results indicate that protamine effectively inhibits the accumulation of all eight biogenic amines, with the 1% treatment group showing the most significant effect (p < 0.05). This study not only provides basis for the precise application of protamine in seafood preservation but also offers guidance for the resource utilization of aquatic by-products. Full article

Fluorescent dyes are commonly used as tracers in hydrological investigations to quantify transport pathways, residence times, mixing behavior, and connectivity in surface water, groundwater, and coastal systems. Despite their long history of application, the ecological implications of deliberate dye releases are not well understood. This review synthesizes current knowledge on the physico-chemical characteristics, environmental behavior, and ecotoxicological effects of major dye classes, with emphasis on rhodamines, fluorescein derivatives, and sulfonated xanthene dyes commonly used in water tracing studies. Toxicity data for algae, cyanobacteria, invertebrates, and fish show large inter-specific variability. Some dyes, particularly rhodamine B and eosin Y, show acute or sub-lethal effects at concentrations detected during poorly controlled applications. By contrast, dyes with high polarity and extensive sulfonation (e.g., rhodamine WT, sulforhodamine B, pyranine, and fluorescein) show consistently low toxicity and minimal bioaccumulation potential. Environmental fate processes, including photolysis, sorption, and transformation into potentially more reactive products, influence exposure dynamics, especially in clear, shallow, or slow-moving systems. This review also evaluates regulatory frameworks and operational guidance for safe use, identifies gaps in toxicological and fate data, and proposes recommendations for minimizing environmental impact through dye selection, mass optimization, injection design, and monitoring. The findings support the continued use of fluorescent dyes but highlight the need for more systematic assessment of transformation products, chronic and sub-lethal responses, and cumulative exposure in sensitive environments. Full article

A liver fluke, Clonorchis sinensis is a representative fish-borne parasite infecting humans, and sensitive detection in fish hosts or aquatic environments is important for monitoring infection sources in endemic areas. Conventional diagnostic methods based on microscopy or conventional PCR often show limited sensitivity, particularly under low-parasite conditions. In this study, we developed a high-sensitive and species-specific molecular marker and established a real-time PCR (qPCR)-based diagnostic method targeting metacercariae isolated from freshwater fish, representing the transmission stage of C. sinensis. Primers and a hydrolysis probe targeting the mitochondrially encoded cytochrome c oxidase 1 (COI) gene were designed, and all primer combinations produced stable amplifications with single melt curves in C. sinensis-positive samples. Among them, one combination was finally selected as the optimal marker due to its high specificity, including validation against mixed trematode samples to confirm species-specific detection. The qPCR assay showed excellent linearity (R² = 0.998), with a detection limit of 10¹ copies per reaction and a quantification limit of 10² copies per reaction. In addition, the assay successfully detected C. sinensis DNA in environmental water samples spiked with metacercariae, demonstrating its applicability to aquatic samples for environmental surveillance purposes. Compared with conventional PCR, the developed qPCR method in this study exhibited markedly improved sensitivity in fish-derived samples. Overall, this qPCR assay provides a robust diagnostic tool for laboratory analysis and has potential utility for environmental DNA-based monitoring of clonorchiasis risk areas within a One Health framework. Full article

Invasive freshwater fishes often display high trophic plasticity, facilitating their establishment and persistence in novel environments. This study examined the feeding ecology, growth patterns, and trophic role of the invasive black bullhead Ameiurus melas in the eutrophic Gruža Reservoir (Central Serbia), with emphasis on ontogenetic dietary shifts and potential ecological impact. Diet composition was analyzed in 103 individuals representing three age classes using traditional diet indices, Costello graphical analysis, self-organizing maps (SOMs), and the Indicator Value (IndVal). Chironomidae, Protozoa, and fish eggs were the dominant dietary components across age classes, although their relative importance varied ontogenetically. Younger individuals exhibited a more generalized feeding strategy, whereas older fish showed increased specialization on benthic prey. SOM-IndVal analyses revealed prey taxa associated with specific feeding patterns at the individual level, identifying Diptera as an indicator prey not detected by population-level indices. Length–weight relationships indicated negative allometric growth (b < 3) across all age classes, consistent with a diet dominated by low-energy prey. These feeding patterns may contribute to altered benthic processes, reduced native fish recruitment, and reinforcement of eutrophic conditions. Overall, the results highlight the pronounced trophic flexibility and ecological plasticity of A. melas, supporting its invasive success in degraded freshwater ecosystems. Full article

Background and Clinical Significance: Plasmablastic lymphoma (PBL) is a rare and highly aggressive B-cell neoplasm most often associated with immunodeficiency. Transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) into PBL is exceptionally uncommon, particularly in immunocompetent individuals. This paper describes a rare synchronous SLL-to-PBL transformation and summarizes current knowledge on synchronous and metachronous cases reported in the literature. Case Presentation A midle-aged immunocompetent patent presented with generalized lymphadenopathy and lumbar pain. Concurrent biopsies of an axillary lymph node and a retroperitoneal mass were obtained. Diagnostic evaluation included immunohistochemistry; fluorescent in situ hybridization (FISH); PCR-based assessment of IGH, IGK, and IGL loci; and next-generation sequencing (NGS) of IGHV to assess clonal relatedness. The patient was treated with six cycles of Dara-CHOP, followed by autologous stem cell transplantation and maintenance therapy with daratumumab and ibrutinib. The axillary node showed SLL (CD20+, CD5+, CD23+), while the retroperitoneal mass demonstrated classic features of PBL (CD138+, MUM1+, MYC+, Ki-67 ~100%, CD20−). FISH detected MYC rearrangement in the PBL component. PCR and NGS confirmed identical IGHV1-69 rearrangements, establishing clonal relatedness and Richter transformation. A review of published cases shows that both synchronous and metachronous CLL/SLL-to-PBL transformations are exceedingly rare. The patient achieved partial metabolic remission after treatment and remains in sustained metabolic response 24 months after diagnosis. Conclusions: This case highlights a rare example of synchronous CLL/SLL-to-PBL transformation in an immunocompetent patient. Integration of detailed molecular diagnostics enabled early recognition and guided a personalized treatment approach incorporating CD38-targeted therapy and BTK inhibition, resulting in an excellent long-term clinical outcome. Full article

Iguanodectes geisleri and I. adujai are freshwater fish from South America. Their taxonomic status and phylogenetic relationships are uncertain due to limited molecular data. High-throughput sequencing was applied to obtain and annotate for the first time the complete mitochondrial genomes of I. geisleri and I. adujai to clarify their phylogenetic positions. Mitochondrial genome sequences of 73 Characoidei species were retrieved from GenBank, with Gyrinocheilus aymonieri and Microphysogobio alticorpus designated as outgroups. Phylogenetic trees were constructed using a mitochondrial protein-coding gene dataset and Maximum Likelihood and Bayesian Inference methods. The complete mitochondrial genome measured 16,774 and 16,802 bp, respectively. Both genomes exhibited highly conserved structures. Despite morphological similarities and a close phylogenetic relationship, differences were detected in genomic structure, base composition, codon usage bias, and the control region between the two species. The two species comprise a strongly supported monophyletic clade and are sister species but represent distinct, independent branches. I. geisleri and I. adujai have been recognized as distinct species based on morphological differences, and this study provides molecular confirmation of their separate taxonomic status. The study provides molecular data for the taxonomic identification of fishes of the genus, Iguanodectes, and foundational mitochondrial genomic data for Characiformes. The study advances research on the genetic evolution of this group and resource conservation. Full article

This study developed and validated a Self-competitive Fishing (SCF) primer qPCR system as a rapid, cost-effective alternative to next-generation sequencing (NGS) for detecting POLE exonuclease domain mutations (EDMs) in endometrial cancer. The system detects 11 pathogenic POLE EDMs using SuperSelective primers combined with wild-type-blocking oligonucleotides that prevent amplification of wild-type DNA, thereby enhancing mutant DNA detection. The validation process involved comparing specificity using genomic DNA from tumors with known POLE mutations identified by NGS. Sensitivity testing used POLE-mutated DNA diluted in wild-type DNA, while precision was confirmed by analyzing 86 endometrial cancer samples against NGS results. The SCF qPCR system demonstrated superior specificity compared to the original SuperSelective primer-based qPCR, achieving 1% mutation-detection sensitivity across various mutation points. Importantly, results from all endometrial cancer cases showed complete concordance with NGS analysis for the 11 pathogenic POLE-EDM points tested. This cost-effective and efficient SCF primer qPCR system provides an accessible method for routine molecular classification of endometrial cancer in clinical settings, offering a practical alternative to NGS for detecting pathogenic POLE mutations and supporting clinical decision-making. Full article

The rapid expansion of offshore wind energy in Korea has raised concerns among coastal fishing communities about potential changes in fish assemblages. We conducted a summer 2022 survey at the Tamra Offshore Wind Farm (Jeju, Korea), comparing turbine-adjacent and reference sites using diver-operated video (DOV), direct capture, and stereo-baited remote underwater video (stereo-BRUV). Across methods, 23 fish species were identified, and stereo-BRUV detected the highest species richness. In stereo-BRUV analysis, the observed fish species and relative abundance metrics were higher in turbine-adjacent sites than reference site, including greater MaxN (maximum number of individuals observed in a single video frame) and Max spp. (maximum number of species observed in a single video frame). Most individuals measured from stereo imagery were 15–25 cm in total length (TL). For dominant taxa, TL distributions derived from stereo-BRUV were comparable to those measured from captured specimens, supporting the practical use of stereo-BRUV for size–structure characterization. Epifaunal assemblages on turbine jackets exhibited higher density and biomass than the reference site and showed clear vertical stratification (upper/mid > bottom). Diet items in captured fish overlapped with dominant jacket epifauna, consistent with a potential trophic linkage. Overall, stereo-BRUV can be used as a non-destructive and auditable approach for documenting fish assemblages around wind-farm structures. Because sampling was limited in spatial and temporal replication, the observed patterns should be interpreted as exploratory and hypothesis-generating for future synchronized and replicated monitoring. Full article