Search Results (610)

Microplastics (MPs) can affect fish health by inducing oxidative stress, but their impact on structural coloration remains poorly understood. This study investigated the effects of environmentally relevant concentrations (16 and 160 μg/L) of MPs and nanoplastics (NPs) exposure on growth, oxidative stress and structural coloration in blue strain guppy fish (Poecilia reticulata). Results showed exposure to 160 μg/L MPs significantly reduced specific growth rate of fish compared to controls. Plastic accumulation followed a dose-dependent pattern, especially within gut concentrations. Oxidative stress responses differed between MPs and NPs: 160 μg/L MPs decreased SOD activity in skin and reduced GSH levels, while 160 μg/L NPs increased MDA levels in gut tissues, indicating severe lipid peroxidation. Structural coloration analysis revealed exposure to 160 μg/L MPs decreased lightness and increased yellowness, demonstrating reduced blue coloration. This was accompanied by an increase in skin uric acid content, suggesting that guanine conversion might occur to combat oxidative stress. These findings demonstrate that MPs, particularly at high concentrations, impair growth and induce oxidative stress in guppies. To counteract stress, guanine in iridophores may be converted into uric acid, leading to a decline in structural coloration. This study is the first to reveal that MPs disrupt structural coloration of fish, providing new insights into the ecological risks of plastic pollution on aquatic organisms. Full article

Fibrocapsa japonica (Raphidophyceae) is a cosmopolitan species frequently associated with harmful algal blooms (HABs) and fish mortality events, representing a potential threat to aquaculture and coastal ecosystems. This study provides the first comprehensive morphological, phylogenetic, pigmentary, and toxicological characterization of F. japonica strains isolated from Argentina. Light and transmission electron microscopy confirmed key diagnostic features of the species, including anterior flagella and the conspicuous group of mucocyst in the posterior region. Phylogenetic analysis based on the LSU rDNA D1–D2 region revealed monophyletic relationships with strains from geographically distant regions. Pigment analysis by HPLC identified chlorophyll-a (62.3 pg cell⁻¹) and fucoxanthin (38.4 pg cell⁻¹) as the main dominant pigments. Cytotoxicity assays using RTgill-W1 cells exposed for 2 h to culture supernatants and intracellular extracts showed strain-specific effects. The most toxic strain (LPCc049) reduced gill cell viability down to 53% in the supernatant exposure, while LC₅₀ values ranged from 1.6 × 10⁴ to 4.7 × 10⁵ cells mL⁻¹, depending directly on the strain and treatment type. No brevetoxins (PbTx-1, -2, -3, -6, -7, -8, -9, -10, BTX-B1 and BTX-B2) were detected by LC–MS/MS, suggesting that the cytotoxicity may be linked to the production of reactive oxygen species (ROS), polyunsaturated fatty acids (PUFAs), or hemolytic compounds, as previously hypothesized in the literature. These findings offer novel insights into the toxic potential of F. japonica in South America and underscore the need for further research to elucidate the mechanisms underlying its ichthyotoxic effect. Full article

Fish coloration plays an important role in reproduction and camouflage, yet capturing color variation under field conditions remains challenging. We present a standardized, semi-automated protocol for measuring body coloration in the popular model fish threespine stickleback (Gasterosteus aculeatus). Individuals are photographed in a controlled light box within minutes of capture, and color is sampled from eight anatomically defined standard sites in human-perception-based CIELAB space. Analyses combine univariate color metrics, multivariate statistics, and the ΔE* perceptual difference index to detect subtle shifts in hue and brightness. Validation on pre-spawning fish shows the method reliably distinguishes males and females well before full breeding colors develop. Although it currently omits ultraviolet signals and fine-scale patterning, the approach scales efficiently to large sample sizes and varying lighting conditions, making it well suited for population-level surveys of camouflage dynamics, sexual dimorphism, and environmental influences on coloration in sticklebacks. Full article

Accurate evaluation of fish feeding intensity is crucial for optimizing aquaculture efficiency and the healthy growth of fish. Previous methods mainly rely on single-modal approaches (e.g., audio or visual). However, the complex underwater environment makes single-modal monitoring methods face significant challenges: visual systems are severely affected by water turbidity, lighting conditions, and fish occlusion, while acoustic systems suffer from background noise. Although existing studies have attempted to combine acoustic and visual information, most adopt simple feature-level fusion strategies, which fail to fully explore the complementary advantages of the two modalities under different environmental conditions and lack dynamic evaluation mechanisms for modal reliability. To address these problems, we propose the Adaptive Cross-modal Attention Fusion Network (ACAF-Net), a cross-modal complementarity learning framework with a two-stage attention fusion mechanism: (1) a cross-modal enhancement stage that enriches individual representations through Low-rank Bilinear Pooling and learnable fusion weights; (2) an adaptive attention fusion stage that dynamically weights acoustic and visual features based on complementarity and environmental reliability. Our framework incorporates dimension alignment strategies and attention mechanisms to capture temporal–spatial complementarity between acoustic feeding signals and visual behavioral patterns. Extensive experiments demonstrate superior performance compared to single-modal and conventional fusion approaches, with 6.4% accuracy improvement. The results validate the effectiveness of exploiting cross-modal complementarity for underwater behavioral analysis and establish a foundation for intelligent aquaculture monitoring systems. Full article

New stable three-dimensional hydrogels were obtained in an inert gas atmosphere in light in an aqueous dispersion of the main components: cod collagen, methyl methacrylate, polyethylene glycol, RbTe_1.5W_0.5O₆ complex oxide, and modifying additives. The analysis of the new hydrogels’ cytotoxicity using the MTT assay showed that the cytotoxicity of the sample extracts was observed in a number of examples, but was decreased with increasing dilution of the extracts. The decrease in cell viability at high concentrations of the extract is likely caused by a decrease in the number of specific components of the complete culture medium used to produce extracts. It is related to the well-known adsorption of medium proteins by the gel component, high-molecular compounds included in the matrix. The stimulating effect of the substances included in its composition was observed with a significant dilution of the extract, i.e., the proliferative activity of the cells increased. The extract of the hydrogel hydrolysate sample and all its dilutions did not show cytotoxicity in the MTT assay examples. It determines the prospect of its use on the wound surface, since hydrogel destruction occurs under the action of body enzymes. The new hydrogel is a promising material for creating wound coverings or scaffolds. Full article

This study examined the effects of rearing, physiological, and processing conditions on the volatile profile of Atlantic salmon. Fish were reared under two different temperature and light conditions, and three harvests were conducted at different time points for male and female fish. Fish were processed to yield fillets with or without skin. Volatiles were analyzed using SIFT-MS headspace analysis. Atlantic salmon reared in cooler temperatures under a 12 h light/dark cycle exhibited significantly lower concentrations of off-odor volatiles compared to those reared in warm conditions under continuous light, suggesting that cooler temperatures with a dark cycle help maintain freshness. A temperature shift from cool to warm further increased volatile accumulation. Longer rearing time resulted in higher volatile concentrations, attributed to greater biochemical products, increased susceptibility to lipid oxidation, protein degradation, and contaminant accumulation from the rearing environment. Males had higher volatile levels at 202 days, while females surpassed males by 242 days, likely due to increased biochemical accumulation associated with reproductive development. Fillets with skin exhibited significantly higher concentration of off-odor volatiles. These findings highlight the role of all studied factors in establishing optimum conditions to minimize spoilage-related volatiles and preserve the freshness of Atlantic salmon, with rearing temperature being the most critical factor. Full article

Substrate is an important component of a fish’s habitat environment. Fish preferences for substrate influence their growth and development, feeding, hiding, schooling, and reproduction. To explore the habitat preference of Brachymystax tsinlingensis, this study was conducted on the preferences of B. pre-smolts, post-smolts, and juveniles for three substrate colors, white, blue, and black, and four substrate types, sand (<0.5 cm in diameter), small gravel (1–2 cm in diameter), medium gravel (5–7 cm in diameter), and large gravel (12–16 cm in diameter), which were investigated in light (10–60 lx) and dark (no light) environments. The results showed that the individual populations of B. tsinlingensis in three periods of time had a clear preference for substrate color, preferring black substrate and staying away from blue substrate under both light and dark environmental conditions; B. tsinlingensis pre-smolts and post-smolts preferred sandy substrate, and juveniles preferred medium gravel substrate. The choice of substrate color and substrate type by B. tsinlingensis is a manifestation of the living environment characteristics of this species, which is conducive to their hiding, better avoidance of enemies, and improvement of their survival rate. Based on the research results and the early biological characteristics of B. tsinlingensis, it is recommended to use black or dark substrate during the cultivation of B. tsinlingensis fry. During the larval fish stage, a sandy substrate environment should be provided. During the juvenile fish stage, a medium-gravel environment should be provided. Full article

Heavy metal pollution of lake sediments is one of the prominent ecological and environmental problems worldwide, and it is of great significance to conduct research on heavy metal pollution in lake sediments to protect the ecological environment, safeguard human health, and promote sustainable development. As an integral part of Dongting Lake, Datong Lake holds a crucial ecological position. More than 10 years ago, due to a series of factors, including excessive fertilizer application and fishing, the water quality of Datong Lake declined, resulting in varying degrees of contamination by Cd, Mn, and other heavy metals in the sediments. After 2017, Datong Lake began to establish a mechanism for protecting and managing the lake, and its ecological and environmental problems have been significantly improved. To clarify the current situation of heavy metal contamination in the sediments of Datong Lake, 15 sediment samples were collected from the lake, and the contents of soil heavy metals Cd, As, Pb, Cr, Cu, Mn, Ni, and Zn were determined. A Monte Carlo simulation was introduced to carry out the ecological and human health risk evaluation of the sediments in the study area to overcome the problem of low reliability of the results of ecological and human health risk evaluation due to the randomness and incompleteness of the environmental data as well as the differences in the human body parameters. The results and conclusions show that (1) the average values of Cd, Pb, Cr, Cu, Mn, Ni, and Zn contents in the sediments of Datong Lake are higher than the background values of soil elements in the sediments of Dongting Lake, and the average values of As contents of heavy metals are lower than the background values of the soil, and the heavy metal contamination in the sediments in the study area is dominated by slight contamination, and the possibility of point-source contamination is slight. (2) The results of both the Geo-accumulation index and Enrichment factor evaluation showed that the degree of heavy metal contamination of sediments was Ni > Cu > Cr > Mn > Cd > Pb > Zn > As. (3) The average value of the single ecological risk index of heavy metal elements, in descending order, was as follows: Cd > As > Pb > Cu > Ni > Cr > Zn > Mn; all the heavy metal elements were at the level of light pollution, and the average value of the comprehensive ecological risk index was 32.83, which is a slight ecological risk level. (4) Both non-carcinogenic and carcinogenic risks for all populations in the study area remain low following heavy metal exposure via ingestion and dermal pathways. Ecological and health risk assessments identified As and Cd as exhibiting significantly higher sensitivity than other heavy metals. Consequently, continuous monitoring and source-tracking of these elements are recommended to safeguard long-term ecological integrity and public health in the region. Full article

Overfishing and climate change have led to the depletion of fishery resources in the offshore South China Sea. The purpleback flying squid (Sthenoteuthis oualaniensis) has emerged as a promising alternative due to its ecological and economic value. However, information on its preferred habitat conditions remains scarce. This study integrates geostatistical and fisheries oceanographic approaches to explore optimal spatial–temporal scales for habitat modeling and to assess habitat changes under warming scenarios. Utilizing fishery data from 2013 to 2017, environmental variables including SST, sea surface temperature anomaly (SSTA), and chlorophyll-a concentration (CHL) were analyzed. Fishing effort data revealed significant seasonal differences, with the highest vessel numbers in summer and the lowest in autumn. Among the six modeling schemes, the combination of 0.5° × 0.5° spatial resolution and seasonal temporal resolution yielded the highest HSI model accuracy (84.02%). Optimal environmental ranges varied by season. Simulations of SST deviations (±0.2 °C, ±0.5 °C, and ±1 °C) showed that extreme warming or cooling could eliminate suitable habitats. These findings highlight the vulnerability of squid habitats to thermal shifts and support adaptive fishery strategies in the South China Sea. Full article

Over the past several decades, clinical cytogenetics has branched out from the use of light microscopy and examination of banded chromosomes to embrace multiple newer techniques, including fluorescence in situ hybridization (FISH), multiple generations of microarray designs, as well as the newest technologies, namely, optical genome mapping (OGM) and genomic proximity mapping (GPM). While these newer technologies have had an increasingly molecular genetic focus over time, they are still rooted in the field of cytogenetics, the genetics of the single cell. This review provides a brief overview of the earliest, as well as the most recent, techniques available to clinical cytogenetics laboratories for both constitutional and neoplastic testing and discusses some advantages and disadvantages of each. Full article

Precious corals from the Corallidae family (Corallium, Hemicorallium, and Pleurocorallium genera) are well known in the high-end jewelry industry due to their colorful and durable axial skeleton. They exist in various colors from white to pink to dark red. One highly appreciated shade is the light pink color, the so-called ‘angel skin’. This color is most often associated with Pleurocorallium elatius and Pleurocorallium secundum, species listed in CITES Appendix III. However, this has been based on an assumption of their visual similarity and has never been underpinned by detailed morphologic or genetic data. In this study, we present the analysis of an ‘angel skin’ coral necklace of exceptional size and homogeneous color and quality. Visual observation and Raman spectroscopy confirmed that the necklace consists of genuine, untreated precious coral material. Following minimally destructive sampling, respectively, drilling 2.2, 2.4, and 2.4 milligrams of material from the existing drill-holes, three randomly selected beads from the necklace were subject to a routine genetic identification assay, which is based on sequencing a short, taxonomically informative mitochondrial region. This genetic analysis identified the coral material as not from P. elatius or P. secundum but from another Pleurocorallium species. We subsequently sequenced additional mitochondrial DNA fragments from one ‘angel skin’ coral bead and compared them against a well-represented, curated reference data set of Pleurocorallium, including the first-ever sequencing of Pleurocorallium gotoense, Pleurocorallium johnsoni, Pleurocorallium cf. pusillum, and Pleurocorallium uchidai. We concluded that the analyzed material of the ‘angel skin’ coral necklace belongs to the Pleurocorallium norfolkicum species complex but is not identical to any hitherto analyzed and published Pleurocorallium specimens. A comparison with further taxonomically unidentified precious coral colony fragments identified a single sample fished in Vietnam to be completely identical to the ‘angel skin’ coral bead in the studied DNA regions. Thus, by the analysis of a high-end jewel, we discovered a species new to the jewelry trade and potentially also unknown to science. This implies that the currently considered list of species present in the precious coral trade is incomplete. Full article

In aquaculture, pre-slaughter fasting reduces stress and improves muscle quality. Fasting periods of 55–58 degree days (°C d) enhance muscle structure and post-mortem biochemistry in rainbow trout (Oncorhynchus mykiss), although optimal durations vary with temperature. This study investigated the effects of fasting from none to extended durations on 495 rainbow trout under summer (22 °C) and winter (8 °C) conditions. In summer, elevated temperatures increased muscle glycogen, leading to lower pH and delayed rigor mortis (RM), especially in fasted groups, where RM peaked at 24 h post-mortem. In winter, RM occurred earlier. Prolonged fasting increased acetylcholinesterase (AChE) activity, with high baseline levels in non-fasted summer fish. Muscle lightness at 0 h post-mortem was highest in non-fasted winter fish but declined to summer levels in fasted groups. Antioxidant enzyme activity (glutathione-S-transferase, glutathione peroxidase) increased with fasting in winter, while summer heat masked responses. The expression of genes for mineralocorticoid receptors and heat shock proteins remained stable in warm conditions. Summer delayed metabolic decline due to higher glycogen-triggered excessive AChE activity from heat stress. Winter supported faster metabolic adjustment and more regulated enzyme activity. These findings highlight the need to adjust fasting strategies seasonally to optimize muscle traits, especially under thermal variations. Full article

The Japanese sardine (Sardinops sagax), a key economic species in the Northwest Pacific Ocean (NWPO), has shown significant increases in both population abundance and catch volume over the past decade. To understand its spatiotemporal dynamics under climate change, this study analyzed light purse seine fishery data (2014–2021) from the NWPO. The results showed that the primary fishing season spans March to December, with peak catches concentrated in 40–43° N, 149–155° E. Annual catches grew steadily, accelerating notably in 2021. The fishing grounds’ center shifted northeastward annually and seasonally (southwest-to-northeast trajectory), driven by directional aggregation. Spatial clustering with global positive autocorrelation was observed, weakening as distance thresholds increased. Resource hotspots migrated northeast, narrowing from 40–42° N (2016) to 42–44° N (2017–2021), while coldspots showed complementary fluctuations. Generalized additive model (GAM) analysis revealed that the catch per unit effort (CPUE) of Japanese sardine in the high seas of the NWPO was governed by temporal–spatial drivers and multivariate environmental determinants. Analytical findings substantiate the significant climate-driven impacts on the spatiotemporal distribution and population dynamics of Japanese sardine. The non-stationary interannual and seasonal patterns of fishing grounds highlight the need for adaptive management strategies. Full article

Optimizing nutrient usage and controlling environmental parameters are crucial for improved crop growth and yield in the cultivation of Cannabis sativa, commonly known as hemp, using controlled-environment agriculture (CEA) systems. Although hemp cultivation in CEA is rapidly growing, the effects of different light-intensity treatments on early vegetative stages of hemp grown in hydroponic and aquaponic systems, along with the impacts on the environment and human health remains limited. This study employed a split-plot design, consisting of two layers of plant grow beds where each layer was exposed to different light intensities (LIs): approximately 752 µmol/m²/s (high light intensity) on the upper layer and 141 µmol/m²/s (low light intensity) on the lower layer. To assess the influence of two different LIs on plant growth indicators, specifically plant length and leaf area, the environmental parameters, including dissolved oxygen (DO), electrical conductivity (EC), pH, and water temperature (WT) were maintained within the same range for both systems. Additionally, the study incorporated a cradle-to-gate life cycle assessment (LCA) to precisely evaluate the environmental performance of both systems. Under the specific environmental and design conditions of this study, hemp plants grown in aquaponics showed greater growth performance in plant length compared to hydroponics (more than 42% higher for both LIs) and leaf area (28.3% greater under 141 µmol/m²/s), although the leaf area was 2.1% lower under 752 µmol/m²/s compared to plants grown in hydroponics. The LCA demonstrated that the aquaponic system provided an efficient and sustainable approach by integrating fish with hemp cultivation. The LCA results showed that aquaponics had a 22% reduction in midpoint and a 15% reduction in endpoint impact in contrast to the hydroponics system for hemp leaf cultivation. This research highlights the potential of aquaponic systems as a viable and sustainable alternative to hydroponic systems for hemp leaf cultivation in CEA under uncertain future climates. Full article

Per- and polyfluoroalkyl substances (PFAS) are used in consumer products and manufacturing. Perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) are long-chain PFAS composed of 9, 10, and 11 carbons, respectively, which exert sublethal toxicity to aquatic species. Here, we review the data regarding the environmental fate and ecotoxicology of these understudied long-chain PFAS in fish. The objectives of this study were to (1) compile the literature to compare physiological or molecular signaling pathways disrupted by PFNA, PFDA, or PFUnDA; and (2) uncover potential biomarkers and pathways of toxicity of longer-chain PFAS using gene ontology computational approaches to shed light on their mechanism of action. Studies show that PFAS have a range of effects on fish, including developmental issues, changes in gene expression, and behavioral modifications. Based on our review, PFNA has been studied more frequently in fish compared to PFDA and PFUnDA; however, longer-chained PFAS are proposed to pose greater toxicity. Based on the computational approach, prominent pathways affected by PFNA include insulin signaling [“Insulin -> CEBPA/CTNNB/FOXA/FOXO”, “Insulin -> STAT Expression Targets”], immune system signaling [“TNF -> STAT Expression Targets”, “IL6 Expression Targets”, and “IL2 Expression Targets”], and growth hormone/prolactin signaling [“GH1/PRLR Expression Targets”, “PRL/GHR -> STAT Expression Targets”, “PRL/PRLR Expression Targets”]. Several transcripts related to cholesterol metabolism were also affected by PFNA. This review summarizes the current knowledge on the distribution, fate, and ecotoxicology of PFNA, PFDA, and PFUnDA in teleost fish, highlighting potential physiological and molecular responses that could aid in assessing long-chain PFAS toxicity in future studies. Full article