Photon-Counting Detector Computed Tomography (PCD-CT) boasts excellent spectral utilization capability. Combined with material decomposition methods, it enables the calculation of the effective atomic number ($Z_{eff}$) and density ($\rho$) of scanned materials. Traditional material decomposition methods derive $Z_{eff}$ and $\rho$ from physical models using either the basis material model or the dual-effect model. However, these methods generally fail to meet high-precision decomposition requirements due to model approximations and suffer from the limitation of severe noise amplification in $Z_{eff}$ images. This study proposes a physics-constrained deep learning network that achieves high-precision joint estimation of $Z_{eff}$ and $\rho$ by dynamically modeling nonlinear X-ray interactions. A Multilayer Perceptron (MLP) is employed to construct dynamic compensation functions dependent on energy ($E$) and $Z_{eff}$ for the photoelectric effect exponent and Compton scattering model in the X-ray interaction model. The decomposition network adopts Swin-Unet as its backbone and utilizes a hybrid loss function, which consists of L1 loss and SSIM loss for $Z_{eff}$/$\rho$, as well as a physics-informed loss derived from the L1 loss between the predicted $Z_{eff}$/$\rho$ and the monoenergetic linear attenuation coefficient images generated by the optimized X-ray model. This design allows the network to simultaneously learn data-driven features and physical principles. Comparative experiments were conducted on a PCD-CT system between the proposed method and four methods (Lan, U-Net, Butterfly-net, and Swin-Unet without physical constraints). The results demonstrate that: for standard materials, the proposed method achieves a Mean Absolute Percentage Error (MAPE) below 5% for both $Z_{eff}$ and $\rho$ decomposition, with superior Noise Power Spectrum (NPS) performance; for biological samples including freshwater crayfish and mouse, the $Z_{eff}$ images generated by the proposed method exhibit higher Multi-Exposure Fusion Structural Similarity Index (MEF-SSIM), reaching 0.9559 for crayfish and 0.8950 for mouse. The method also demonstrates superior detail recovery capability in the restoration of the speckled tissue structure of crayfish and the tissue regions of mouse. By incorporating constraints from monoenergetic images generated based on the dynamic X-ray interaction model, the network effectively learns the nonlinear decomposition process of $Z_{eff}$ within a data-driven framework. The proposed method improves decomposition accuracy while reducing decomposition noise and enhancing the quality of decomposed images.

In-depth transcriptome analysis of the Hardin crayfish, Faxonius wrighti.

Performance Egg Yolk Absorption and Digestive Enzyme Activity in Promoting Early Development of the Freshwater Crayfish (Cherax quadricarinatus)

Tumor necrosis factor alpha-induced protein 8-like mediates immune responses of Procambarus clarkii through protein-protein interactions.

Aphanomyces astaci, the etiological agent of crayfish plague, varies in virulence depending on their genetic strains. Five genotype groups (A-E) are well characterized and, with exception of genotype group A, cause significant mortality in European freshwater crayfish species. In this study, we aimed to investigate the presence and diversity of A. astaci genotype groups in Switzerland by adapting the qPCR assays (Simplex-qPCR and Duplex-qPCR) published by Di Domenico et al. (2021) to a Pentaplex-qPCR assay. The Pentaplex-qPCR was compared to Simplex-qPCR, Duplex-qPCR and Triplex-qPCR assays using artificial DNA fragments, culture and tissue samples. We performed the Pentaplex-qPCR on DNA extracted from formalin-fixed, paraffin-embedded tissue samples (1991-2020) and fresh tissue samples (2020-2024) of crayfish collected in Switzerland. Crayfish were mainly native crayfish species undergoing a crayfish plague outbreak and few invasive crayfish tested positive for A. astaci. The intra-assay repeatability and inter-assay reproducibility of the qPCR was assessed. The Pentaplex-qPCR assay was not inferior to the other qPCR assays (Simplex-qPCR, Duplex-qPCR, Triplex-qPCR) and reliably detected genotype groups A, B, D, and E in 31 of 45 crayfish populations (68.9%) across Switzerland. Most positive samples were linked to crayfish plague outbreaks in European crayfish species, except for four populations, where genotype groups B and D were found in North American signal crayfish (Pacifastacus leniusculus) and Louisiana red swamp crayfish (Procambarus clarkii), respectively. Genotype group C was not detected in any of the samples. Genotype group occurrence and heterogeneity were highest in the Rhine basin, particularly between 2016 and 2020, where groups A, B, D, and E were all detected. In the Ticino basin, genotype group diversity was high and genotype groups B, D and E were detected, while in the Rhone basin, only genotype group B was found. Genotype group D, typically associated with Louisiana red swamp crayfish, was identified in the Rhine basin in 1991 and suspected in 1994, respectively four and one year before the first known detection of its carrier species. Genotype group A was detected once in 2017 in the Rhine basin, causing limited mortality in a European crayfish population. The use of archived samples revealed a long history of A. astaci presence, dating back to 1991, providing valuable insights into the spatiotemporal dynamics of crayfish plague. Identifying genotype groups helps clarify potential routes of introduction for both pathogen genotype groups and carrier host species. Furthermore, it facilitates tracking outbreaks and identifying possible primary sources of spread. Future studies are needed to deepen our understanding of the pathogen's genetic variability in relation to virulence differences and spread.

ABSTRACT Freshwater crayfishes of the South American family Parastacidae include the Chilean‐endemic genus Virilastacus , currently comprising four described species. Despite their ecological importance and restricted distributions, the genetic diversity, phylogenetic relationships, and species boundaries within Virilastacus remain poorly understood. Here, we analyze mitochondrial DNA (COI) sequences from populations across the genus's known range in southern Chile to assess species limits, divergence times, and geographic structure. Phylogenetic analyses and multiple single‐locus species delimitation methods support the identification of five candidate species, comprising the four currently recognised species and a newly identified lineage, Virilastacus sp. ‘Calfuco’. Divergence time estimates place the origin of Virilastacus in the Middle Oligocene, indicating an ancient evolutionary history. We also report an expanded range for V. jarai , a narrower distribution for V. araucanius , and strong geographic structuring across the genus. These findings highlight previously overlooked diversity in Virilastacus and emphasise the need for further integrative taxonomic and conservation assessments.

This review is devoted to the systematization of modern technologies for the cultivation of freshwater crayfish. The purpose of the work was to generalize an extensive array of scientific data to identify key problems and determine the most effective and promising approaches in their aquaculture. As a result of the research conducted on the basis of the analysis of more than 120 domestic and foreign sources, the following results were obtained. It has been established that the biological features of crayfish, in particular, asynchronous growth and pronounced cannibalism, are the determining factors that form the fundamental differences between their cultivation and the technologies of working with other hydrobionts. Cannibalism is identified as the main limiting factor of planting density and overall productivity. In the course of the analysis, two main directions in crayfish aquaculture were identified and characterized in detail: industrial (RAS, pools) and pasture (natural reservoirs). It was determined that industrial methods make it possible to organize yearround production in controlled conditions, but require significant energy costs, while pasture cultivation is economically beneficial due to the use of a natural fodder base, but its effectiveness critically depends on external abiotic factors, primarily the temperature regime. To solve the key problem of cannibalism, a complex of technological measures was developed and systematized, including the provision of shelter, regular sorting of individuals by size groups, strict standardization of planting density, as well as innovative methods, such as immobilization of claws. A hybrid approach is defined as the most rational and promising production model, which integrates the stages of industrial production and growth of viable planting material in controlled RAS conditions with subsequent growth to marketable condition in natural reservoirs. This strategy makes it possible to level the shortcomings of each of the methods separately and promotes the maximization of economic efficiency and ecological sustainability of the production of valuable hydrobionts.

ABSTRACT In recent years, European countries have intensified efforts to control or limit the spread of invasive freshwater crayfish and the crayfish plague pathogen Aphanomyces astaci , while working to conserve native species such as the noble crayfish ( Astacus astacus ). Although crayfish shed relatively low amounts of DNA into their environment, environmental DNA (eDNA) approaches have proven effective for detecting their presence. A range of protocols and equipment is currently used in eDNA‐based monitoring of freshwater crayfish. To evaluate how methodological variation influences detection accuracy, we conducted the first European interlaboratory ring test using eDNA to detect A. astacus , the invasive signal crayfish Pacifastacus leniusculus , a chronic carrier of A. astaci , and the pathogen itself. The aim is to harmonize monitoring methods for crayfish and disease surveillance across laboratories. Eleven teams from thirteen European countries participated, each using its own equipment and protocols to collect and filter water from indoor tanks and outdoor ponds where the presence of A. astacus and P. leniusculus had been experimentally manipulated, as well as from a natural lake containing a P. leniusculus population. The resulting samples were analyzed in each team's laboratory. Despite methodological differences, all teams successfully detected DNA from both crayfish species in indoor tanks (3–10 crayfish/m 3 ). However, detection accuracy declined in outdoor ponds where crayfish density was an order of magnitude lower (0.32 crayfish/m 3 ). Detection was most variable for A. astaci , likely due to its very low prevalence in the host stock. Our study demonstrates the challenges of achieving consistent eDNA results across laboratories and highlights the importance of interlaboratory comparisons. It also underscores the need to identify sources of variability and error, an essential step toward developing robust and standardized protocols. This multinational intercalibration and exchange of knowledge improved methodology and enhanced reliability in crayfish detection.

This study evaluated the effects of natural calcium carbonate sources, eggshell (ES) and seashell (SS) powders on growth performance, survival, molting frequency, and exoskeletal calcium accumulation in juvenile red claw crayfish (Cherax quadricarinatus). Juveniles (0.21 ± 0.01 g) were reared for 60 days under five treatments (0, 5, 10, 15 mg ES L⁻1 and 15 mg SS L⁻1) in a static-water culture system equipped with biofiltration. All groups were fed a formulated diet containing 30% crude protein, 8% crude lipid, and 6% eggshell powder. No significant differences (P > 0.05) were observed in growth performance (2.55–2.65% day⁻1), FCR (1.55–1.69), or survival (71–78%) among treatments. Nevertheless, there is a trend of improved growth performance with the addition of calcium in water. In addition, molting frequency and carapace calcium content were significantly higher (P < 0.05) at 15 mg L⁻1 for both ES and SS treatments compared with other treatments. Both calcium concentration in culture water (R = 0.89) and carapace calcium (R = 0.82) exhibited strong positive correlations with molting frequency. While supplementing calcium through the water appeared to have minimal effects on growth and survival once dietary calcium requirements were met, it exerted clear positive effects on molting performance. Considering their abundance and low cost, eggshells therefore represent a practical, affordable, and sustainable calcium source for enhancing molting success in freshwater crayfish culture systems.

We provide a comprehensive survey on the bibliometric analysis of scientific publications on Pontastacus leptodactylus published in Web of Science (WoS). We found, based on 822 WoS publications, that countries such as Türkiye, France and Iran were among the leading contributors in this field during 1965-2023. Türkiye led with 216 publications, followed by France with 116 and Iran with 64 publications. The majority of publications consisted of articles, while Fisheries, Marine and Freshwater Biology and Zoology were among the main focus categories of publications. Comprehensive analysis identified some of the main academic trends in the field by detailing the scientific knowledge and collaboration networks in research on P. leptodactylus. In conclusion, this bibliometric analysis not only highlights the significant contributions of Türkiye, France and Iran to the study of P. leptodactylus, but also underscores the importance of collaboration and citation dynamics in shaping the academic landscape of the field, thereby providing valuable insights for future research directions.

Abstract. Climate change may reduce available habitat for native species, while simultaneously increasing suitable habitat for invasive species, which then compete with or predate on native species. Thus, climate change and invasive species can interact synergistically to negatively affect native species. It is important to identify climate refugia that are likely to be both suitable for native species and unsuitable for invasive species, under both present and future climate conditions. We propose a refugia habitat metric (RHM) based on ecological niche modelling. We demonstrate the utility of the metric via a case study of an endemic freshwater crayfish, or kōura (Paranephrops planifrons), which is threatened by both climate change and predation from the invasive brown bullhead catfish (Ameiurus nebulosus) in Aotearoa / New Zealand. We used maximum entropy (MaxEnt) ecological niche models to predict current and future habitat suitability for the two species across Aotearoa / New Zealand. By the period 2080–2100, suitable habitat will increase across the northern and western North Island for catfish, while suitable habitat for kōura will decrease overall and shift southwards and towards more mountainous regions. Using the refugia habitat metric, we identified areas of habitat within the current range of kōura, with significant potential refugia habitat outside the species current range. Using the refugia prioritization metric will allow conservation managers to identify habitat for protection and potentially translocation target sites for vulnerable native species.

Paragonimiasis, most commonly caused by Paragonimus westermani, is endemic in East and Southeast Asia and commonly transmitted through ingestion of raw or undercooked freshwater crab or crayfish. While pulmonary manifestations predominate, extrapulmonary involvement such as cerebral paragonimiasis can occur. We describe three cases of imported familial pulmonary and extrapulmonary paragonimiasis from Southeast Asia and diagnosed in Korea. A 12-year-old boy presented with dizziness, headache, nausea, and vomiting. Brain magnetic resonance imaging revealed a hemorrhagic mass-like lesion with leptomeningeal enhancement, and chest tomography showed serpiginous tubular opacities with multifocal consolidations. Laboratory evaluation revealed marked eosinophilia (46.2%). Further history revealed habitual consumption of raw crayfish while residing in Cambodia. Serology was positive for P. westermani and Clonorchis sinensis IgG. Treatment with albendazole and praziquantel resulted in resolution of symptoms and normalization of eosinophil counts. Further evaluation identified similar findings in his parents who were misdiagnosed as tuberculosis and cerebral hemorrhage, and the family was treated with praziquantel. This familial cluster highlights the importance of detailed dietary and travel history in patients with eosinophilia and neurological symptoms. This case was discussed at the Clinical Grand Round of the Korean Society of Infectious Diseases on November 7, 2024.

Context: IoT (Internet of Things) is a network of sensors connected to a microcontroller that collect data and then send it via the Internet to a platform for processing and visualization. Objective: The objective of this project was to develop an IoT prototype to monitor water parameters in an aquaculture farm (tilapia and freshwater lobster) at the Faculty of Natural Sciences of the University of Guayaquil. Method: Applied research allowed us to acquire theoretical and practical knowledge, complemented by interviews and surveys conducted with the researchers responsible for the multitrophic farm. The project was organized using the Scrum framework. Results: The survey of those responsible for aquaculture showed that the IoT prototype facilitates real-time monitoring of aquaculture parameters, which can be viewed from the ThingSpeak platform via a wireless connection. Conclusions: The main parameters that must be monitored in an aquaculture farm to ensure the health and optimal growth of aquatic organisms are: pH, temperature, water level, flow, and turbidity. The ESP32 controller allows connection to the Internet, and the choice of reliable and properly calibrated sensors is essential to ensure accurate measurements.

Freshwater crayfish Pontastacus leptodactylus is an indigenous European species of considerable ecological and commercial significance. However, it is highly susceptible to the oomycete Aphanomyces astaci, the causative agent of crayfish plague. Although its importance is widely recognized, little information exists on how seasonality affects the physiology and welfare of this species. The present study was designed to (i) investigate seasonal effects on the physiological responses of P. leptodactylus in relation to abiotic factors and crayfish plague outbreak, and (ii) identify the most suitable period for restocking in temperate regions. To achieve this, we characterized for the first time the mRNA expression of hsp70, hsp90, hif-1α, ubiquitin, and gapdh (as endogenous control gene), alongside protein levels of Hsp70, Hsp90, hydroxylated Hif-1α, ubiquitin conjugates, cleaved caspases, Bax/Bcl-2 ratio, and interleukin-6 (IL-6). Our findings revealed that cold stress triggered both the heat shock response and apoptosis. Interestingly, despite the activation of apoptosis, which generally suppresses inflammation, IL-6 levels increased, suggesting a possible association with A. astaci infection. Moreover, elevated Hif-1α levels indicated hypoxic stress during warmer months, likely linked to reduced oxygen availability and turbidity. Overall results suggest that crayfish plague epidemics may intensify with rising temperatures, whereas winter appears to be the optimal period for restocking. Interestingly, in addition, freshwater crayfish in temperate latitudes are organisms that face both cold and heat stress seasonally in the same ecosystem.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-26804-5.

Objective: The reproductive potential of Procambarus llamasi was evaluated in an aquaculture recirculation system (ARS). Design/methodology/approach: The organisms were collected in the community of Xmaben, Hopelchén, Campeche. The experiment was carried out from August to September 2023 in the livestock area of the Colegio de Postgraduados, Campus Campeche. An experimental design with three treatments and one control was used, each with three replicates, randomly distributed in an ARS as follows: T1: 1Male:2Females, T2: 1M:3F, and T3: 1M:4F, and the control. Water physicochemical parameters were recorded daily, and biometric measurements were taken biweekly along with the count of ovigerous females. Results: The culture of P. llamasi in ARS allows for development and reproduction. Furthermore, there was no significant difference in the behavior of the water’s physicochemical parameters, despite ammonium levels fluctuating around 0.2 mg/L. The optimal ratio with the highest number of ovigerous females was treatment two (1M:3F), making this the recommended ratio for Procambarus culture in Campeche. Study limitations/implications: It is necessary to test this type of culture system with other Procambarus species found in the state, analyzing molting production and calcium concentration in the aquaculture recirculation system. Findings/conclusions: The acocil (freshwater crayfish) is a viable alternative for obtaining animal protein and can be cultivated in family backyard systems in rural areas of Campeche.

The freshwater lobster Cherax quadricarinatus is an aquaculture commodity with high economic value, yet it remains relatively unfamiliar to the general public. Nevertheless, market demand for this species has shown a significant upward trend, both domestically and internationally. In Indonesia, the increase of aquaculture production specially on freshwater lobster has not been sufficient to meet existing demand, primarily due to the limited availability of high-quality broodstock and the low reproductive capacity of female brood lobsters. One potential strategy to address this issue is the optimization of feed quality. This study aims to evaluate the effects of a dietary combination consisting of mung bean sprouts (Vigna radiata), white sweet potatoes (Ipomoea batatas), and commercial pellets enriched with vitamin E on the reproductive performance of female freshwater lobsters. The results indicated that the best feed formulation was observed in Treatment P3, which consisted of 25% mung bean sprouts, 50% Fengli 3 pellets + vitamin E, and 25% white sweet potatoes. This treatment accelerated gonadal maturation to 25 days and resulted in a fecundity of 467.33 eggs, a fertilization rate (FR) of 97.84%, a hatching rate (HR) of 92.70%, and a survival rate (SR) of 90.87%. The content of vitamins A, C, and E in mung bean sprouts is known to stimulate spawning and enhance embryo hatchability, while bioactive compounds in white sweet potatoes contribute to the synthesis of reproductive hormones such as estrogen and vitellogenin.

The invasive oomycete pathogen Aphanomyces astaci significantly threatens native European crayfish populations, prompting investigations towards the effects of protective immunostimulation on the immune response of the vulnerable noble crayfish (Astacus astacus). Here, we evaluate the effect of three oomycete-derived immunostimulant treatments: laminarin (β-1,3-glucan found within the Ap. astaci cell wall), inactivated Ap. astaci spores and Ap. astaci hyphal homogenate. Our findings reveal immediate changes in the noble crayfish total haemocyte count (THC), differential haemocyte count (DHC), and gene expression. A short-term increase in the THC was observed in all treatments, with a gradual return to normal values 8h post immunostimulation. Granular haemocytes seem to be involved in response to immunostimulation with inactivated Ap. astaci spores, while the number of semi-granular and hyaline haemocytes increased in response to laminarin and Ap. astaci hyphal homogenate. Analysis of the differentially expressed genes showed that the Prophenoloxidase pathway genes and Toll pathway genes are involved in the response to oomycete-derived immunostimulants. Prolonged effects of immunostimulation were reflected in the decreased C/EBP and Kr-h1 gene expression in the hyphal homogenate group as well as decreased Kr-h1 expression in the spore group. Taken together, our results indicate that immunostimulation causes a dynamic change in the noble crayfish immune system response, with similarities in the gene expression patterns between immunostimulated and Ap. astaci infected noble crayfish. As a future research focus, we highlight the importance of molecular characterisation of the genes involved in the anti-oomycete response which could provide valuable insights into pathogen resistance in freshwater crayfish. In the context of the Ap. astaci mediated downfall of the noble crayfish stocks across Europe, further exploration is needed regarding the benefits of the oomycete-derived immunostimulation that can potentially support conservation and aquacultural efforts.

Procambarus acanthophorus is a freshwater crayfish species endemic to Mexico with high aquaculture potential. Monitoring genetic diversity during the early stages of domestication is crucial to avoid the erosion of adaptive potential and ensure the success of breeding programmes. This study analysed changes in genetic variability across four consecutive populations: a wild founder population (G0) and three captive-bred generations (G1, G2, G3), using five mitochondrial markers (COI, COII, COIII, tRNA-Asn/12S and D-loop) and one nuclear marker (elongation factor 2, EF-2). A total of 21 haplotypes were detected, with decreasing haplotype richness from G0 (n = 10) to G3 (n = 5), although haplotype and nucleotide diversity remained within moderate to high ranges (Hd = 0.65-0.90; π = 0.0020-0.0466), consistent with diversity levels reported in other early-stage domestication studies. AMOVA revealed that 68% of the total genetic variation was among generations, and pairwise Fst values confirmed progressive differentiation. These findings suggest that while some genetic erosion is occurring, the implemented breeding practices have preserved a substantial portion of genetic diversity during early domestication. This study provides a preliminary genetic baseline for the management of P. acanthophorus breeding programmes and underscores the need for continued monitoring using complementary nuclear markers.

Habitat influences the evolution of antennae and antennule size in freshwater crayfishes

Paragonimus westermani, a zoonotic lung fluke, causes respiratory symptoms resembling tuberculosis. In Asia, human infections typically occur through the consumption of raw or marinated freshwater crabs or crayfish containing P. westermani metacercariae. With increasing global food trade and occasional exposure during international travel, cases have been reported in non-endemic regions, raising significant food safety concerns. In this study, naturally infected freshwater crayfish (Cambaroides similis) were collected from Haenam, South Korea. Crayfish were marinated in soy sauce containing either 10% or 20% sodium chloride (NaCl) and stored at 4°C for 1-60days. P. westermani metacercariae were recovered at each time point and morphologically classified as viable, borderline (uncertain viability), or dead. To assess infectivity, 100 P. westermani metacercariae from each group were orally inoculated into beagle dogs (n=3 per group), and worm recovery was assessed after 12weeks. After 14days of marination, the survival rates of P. westermani metacercariae were 83.3% in 10% NaCl and 2.0% in 20% NaCl soy sauce. Complete inactivation occurred after 60days in 10% NaCl and 30days in 20% NaCl. Infectivity tests showed worm recovery rates of 82.5% (viable), 33.7% (borderline), and 0% (dead). These findings indicate that even high-salt, cold-storage marination does not guarantee parasite inactivation. Viable P. westermani metacercariae can persist in marinated crayfish under commonly used culinary conditions. These results underscore the risk of foodborne lung fluke infections and emphasize the need for clearer public health guidance regarding the consumption of undercooked or inadequately processed freshwater crustaceans.