Search Results (1,455)

Little is known about the vertical distribution of microplastics (MPs) in deep stratified lakes. This study investigates the MPs in the large and deep Lake Trichonis during the thermal stratification period, using two nets of different porosity (50 μm and 200 μm) in three depth strata. Fibers dominated over fragments with an average abundance of 10.63 ± 1.00 items m⁻³ and 3.10 ± 0.52 items m⁻³ respectively in the samples of the 50 μm net in the entire water column, while the respective values for the 200 μm net were 1.4 and 7.4 times greater. Fibers had the highest abundance within the thermocline, and most of them were blue with a length 1–2 mm. There were only abundance differences between the two nets and no qualitative disparities concerning color, size, shape and polymer types. There was a strong positive correlation between the abundance of fibers and the adults of the dominant copepod Eudiaptomus drieschi, which also accumulated within the thermocline. Considering that the adults of E. drieschi are among the preferred prey of Atherina boyeri, the most important commercial fish, certain issues arise concerning possible fiber bioaccumulation on the food web. The study highlights the importance of investigating MPs in connection with biotic elements. Full article

Probiotics are widely studied as antibiotic alternatives in commercial aquaculture, yet their effects on fish maintained under long-term aquarium conditions remain poorly understood. This study addressed this gap by evaluating dietary Escherichia coli Nissle 1917 (EcN) supplementation on gut microbiota and inflammatory cytokine expression in hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂) from a recirculating aquarium system. In this study, hybrid grouper were maintained in triplicate tanks under long-term aquarium environments, and fed a basal diet with 1 × 10⁸ CFU/g EcN (SS group) or a control diet (CS group) for 28 consecutive days. Based on 16S rRNA high-throughput sequencing and qPCR, the intestinal microbiota and expression levels of IL-4, TNF-α, and IL-1β were measured. At the phylum level, the relative abundance of Firmicutes increased from 15.63% (CS) to 66.70% (SS), while Proteobacteria decreased from 76.77% to 30.61%. At the genus level, Exiguobacterium became the dominant taxon in the SS group. Furthermore, EcN supplementation significantly upregulated IL-4 expression and downregulated TNF-α and IL-1β expression. EcN supplementation significantly altered gut microbiota composition, with marked changes in community structure and notable shifts in dominant taxa. Thus, this study provides one of the investigations into EcN-mediated restructuring of intestinal bacterial communities and modulation of host immune transcriptional responses in hybrid grouper maintained under controlled aquarium settings. These findings offer a foundation for designing microbiome-targeted interventions in captive marine fish systems. Full article

The Japanese mantis shrimp (Oratosquilla oratoria) is a commercially important crustacean species distributed around the coastal waters of China, which is harvested with both active and passive fishing gears. Among these, traps are one of the primary passive gears used in the Bohai Sea, which is one of the most important fishing grounds for Japanese mantis shrimp in northern China. However, the use of traps with a small mesh size challenges the sustainability of this fishery. Therefore, this study quantified the size selectivity and harvesting pattern for traps with different mesh sizes for harvesting Japanese mantis shrimp in the Bohai Sea. Results showed that the 50% retention length increased from 6.39 cm to 12.44 cm as mesh sizes increased from 20 (T20) to 60 mm (T60). T20 retained 86.8% and 100% of individuals, respectively, below (np-) and above (np+) the minimum landing size. Increasing mesh sizes decreased both np- and np+. Compared with T20, T30 reduced undersized catch by 67.8% while decreasing legal-sized catch by 8.2%. Increasing mesh sizes beyond T40 provided no significant reduction in np- but caused further reduction in np+. Therefore, the T30 mesh trap was recommended to replace the currently applied T20 in the Bohai Sea. Full article

Background/Objectives: Course-based Undergraduate Research Experiences (CUREs) represent a form of student crowdsourcing in which individuals perform authentic discovery-based research in a class setting with interest to outside stakeholders. Here, the renowned Tiny Earth (TE) CURE is being utilized to teach microbiology and perform natural product discovery research by students in the course. Methods: In our TE CURE, students collect soil samples from their hometown and characterize bacteria that can inhibit plant and animal pathogens. This unique growing collection of isolates from across Ohio has provided opportunities to facilitate drug discovery and establish biotechnology collaborations. Results: In this study, we describe two outcomes using our environmental strain collection that initiated biotechnology collaborations and identified bacterial candidates for drug discovery. Results from one project led to a partnership with an aquaculture company. A novel biosynthetic gene cluster involved in antagonistic activity was identified, whose product inhibits Aeromonas pathogens, which cause disease in freshwater fish. The other project involves a collaboration with a global commercial cleaning and equipment company to identify lipase activity among Bacillus strains for its potential use in bioremediation. Conclusions: The unique strain collection generated by students in the CURE led to collaboration with biotechnology companies, which contributed to natural product discovery of an antimicrobial product and active enzymatic activity, all of which benefit education and scientific discovery. Full article

This study evaluated locally available dry feed formulations (FFs) as practical alternatives to fresh Chlorella sp. for culturing the freshwater fairy shrimp Streptocephalus sirindhornae. Seven dietary treatments were evaluated, including fresh Chlorella sp. at 1 × 10⁶ cells mL⁻¹ (FF1; control) and six mixed dry diets (FF2–FF7) formulated from spirulina powder, commercial shrimp feed, fish meal, and rice bran. Fairy shrimp were cultured for 20 days in a completely randomized design with three replicates per treatment at a stocking density of 30 individuals L⁻¹. Growth performance (body length and wet body weight) and survival were assessed across three developmental stages (1–5, 6–10, and 11–20 days post-hatch). Across all developmental stages, FF2 (50% spirulina powder + 50% commercial shrimp feed) consistently supported culture performance comparable to that of the control treatment. During the early developmental stage (1–5 days post-hatch), shrimp fed FF2 exhibited growth and survival rates comparable to those of the control group and significantly higher (p < 0.05) than those observed in several other dry diet treatments. During the late developmental stage (11–20 days post-hatch), survival of shrimp fed FF2 (62.45 ± 5.28 percent) did not differ significantly from that of the control group (61.85 ± 4.25 percent) but was significantly higher (p < 0.05) than survival in the other dry diet treatments. In addition, shrimp biomass produced with FF2 showed greater protein, lipid, carotenoid, and amino acid contents than shrimp fed fresh Chlorella sp. Protein, lipid, and amino acid contents were determined using standard AOAC methods, and carotenoid content was analyzed by HPLC. These findings suggest that FF2 may serve as a practical algae-independent diet for maintaining growth and survival of S. sirindhornae under controlled hatchery conditions. Full article

The sustainable development of all economic sectors, including transport, requires decarbonization approaches that reduce greenhouse-gas emissions while preserving operational viability. This article develops a segment-based preliminary multi-criteria framework for evaluating the rational applicability of decarbonization technologies to commercial fishing vessels and demonstrates it for existing medium-to-large trawlers. The central premise is that decarbonization technologies cannot be ranked universally for the whole fishing fleet because vessel type, fishing gear, operating cycle, autonomy, onboard energy demand, and port dependence strongly affect practical applicability. Ten alternatives are assessed: sustainable drop-in biofuels/biodiesel/HVO (Hydrotreated Vegetable Oil), LNG/BioLNG/LBG, methanol, hydrogen fuel cells, ammonia, hybrid systems, operational measures, hull-form or hydrodynamic modifications, waste heat recovery and wind-assisted propulsion. Seven benefit-type criteria are combined using trawler-specific Rank-Order Centroid weights, Simple Additive Weighting, and a dynamic rationality extension for 2026, 2030, 2040, and 2050. The 2026 baseline results place operational measures and sustainable drop-in biofuel/HVO pathways in the leading practical group, while hydrogen and ammonia remain weak because of storage, safety, infrastructure, cost, and integration constraints. By 2050, a mixed long-term group emerges where HVO, LNG/BioLNG/LBG, methanol, ammonia, and hydrogen are all relevant, with no single dominant alternative. The framework supports early-stage screening before vessel-specific LCA, LCCA, CFD, safety assessment, and retrofit or newbuild design. Although this methodological approach was demonstrated for existing medium-to-large trawlers, the authors believe that it can be adapted for retrofit cases, other fishing vessel segments, and other types of seagoing vessels. Full article

Chub mackerel (Scomber japonicus) is a commercially important pelagic species in the northwest Pacific Ocean. Accurate identification of its fishing grounds can provide a more robust and targeted scientific basis for fishery management and ecological research. Based on fishing effort and five environmental factors (i.e., sea surface temperature [SST], chlorophyll-a concentration [CHL], SST gradient [GSST], sea surface height [SSH], and current speed), this study developed a Classification and Regression Tree (CART) rule-guided MaxEnt model. Specifically, rules generated by the CART model were first extracted and then incorporated as constrained feature functions into MaxEnt for model training. To select the optimal model scheme, four combinations of rule compositions and feature function outputs were designed, and model performance on the validation dataset was evaluated using ROC curves. Finally, the model was further verified with in situ environmental and fisheries data from April to November 2024. Results showed that the predicted fishing grounds were highly aligned with the actual monthly fishing grounds in 2024, and the predicted migration routes matched the movement trajectory of fishing vessels. The model also exhibited satisfactory performance, achieving an average AUC of 0.722 ± 0.033, a sensitivity of 0.604, a specificity of 0.834, and a negative predictive value (NPV) of 0.978. In conclusion, the CART rule-guided MaxEnt model, integrating the interpretability of CART and the predictive power of MaxEnt, effectively predicts the spatial distribution of chub mackerel fishing grounds in the northwest Pacific Ocean, providing technical support for fishery management and ecological research. Full article

This study examined the growth dynamics of Salmonella enterica and Listeria monocytogenes in two food matrices, cheddar cheese sauce (CCS) and salmon spreadable paste (SSP), and assessed the antimicrobial efficacy of freshly extracted essential oils (EOs) from Citrus limon cv. Femminello Santa Teresa (FST) compared with commercial (COM) EOs. Sensory sniffing tests indicated that lemon EOs were unsuitable for bio-preserving CCS. SSP supported rapid growth of both pathogens, whereas CCS caused an immediate and progressive population decline, highlighting strong matrix-dependent effects mainly related to pH. When applied to SSP, FST EOs significantly modified microbial behaviour, showing bacteriostatic activity against S. enterica and a rapid, irreversible bactericidal effect against L. monocytogenes, with complete inactivation within 24 h and no regrowth. In contrast, COM EOs showed weaker antimicrobial activity, producing limited growth reductions. SSP exhibited high growth potential (δ > 0.5) for both pathogens, with intra-species variability. FST EOs eliminated L. monocytogenes growth, yielding strongly negative δ values, while Salmonella δ values remained > 0.5, indicating reduced yet persistent growth. Throughout the experiments, pH and water activity (a_w) remained nearly unchanged after EO addition, confirming that inhibition depended on EO bioactivity rather than matrix modification. Overall, FST lemon EOs represent a promising preservation strategy for fish spreads. Full article

The impact of a commercial microbial population (product name “RAS Right”) on the off-flavours geosmin and 2-methylisoborneol (2-MIB) in water and fish of a recirculating aquaculture system (RAS) for Nile tilapia production was studied over five months. The “RAS Right” product contains a microbiome that is reported to reduce geosmin. In the system that received “RAS Right”, geosmin ranged from 1.6 to 171.2 ng/L, while 2.4 to 89.3 ng/L occurred in the control RAS. After fluctuations in the first two months, water in the control RAS had lower geosmin concentrations (mean of 8.8 ng/L) than the treated RAS (mean of 16.6 ng/L). 2-MIB was low (<4.3 ng/L) or undetectable in both the control and treated systems. In the fish, geosmin varied from 112 to 3683 ng/kg, with the highest levels measured in the treated RAS during three of eight samplings. 2-MIB in the fish ranged from 11.6 to 136 ng/kg and peaked in the treated RAS in one sampling. The results indicate that “RAS Right” did not produce a significant reduction of geosmin or 2-MIB in water or fish. However, optimisation of the treatment with respect to dose or addition frequency may improve its effect, though this remains to be examined. Full article

Eastern Boundary Upwelling Systems (EBUSs) are among the most productive marine biomes globally, renowned for their substantial pelagic fisheries. While the role of wind-driven upwelling in stimulating primary production is well-documented, the integral contributions of the marine benthos in maintaining ecosystem productivity and fishery yields are often underrepresented. This article analyzes evidence from the Humboldt, California, Benguela, and Canary Current systems to delineate the critical functions of the seabed and its resident communities. Three primary pathways through which the benthos supports fisheries are described: (1) by facilitating the efficient regeneration of nutrients from sedimenting organic matter, thereby replenishing the inorganic nutrient pool for subsequent primary production; (2) by providing essential habitat structure that supports the life history of a myriad of species, including demersal and coastal fish species, serving as nursery and feeding grounds; and (3) by forming the foundational trophic base for benthic-feeding fishes and invertebrates of commercial importance. By comparing system-specific characteristics, such as the influence of oxygen minimum zones on benthic community structure, the integrity of the benthic subsystem as a fundamental determinant of the productivity and sustainability of EBUS fisheries is demonstrated. A holistic management approach that includes benthic habitat conservation is therefore paramount. Full article

The authentication of fish maw is of considerable importance for preventing product substitution and protecting market confidence in high-value aquatic foods. This study developed a rapid and nondestructive authentication strategy by combining hyperspectral imaging (HSI) with wavelength selection and a Kolmogorov–Arnold Network (KAN) to discriminate 10 commercially representative fish maw varieties. Hyperspectral datasets were collected in the visible and near-infrared (VNIR, 400–1000 nm) and short-wave infrared (SWIR, 900–1700 nm) regions. To improve spectral quality and model robustness, four preprocessing methods (SG, SG−MeanNor, SG−DT, and SG−SNV) were evaluated, followed by the construction of PLS-DA, SVM, MLP, CNN, and KAN models. Feature wavelengths were subsequently selected separately from the VNIR and SWIR spectra using CARS, iVISSA, and SPA to establish reduced-variable authentication models. The results showed that SG-DT achieved the best overall preprocessing effect, confirming its ability to reduce spectral noise and baseline variation. In addition, SWIR-based models consistently outperformed VNIR-based models, suggesting that compositional information captured in the SWIR region played an important role in fish maw authentication. Among all tested models, the SWIR@SG-DT-SPA-KAN model exhibited the best performance, achieving 98.67% accuracy, 98.75% precision, 98.67% recall, and 98.64% F1-score using only 16 SPA-selected wavelengths from the SG-DT-preprocessed SWIR spectra. This study demonstrates that HSI coupled with feature wavelength and KAN modeling can provide an accurate and efficient tool for fish maw authentication. More importantly, the reduced-wavelength model offers practical potential for developing fast and cost-effective multispectral systems for authenticity screening in the aquatic food market. Full article

The accumulation of un-ionized ammonia (NH₃) during the transport of live ornamental fish poses a critical threat to animal welfare and post-transport survival. This study evaluated the efficacy of calcium alginate-encapsulated native Amazonian microalgae, Ankistrodesmus sp., Chlorella sp., Scenedesmus sp., and Synechococcus sp., for NH₃ bioremediation during a 15-day simulated transport of female Poecilia reticulata. Biometric endpoints were selected using a four-criterion framework, identifying specific growth rate by weight (SGRW), specific growth rate by length (SGRL), and Fulton’s condition factor (K) as essential non-redundant parameters. Time-weighted average (TWA) NH₃ served as the primary dose variable for four-parameter log-logistic modeling fitted to biological replicate means (n = 15). Ankistrodesmus sp. and Scenedesmus sp. maintained 97.8% survival and restricted TWA NH₃ to 0.036 and 0.047 mg/L, respectively, whereas the empty capsule control reached 6.7% survival and 0.150 mg/L TWA NH₃. Kruskal–Wallis tests on biological replicate means confirmed significant treatment effects on all biometric endpoints (SGRW: H(4) = 13.50, ε² = 0.950; SGRL: H(4) = 13.50, ε² = 0.95; p < 0.01). Chronic EC₅₀ values of 0.10505 mg/L NH₃ (SGRW; Adj-R² = 0.828) and 0.09967 mg/L NH₃ (SGRL; Adj-R² = 0.812) were established, representing approximately 7.8% and 7.4% of the female-specific acute LC₅₀ (1.34 mg/L NH₃), respectively, yielding chronic-to-acute ratios of approximately 13 for both growth endpoints and confirming that sublethal growth impairment precedes lethality. Partial disruption of the calcium alginate capsule matrix was observed from day 5 onward; the relative contributions of encapsulated and free-cell fractions were not quantified. Under the experimental conditions tested, 15-day simulated transport of female P. reticulata under controlled illumination and without feeding, calcium alginate-encapsulated Ankistrodesmus sp. and Scenedesmus sp. treatments represent effective, scalable, and residue-free alternatives to chemical ammonium neutralization for comparable ornamental fish transport scenarios; extension to dark commercial air transport or other species requires further experimental validation. Full article

In situ hybridization (ISH) has undergone a rapid evolution from a low-throughput histological staining technique to a diverse family of modern methods for sensitive, specific and multiplexed molecular detection in intact cells and tissues, and to a cornerstone technology for image-based spatial transcriptomics. This transformation has been driven by advances in probe design, signal amplification, cyclic imaging, combinatorial barcoding, automated fluidics and computational decoding, which together allow RNA molecules to be measured within preserved cellular and tissue architecture. In this review, we examine the molecular and engineering principles that underlie modern ISH methods and their extension into ISH-based spatial profiling, with emphasis on hybridization chain reaction, branched-DNA amplification, SABER-FISH, rolling-circle-amplification-based approaches, seqFISH, MERFISH, RAEFISH and selected commercial implementations. We discuss how sensitivity, specificity, tissue compatibility, optical crowding, imaging burden, cost, reproducibility and computational uncertainty shape the practical use of each method. Sequencing-based spatial capture platforms are not reviewed comprehensively, but are considered where comparative benchmarks help clarify trade-offs in spatial resolution, transcriptome breadth, tissue area or analytical interpretation. We also consider how recent benchmarking and standardization efforts are beginning to define quantitative criteria for comparing platforms, and how advances in segmentation, barcode decoding, spatial integration and cell–cell communication analysis convert raw images into biological insight. Finally, we highlight applications in targeted transcript detection, tissue-based validation, neuroscience, cancer, developmental biology, non-model organisms and spatial functional genomics, where modern ISH methods and ISH-based spatial profiling provide information that bulk and dissociated single-cell approaches cannot capture. Together, these developments trace how ISH has expanded from targeted molecular visualization into a broad methodological framework for in situ detection and spatially resolved transcriptomic analysis. Full article

Efficient feed management is essential in aquaculture, especially for bottom-feeding species such as shrimp that require feed delivery at the tank bottom. Most commercial automated feeders are designed for surface-feeding fish and are unsuitable for benthic organisms, leading to feed waste and uneven distribution. This study developed and evaluated an automatic bottom feeder capable of dispensing sinking pellets directly to the substrate. The system integrated a 3D-printed auger for precise feed metering and a closed-type centrifugal impeller positioned at the water surface to achieve radial dispersion of feed. An Arduino Uno microcontroller operated the impeller speed (285.98–586.85 rpm), feed mass (95.23–285.68 g), and dispersion time (2–8 s). A Box–Behnken response surface methodology was used to analyze the influence of these parameters on the mean radius spread of feed, supported by image-based uniformity assessment using OpenCV. Results identified impeller speed as the most significant factor (p = 0.010), with optimal dispersion observed at moderate speeds and longer spread durations. The system demonstrated reliable mechanical performance and precise control, providing a novel, programmable solution for uniform feed delivery in shrimp aquaculture and a promising foundation for scalable, automated bottom-feeding technologies. Full article

Sustainable phosphorus (P) management in agriculture requires a circular economy approach through the use of so-called bio-based fertilizers (BBFs). The properties of BBFs vary widely depending on raw materials and production processes. However, it is still unknown how these properties, and particularly the dominant P compounds determine not only the efficiency of BBFs in supplying P to crops, but also their effects on soil functioning and crop quality. This study aimed to evaluate the efficiency of a representative set of BBFs, and relate this efficiency to their composition and dominant P compounds. To this end, 14 BBFs were studied: four from water purification (struvite, vivianite, and sewage sludge with and without composting), four composts (municipal solid waste (MSW), vineyard residues, and two using olive husks), three vermicomposts (two homemade and one commercial), fish meal, digestate, and a commercial organic fertilizer. Phosphorus forms in BBFs were determined using ³¹P nuclear magnetic resonance spectroscopy (P-NMR). The BBFs were compared to a single superphosphate (SSP) in a pot experiment growing wheat in two different alkaline soils, one rich in iron (Fe) oxides and one rich in carbonates. The effects on critical elements in grain [magnesium, Fe, zinc (Zn), manganese, and copper] and enzyme activities related to soil functioning and P cycling were also assessed. The dominant P compound in the BBFs was orthophosphate (73.8–89.5% of the total P in the NaOH–EDTA extracts). The MSW had the highest polyphosphate content (4.1%), a complex inorganic P compound. The organic P content ranged from 9.2% (fish meal) to 25.5% (Moge). Sewage sludge and composted sludge contributed high levels of phosphonates (4.1 and 5.6% of extracted P). The most abundant organic P compound class was inositol hexakisphosphates (IHPs), and myo-IHP (phytate) was the dominant IHP stereoisomer (1.2–6.4%) followed by D-chiro-IHP and scyllo-IHP. Plant dry matter and grain yield with most BBFs were not significantly different from that of SSP in both soils, likely due to the high concentrations of phosphate in relatively soluble forms in most of the BBFs. Vivianite and sewage sludge resulted in significantly higher grain yield than SSP (43% and 40%, respectively) in the carbonate-rich soil, likely due to progressive phosphate dissolution, which decreased the precipitation rate of insoluble calcium (Ca) phosphates. The highest P recoveries were obtained with horse manure vermicompost (65% and 15% higher than SSP in the Fe oxide-rich and in the carbonate-rich soil, respectively), partially attributed to the decreased precipitation rate of insoluble Ca phosphates with the added organic matter. Some BBFs increased micronutrient concentrations in grains and most decreased the P-to-Zn ratio relative to SSP. Overall, phosphatase and β-glucosidase activities increased with carbon-rich BBFs. Most of the studied BBFs could effectively replace fertilizers from non-renewable sources, in some cases with better crop P recoveries. Furthermore, some BBFs could provide additional benefits to grain quality, in terms of micronutrient supply for humans, and soil functioning. Full article