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The quality of water used in aquaculture ponds is one of the crucial factors influencing the smell and sensory properties of fish. The water samples were taken from the rainbow trout fish ponds from three different fish farms in three provinces in Türkiye in four different seasons. The samples were analyzed for the volatile components by employing HS-SPME/GC–MS. Seven different volatile groups including aldehydes, ketones, esters, alcohols, volatile phenols, terpenes and other aromatic substances were identified in the samples. Among these, aldehydes were found to be the most dominant. (E)-2-Heptenal, nonanal, acetophenone, and 2-ethyl-1-hexanol are thought to be responsible for the off-odors in the water that have the potential to cause off-odors in fish. It was also determined that the amounts of these compounds increases in winter due to lower water temperature. Fish producers should monitor water quality on a regular basis to prevent off-odor compounds that degrade fish quality. [ABSTRACT FROM AUTHOR]

The article explores the seasonal piscivory behavior of pumpkinseed sunfish in pond ecosystems in Southern Ontario, Canada. The study reveals that pumpkinseed sunfish exhibit extensive seasonal fish consumption in ponds, even in the absence of large predators. The findings suggest that mesopredator fish like pumpkinseed may fill the top predator niche in pond ecosystems, highlighting the importance of considering ponds in ecological research and understanding the impacts of expanding mesopredator species on aquatic food webs. The study emphasizes the need for further research to test the mesopredator release hypothesis and quantify the consequences of meso- and top predator expansion in pond ecosystems. [Extracted from the article]

We study the comparative advantage of firms with focused and multidivisional organizational forms at attracting valuable human capital. Using the merger and acquisition (M&A) advisory industry as a laboratory, we show that high-performing individuals are more likely to migrate to boutique (focused) banks, especially those who are still on the upward trajectory of their career. Such migration is amplified by the cross-subsidization inside bulge bracket (multidivisional) firms, proxied by poor performance of their non-M&A departments. The transition of skilled labor improves the performance of the boutique sector, potentially contributing to the rise of boutiques over the past two decades. Moreover, M&A deal outcomes differ when having boutique advisors. Our findings suggest that corporate organizational structure and labor migration can jointly shape industry dynamics. This paper was accepted by Victoria Ivashina, finance. Funding: W. Wang gratefully acknowledges financial support from the Daniel C. Smith Fellowship. Supplemental Material: Data and the internet appendix are available at https://doi.org/10.1287/mnsc.2021.03829. [ABSTRACT FROM AUTHOR]

This study investigated 3‐ to 5‐year‐olds' (N = 64, 37 girls, 62.5% White, data collected between 2021‐2022) ability to use probabilistic information gleaned through active search to appropriately change or maintain expectations. In an online fishing game, children first learned that one of two ponds was good for catching fish. During a subsequent testing phase, children searched the ponds for fish. Half saw outcomes that were probabilistically consistent with training, and the other half saw outcomes that were probabilistically inconsistent. Children in the Inconsistent condition adapted their search strategies, showing evidence of changing their expectations. Those in the Consistent condition maintained their initial search strategy. Trial‐by‐trial analyses suggested that children used a combination of heuristic and information integration strategies to guide their search behavior. [ABSTRACT FROM AUTHOR]

Featured Application: Although this is a fundamental microbiological study, its results indicate the necessity of changing the approach to fish ponds maintenance and focusing all hygiene measures on the eradication of biofilms and not on a simple disinfection. Also, the practical laboratory approach to testing biofilms of A. salmonicida subspecies salmonicida should be changed. Biofilm formation of clinical isolates of Aeromonas salmonicida subspecies salmonicida was compared using scarce (minimal M9 and ABTG w/o amino acids) and enriched nutrient media (Tryptone Soya broth) at 8 °C, 16 °C, and 25 °C using direct enumeration of viable cells in biofilm (log CFU), crystal violet staining (ODc) of the formed biofilm biomass, and liquid–air border biofilm formation (pellicle test). Whole-genome sequencing (WGS) was performed with the usage of an Oxford nanopore system by Genomics and Transcriptomics Labor Düsseldorf (Heinrich-Heine-Universität Düsseldorf, Germany). A bioinformatic analysis was performed with the usage of Geneious Prime® 2023.0.4 (Biomatters, Inc., Boston, MA, USA). All data were analyzed using Statistica software version 13.0, and changes in biofilm production in correlation to changes in the type of nutritional medium and temperature were compared between groups using a one-way ANOVA analysis and Tukey's test. All isolates formed biofilms in minimal M9 at 8 °C and 16 °C, and nine isolates failed to form biofilms in minimal M9 at 25 °C. In an ABTG medium, all isolates produced biofilms at 8 °C; however, three isolates at 16 °C and seven isolates at 25 °C failed to form any biofilms. Significant biofilm formation was observed in TSB at all temperatures. Some strains that formed a good biofilm in solid–liquid interface did not have the ability to form a pellicle (liquid–air border biofilm), and vice versa. In all cases of nutritional medium and temperature changes, there were statistically significant differences in the intensity of biofilm production, especially in the detected number of viable cells inside biofilms (log CFU, p < 0.005). Multiple biofilm-production genes, including polar flagella (filM) LuxR family (transcriptional regulators) and VapA family of histidine-kinase-associated genes, were sequenced from all studied isolates. Genetic differences based on geographical origin were not observed among the isolates. Significant variations in isolates' ability to form biofilms were observed, possibly due to epigenetic factors. The optimal temperature for biofilm formation of A. salmonicida subspecies salmonicida in scarce media was 8 °C, and the majority of isolates were not capable of biofilm formation at 25 °C without enriched nutrient media. [ABSTRACT FROM AUTHOR]

The significant role played by the gut microbiota in fish growth, development, immunity, and overall health has been widely established. Nevertheless, there remains a lack of clarity regarding the interaction and origin between the environmental microbiota and the gut microbiota of aquaculture species within the aquaponics coupling system. Thus, we conducted an analysis of the gut microbiota of largemouth bass (Micropterus salmoides) obtained from an indoor enclosed circulating water aquaponics coupling system located in greenhouses in northern China. Additionally, we examined the microbiota of the fish pond water and tomato rhizosphere soil using high-throughput sequencing of the 16S rRNA gene. Our results demonstrated significant differences in the compositions of fish pond water, rhizosphere soil, and the gut microbiota of largemouth bass. Moreover, these compositions changed throughout the culture period. Approximately 11.99% of the bacterial composition in the gut microbiota of largemouth bass could be attributable to the rhizosphere soil microbiota, while 62.01% of the bacterial composition could be attributable to the fish pond water microbiota. However, the proportion of bacteria in the gut microbiota from the fish pond water microbiota remained respectively 40.90% and 56.15% in May and September, which increased markedly to 88.97% in July. Similarly, the proportion of bacteria in the pond water microbiota from the tomato rhizosphere soil microbiota were respectively 0% and 8.95% in samples collected in May and September, which increased markedly to 69.26% in July, and the proportion of bacteria in the gut microbiota from the tomato rhizosphere soil microbiota were respectively 0.07% and 0% in samples collected in May and September, which increased to 0.45% in July. The research results offer essential insights into the interactions and origins of environmental microbiota and gut microbiota in the aquaponics system of cultured fish. This knowledge could enhance green aquaponics practices for largemouth bass. [ABSTRACT FROM AUTHOR]

Research into freshwater communities often aims to link patterns of species distribution in ponds with underlying biotic factors. However, errors with species detection (e.g. false negatives) may underestimate distribution and bias assessments of community structure. Occupancy models that account for imperfect detection offer a solution to this problem. Here, we used three methods (call/visual encounter surveys, dip‐netting and newt trapping) to survey amphibians and fish (potential amphibian predators) at 100 ponds in an urbanised landscape in Hungary over one breeding season. We estimated species detection probabilities for amphibians (all life stages combined) and fish using occupancy models to gain insight into amphibian‐fish relationships and other survey‐specific variables. We detected nine amphibian and 20 fish species. There were relatively low but variable estimated probabilities of detection for amphibians (mean: 0.320, 95% Bayesian credible interval: 0.142–0.598), with three species having detection rates < 0.1. Probabilities of detection peaked in the middle of the breeding season and increased with survey effort. Detection probabilities of five species were negatively associated with the detection of fish at a pond, while there were positive relationships between detection and emergent vegetation cover. We found no substantial differences in detection rates among the three survey methods. The probability of detecting fish was much higher than for amphibians (0.588, 0.503–0.717) but was lower at ponds with high emergent vegetation where amphibian detection was higher. Our results underscore the importance of accounting for the imperfect detection of both response organisms and potentially interacting species in aquatic community studies. We recommend applying multi‐species occupancy models to enable inference for both common and rare species at ponds in landscapes subjected to human disturbances. [ABSTRACT FROM AUTHOR]

In this study, the current status of water quality in Güllük Lagoon and Köyceğiz-Dalyan Lagoon was examined by comparison using water quality indexes, multivariate statistical analyses and geographical information systems. Water quality parameters comprised of 9 variables i.e., WT, pH, DO, NO2-N, NO3-N, NH4-N, TP, SSM, BOD5 were measured in Güllük Lagoon and Köyceğiz-Dalyan Lagoon. Although there are important activities such as earthen pond fish farms, fish hatcheries, feldsbat and marble quarries, streams carrying domestic wastes, port, secondary residences and agricultural activities in Güllük Lagoon, there are intense tourism and agricultural activities in Köyceğiz-Dalyan Lagoon. The average concentrations of DO, TP, NO2-N results in Güllük Lagoon and DO, TP and NH4-N results in Köyceğiz-Dalyan Lagoon were determined in second class water quality according to surface water quality criteria. While both lagoons were found to be in "Good" quality class as a result of water quality index, Güllük Lagoon was found to be "medium polluted" and Köyceğiz-Dalyan Lagoon was found to be "slightly polluted" quality class as a result of comprehensive pollution index. It was observed that water quality index values of both lagoons decreased in the dry season, while their comprehensive pollution index values increased in the dry season. On the basis of the general averages of water quality index, it was found as Köyceğiz-Dalyan Lagoon (85.0) > Güllük Lagoon (84.05), and on the basis of the general averages of comprehensive pollution index, it was found as Güllük Lagoon (1.34) > Köyceğiz-Dalyan Lagoon (0.79). Relationships between variables were determined by geographical information systems (IDW technique) and statistical analyses (Descriptive statistics, Spearman rho correlation, Kruskal-Wallis test, multiple linear regression and Principal component analysis). As a result of multiple linear regression analysis in measured parameters, it was determined that the most important parameter affecting the water quality index in Güllük Lagoon was NH4-N, and the most important parameter affecting the comprehensive pollution index was SSM. In Köyceğiz-Dalyan Lagoon, it was observed that the water quality index was affected by the WT parameter and the comprehensive pollution index was affected by the SSM parameter. There is no difference in the concentrations of the average water quality parameters measured in both lagoons, and both lagoons are generally in the first and second class surface water quality class. However, Güllük Lagoon, which contains more different pollutant sources than Köyceğiz-Dalyan Lagoon, is shown to be more polluted according to water quality indexes. In addition, it has been determined that SSM is the most important parameter that determines the water quality among the measured water quality parameters of both lagoons. [ABSTRACT FROM AUTHOR]

Urbanisation results in the loss and alteration of natural wetlands and ponds. However, garden ponds in cities and towns can potentially act as rich reservoirs of aquatic biodiversity and stepping stones for dispersal. Homeowners with a range of different motivations, including biodiversity values, install garden ponds. Here, our main aim was to study whether the design and management choices of garden pond owners depended on the location of ponds (capital city vs. countryside), when ponds were installed (pond age), or whether fish were introduced. We surveyed 834 garden pond owners across Hungary using a citizen science questionnaire, asking questions on pond size, location, construction date and materials, vegetation structure, introduction of fish and management practices. From 753 validated responses, we found that the introduction of fish into ponds and high urbanisation were strongly associated with local features and management practices, especially large ponds with a water circulation feature, irrespective of pond age. A typical garden pond in Hungary is ~ 20 m2, < 10 years old, made of rubber lining, contains fish, aquatic vegetation and circulating water, and is actively managed. There was a spatial separation of ponds based on local features between ponds in the capital city (Budapest) and elsewhere. These findings suggest that garden pond owners in the city were more likely to make different choices in pond design and management compared to owners in regional areas. Our results also suggest that pond owners may primarily select management practices to improve habitat quality for ornamental fish. Our findings have important implications for maintaining aquatic biodiversity in urban areas, where garden ponds may be the only aquatic habitat available. [ABSTRACT FROM AUTHOR]

The Delta Select channel catfish strain (DS) was developed by selection for increased growth and carcass yield. Progeny from DS and the Delta Control (DC) strain (a randomly bred strain from the same base population as DS) were compared in three trials. Trial 1: unvaccinated ~1‐year‐old fingerlings from each strain reared communally in 0.4‐ha ponds. Trial 2: vaccinated ~ 1‐year‐old fingerlings from each strain grown in separate replicated 0.4‐ha ponds and fish in about half the ponds were given an ESC vaccine‐booster at 13 months post‐hatch. Trial 3: same procedures as Trial 2, except fish were raised in replicate 0.04‐ha ponds with no vaccine‐booster. In Trial 1 DS were larger at stocking, larger at harvest, and had higher carcass yield than DC; in Trial 2 DS were larger at harvest, had better survival and higher production/ha than DC. Vaccine‐booster had no effect on fish growth or survival. DS and DC were not different for any traits in Trial 3. Although outcome varied among trials, the overall results indicated a vaccine booster did not affect growth or survival, DS strain fingerlings grew faster than DC fingerling, and DS had higher carcass yield than DC strain fish when reared communally. [ABSTRACT FROM AUTHOR]

This study explored how increased water turbidity in open-aquaculture ponds as a result of enhanced fertilization influences piscivorous bird assemblages and predation pressure on fish. Fertilization treatments were applied to 24 earth-bottom ponds, and bird assemblages, visitation frequencies, diversities and predation rate responses were compared at species richness and across four functional group scales during six months. Bird visitation frequency, species richness and functional diversity increased around unfertilized ponds, especially for large wading birds. Fertilization and bird species richness were each negatively related to bird predation rate, whereas functional diversity was positively associated with predation rate regardless of pond fertilization. Furthermore, predation rate reduced in response to pairwise interactive effects of fertilization and functional group identity, but increased with fertilization's respective interaction with functional diversity and visitation frequency. Contrastingly, species richness showed no interactive effect with fertilization or visitation rate. Thus, in applying enhanced pond water fertilization as a mitigation measure for controlling and tracking damage impact caused by piscivorous birds, it is potentially more beneficial to adopt a bird functional rather than species-based approach, given the observed higher sensitivity of functional diversity in predicting predation rates. The findings present novel, farmer-centered and affordable strategies for piscivorous problem-bird control toward sustainable aquaculture. [ABSTRACT FROM AUTHOR]

This study aimed to achieve a better understanding of the features of zooplankton assemblages in small water bodies and their biodiversity and composition in relation to the presence of fish and accompanying environmental characteristics. This study was conducted in 16 mid-field ponds. Compositional and biodiversity indexes and ordination methods were used to analyze the relationship between zooplankton assemblages in unstable fishless and stable fish ponds. A total of 121 zooplankton taxa were identified. Compositional indicators revealed significant differences in zooplankton assemblages between fish ponds (FPs) and fishless ponds (FLPs). Canonical correspondence analysis indicated that variation in zooplankton assemblages depended on the ponds' features. Most of the high trophic state indicator species were present only in FPs or occurred sporadically in FLPs. Rarefaction and extrapolation indicated a higher number of zooplankton taxa in FPs than in FLPs. The stability of the ecosystem was essential for maintaining the high species richness of zooplankton. Diversity indices were not influenced by variations in species composition or environmental differences among ponds. Diversified pond types are necessary to maintain the heterogeneity of mid-field ponds, which support the high regional biodiversity of zooplankton assemblages. [ABSTRACT FROM AUTHOR]

In order to explore the effect of fishponds on soil water, salt transport and salinization in cropland wasteland, a study on soil water balance and salt distribution pattern in a cropland–wasteland–fishpond system was carried out in 2022–2023 in a typical study area selected from the Yichang Irrigation Area of the Hetao Irrigation District. A water balance model was established for the cropland–wasteland–fishpond system to analyze the effects of irrigation on soil salinity at the boundaries of the cropland, wasteland, and fishpond. The results showed that the lateral recharge from the cropland to the wasteland during spring irrigation in 2022 was 24 mm, the lateral recharge generated by fishponds to wasteland was 18 mm, and the lateral recharge from fishponds to fishpond boundaries was 34 mm. In the fertility period of 2023, the lateral recharge from cropland to wasteland was 15 mm, the lateral recharge from fishponds to wasteland was 9 mm, and the lateral recharge from fishponds to fishpond boundaries was 21 mm. Due to the low salinity content of fishpond water, it diluted the groundwater of the wasteland, and the soil salinity at the boundary between the wasteland and the fishpond was monitored. The data show that the soil salinity at the boundary of the fishpond was smaller than that of the wasteland, which indicates that the migration of fishpond water to the wasteland will not lead to an increase in the soil salinity of the wasteland, but rather to a decrease in the soil salinity of the wasteland. Fishpond regulation has a significant impact on soil and groundwater, and when the topographic conditions of the Hetao irrigation area allow, the model of cropland–wasteland–fishpond can be appropriately adopted to solve land degradation and increase the economic income of farmers; the results of the study provide a contribution for the improvement of the management of land use and soil salinization in the Hetao irrigation area. [ABSTRACT FROM AUTHOR]

The ectoparasitic copepod Lernaea cyprinacea (anchor worm) has more than 100 host species among teleost fishes and affects cyprinids both in fish farms and natural waters. In addition, while L. cyprinacea infection in amphibians has been recorded in Asia, North and South America, there is no data available in the literature on their presence in Europe. In this study, we first reported L. cf. cyprinacea parasitising an anuran tadpole in Europe. Specimens of L. cf. cyprinacea were observed attached to a tadpole of the agile frog (Rana dalmatina), which was caught during fishing of crucian carp fingerlings (Carassius carassius) from a small fish pond in Hungary during the summer of 2012. The infected tadpole was collected from a rearing pond, where juvenile crucian carps were kept. The tadpole was inspected in the laboratory, and digital photos were taken. The parasites were found attached to the body-tail junction and to the leg of the tadpole (at Gosner stage 41). The parasite species was identified as L. cf. cyprinacea based on morphological traits. [ABSTRACT FROM AUTHOR]

Out-of-season breeding is an effective method for addressing seasonal shortages of fry in aquaculture species such as largemouth bass (LMB) for year-round production. Off-season breeding of LMB can be achieved by subjecting breeding LMB to prolonged low-temperature conditions; however, this can alter reproductive rhythms, affecting the quality of their sperm and leading to a decrease in reproductive efficiency. Therefore, it is crucial to investigate issues such as the damage to the testes and the related mechanisms caused by low-temperature stress during out-of-season breeding. In this experiment, we assessed the changes in the testes during this time in LMB by comparing reproductive rhythms, testicular histomorphology, ultrastructure, antioxidant capacity and apoptosis. We synthesized measurements of LMB from three identically treated cement ponds and fish exposed to water temperatures of 13–16 °C to assess the changes in the testes. The results showed that (1) out-of-season reproduction delayed sperm production and promoted sperm redevelopment in LMB, various hormone levels have changed over time (e.g., LH, FSH, and T). (2) The head plasma membrane of LMB spermatozoa was separated, and the middle mitochondria were swollen. (3) The expression levels of antioxidant enzymes (cat, sod, and gpx) were upregulated, and oxidative stress occurred in LMB. (4) The expression levels of apoptosis genes (e.g., bax, bcl2, and caspase3) were upregulated, and apoptosis occurred in LMB due to off-season breeding. Moreover, important genes of the mitochondrial apoptosis pathway (bid, CYT-C) were upregulated, indicating that spermatozoan apoptosis in LMB was probably achieved through the mitochondrial apoptosis pathway. These results suggest the delays, damage, and regeneration of LMB testes. Our findings provide new insights into the molecular mechanisms that trigger changes in sperm quality during out-of-season breeding in fish. [ABSTRACT FROM AUTHOR]

Periphyton communities are fundamental components of freshwater ecosystems that influence water quality, nutrient cycling, and productivity. Additionally, periphyton communities serve as valuable food sources in aquaculture. The periphyton communities on two substrates—heather mats and geotextiles—were compared in four temperate fishponds. After 51 days of immersion, the geotextiles exhibited significantly greater fluorescence, indicating a greater abundance of algae and cyanobacteria. Conversely, the abundance (and biomass) of periphyton invertebrates on heather mats was greater than that on geotextiles, and the difference became more pronounced over time. These differences resulted from significantly greater dipteran larval abundances (biomasses) on the heather mats than on the geotextiles. This study suggested that heather mats can significantly enhance food abundance and availability within the water column under Central European conditions. [ABSTRACT FROM AUTHOR]

This paper is inspired by traditional rural fishing methods and proposes a new metaheuristic optimization algorithm based on human behavior: Catch Fish Optimization Algorithm (CFOA). This algorithm simulates the process of rural fishermen fishing in ponds, which is mainly divided into two phases: the exploration phase and the exploitation phase. In the exploration phase, there are two stages to search: first, the individual capture stage based on personal experience and intuition, and second, the group capture stage based on human proficiency in using tools and collaboration. Transition from independent search to group capture during the exploration phase. Exploitation phase: All fishermen will surround the shoal of fish and work together to salvage the remaining fish, a collective capture strategy. CFOA model is based on these two phases. This paper tested the optimization performance of CFOA using IEEE CEC 2014 and IEEE CEC 2020 test functions, and compared it with 11 other optimization algorithms. We employed the IEEE CEC2017 function to evaluate the overall performance of CFOA. The experimental results indicate that CFOA exhibits excellent and stable optimization capabilities overall. Additionally, we applied CFOA to data clustering problems, and the final results demonstrate that CFOA's overall error rate in processing clustering problems is less than 20%, resulting in a better clustering effect. The comprehensive experimental results show that CFOA exhibits excellent optimization effects when facing different optimization problems. CFOA code is open at https://github.com/Meky-1210/CFOA.git. [ABSTRACT FROM AUTHOR]

Introduction: An important blind spot in current aquaculture governance research and practice is recognizing the high dependency of the sector on commons (i.e., shared resources), and their interconnectivity with other sectors such as agriculture. This is particularly evident in Indonesia where there is general lack of social and governance research on aquaculture. The purpose of this study is to: (1) identify the commons that need to be governed in pond aquaculture systems, and (2) identify the arising governance challenges from those commons and potential solutions. Methods: We apply Elinor Ostrom's Socio-Ecological Systems Framework (SESF) to identify variables influencing collective action through semistructuredinterviews with relevant key informant actors in a milkfish aquaculture village in Gresik, Indonesia. Our case study approach allows for a rich description through qualitative data to understand system interactions. We interviewed 22 stakeholders including regional and local government officials, fish farmers (owners and workers), patrons and local academics. Results and discussion: Our findings indicate five governance challenges influencing collective action: (1) limited access to capital and dependence on patrons, (2) lack of govern institutions, (3) continued government program failure, (4) lack of community leadership, and (5) lack of motivation and incentives to collectively act. These imply that governance policies may be more successful if monitoring mechanisms are applied to ensure that government funding is more precisely targeted at improving the livelihoods of traditional fish farmers. Furthermore, attempts to support social capital, network structures, and improve trust-reciprocity among relevant stakeholders (i.e., farmers, extension officers, private business actors) in the form of capacity building is likely more effective than other monetary incentives or the enforcement of top-down rules that don't fit local needs. [ABSTRACT FROM AUTHOR]

Background: This study examines seasonal and regional trends in chlorophyll-a concentrations and the dynamics of nitrogen (N) and phosphorus (P) in 32 fishponds (resulting in 150 pond-year cases) employed for fish production. Fishponds have a poor ecological state, requiring further insights for pond management. To gain those insights, monthly data on the pond environment were collected over the growing seasons from April to September (up to 14 years) across lowland to highland regions in Czechia. We used a ratio of dissolved inorganic nitrogen to total phosphorus (DIN:TP) to investigate seasonal patterns of N and P limitations. Results: Fishponds in the lowland region (below 199 m above sea level, a.s.l.) were predominantly N-limited (80%), while ponds in the midland region (200–449 m a.s.l.) exhibited P limitation at the beginning of the growing season (April–May) and N limitation by the end of the season (August–September; 90% of fishponds). Highland fishponds (above 450 m a.s.l.) showed frequent P limitations, especially during the beginning of the season. Chlorophyll-a concentrations varied on both regional and seasonal scales, with the overall phytoplankton biomass peak at 31 ha of pond surface area. Chlorophyll-a remained stable at the beginning of the season regardless of the DIN:TP ratio but increased with a lower DIN:TP ratio by its end. The chlorophyll-a concentrations were lowest at the beginning and highest at the end of the season and decreased with altitude. Conclusions: Seasonal and regional variations in nutrient limitations and chlorophyll-a occur in fishponds. Our study suggests that targeted seasonal nutrient input and enhanced monitoring can significantly improve fishpond management practices and ecosystem stability. [ABSTRACT FROM AUTHOR]

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To investigate difference in the quality of the different parts (back, tail muscles, and fish skin) of Opsariichthys bidens from pond and rice field cultures, a comparative study was conducted in terms of nutritional composition, volatile flavor profiles and gut microbiota. In detail, the texture, free amino acids, fatty acids were further assessed. The results suggested that the moisture content, crude protein and crude fat content in the skin of O. bidens are higher than those in the back and tail muscles, regardless of breeding modes. The fish cultured in the rice field had a higher protein content than those from the pond culture, while the fat content of the rice field-cultured fish was significantly low compared to the fish from the pond culture, especially in the back and tail parts. A total of 43 volatile components were detected by Gas Chromatography–Mass Spectrometry (GC-MS), with a maximum of 18 types of aldehydes and the highest concentration being nonanal. Compared to pond cultures, the fish from the rice field cultures showed more abundant flavor composition and odor-active compounds. The total content of DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid) in the rice field-cultured fish was higher than that of the pond group, while no significant disparity in amino acid composition was observed (p > 0.05). Comparative and clustering analyses of gut microbiota revealed notable discrepancies in the gut microbiota of O. bidens from two aquaculture systems. However, an inherent correlation between the gut microbiome and meat quality would be further emphasized in further studies. This study can offer a theoretical reference for the development of high-quality aquatic products by selecting the appropriate aquaculture models. [ABSTRACT FROM AUTHOR]

Blooms of Microcystis are common in fish ponds in Bangladesh which vary distinctly with season to season. A study on the seasonal changes of Microcystis and Anabaena was carried out over a period of 12 months from March 2021 to February 2022 in two rural fish ponds to see the effect of environmental factors on the seasonal dynamics of these two species. Cyanobacterial community comprised of seven genera and 15 species of which Microcystis was found to be the most dominant genus. Overabundance of Microcyctis may suppress the growth of Anabaena and other microalgal species. In both ponds, Microcyctis was found to be the dominant during the summer and the spring, whereas Anabaena was only characterized in summer. Moderately higher temperature, nitrate–nitrogen, and phosphate–phosphorus enrichment increased the biomass of both Microcystis and Anabaena. Microcystin was found in all the seasons with the highest quantity in summer in the cyanobacteria samples collected from both of the ponds. The highest concentrations of MCs were 22 and 65 μg/L of the sampled water during the peak bloom period of blue‐green algae in pond 1 and pond 2, respectively. The high concentration of microcystin in water seems to be a pernicious warning for aquatic organisms as well as human health. Further studies in detail on the relationship between microcystin and cyanobacterial growth under different environmental factors seem to be necessary. [ABSTRACT FROM AUTHOR]

Aquaculture is increasing globally, providing protein to a growing population, but little is known regarding the nutrient budgets in aquaculture. To obtain insight into how management practices impact nutrient fluxes in freshwater aquaculture earthen ponds worldwide, we conducted a literature review. Our literature search yielded 23 papers in which nutrient budgets were reported. Our results showed that the main nutrient inputs are inlet water, feed, and fertilizers, but they varied according to location and management practices. Overall, feed and fertilizers constituted the predominant nutrient sources, accounting for up to 99% of the total inputs. The most quantified outputs were outlet water, fish, and sedimentation. Our findings indicate that only up to 20% of carbon, 45% of nitrogen, and 60% of phosphorus are assimilated by the fish. In some systems, up to 80% of carbon, 80% of nitrogen, and 60% of phosphorus accumulate in pond bottoms; in other systems, the outflow represents substantial losses of up to 16% of carbon, 76% of nitrogen, and 55% of phosphorus. More insight into nutrients' fate in fishponds is crucial from a sustainability perspective, as feed and fertilizer use can likely be optimized, reducing operational costs and the potential impact on the surrounding environment and atmospheric greenhouse gas concentrations. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: This study presents the initial findings on how rice cultivation impacts water quality and the microbial community structure in ponds where mandarin fish are being fed an artificial diet. The results indicated that rice cultivation plays a significant role in reducing nutrient salt levels in the water, thus regulating the overall aquatic environment. Furthermore, the cultivation of rice has been found to alter the composition of microbial communities in the water, leading to a decrease in diversity and affecting the abundance of bacteria involved in carbon, nitrogen, and phosphorus metabolism. The study identified Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, and Deinococcus-Thermus as the dominant bacterial phyla in ponds where mandarin fish are being fed an artificial diet. Additionally, it was observed that Proteobacteria showed a particular preference for proliferation in the aquatic environment with rice cultivation on the water surface. These results provide a valuable foundation for the potential application of aquaculture practices involving mandarin fish fed an artificial diet and rice floating beds. The culture of mandarin fish using artificial feed has been gaining increasing attention in China. Ensuring good water quality in the ponds is crucial for successful aquaculture. Recently, the trial of pond-based rice floating beds (PRFBs) in aquaculture ponds has shown promising results. This research assessed the impact of PRFBs on the microbial community structure and overall quality of the aquaculture pond, thereby enhancing our understanding of its functions. The results revealed that the PRFB group exhibited lower levels of NH4+-N, NO2−-N, NO3−-N, TN, TP, and Alk in pond water compared to the control group. The microbial diversity indices in the PRFB group showed a declining trend, while these indices were increasing in the control group. At the phylum level, there was a considerable increase in Proteobacteria abundance in the PRFB group throughout the culture period, suggesting that PRFBs may promote the proliferation of Proteobacteria. In the PRFB group, there was a remarkable decrease in bacterial populations related to carbon, nitrogen, and phosphorus metabolism, including genera Rhodobacter, Rhizorhapis, Dinghuibacter, Candidatus Aquiluna, and Chryseomicrobium as well as the CL500_29_marine_group. Overall, the research findings will provide a basis for the application of aquaculture of mandarin fish fed an artificial diet and rice floating beds. [ABSTRACT FROM AUTHOR]

Snails are the first intermediate host in the life cycle of trematodes. Previous research found that Trichopodus microlepis fish, cultured in earthen ponds in Tan Nhut Commune, Binh Chanh District, Ho Chi Minh City, Vietnam had a high infection rate with metacercariae of Centrocestus formosanus and Procevorum sp. It is necessary to investigate whether habitats supplying water to the ponds may contribute to the transmission by carrying intermediate hosts and/or cercariae into these ponds or not. A study of cercariae and snail composition in rice fields and canal supplying water directly to these Trichopodus microlepis ponds was carried out with six samplings in the years 2022 and 2023. A total of 1,151 snails were collected, and nine snail species belonging to 8 genera and 6 families were identified. Three snail species in both rice fields and canal were infected with trematode (cercariae stage) including Bithynia siamensis, Lymnaea viridis and Indoplanorbis exustus. The overall prevalence in the dry season (25.9%) was significantly higher than in the wet season (10.6%) (P<0.05). Three cercariae morphotypes were recovered from snails: xiphidio (in all three snails), echinostome (in Lymnaea viridis and Indoplanorbis exustus), and pleurolophocercous in Bithynia siamensis. This finding shows that Bithynia siamensis is one of the infected sources for Trichopodus microlepis fish cultured in ponds, as pleurolophocercous is also the cercariae in the family of Heterophyidae (including Centrocestus formosanus and Procevorum sp.). Further research should be done to clarify the transmission of fish-borne zoonotic diseases to cultured Trichopodus microlepis in other habitats including the actual fishponds, and sources of trematodes in order to produce Trichopodus microlepis free of metacercariae, contributing to clean aquaculture development and safe food for local people in the area. [ABSTRACT FROM AUTHOR]

Raising fish in ponds for an extended period can have an impact on the accumulation of bacteria that can affect the health of the fish. Using plant extracts is an interesting option to consider for reducing bacterial contamination in ponds. This study investigated the effectiveness of cinnamon extract in reducing bacterial contamination in the water used for raising Siamese fighting fish (Betta splendens). Optimal concentrations of cinnamon extract were determined for microbial reduction in the water used for the cultivation of these fish. Test the ability to resist infection at the concentrations of cinnamon extract 1:1, 1:2, 1:4, 1:8, 1:16, and 1:64, against 3 bacterial species (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa). The concentrations of cinnamon extract at 1:1 and 1:2 inhibited all three tested pathogens, while up to 1:4 inhibited S. aureus. Water samples taken from the ponds for testing were studied at 4 cinnamon extract concentrations: 0, 1, 2, and 3 gL-1. The treated water samples were collected at 0, 24, and 48 hours to quantify microbial activity. There were significant (p<0.05) differences among the concentrations, with the numbers of microorganisms in the treated water at 48 hours being 3.84x105, 2.92x104, 2.69x10³, and 2.89x10³ CFU mL-1, respectively. The experimental groups with concentrations of 2 and 3 gL-1 were the most effective in reducing bacteria in the fishpond after 24 h. Our study demonstrated that cinnamon extract could reduce microbial growth in water used to raise Siamese fighting fish. [ABSTRACT FROM AUTHOR]

This study analyses land use and land cover (LULC) changes during the last five decades (1970-2021) in East Java Province, Indonesia. The changes are analysed by comparing four maps interpreted from Landsat images (MSS 1972, TM 1997, OLI 2013, and OLI 2021). The main research procedures consist of (1) data collection, (2) field survey, (3) image classification, and (4) LULC change interpretation. The classification uses the maximum likelihood algorithm, achieving an overall kappa accuracy of > 75%. The classification produces eight classes, i.e., built-up land (BU), heterogeneous agricultural land (HAL), bare soil (BS), paddy fields (PF), open water (OW), vegetation (VG), shrubland (SH), and wetlands (WL). The analysis shows a significant shift in land use from 1972 to 2021, with HAL declining by 46%, SH by 91%, and BS by 88%. In contrast, PF has increased by 105%, VG (forest and plantation) by 64%, and built-up areas by a remarkable 366%. These changes show a significant shift from dryland agriculture, shrublands, and barren lands to irrigated regions, vegetated areas, and urban growth. Furthermore, there are increases in water bodies due to the construction of several reservoirs to support water availability. In coastal regions, the development of inland aquaculture leads to a proliferation of wetlands (salt evaporation ponds, fish ponds, and rice-fish integrated farming). [ABSTRACT FROM AUTHOR]

Objective: Automatic feeders are commonly used in aquaculture, but the feed delivery pattern cannot be adjusted to accommodate a variety of rearing unit sizes. For those few feeders that can be adjusted, their use has been limited because of initial costs, availability, and other issues. This paper describes modification to a commercially available fish feeder (Texas Hunter Products 31.75‐kg [70‐lb] Lake and Pond Directional Fish Feeder) to effectively provide feed to different‐sized ponds. Methods: This feeder has a 14‐m fish feed distribution pattern, making it unusable for smaller ponds. To reduce the distance of fish feed projected from the feeder, a resistor (rheostat) was installed in series with the fan motor. Result: The rheostat reduced the power to the fan motor, thereby decreasing the feed projection distance. In addition, because the rheostat was adjustable, the resistance—and the resulting power to the fan motor—could be easily changed, making it possible for the same feeder to be used in different‐sized ponds while using approximately the same amount of power from the battery and solar panels. Conclusion: This modification was inexpensive and relatively easy to perform. The feeders reliably dispensed feed in a number of small ponds during an 8‐month evaluation period. Impact statementThis paper describes an inexpensive and relatively easy to perform modification to a commercial fish feeder so that it can effectively dispense feed in small rearing ponds. [ABSTRACT FROM AUTHOR]

Although aquatic larvae need natural food, relevant sources in the food web have not been extensively researched and used in aquaculture. The zooplankton community at the ecological black tiger shrimp (Penaeus monodon) ponds in the Ca Mau mangrove forest in Vietnam was studied for its potential as a natural food source in these and other, similar ecosystems (fish ponds, mollusc ponds). This study examined eight ecologically distinct shrimp ponds in the dry, transitional, and rainy seasons. Thirty-seven zooplankton species from 31 genera, 19 families, and 4 phyla were identified in these shrimp ponds. The zooplankton density was 1167-53 330 individuals/m3 with over half the species and density being copepods. Five Copepoda species were common and of high population density, including Limnoithona sinensis , Thermocyclops hyalinus , Tropocyclops prasinus , Eodiaptomus japonicus , and Euaugaptilus elongatus. This natural food can feed shrimp larvae and adults and thereby supply high quality nutrients for their development. However, the pond's zooplankton was lacking in diversity. Thus, providing natural nutrients to the pond may increase zooplankton diversity and facilitate sustainable aquaculture. [ABSTRACT FROM AUTHOR]

Aquaculture plays a vital role in global food production, with fish pond water quality directly impacting aquatic product quality. The Guangdong-Hong Kong-Macao Greater Bay Area (GBA) serves as a key producer of aquatic products in South China. Monitoring environmental changes in fish ponds serves as an indicator of their health. This study employed the extreme gradient boosting tree (BST) model of machine learning, utilizing Landsat imagery data, to assess Chlorophyll-a (Chl-a) concentration in GBA fish ponds from 2013 to 2022. The study also examined the corresponding spatiotemporal variations in Chl-a concentration. Key findings include: (1) clear seasonal fluctuations in Chl-a concentration, peaking in summer (56.7 μg·L−1) and reaching lows in winter (43.5 μg·L−1); (2) a slight overall increase in Chl-a concentration over the study period, notably in regions with rapid economic development, posing a heightened risk of eutrophication; (3) influence from both human activities and natural factors such as water cycle and climate, with water temperature notably impacting summer Chl-a levels; (4) elevated Chl-a levels in fish ponds compared to surrounding natural water bodies, primarily attributed to human activities, indicating an urgent need to revise breeding practices and address eutrophication. These findings offer a quantitative assessment of fish pond water quality and contribute to sustainable aquaculture management in the GBA. [ABSTRACT FROM AUTHOR]

Many marsh birds, like bitterns or rails, are endangered species inhabiting only natural habitats and dependent exclusively on different types of emergent vegetation. In a changing environment, some of these habitat specialists are becoming more flexible, shifting their preferences by colonizing man-made habitats. We studied habitat selection by Little Bitterns (Ixobrychus minutus minutus) breeding in a fishpond landscape in south-eastern Poland. Applying a large-scale research approach, we examined several habitat features in order to predict the presence of the Little Bittern from a direct comparison of areas with and without breeding birds. Partial least squares (PLS) regression identified two components of several variables that explained 53% of the variation in the presence of the Little Bittern in a fishpond habitat. The occurrence of the Little Bittern was limited to high-quality patches of emergent vegetation, the height, width and area of which were all significantly greater in the area with breeding birds than in unoccupied patches. Patches with a highly variable edge line in the form of fringes or indentations were less favoured. An optimal water level throughout the breeding season was crucial for nest-site selection and ensured access to food. The heterogeneity of the pond dykes and pond canals positively predicted the presence of the Little Bittern by creating potential nesting or foraging sites. Interestingly, the proportion of bulrushes (Typha spp.) in the emergent vegetation patches had a negative effect on the presence of the Little Bittern. The main threat to this habitat‐sensitive species was the cutting of perennial emergent vegetation, in particular the Common Reed (Phragmites australis). [ABSTRACT FROM AUTHOR]

Over the decades, the aquaculture sector has witnessed substantial growth, contributing significantly to the nation's economy. However, the menace of CyanoHABs threatens the sustainability of fish farming. Considering the possible hazards linked to cyanotoxins in food and water, a comparative study design between commercial fish in Nigeria and South Africa was employed to investigate cyanotoxins in the water from fishponds. Six commercial fishponds in Calabar Municipality—Nigeria and Duthuni—South Africa with varying climatic zones were selected. Water samples from the ponds were collected at intervals during different seasons (summer, winter, dry, and wet seasons) to capture climate-induced variation. Liquid chromatography–mass spectrometry (LCMS) in combination with the metabolites database was used for the identification of toxic cyanometabolites in water samples. The molecular networking approach, coupled with the Global Natural Products Social Molecular Networking (GNPS) database and CANOPUS annotation, enabled the putative identification of cyanometabolites. The resulting molecular network unveiled discernible clusters representing related molecule families, aiding in the identification of both known cyanotoxins and unfamiliar analogues. Furthermore, the molecular network revealed that water samples from different fishponds shared specific metabolites, including ethanesulfonic acid, pheophorbide A, cholic acid, phenylalanine, amyl amine, phosphocholine (PC), and sulfonic acid, despite variations in location, local climatic factors, and sampling sites. The fishponds in Nigeria showed the presence of multiple cyanotoxin classes in the dry, wet, and summer seasons in the water. Aflatoxin was identified in all sampling sites in Nigeria (N1, N2, and N3). The Duthuni, South Africa, sampling sites (P1, P2, and P3) exhibited the presence of microginins and microcystins. All the fishponds displayed a widespread occurrence of anabaenopeptins, aplysiatoxins, aflatoxin, microcolins, and marabmids during the selected summer. In conclusion, the untargeted metabolome analysis, guided by GNPS, proved highly effective in identifying both toxic and non-toxic metabolites in fishponds. [ABSTRACT FROM AUTHOR]

Studies have emphasized that the presence of heavy metals in freshwater fish represents a global public health issue. Nigeria, being a developing nation with less emphasis on the quality of seafood consumed by the residents, ranks this study very vital. The policy implication of this study is the advancement of a healthy population in contemporary Nigeria. Hence, this study assessed heavy metal concentration in two fish species, Clarias gariepinus (Catfish) and Oreochromis niloticus (Nile Tilapia), in the Anambra River. The sample included twenty fishes, of which eighteen were collected from the three sampling locations (the fish ports of Anambra River), namely Otu-nsugbe, Otuocha, and Ikemivite) while two control samples were collected from a pond about 200 m away from the river. The levels of heavy metals were determined using Varian AA 240 atomic absorption spectrophotometer (AAS). The results showed that the concentrations of heavy metals (cadmium and arsenic) in the sampled fishes from Anambra River exceeded the joint World Health Organization and Food and Agriculture Organization (FAO/WHO) standard for fish and fish product consumption, while the concentration of chromium, mercury, and lead are within the permissible limit. The study also showed the distribution of the heavy metals in the fish organ varies among fish species. Heavy metals occur higher in Clarias garepinus than in Oreochromis niloticus, while tissue preference for heavy metal accumulation is in the order of gill > liver > muscle. It was recorded from this study that the heavy metal concentration in the fish from the pond is generally higher than the fish from the river for some metals. The high level of heavy metals in the sampled fish was attributed to heavy metals contamination of the river as a result of various anthropogenic activities such as mining, burning of fossil fuel and emission from the exhaust of boats/vehicles, overuse of fertilizers and pesticides, discharge of effluent, sewage, and hospital waste. This study concluded that long-term consumption of fish from the river may pose health risks to the consumers due to the possible bioaccumulation of heavy metals, especially cadmium and arsenic. It was recommended that continuous monitoring of heavy metal levels in the fish and water, public awareness, and appropriate legislative provisions should be put in place to ensure that harvested fish and fish products may be safe for human consumption. [ABSTRACT FROM AUTHOR]

In most coastal communities, aquaculture has been the way to address the continuous urbanization and growth in population in these areas. Aquaculture has proven to be economically important, but mismanagement of the coastal resource has often led to decline in productivity. Batan Bay Estuary in Aklan has been experiencing lower productivity and shallower bay waters over years of urbanization and thriving aquaculture activities. Given the limitation of actual data gathering techniques to represent physical processes of water bodies such as estuaries, numerical modelling has been used as a tool to describe estuarine processes as well as aid in the management and preservation of its different ecosystem services. This study aimed to describe and understand the sediment dynamics of Batan Bay Estuary using numerical modelling. Sediment yields were simulated using the Soil and Water Assessment Tool+ (SWAT+) to describe the long-term hydrology while Delft3D was utilized in understanding the hydrodynamics and sediment dynamics of the bay. Based on the morphologic simulation results, erosion areas were identified at the narrow channels between fishpond dikes while sediment deposition areas were identified at fishpond dike entrances and near the bay mouth. A scenario for bay management such as removing abandoned fishpond dikes in the bay and its effects on the sediment dynamics was also examined. Simulation showed that areas near the removed dikes resulted in an increase in velocity by as much as 0.5 m/s thus resulting in more erosion near these areas. The results generated from the models can aid the community in understanding the effects of future aquaculture developments on the sedimentation dynamics of the bay. This study has shown the value of utilizing advanced numerical modelling techniques and data analysis in understanding sediment dynamics of coastal resource and effectively come-up with scientific-based information to support bay-wide conservation and resource-use efforts. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ondokuz Mayis University Journal of Education is the property of Ondokuz Mayis University Faculty of Education and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study aims to evaluate the potential effects of cyanobacteria on water quality parameters and Oreochromis niloticus in the fish ponds at Al-Abbassa Fish Hatchery, Sharkia Governorate, Egypt. The study identified five cyanobacterial genera: namely, Anabaena, Gleotrichia, Lyngbya, Oscillatoria and Phormidium. Oscillatoria sp. was the dominant genus in the selected fish ponds. Physico-chemical parameters of water samples showed significant variations during the four seasons. Anabaena sp. extract had the most toxic effect on the survival rate of O. niloticus after 72 h of exposure. Biochemical parameters of collected O. niloticus fish significantly increased compared to the control group. We concluded that the detected cyanobacterial genera in the fish ponds affected water quality and O. niloticus fish. [ABSTRACT FROM AUTHOR]

Increasing nitrogen (N) input to coastal ecosystems poses a serious environmental threat. It is important to understand the responses and feedback of N removal microbial communities, particularly nitrifiers including the newly recognized complete ammonia-oxidizers (comammox), to improve aquaculture sustainability. In this study, we conducted a holistic evaluation of the functional communities responsible for nitrification by quantifying and sequencing the key functional genes of comammox Nitrospira-amoA, AOA-amoA, AOB-amoA and Nitrospira-nxrB in fish ponds with different fish feeding levels and evaluated the contribution of nitrifiers in the nitrification process through experiments of mixing pure cultures. We found that higher fish feeding dramatically increased N-related concentration, affecting the nitrifying communities. Compared to AOA and AOB, comammox Nitrospira and NOB were more sensitive to environmental changes. Unexpectedly, we detected an equivalent abundance of comammox Nitrospira and AOB and observed an increase in the proportion of clade A in comammox Nitrospira with the increase in fish feeding. Furthermore, a simplified network and shift of keystone species from NOB to comammox Nitrospira were observed in higher fish-feeding ponds. Random forest analysis suggested that the comammox Nitrospira community played a critical role in the nitrification of eutrophic aquaculture ponds (40-70 µM). Through the additional experiment of mixing nitrifying pure cultures, we found that comammox Nitrospira is the primary contributor to the nitrification process at 200 µM ammonium. These results advance our understanding of nitrifying communities and highlight the importance of comammox Nitrospira in driving nitrification in eutrophic aquaculture systems. [ABSTRACT FROM AUTHOR]

Accurately identifying the fish feeding intensity is crucial for timely understanding the feeding demand, dynamically adjusting the feeding strategy, and reducing costs. For the variability and uncontrollability of the pond aquaculture environment, the densities of feeding fish schools aggregating to the feeding point exhibit significant variations. Consequently, different densities of fish schools present inconsistent characteristics in the image, even under the same feeding intensity, making the precise identification of feeding intensity difficult. To tackle this issue, a method for identifying the feeding intensity of pond fish schools based on dual-label and MobileViT-SENet (DL-MobileViT-SENet) was proposed. The fish school images were marked with labels indicating density and feeding intensity to establish the dual-label dataset. Subsequently, a proposed MobileViT-SENet network is trained using the dataset to obtain the dual-label pre-training weight incorporating both fish density and feeding intensity features. Two models are trained to identify density and feeding intensity based on the obtained weight. Finally, a dynamic feeding strategy for fish that integrates biomass, density, and feeding intensity is presented. The proposed method combines the density and feeding intensity labels to enhance the accuracy of identifying the feeding intensity of pond fish schools across various densities, and lays the groundwork for designing a dynamic feeding strategy. It was tested on authentic pond fish school images and yielded an accuracy of 97.95%. This value is superior to these comparison methods, demonstrating that this method can accurately identify the feeding intensity of pond fish and provide support for formulating a dynamic feeding strategy. • A method for identifying fish feeding intensity at different densities is proposed. • To improve feature representation in pond culture, a MobileViT-SENet is introduced. • A dual-label pre-training method is proposed to shorten the model training. • A dynamic feeding strategy for pond fish is provided. [ABSTRACT FROM AUTHOR]

Simple Summary: Water colour is an important physicochemical property of water that affects aquatic communities. Land-use change has led to water colour darkening in lotic habitats, such as streams and rivers. Here, I evaluate whether urban land-use change affects water colour in urban ponds, a type of lentic habitats, and how diving beetles (Dytiscidae) respond to the water colour gradient in the Helsinki Metropolitan Area, Finland. The results show that urbanisation may not drive water darkening in urban ponds, possibly because urban ponds are often not connected to stormwater pipes. Diving beetles responded to the increasing pond water colour differently in the presence or absence of fish. Diving beetle species richness and abundance significantly increased along the water colour gradient in ponds with fish, but not in ponds without fish. Some species, such as the great diving beetle (Dytiscus marginalis), appear tolerant to brown water, whereas some species, such as the cherrystone beetle (Hyphydrus ovatus), prefer clear water. This study highlights that not all species benefit from increasing water colour. It is important to provide ponds with a gradient of water colour from clear to brown water in the landscape to meet the habitat requirements of different species for urban biodiversity conservation. Dramatic land-use changes in urban landscapes can drive water colour darkening by washing compounds, such as organic matter and iron, from terrestrial ecosystems into urban blue space, consequentially affecting aquatic communities. Here, I studied how pond water colour changes along an urban gradient and how diving beetles (Dytiscidae) respond to the water colour gradient in 11 ponds with fish and 15 ponds without fish in the Helsinki Metropolitan Area, Finland. I found that the pond water colour exhibited a non-significant decreasing pattern along the urban gradient, indicating that urbanisation may not necessarily drive brownification in urban ponds. Dytiscid species richness and abundance exhibited significant positive correlations with increasing water colour in ponds with fish but no significant correlation in ponds without fish. Some species, such as Agabus spp. and Dytiscus spp., appeared tolerant to highly coloured water, whereas some species, such as Hyphydrus ovatus and Hygrotus spp., tended to occur in clear water, indicating that brown water may provide dytiscids with prey refuges, but some species are intolerant to brown water. The study highlights the importance of urban pondscape heterogeneity to meet the needs of aquatic invertebrates that prefer different water colours and for the multifunctioning of urban ponds. [ABSTRACT FROM AUTHOR]

Knowledge of the relationships between food habits and habitat is crucial for the assessment of habitat quality for birds. The present study investigated the diet and reproductive success of Little Bitterns Ixobrychus minutus nesting on cyprinid fish ponds, an important breeding habitat of this species in central and eastern Europe. Being subject to different management practices, fish ponds provide food resources of uneven availability for this small heron. Prey items regurgitated by nestlings were examined, and breeding success was estimated on monoculture ponds stocked either with small fish (of a size suitable for feeding nestlings) or large fish (unavailable to Little Bitterns and adversely affecting their non-fish prey), on abandoned ponds dominated by small fish but with large fish also present, and on angling ponds dominated by large sport fish but harbouring significant numbers of small fish as well. A total of 1356 prey items from 78 broods were identified. Although Little Bitterns exhibited dietary flexibility in response to the contrasting availability of prey on their nesting ponds, the bulk of the nestlings' diet consisted of fish. The size of fish brought to the nest increased significantly with brood age, showing that parents adjusted the prey size to the gape constraints of their young. The chick production determined for 73 broods did not differ with respect to pond management, but the dietary composition indicated that to compensate for food shortages, birds nesting on ponds containing mainly large fish made foraging flights to food-richer ponds. The abundance of small-sized fish prey may be a factor limiting the breeding success of small- and medium-sized predatory waterbirds and should be taken into consideration in management strategies of habitats dominated by fish. [ABSTRACT FROM AUTHOR]

Differences between peak-season and off-season dry mass, organic matter mass, and both concentrations and pools (standing stocks) of ash, N, P, K, Ca, Mg and Na were investigated in the rhizosphere soil, and live and dead aboveground plant biomass at 14 sites hosting 4 plant community types in the littoral zone of a eutrophic ancient shallow reservoir of about 5 km2 area, the Rožmberk fishpond (S. Bohemia, CZ). Comparisons between the peak-season and off-season data and several stoichiometric relations calculated from them provided an insight into the mineral nutrient economy of the examined types of the fishpond littoral vegetation. It is rooted in relatively nutrient-poor sandy soil, but differently enriched with nutrients contained in either the percolating fishpond water, or that of springs located at the landward edge of the littoral zone. The degree of eutrophication of our sampling sites and their vegetation thus seem to be positively correlated with the degree of contact of the plants´ rhizosphere with the nutrient-richer fishpond or spring water. [ABSTRACT FROM AUTHOR]

The population decline of the endangered bitterling species, Acheilognathus typus, following non-native bitterling invasion underscores the need to understand interspecific interactions among bitterling fishes. In this study, the dietary habits of A. typus, alongside introduced non-native bitterling species (Acheilognathus rhombeus and Rhodeus ocellatus ocellatus) and other omnivorous fishes (Oryzias latipes, Pseudorasbora parva, and Rhinogobius sp.), were investigated in a small pond in Japan using gut content and stable isotope analyses (δ13C and δ15N). Analysis revealed that microalgae, particularly diatoms with periphytic or benthic life forms, dominated the gut contents of the three bitterling species, which exhibited high dietary overlaps (Pianka's index range 0.89–0.98). Although bitterling species displayed similar δ13C (mean range −18.4 to −16.1‰) and δ15N (12.1 to 12.6‰) values, the other omnivorous fishes exhibited distinct isotopic signatures: lower δ13C and higher δ15N values. Isotopic niche overlaps among the three bitterling species were limited (0–2.4%). Furthermore, A. typus and A. rhombeus showed no overlap in the corrected standard ellipse area. These findings suggest that the three bitterling species may forage on similar food items, primarily microalgae, with differing stable isotope ratios, enabling them to partition foraging sites within the confines of a small pond where competition may arise. [ABSTRACT FROM AUTHOR]

Climate variabilities continue to hinder sustainable food production with an increasing need to use resources such as water and soil efficiently. The quest for these efficiencies in agriculture systems drives innovations among farmers. However, limited data on farm practices, such as irrigating with fishpond water and their effects on soil health, hinder their adoption as climate-smart innovations. In a nearly twenty-year-old vineyard with two distinct irrigation practices (irrigation with recycled fishpond water and irrigation with ditch water), this study was carried out as an exploratory study to investigate the influence of recycling fishpond water on soil health parameters and yield. Soil samples were taken from two different irrigation fields in summer and winter for lab analysis on soil health parameters (organic matter and carbon, nitrogen, phosphorus, microbial biomass, and microbial respiration). Averages over the two seasons of field measurements indicate that long-term irrigation using recycling fishpond water increased the measured soil health parameters (organic matter (13%), organic carbon (30%), nitrogen (17%), phosphorus (46%), microbial biomass (18%), and microbial respiration (56%)) in both summer and winter months when compared to fields receiving just ditchwater irrigation. Using water in a way that can improve soil health increases biodiversity and improves the efficiency of our limited water resources in semi-arid agricultural lands, and this strategy is a climate-smart tool that can help reduce water risks in dry agricultural regions such as Arizona. [ABSTRACT FROM AUTHOR]

Studies of the physiological state of 3-year-old pikeperch from a lake (natural habitat), ponds, and fish farm cages show significant differences in the size, mass, biochemical, hematological, and histophysiological parameters of fish. Farmed fish are larger (length 26.2 cm; weight 242.1 g) than lake individuals (27.6 cm and 278.2 g, vs. 23.7 cm and 162.6 g in pond pikeperch) and have higher index values of liver (3.68 vs. 1.42 and 1.03% in lake and pond fish, respectively), gonads (0.73 vs. 0.15 and 0.08%), and abdominal fat (8.61 vs. 1.87 and 2.30%). The chemical composition of the body of farmed fish is characterized by a large quantity of lipids (9.4 vs. 2.5 and 3.6%, respectively) and nitrogen-free extracts (NFEs) (3.4 vs. 2.5 and 2.4%), muscle—protein (21.0 vs. 19.0 and 19.2%), and liver—lipids (26.6 vs. 11.1 and 7.5%, respectively) and NFEs (9.6 vs. 1.9 and 2.5%), as well as low moisture (51.7 vs. 69.3 and 71.5%), protein (11.2 vs. 16.6 and 17.2%), ash (0.9 vs. 1.1 and 1.3%), and vitamin C (67.5 vs. 87.9 and 97.6%) contents. The fatty acid (FA) composition of the muscle lipids of farmed fish is generally comparable to that of lake and pond fish—the main groups of FAs are at a similar level: polyunsaturated FAs in the range of 37.0–40.6% of the total FAs, saturated FAs 25.5–29.6%, and monounsaturated FAs 28.0 and 23.2% in farmed and lake fish and 17.5% in pond fish. The content of arachidonic acid 20:4n-6 in farmed fish is extremely low (1.0 vs. 8.0 and 11.5% of the total FAs). Liver lipids of farmed fish contain a large amount of oleic acid 18:1n-9 (30.3 vs. 16.2 and 15.0% of the total FAs in lake and pond fish) and n-6 polyunsaturated FAs (17.5 vs. 8.4 and 7.1%), in particular, linoleic acid 18:2n-6 (7.0 vs. 1.9 and 0.2%). The blood of farmed fish, compared to pond fish, differs in a lower content of hemoglobin (64.8 vs. 74.8 g/L) and an increased content of immature lymphocytes (11.6 vs. 6.1%) and immature erythrocytes (2.2 vs. 1.1%). The gonads of farmed fish are at stage III of maturity with an average oocyte diameter of 478.9 µm; lake fish has two stages of oocyte maturity—the previtellogenic oocytes of protoplasmic growth, 62.7 µm in size, and significantly larger vitellogenic oocytes of trophoplasmic growth, 227.6 µm. In pond pikeperch, gonads correspond to stage II of maturity and oocytes are 58.3 µm in size. Certain differences in pikeperch from lakes, ponds, and farm conditions are associated with the different conditions in which they are kept and fed. [ABSTRACT FROM AUTHOR]

Utilization of waterlogged areas for fish culture in Cauvery command area of Karnataka. For Cauvery command area under waterlogged condition, the three beneficiaries were provided with quality carp seed and 2 tons of supplementary feed to each. Meanwhile, the water quality, fish survival, health and growth were monitored throughout the study period. Scientific fish farming using the water logged area was monitored throughout the study period and the farmers were demonstrated with importance of the stage wise management. The hardness of fish pond water reduced by 7.14%, from 280 to 260 mg/l during the demonstration period and there was reduction in the total dissolved solids (TDS) from 350.60 to 200.44 mg/l and was evident by 42.82% reduction. Salinity content of pond water showed little fluctuation during different months of culture. Among the different fish species, Amur common carp recorded highest weight (1706g) followed by Common carp (1486 g) and Catla (1108 g) and the total fish production from one acre demonstration pond was 3816 kg with the total gross revenue realized by the farmers of Rs. 4.96 lakhs. [ABSTRACT FROM AUTHOR]

Objective: The sunshine bass (female White Bass Morone chrysops × male Striped Bass M. saxatilis) is an important food fish raised in U.S. aquaculture. Spawning is performed by manually stripping and fertilizing White Bass eggs with Striped Bass sperm. Embryos hatch in approximately 48 h. Mature sunshine bass females can become fertile and produce viable eggs, which is problematic in commercial food‐fish production; therefore, triploid fish are desired. Methods: The present nonreplicated study incorporated three warm and three cold temperature shocks, along with three postfertilization initiation times and three exposure times for each temperature, during initial stages of incubation to induce triploidy. After exposure to temperature shocks, fertilized eggs were incubated in experimental hatching systems. The best performing cold and warm temperatures and times (and an ambient diploid control) were then used to incubate fertilized eggs in a commercial‐scale trial using standard industry practices with a single batch of eggs. Larvae were stocked at about 185,000 larvae/ha (75,000 larvae/acre) in newly filled and fertilized ponds. Fry were sampled weekly and harvested at 30 days. Result: There were 15 survivors from the pond containing fish derived from cold‐shocked fertilized eggs; these individuals were tested via Coulter Counter, and no triploids were detected. Testing of 50 survivors from the pond containing fish derived from warm‐shocked fertilized eggs indicated that 14% were triploid. Conclusion: Therefore, initial trials indicate that warm temperature shock is preferable to cold shock for inducing a greater percentage of triploid sunshine bass. Impact statementSuccessful use of temperature shock during the initial stages of fertilized egg incubation to produce triploid sunshine bass leads to a new method to improve sustainability and profitability for farmers. [ABSTRACT FROM AUTHOR]