The efficient underwater sensing and attack mechanisms of electric eels provide significant inspiration for the development of biomimetic equipment. To this end, this paper investigates the response strategies and discharge patterns of electric eels under various behavioral intents. By constructing specialized test scenarios and integrating behavioral recordings, data acquisition, and bio-electric field simulations, we systematically analyzed the correlation between attack/defense postures and discharge logic, as well as the corresponding discharge characteristics of electric organs. The results reveal that a curled attack posture enhances targeting efficiency through synergistic electric field and circuit interactions. Simulations indicate it can increase the voltage delivered to prey more than three times. Touch-based experiments further identified a deep-water passive defense mechanism through double/triple pulses. By comparing behavioral and electrogenic organ discharge (EOD) patterns in active and passive defense, this study concludes that active defense is suitable for shallow water, while passive defense is suitable for deep water environments, providing a more complete theoretical framework for understanding the different biological behaviors in electric eels.

To investigate the effects of photoperiod on the feeding rhythms and gastrointestinal evacuation dynamics of second-instar juvenile Tachypleus tridentatus, this study examined diel feeding rhythms in second-instar juvenile T. tridentatus using eight observation time points over 24h under three photoperiod regimes: natural photoperiod, constant light, and constant darkness. Feeding rhythms were assessed via gastrointestinal satiety indices, and evacuation dynamics were tracked for 24h after satiation. The results showed that there were no significant differences in average satiety among time points within any photoperiod at 3h or 6h post-feeding. Under natural photoperiod at 3h, satiety was significantly higher at night than during the day, whereas no clear diel differences were observed under continuous light or darkness. By contrast, at 6h post-feeding, satiety indices were consistently higher at night than during the day under all three photoperiods. Feeding peaks under the natural photoperiod at 3h post-feeding occurred during the night-time period (21:00—06:00), while no distinct diel feeding rhythm was detected under continuous light or darkness. However, at 6h post-feeding, clear feeding rhythms emerged under both continuous light and continuous darkness, with feeding peaks occurring at 21:00—09:00, and 21:00—06:00, respectively. Most juveniles achieved substantial food intake within 3h, with only marginal increases observed by 6h. Gastrointestinal evacuation exhibited a biphasic pattern characterized by an initial rapid phase followed by a slower phase. First-time feeding juveniles reached 50% evacuation at 14.7h and 80% at 27.1h after satiation, whereas non-first-time feeding juveniles reached the same benchmarks at 8.8h and 16.3h, respectively. These findings demonstrate that second-instar juvenile T. tridentatus exhibit a pronounced diel feeding rhythm, only weakly influenced by photoperiod. Based on these results, it is recommended that juvenile rearing be conducted under a natural photoperiod with at least one feeding event after dusk and moderately extended during the early feeding stage. This study provides a scientific basis for optimizing feeding strategies in the artificial culture of juvenile T. tridentatus.

To investigate the relationship between personality traits and cognitive abilities in fish, this study used juvenile Chindongo demasoni, a highly social cichlid species, as the model organism. Through associative learning training and tests based on a “color-food reward” paradigm, we assessed cognitive performance and analyzed its correlation with three personality traits: activity, boldness, and sociability. The results showed that: (1) Activity and boldness were positively correlated in Chindongo demasoni (P=0.024), supporting the Behavioral Syndromes Hypothesis; (2) The fish successfully formed associations between color cues and food rewards through associative learning, with the correct choice rate increasing significantly over training days (P<0.001); (3) Sociability was positively correlated with cognitive performance, as measured by the correct choice rate during the test phase (P=0.006), while no significant relationship was found between cognitive performance and either activity or boldness. The link between sociability and cognitive ability supports the Social Brain Hypothesis, suggesting that for social fish, the demand to process complex social information may be an important driver in the evolution of cognition.

The construction of the Guxian Water Control Project causes blockage of river sections, hindering population exchange between fish upstream and downstream across the dam. Fish passage facilities can mitigate this barrier, and detailed knowledge of fish swimming behavior is critical for their effective design. This study targeted two main fish species for the project: Leuciscus waleckii Dybowski and Opsariichthys bidens-and tested their induced velocity and critical swimming speed. The study also analyzed ecological behavioral indicators including tail-beat frequency, tail-beat amplitude, body wave velocity, body wave length, maximum head angle, and maximum head angle velocity during upstream swimming at three swimming velocitys (2, 4, and 6 BL/s). The results showed that the absolute induced velocities of Leuciscus waleckii Dybowski and Opsariichthys bidens were (0.06±0.01) and (0.11±0.03) m/s, respectively, with corresponding relative values of (0.55±0.11) and (1.11±0.27) BL/s. The absolute and relative rheoreaction velocities of Leuciscus waleckii both exhibited significant negative correlations with body length (P<0.05), whereas the absolute rheoreaction velocity of Opsariichthys bidens showed a significant positive correlation with body length (P<0.05). The absolute critical swimming speeds of Leuciscus waleckii Dybowski and Opsariichthys bidens were (0.99±0.20) and (0.96±0.14) m/s, respectively, and the relative critical swimming speeds were (9.30±1.14) and (10.07±1.47) BL/s, respectively. Both absolute and relative critical swimming speeds of Leuciscus waleckii Dybowski were significantly positively correlated with body length (P<0.05). For both species, tail-beat frequency, body wave velocity, and maximum head angle velocity increased with flow velocity, while tail-beat amplitude and maximum head angle decreased with increasing flow velocity. The body wave length of Leuciscus waleckii Dybowski at 2 BL/s was significantly higher than that under the other two swimming velocitys (P<0.05), whereas the body wave length of Opsariichthys bidens showed no significant change with increasing flow velocity (P>0.05). Among the ecological behavioral indicators, tail-beat frequency, maximum head angle velocity, and body wave velocity showed the strongest correlations with swimming speed, suggesting their central role in propulsion. For fish-passage designs targeting Leuciscus waleckii Dybowski and Opsariichthys bidens, we recommended an entrance velocity of 0.9—1.2 m/s for upstream collection vessels and an internal velocity of 0.1—0.9 m/s within the collection chamber. This study quantifies the swimming ability and key swimming behavioral characteristics of two representative fish-passage target species, providing a reference for the design and optimization of fish passage facilities.

Group living brings numerous ecological benefits and costs, and changes in social status (such as from group living to social isolation) have a profound effect on the morphology, physiology, behaviour, and life history characteristics of social animals. Refuges are intricate and variable, however, most earlier studies on animal group behavior focused on a single ecological context. Therefore, to examine the effect of social isolation and ecological contexts on the group behaviour of cyprinid fish, we utilized common carp (Cyprinus carpio) as the experimental subjects, setting up two social status treatment groups (group-rearing, 5 fish maintained together; isolation group, single fish isolated alone). After 28 days, we measured the collective behavior of each treatment across three contexts: open water, food presence, and food+refuge. We found that, social isolation had no significant effect on the individual behaviour of common carp, but in the food context, both two groups had the fastest individual swimming speed, and in the food+refuge context, the synchronization of speed synchrony was the lowest. Social isolation and contexts have an impact on the collective behaviour and structure. The group speed and the percentage of time spent moving in group-rearing increased with context complexity. The isolation group exhibited a decrease in polarization and in both the open water and food+refuge displayed decreased group coordination and cohesion. After 28 days, foraging efficiency increased significantly in both treatments compared to day 0, while time spent in refuge decreased significantly. Group size in the isolation group was also significantly higher at day 28 than that at day 0. The study shows that social isolation reduces the activity and group coordination in common carp, and that increasingly complex ecological contexts improve the movement ability at the expense of group coordination.

To investigate interspecific variations in group behaviour characteristics among six Cyprinidae species and their responses to exercise training, we selected Carassius auratus, Tinca tinca, Cyprinus carpio, Spinibarbus sinensis, Procypris rabaudi, and Acrossocheilus fasciatus as experimental subjects. At 25℃, each species was divided into control groups, anaerobic exercise training groups (1 session/d), and aerobic exercise training groups [4 times body length per second (bl/s), 18h/d] for three weeks. Subsequently, within a six-arm maze, the following parameters were measured under both non-predator and simulated predator stimuli: centre density (CD), shelter density (SD), non-shelter density (NSD), and cohesion index (I_c). The results indicated that under both non-predator and simulated predator stimulation, the control groups of C. auratus, T. tinca, C. carpio, and S. sinensis exhibited relatively higher CD, NSD, and I_c values along with lower SD, whereas the control group of P. rabaudi showed relatively lower CD and NSD along with I_c higher SD and I_c values. The control group of A. fasciatus displayed relatively lower CD, SD, and I_c values but higher NSD. Regardless of predator stimulation, exercise training did not produce statistically significant effects on the collective behavioral characteristics of C. auratus, T. tinca, and C. carpio. Anaerobic exercise training led to an 81% significant decrease in NSD and a 21% significant increase in I_c values in P. rabaudi under non-predator stimulation (P<0.05); anaerobic exercise training resulted in a 39% significant increase in I_c values in A. fasciatus under simulated predator stimulation (P<0.05); aerobic exercise training caused a 17% significant decrease in I_c values in S. sinensis under non-predator stimulation (P<0.05). The study demonstrates that: (1) There are significant interspecific differences in the collective behavioral characteristics among the six cyprinid species, which may be related to their living habits and habitat factors; (2) Exercise training exerts varying degrees on collective behavioral characteristics by fish species and training regimen.

In order to find out the difference of rheotaxis between narrow range species Pseudorasbora elongata and widespread species Pseudorasbora parva, and whether differences in flow sensitivity contribute to their contrasting distribution patterns, with the aim of informing conservation measures for P. elongata. In this study, we examined the induction velocity for P. elongata and P. parva with the increasing velocity protocol. The results showed that absolute induction velocity (AIF) was (2.88±1.00), (6.81±1.20), (9.63±2.28) cm/s, and relative induction velocity (RIF) was (0.47±0.11), (0.83±0.11), (1.09±0.24) BL/s for body length of 5.0—6.9, 7.0—8.4, 8.5—9.0 cm for P. elongate, respectively. Both AIF and RIF differed significantly among length groups (P<0.05). The AIF and RIF for body length of 5.0—6.9, 7.0—7.9, 8.0—9.0 cm was (5.25±0.82), (7.34±0.46), (7.91±1.03) cm/s, and (0.83±0.10), (0.98±0.06), (0.94±0.10) BL/s for P. parva, respectively. Except for the groups between 7.0—7.9 cm and 8.0—9.0 cm, there were significant differences in AIF and RIF between the other body length groups (P<0.05). The AIF and RIF were positively correlated with body length for both two species (P<0.001). Independent-samples t test showed that the AIF and RIF of P. elongata were significantly lower than that of P. parva (P<0.05). The greater sensitivity of the narrow-ranged P. elongata to water flow, compared to the widespread P. parva, is likely a key factor constraining its distribution. Therefore, conservation of P. elongata habitats should fully account for its rheotactic characteristics. River realignment should follow natural variations in channel width and morphology while meeting flood-discharge safety requirements. In addition, in the sections where the P. elongata has been distributed, the density of lower head dams should be reduced to maximize free-flowing intervals, and removal should be considered where feasible.

This study investigated the relationships among energy metabolism, personality traits, and social hierarchy in breeding-season rosy bitterling (Rhodeus ocellatus), with further analysis of sex-specific differences. The results showed that male R. ocellatus had significantly higher standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS) than females (P<0.05), indicating a greater metabolic potential in males, likely linked to the high-energy-demand activities during reproduction. In females, SMR was positively correlated with both MMR and AS (P<0.05). In males, SMR was positively correlated with activity, while MMR and AS showed significant positive correlations with aggressiveness (P<0.05). The observed sexual differences in the relationships between metabolism and personality may stem from the distinct selective pressures and behavioral strategies experienced by males and females during reproduction. In both sexes, only activity was significantly and positively correlated with social hierarchy (P<0.05), while metabolic rates showed no correlation with hierarchy. These findings suggest that social hierarchy in R. ocellatus is determined more by behavioral traits than by metabolic levels, and while sex influences the relationship between energy metabolism and personality, it does not affect the mechanism determining social hierarchy.

To investigate the impact of the ten-year fishing ban on fish community structure and diversity, this study conducted fish resource surveys in four sections of the middle Yangtze River—Zhijiang, Jianli, Yueyang, and Huangshi—during the spring and autumn seasons from 2022 to 2024. A total of 91 species belonging to 15 families and 10 orders of fish were investigated. Cyprinidae fish are the most abundant (59 species, 64.84%), with lake-type fish (47.25%) and omnivorous fish (65.93%) being the predominant ecological types. Relative Importance Index (IRI) analysis identified eight dominant species: silver carp, bighead carp, crucian carp, grass carp, silver bream, snakehead, shortjaw goby, and yellow catfish, predominantly medium-to-large economic fish. In 2024, 72 fish species were monitored in the middle reaches of the Yangtze River, representing an increase of 10 species compared to 2022, while the average catch per unit effort (CPUE) rose by 11.35% to 10.40 kg per haul. The Shannon-Wiener diversity index remained relatively stable (3.06—3.22). The abundance/biomass comparison curve indicated low disturbance in the fish communities. Cluster and NMDS analyses separated the fish community into two distinct clusters: Zhijiang formed one cluster, while Jianli, Yueyang, and Huangshi formed another. Following the implementation of the 10-year fishing ban in the Yangtze River, CPUE showed an upward trend. Key fish resources such as the four major carp species and croaker recovered relatively quickly, indicating phased success of the ban. However, the diversity index remained relatively stable, suggesting that species diversity recovery is a long-term process. These findings provide scientific support for evaluating the effectiveness of the fishing ban and dynamically adjusting related policies.

To understand the diversity characteristics and interannual variations of the fish community in the middle reaches and tributaries of the Huishui River during the early stage of the fishing ban, fish resource surveys were conducted from 2021 to 2023. A total of 59 fish species were collected, belonging to 40 genera, 12 families, and 7 orders. Among them, Cyprinidae fish were in an absolute dominant position, accounting for 67.80% of the total species, 89.22% of total abundance, and 91.65% of total biomass. The ecological types are dominated by benthic, omnivorous, and spawn-laying fish, with the proportions of species being 55.93%, 55.93%, and 44.07% respectively. Interannual characteristics showed that species richness ranged from 35 to 49, among which the common dominant species were Zacco platypus and Acrossocheilus fasciatus. The Margalef index, Shannon-Wiener index, and Pielou index all showed a fluctuating upward trend overall, ranging from 4.18—5.34, 1.97—2.37, and 0.55—0.62, respectively, while the Simpson index showed a downward trend from 0.19 to 0.31. Cluster analysis showed that community structure in spring, summer, and winter of 2021 was similar, as was that in winter of 2022 and winter of 2023; all other sampling occasions grouped together. This suggests that community recovery followed distinct phases, with a unique response pattern in the early stage (2021). Spatially, the main stream and tributaries generally formed separate clusters, indicating that habitat-driven differences remained dominant. Overall, the recovery of community structure was driven by multiple factors under temporal dynamics, including habitat conditions and seasonal variation, exhibiting phased progression and spatial heterogeneity. This research clarifies the characteristics and diversity trends of the fish community in the Huishui River during the initial stage of the fishing ban, providing a basis for the assessment of the fishing ban effect and the scientific management of aquatic biological resources.

The functional restoration of large river ecosystems represents a significant global challenge. The “Ten-Year Fishing Ban” implemented across the Yangtze River Basin, a large-scale ecological intervention, offers an unprecedented opportunity to investigate the recovery processes in a highly regulated aquatic ecosystem. This study aimed to comprehensively explore structural changes in the fish community food web in the tailrace of the Three Gorges Reservoir (TGR) after the fishing ban. We focused on two hydro-morphologically distinct river sections, the downstream Fuling section and the upstream Mudong section, to analyze the spatio-temporal responses of the food web. Our methodology integrated stable isotope analysis (δ¹³C and δ¹⁵N), an advanced Bayesian Isotope Mixing Model (BIMM) incorporating trophic-level constraints and prior dietary information, and food web topological analysis. Fish and basal food source samples were collected before (2018—2019) and after (2023) the ban implementation. Our results reveal that although species richness recovered similarly in both sections (increasing to 36 species each), food web restructuring followed two divergent pathways shaped by local habitat. The food web exhibited “vertical deepening”: connectance decreased from 0.085 to 0.070 and generalization index from 2.55 to 2.44, indicating more specialized trophic interactions. Concurrently, an expanded δ¹⁵N range (10.94‰ to 11.51‰) reflected food chain elongation, and the proportion of omnivorous species rose from 58.3% to 65.5%. These shifts, together with an increased piscivorous diet in the key predator Siniperca kneri, support a top-down recovery cascade driven by restored predator populations. In contrast, the riverine Mudong section underwent “bottom-up reorganization” toward a flatter structure: connectance increased from 0.070 to 0.077 and the generalization index from 2.21 to 2.69, suggesting more generalized feeding links. However, this was accompanied by a compressed δ¹⁵N range (11.77‰ to 10.47‰), indicating a shorter food chain, and a decline in omnivory from 65.4% to 55.2%. Isotopic data revealed greater reliance on terrestrial C3 plant-derived carbon sources. The diet of the key predator, Culter alburnus, shifted from 78.9% to 64.9%, reflecting increased use of lower-trophic-level resources. This pattern suggests that the recovery was primarily driven by enhanced primary production and terrestrial organic matter inputs, facilitated by stronger land-water coupling and Flood Pulse Concept. In conclusion, ecological recovery after a major conservation intervention such as the fishing ban is not uniform; trajectory depends on local environmental conditions such as flow velocity and floodplain connectivity. These findings underscore the critical importance of assessing functional attributes like food web structure alongside biodiversity metrics. This research provides a crucial scientific foundation for developing and implementing spatially differentiated, adaptive management in the Yangtze River Basin to improve the effectiveness of large-scale conservation efforts.

To explore the influence of nutrient sources on the beta diversity patterns of macrozoobenthic communities in plateau lakes, a quantitative survey of macrozoobenthos and their nutrient sources was conducted in the Zhaling Lake and Eling Lake basins from 2022 to 2024 in the dry and wet seasons. A total of 108 taxa belonging to 8 orders, 39 families were collected. Overall, the lake, habitat, season, and their interactions showed no significant effects on zoobenthos species richness (P>0.05). However, total beta-diversity was relatively high and primarily driven by turnover component. We used parameters in water (chlorophyll a, phytoplankton, total nitrogen, total phosphorus) and catchment characteristics (vegetation coverage, altitude differences, precipitation) to quantify allochthonous inputs and autochthonous nutrients. The Chl.a was significantly higher in the wet season than that in the dry season (P<0.001), and the allochthonous input in the littoral zone of Eling Lake was significantly higher than that in the river region (P<0.01). The Random Forest model indicated that allochthonous nutrient had a stronger correlation with the beta-diversity of the macrozoobenthic community. Allochthonous inputs outweighed autochthonous nutrients in both river and littoral zones during the wet season. In contrast, during the dry season in littoral zone, the importance of autochthonous nutrients such as chlorophyll a and total phosphorus increased significantly, revealing a co-dominant pattern driven by internal and external sources. The total beta diversity and its turnover component exhibited greater sensitivity to allochthonous input, while nestedness in river zone during the wet season also showed certain responsiveness to autochthonous nutrient. These findings provide fundamental scientific support for the ecological management of plateau lake ecosystems.

Influenced by natural geographical conditions and intensity of human activities, the water environment of different areas in Erhai Lake exhibits significant differentiation. To analyze the spatiotemporal variation characteristics of the water environment in Erhai Lake, this study constructed water quality correlation networks at overall, annual, and quarterly scales for three lake regions (the north, middle, and south) based on 19 water physicochemical indicators monitored quarterly at the lake center and corresponding bays (Shaping Bay, Wase Bay, and Xiangyang Bay) from 2017 to 2024. The results indicate that: (1) The water quality network at the center of Erhai Lake is sparser and structurally simpler than that in the lake bays. This low connectivity and high modularity structure can localize disturbances such as pollution, thereby endowing higher resistance. In contrast, the bay networks are more complex and densely connected, making them more prone to chain fluctuations under external disturbances and having relatively weaker resistance; (2) The core nodes quality in the center lake network water are TN, TP, SD, and Chl.a, with TP serving as a common key driver. Its regulation can produce an efficient lever effect. Although water quality indicators in the bays have more connections, they possess fewer key nodes and rely more on random connected paths for buffering disturbances, thus having relatively lower stability; (3) The network structure of water quality in the bays undergoes seasonal evolution, gradually becoming more complex and compact from spring to winter, which may be jointly driven by seasonal fluctuations in rainfall runoff and aquatic plants. Therefore, by regulating the aquatic plant communities in the bays, the local network density can be reduced and modularity enhanced, thereby providing a key pathway toward simplifying and stabilizing the overall lake water quality network. This study is the first to incorporate the network stability framework into water quality assessment of plateau lakes. The proposed “water quality network structure characteristics” offer novel early-warning indicators (such as modularity and density) for zonal management of Erhai Lake and indicate the precise governance approach of reducing external loads and regulating aquatic vegetation to drive the network towards a more favorable configuration.

To investigate the synergistic effects of probiotics and microalgae on larval rearing performance of giant freshwater prawn (Macrobrachium rosenbergii), this study selected Haematococcus pluvialis and Oocystis borgei, which were respectively combined with Clostridium butyricum and Lactobacillus for treatment. The impacts of different probiotic-microalgal combinations on larval survival, growth, development, water quality, and physiological parameters were systematically evaluated. The results showed that the O. borgei+Lactobacillus treatment achieved the highest survival rate (85.80%), significantly higher than that of the control group (50.2%, P<0.05), while the O. borgei+C. butyricum combination exhibited optimal performance in promoting larval growth and development. The two microalgae species demonstrated functional differentiation in water quality regulation: H. pluvialis showed significant advantages in nitrogen removal, whereas O. borgei was most effective in reducing organic matter load (COD_cr). Physiological analysis showed that probiotic-microalgal combinations could effectively alleviate oxidative stress in larvae, with malondialdehyde (MDA) content reduced by 68.3%—87.3% compared to the control (P<0.05), among which the H. pluvialis+C. butyricum combination demonstrated the strongest overall performance in antioxidant, immune, and digestive functions. Stepwise regression analysis revealed that total inorganic nitrogen (TIN) concentration and MDA were the key driving factors affecting larval survival rate, jointly explaining 61.0% of the variation. This study elucidates the mechanism by which probiotic-microalgal synergy enhances larval rearing efficiency through nutrient cycling and physiological regulation, providing theoretical basis and technical reference for microecological intervention in crustacean larviculture.

Polycyclic aromatic hydrocarbons (PAHs), as a class of persistent organic pollutants (POPs), tend to accumulate in organisms due to their lipophilic. Penaeus vannamei, widely cultivated in such settings, is particularly susceptible to PAHs contamination, which may ultimately endanger human health. In this study, the contamination characteristics, ecological risks, and human health risks of 16 PAHs in a cultured water-biological system were investigated. Results showed that the total concentrations of the 16 PAHs (∑PAHs) in aquaculture water ranged from 44.62 to 350.46 ng/L, with Nap, Phe, BaA, Pyr, Chr, Flu, and Ace being the main pollutants. Pollution source analysis based on characteristic ratios showed that PAHs originated primarily from oil, coal combustion, and other biomass combustion. In shrimp muscle, the total concentrations of 16 PAHs ranged from 0.34 to 208.37 μg/kg (dry weight, dw), with 12 PAHs detected, and LMW PAHs predominated, while 5- and 6-ring PAHs accounted for minor proportions. The ILCR values associated with dietary exposure to shrimp ranged from 1.08×10^–11—2.02×10^–8, which was much lower than the USEPA standard value of 1×10^–6, indicating negligible carcinogenic risk under current conditions.

This study used the Soil and Water Assessment Tool (SWAT) to simulate the transport and export of butachlor, a typical herbicide, under agricultural non-point source pollution conditions in the Caizi Lake basin. Model calibration and validation indicated satisfactory simulation performance. The results revealed pronounced spatiotemporal variation in butachlor export. Temporally, 79.32% of the annual butachlor load occurred between June and July, closely associated with intensive rainfall and increased runoff following herbicide application in May–June. Daily butachlor export was significantly and positively correlated with daily runoff (P<0.01, r=0.632). Interannual differences were also evident, with export loads in wet years (e.g., 2016) substantially exceeding those in dry years (e.g., 2018). Spatially, the lower sub-watersheds (sub-basins 13, 17, and 19) were identified as primary export zones, with markedly higher outputs than upstream areas. Among land use types, water bodies had a significant effect on butachlor export, whereas cropland and forestland showed relatively weak impacts, highlighting the retention and transmission function of pond networks in multi-pond systems. These findings provide a scientific basis for managing agricultural non-point source pollution and pesticide use in the Caizi Lake basin, with important implications for safeguarding watershed water quality and optimizing regional agrochemical strategies.

This study investigated the phytoplankton community structure, dominant species’ niche characteristics, and interspecific association in the Donghu Reservoir, Datun Reservoir, and Shuangwangcheng Reservoir along the Eastern Route of the South-to-North Water Diversion Project in Shandong Province. During the survey, 8 phyla, 59 genera, and 116 species of phytoplankton were identified, with Cyanophyta, Chlorophyta, and Bacillariophyta being the dominant groups. The phytoplankton communities in the reservoirs exhibited distinct seasonal succession patterns, that is, spring was characterized by a co-dominance of Bacillariophyta and Chrysophyta; Cyanophyta was absolutely dominant in summer and autumn, with harmful bloom-forming cyanobacteria such as Microcystis spp, Pseudoanabaena limnetica, and Cylindrospermopsis raciborskii were the dominant species; while Cyanophyta and Bacillariophyta were co-dominant phylum, with abundance of Pseudoanabaena limnetica reaching as high as 7.17×10⁶ cells/L. Niche analysis revealed that the average niche width (B_i) of dominant species in Cyanophyta increased by 77.3% and 34.0% in summer and autumn, respectively, indicating significant expansion during these seasons. Seasonal changes in niche overlap (ΔSO_ij) showed that Chlorophyta and Bacillariophyta were in developmental stages in spring, while the niche overlap of Cyanophyta continued to rise to 77.8% in summer and autumn, but the resource competitiveness of Cyanophyta gradually declined in autumn. Interspecific association analysis revealed that there was an overall non-significant negative association in spring and summer, and a significant positive association between the Cyanophyta and Chlorophyta in autumn, reflecting the functional complementarity and niche differentiation among these species. Among the 924 dominant species pairs, 57.47% showed significant association, with as many as 506 pairs having extremely significant negative associations, indicating that the community as a whole was in a state of intense competition. Based on these findings, it is recommended to incorporate positively associated species pairs with high niche overlap as water bloom early warning indicators into the risk management system, providing a scientific basis for ensuring drinking water safety.

As a crucial in-situ remediation technology for river and lake water bodies, ecological enclosure technology effectively inhibits pollutant diffusion, improves the aquatic environment, and enhances stability of river and lake ecosystems through multiple mechanisms such as physical isolation, chemical regulation, and biological enhancement. This paper reviews the operational mechanisms, types, and application effects of ecological enclosure technology in the ecological restoration and protection of rivers and lakes. Building on current literature, we identify existing limitations and propose future directions for both basic research and engineering applications. Future development should prioritize novel materials and technologies for key enclosure components while optimizing construction methods to ensure long-term stability and effectiveness. In addition, systematic numerical simulation methods should be incorporated to predict enclosure durability and ecological impacts, supporting the evolution of enclosure structures towards modularization and intelligence. Ultimately, the comprehensive performance of ecological enclosures should be improved under the premise of reducing management and operation costs and minimizing ecological risks. This study not only provides theoretical support for enhancing the stability and functionality of ecological enclosure technology but also offers technical references for professionals in the aquatic ecological restoration industry. It is expected to promote the sustainable application of this technology.