Fluctuating asymmetry (FA) reflects developmental instability in bilaterally symmetrical organisms under environmental stress. This study systematically compared the otolith FA of two ecologically sympatric Callionymidae species-Repomucenus olidus (n = 273) and Callionymus beniteguri (n = 151)-among different total lengths and habitats in Haizhou Bay, China. Four otolith morphological characters (length, width, perimeter, and area) were measured, and the asymmetric square coefficient of variation (CV2a) was calculated. The results showed that R. olidus exhibited higher FA (CV2a range: 8.19-15.13) and larger proportions of individuals exhibiting significant asymmetry (77.66%-80.95%) than C. beniteguri (CV2a range: 3.78-8.87; proportion of asymmetric individuals: 60.13%-78.48%). FA generally decreased with total length, though peaks were observed at 120-130 mm (R. olidus) and 80-90 mm (C. beniteguri). Compared to the natural area (NA), R. olidus and C. beniteguri showed lower FA in the artificial reef area (ARA). The Generalized Additive Models (GAM) analysis indicated that increasing nutrients (NO3- -N, NO2- -N, and NH4+-N), temperature, salinity, and pH levels were associated with higher FA, with a more significant effect on R. olidus. This study demonstrates distinct FA patterns between the two confamilial species and supports the potential use of otolith FA as a bioindicator in coastal management.

Artificial reefs are crucial for coastal ecological restoration, yet their long-term ecological effects and evolutionary mechanisms remain largely unknown. This study analyzed the structural and functional changes of artificial reef ecosystems in the national marine ranching demonstration area of Haizhou Bay (Jiangsu Province, China) by constructing ecosystem models for 2003 and 2023 using the Ecopath with Ecosim (EwE) framework. The Ecopath results indicated that total system throughput (TST) increased by 26% from 2003 to 2023, rising from 1212.63 to 1526.32 t/km2/year. Trophic transfer efficiency (TTE) improved from 13.7% to 15.16%, and system maturity also increased, with the primary productivity to respiration ratio (PP/R) changing from 7.08 to 7.43 and the system organization index (SOI) moving from 0.238 to 0.284. Notably, the keystone species shifted from Sciaenidae in 2003 to Oratosquilla oratoria in 2023. However, trawling operations continued to suppress high-trophic-level species, such as conger. Ecosim scenario simulations suggested that banning trawling could enhance the recovery of higher-level consumers like congers. Despite this, most species showed a declining biomass trend due to increased intraspecific competition. The findings demonstrate that while artificial reefs can enhance ecosystem function by boosting primary productivity and energy transfer efficiency, trawling still poses a significant barrier to the recovery of ecosystem status. To address these challenges, it is recommended to implement stricter controls on fishing gear, optimize policies by establishing no-fishing zones, improve reef structures to enhance energy transfer efficiency, and maximize the utilization of basic resources. Regular stock enhancement activities should be conducted to adjust the proportions of dominant species, such as O. oratoria. Additionally, ongoing ecological monitoring and assessments of management effectiveness are essential to balance ecological restoration with the sustainable use of fishery resources, providing a scientific framework for effective marine ranching management.

This study delves into the trophic interaction of two Sciaenidae fish, Larimichthys polyactis and Collichthys lucidus, within marine ranching and adjacent habitats (artificial reef area, comprehensive effect area and estuary area) in Haizhou Bay, China, utilizing stable isotope analysis. Isotopic analyses revealed significant differences in delta 13C and delta 15N values of the two species in artificial reef area (P < 0.05). Their isotopic niches exhibited minimal overlap in artificial reef area, substantial overlap in comprehensive effect area, and no overlap in estuary area. Dietary source analysis indicated fluctuating proportions of diet contributions for L. polyactis across habitats, contrasting with relatively consistent proportions for C. lucidus. Connectivity analyses highlighted L. polyactis' higher bidirectional connectivity values between estuary area and comprehensive effect area, while C. lucidus demonstrated elevated bidirectional connectivity values between estuary area and artificial reef area. Moreover, L. polyactis exhibited greater connectivity to comprehensive effect area, suggesting a higher dependency, while C. lucidus showcased a stronger reliance on artificial reef area. Furthermore, as temperature and salinity increased, connectivity for both species tended to rise, contrasting with current speed trends. Depth and distance from the coastline influenced connectivity dynamics differently for L. polyactis and C. lucidus. We posit that consolidating consumers' dietary sources can enhance the accuracy of quantifying habitat connectivity, emphasizing that the quantity and types of dietary sources significantly impact quantitative connectivity outcomes. To enhance precision, we advocate for comprehensive isotopic data collection from all food web consumers. Establishing quantified baseline values will be instrumental in evaluating habitat connectivity. The findings in this study will provide valuable insights for prompting the ecological effect of marine ranching and implementing the stock enhancement activities in coastal water in the future.

Protist communities play critical roles in coastal ecosystem functioning through their mediation of carbon cycling and trophic interactions, yet their ecological responses to habitat heterogeneity and anthropogenic pressures remain undercharacterized. This study elucidates the spatiotemporal dynamics of protist communities in surface (S) and bottom (B) water layers across three distinct habitats in Haizhou Bay, China: estuarine area (EA), comprehensive effect area (CEA), and artificial reef area (ARA). Alpha diversity analysis revealed significantly elevated protist diversity in EA_B (Shannon index, Simpson index, Species Rich and Chao1: P < 0.01) compared to other habitats. Beta diversity patterns (PERMANOVA: P = 0.02) demonstrated significant compositional divergence of protist community between ARA and EA, with LEfSe identifying habitat-specific biomarkers including Pyrrophyta (phylum) in ARA_S, Heterokonta (phylum) in CEA_S; Chlorophyta (phylum) in EA_S; Endomyxa (phylum) in EA_B. Co-occurrence network analysis identified key ecological bridges (e.g. ARA_B, CEA_B, EA_S) facilitating cross-habitat connectivity. Redundancy analysis quantified four principal environmental drivers (temperature, salinity, pH, dissolved oxygen) explaining 23.38 % of community variation. Notably, protist communities in EA and ARA exhibited divergent taxonomic profiles but maintained spatial connectivity through hydrodynamic transport and functional convergence. Artificial reef structures exacerbated protist niche partitioning while promoting vertical connectivity through localized upwelling dynamics. This study underscores the importance of preserving ecological connectivity and habitat complexity in coastal systems, positioning protists as sensitive bioindicators for marine environmental protection. Our findings can guide conservation strategies that enhance resilience against climate change and protect microbial biodiversity hotspots.

“Edible wild shrimp” play a crucial role in marine ecosystems and food chains, yet research on microplastic (MP) impacts on the dominant shrimp species of the Haizhou Bay Marine Ranch remains scarce. This study examined shrimp from Haizhou Bay, evaluating the distribution, nutritional characteristics, and health risks associated with microplastics in their tissues. Analytical techniques included Fourier transform infrared spectroscopy, the hot needle method, stable isotope analysis, and microplastic risk assessment. The results revealed that microplastics comprised 40.93% of all particles identified, with Oratosquilla oratoria exhibiting the highest intestinal contamination, followed by Alpheus distinguendus. Most MPs were fibrous (86.3%), predominantly blue (57.32%), and approximately 80% consisted of Polyethylene Terephthalate. Significant interspecies differences were observed in the gastrointestinal distribution of MPs, while individuals of the same species showed no notable differences across body-length groups due to molting. The estimated daily intake and margin of exposure for human consumers remained well below the no-observed-adverse-effect level, suggesting negligible health risks. These findings provide a theoretical and empirical basis for understanding the migration, sources, and ecological implications of microplastics in shrimp, offering valuable insights for assessing nearshore environmental pollution and food web dynamics.

Fluctuating asymmetry (FA) in otoliths serves as a sensitive biomarker for assessing developmental instability in fish under environmental stress. This study compared otolith FA across three ecologically distinct species-Thryssa kammalensis, Johnius belangerii, and Cynoglossus joyneri-in relation to standard length groups and habitats (Artificial reef area (ARA), Nori culture area (NCA), Oyster reef area (ORA), and Natural area (NA)). Results revealed significant interspecific differences: C. joyneri exhibited extreme FA (CV2a up to 47.89 for otolith area; >80 % asymmetric individuals), while J. belangerii demonstrated resilience (CV2a < 2 across characters) across habitat adaptations. T. kammalensis showed intermediate FA (CV2a 5.46-10.37), peaking in the 80-90 mm standard length group, reflecting growth-phase-specific metabolic trade-offs. Habitat complexity in ARA reduced FA (e.g., T. kammalensis otolith length CV2a: ARA < NCA, P < 0.05) by mitigating anthropogenic disturbances, whereas intensive aquaculture in NCA amplified stress (C. joyneri otolith area CV2a: NCA > ORA, P < 0.05). FA progression with body size highlighted cumulative stress in C. joyneri (CV2a = 20.15 for perimeter in 150-160 mm group), contrasting with J. belangerii's stable CV2a. The findings underscore species-specific vulnerabilities: C. joyneri's benthic ecology heightens sensitivity to pollutants, while J. belangerii's euryhaline traits buffer habitat flexibility. These results advocate for habitat-specific conservation, prioritizing pollution regulation in benthic zones and leveraging FA as a tool to monitor anthropogenic impacts. Management strategies should focus on protecting high-FA species like C. joyneri while utilizing resilient taxa like J. belangerii as ecological indicators in coastal ecosystems.

This paper focuses on three artificial reefs with different functionalities that are to be placed in the marine pasture in South Sulawesi Province, Indonesia, investigating the effects of different incoming current velocities and headward current angles on their flow field effects and aiming to explore the flow field effects of the three reefs and analyze the functionality of their flow fields and flow regimes on the sea area. A combination of PIV experiments and numerical simulation is used to analyze the velocity at the measurement point of the flume, the characteristics of the cross-section flow pattern, and the flow field effects under different incoming velocities and head-on angles, and the accuracy of numerical simulation is verified by flume tests. The results show that the changes in the incoming velocity and the angle of flow on the three reefs have different effects on the volume of upwelling and back eddy; the shape of the reef and the internal structure of the reef do not have any impact on the flow pattern, and the changes in the flow field are different under different conditions. The scale of the flow field reaches optimization under specific conditions.

Marine ecosystems are encountering a variety of environmental challenges as a result of global climate change. In response to these challenges, the development and expansion of marine ranching have emerged as a crucial solution. Notably, zooplankton is acknowledged as an essential indicator for evaluating the ecological health of marine ranching. This study examined the spatiotemporal distribution of copepod abundance and its reaction to environmental factors, utilizing data collected from the marine ranching area of Haizhou Bay (Lianyungang, Jiangsu, China) between 2003 and 2022. The results showed that copepod abundance exhibited a notable pattern, with higher levels in spring compared to summer and autumn, and was consistently distributed uniformly in the central region of the marine ranching area. During El Nino years, copepod abundance was more likely to be found outside the bay, unlike non-El Nino years, where the opposite distribution was noted. The generalized additive model (GAM) revealed that the primary environmental factors influencing copepod abundance across various seasons included temperature, SiO3--Si, NO3--N, and Chlorophyll a. However, during El Nino events, the key environmental factors shifted to temperature, NO3--N, and dissolved oxygen (DO). The study concluded that nutrients influence copepod abundance across different climate conditions. During intense El Nino events, temperature was also found to affect copepod abundance indirectly. It was also noted that diatoms are less likely to directly impact copepod abundance through direct predation-prey interactions. The findings of this study provide valuable insights that can enhance our ability to predict changes in zooplankton populations within marine ranching systems as they respond to global climate change. This knowledge is crucial for conducting thorough assessments of the ecological benefits associated with marine ranching and for guiding its sustainable development. Ultimately, this research's data and scientific references generated from this research will be instrumental in evaluating offshore ecological environments and facilitating practical ecosystem restoration efforts.

In this study, we aim to optimize the design of artificial reefs and improve their applicability and durability in the marine environment. Three types of reefs were selected to be placed in Indonesian waters as the target, and we analyzed the local scour characteristics and the influence of structural parameters of the artificial reefs at four different flow velocities through flume model tests and numerical simulations. The results showed that the local scour was insignificant when the flow velocity was less than 0.8 m/s and became severe when it reached 0.8 m/s. The structure of the reefs affects the degree of scouring, and a multi-column support structure will form a complex flow field, which can be optimized by combining with the design of sand content; the high and low values of the flow field, the bed shear, and the vortex field in the numerical simulation correspond to the areas of the local scour in the test. In conclusion, this study provides an essential basis for the design, deployment, and later management and maintenance of artificial reefs, which can help to improve their stability, better fulfill their ecological function, and promote the sustainable development of marine fisheries.

Artificial reefs (ARs) play a vital role in marine habitat restoration; however, their influence on microbial communities remains poorly understood. In the present study, we investigated seasonal- and habitat-driven variations in plankton and meiofauna communities (herein referred to as microbial communities) in Haizhou Bay, China, by performing 18S rDNA sequencing and co-occurrence network analysis. Samples were collected from AR surfaces and adjacent seawater in spring and autumn, and the environmental parameters, such as temperature, salinity, and depth, were concurrently detected. The results revealed significant alpha-diversity differences. Autumn bottom waters exhibited the highest richness, whereas AR surfaces exhibited decreased Shannon indices (P < 0.001). beta-Diversity analysis revealed distinct community structures between ARs and water columns (P < 0.001), which were largely driven by seasonal shifts in temperature and salinity. Reef surfaces supported complex networks with >80 % positive correlations, suggesting mutualistic interactions. Vertical stratification on ARs led to depth-dependent specialization, with increasing Annelida abundance at deeper layers in spring (P = 0.012). Linear discriminant analysis effect size identified habitat-specific biomarkers, such as Cnidaria in autumn ARs and Ciliophora in spring water, suggesting niche partitioning. Redundancy analysis revealed salinity and temperature as major environmental drivers. Altogether, our findings suggest that ARs enhance biodiversity and ecosystem stability through habitat heterogeneity and modular networks, buffering environmental changes. These findings offer practical insights for optimizing AR designs and formulating strategies to support sustainable sea ranching development and coastal restoration.

Increasing attention has been directed toward the toxic effects of microplastics (MP) on marine mollusks in recent years. To evaluate these effects, Pacific oysters (Crassostrea gigas) were acclimated and cultured in a 140-Liter container, where two types of MP, polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC), were introduced into their feed. MP concentrations in the water were maintained at 300 μg/L, 600 μg/L, and 900 μg/L to assess oxidative stress, DNA damage, and metabolic disorders in these organisms. Significant alterations in antioxidant enzyme activities were detected in C. gigas exposed to these pollutants. After 30 days of exposure to high concentrations of PMMA, superoxide dismutase (SOD) activity in the adductor muscle was reduced by 59% compared to the control group, while catalase (CAT) activity increased by 67%. DNA damage assessments revealed that NF-κB expression levels reached a maximum value of 2.46 in the high-concentration PMMA group after 30 days, the highest among all experimental groups. Additionally, metabolic pathway alterations in the hepatopancreas of C. gigas were observed, including reduced expression levels of uridine and methylmalonic acid (MMA), alongside significantly elevated expression levels of glutamic acid and asparagine. This study offers essential toxicological data for understanding and quantifying the impacts of PMMA and PVC MP on marine mollusks.

Collichthys lucidus is a eurythermic and euryhaline fish that prefers to live in middle and bottom waters and is widely distributed in the coastal waters of China. In recent years, the situation of C. lucidus resources has not been optimistic due to the overexploitation of fishery resources in offshore waters. In this study, the population structure of C. lucidus in the Haizhou Bay Fishing Ground (HZBFG), Xiangshan Bay Fishing Ground (XSBFG) and Lvsi Fishing Ground (LSFG) in the coastal waters of China was compared based on otolith morphology and microchemistry. The traditional morphological indicators and elliptic Fourier indicators of otoliths showed that there is a significant difference between the HZBFG population and the LSFG population (P < 0.05), and the XSBFG population (P < 0.05), mainly reflected in the differences between basal lobes, wing lobes and main interstitial sulci. The overlap degree of otolith contour between the LSFG and XSBFG populations was higher. The combination mechanism of microchemical elements in otoliths showed that Sr/Ca, Mg/Ca and Ba/Ca of C. lucidus in the otolith core zone was not significant (PERMANOVA, P = 0.051), and that in the otolith edge zone was significantly different (PERMANOVA, P = 0.001). Generally, the LSFG and XSBFG populations probably belong to the same population, while the HZBFG population located in the northern Yellow Sea can be identified as a separated population. We conclude that C. lucidus was distributed in the coastal waters of the East China Sea and the Yellow Sea during the early life period and eventually formed a north-south differentiation pattern through migration after reaching adulthood. This study can be used as a basic reference for the conservation and sustainable utilization of the resources of C. lucidus.

Since the 1950s, plastic pollution and its risk have been recognized as irreversible and nonnegligible problems as global plastic production has increased. In recent years, the transport and trophic transfer of microplastics (MPs) in biotic and abiotic environment have attracted extensive attention from researchers. In this study, based on the Ecotracer module from Ecopath with Ecosim (EwE) model, the marine ranching area of Haizhou Bay, Jiangsu Province, China, was taken as a case study by linking the environmental plastic inflow with MPs in organisms to simulate the variation of MPs in the marine food web for 20 years, as well as its potential trophic transfer and biomagnification. We found that the concentration of MPs in top consumers first increased when the concentration of MPs in the environment increased, while that in primary consumers first decreased when the concentration of MPs in the environment decreased. Moreover, high TL consumers had a stronger ability to accumulate MPs, and pelagic prey fishes was the opposite. From the perspective of the food web, all functional groups showed significant trophic magnification along with the trophic level and no biodilution. Generally, there is a direct relationship between the MPs in marine organisms and environmental inflow. If the pollutants flowing into the environment can be reduced, the MP pollution problem in coastal waters will be effectively alleviated. Our research can further provide a scientific basis for ecological risk assessment and management of MPs and biodiversity protection in marine ecosystems.

One significant "sink" for microplastic (MP) pollution is the sediments. There's a considerable lack of reliable data regarding the historical status of MPs contamination in sediments within marine ranching. In this research, the study area encompassed Haizhou bay marine ranching and adjacent seas. The primary objective was to explore the potential relationships between the accumulation of MPs and both the sample depth and sediment characteristics within the cores. The results unveiled significant contamination of MPs within the sediment cores. The average MPs concentration of sediment was 1.01 +/- 1.28 n/g. Fibrous polymers and particles smaller than 1000 mu m were frequently found in the sediment. The abundance of MPs exhibited a tendency to decrease with an increase in sediment depth. Artificial reefs and currents affected on MPs distribution in sediment cores. The accumulation of MPs showed a significant correlation (P < 0.05) with the sediment content of different particle sizes, suggesting that the composition of sediment can serve as an indicator of the abundance of MPs. The risk of MP pollution in the sediments of the study area was assessed by establishing a risk assessment model using concentration data of MPs and polymer types. Due to the higher hazard score of polymers (PA and PET) in MPs, the Polymer hazard index (PHI) was elevated to grade II. However, it had a Pollution load index (PLIzone) value of 1.95 (level I). This suggested that contamination was minimal, yet the ecological risk remained relatively high. The ecological risk assessment of MPs served as the foundation for gaining a detailed understanding of the distribution characteristics of MPs. It also furnished essential data support for conducting a comprehensive assessment, developing feasible management strategies, and establishing water quality standards related to plastic waste.

Artificial reefs are widely recognized for their role in improving the ecological environment and creating protected habitats for marine organisms, ultimately enhancing biodiversity within the food web and fisheries resources. This study utilizes stable isotopes to analyze fish samples ranging from 3.4 to 1067 g in body mass, collected within the artificial reef area of Haizhou Bay. The objective is to determine if the δ15N-based fish body mass acts as a driving factor in shaping the food web structure. The results showed a certain level of overlap among all trophic guilds, suggesting that most trophic guilds within this region share similar living environments and feeding habits. The multiple linear regression showed a slight increasing trend between δ15N values and body mass. Furthermore, the predator–prey mass ratio (PPMR) was calculated to be 430:1 based on the δ15N–body mass relationship. This implies that larger reef fish within this artificial reef ecosystem tend to have higher δ15N values compared to smaller fish, indicating a shorter food chain in this ecosystem. In summary, this analysis provides valuable insights into the fish community structure within artificial reef ecosystems. Therefore, it is recommended that future studies focus on further characterizing the fish community structure using body mass information.

Since the 20th century, as research on the fluctuating asymmetry (FA) of otoliths in sedentary fish has deepened in a gradual way, many scholars have focused on exploring the ability of their otolith FA to indicate different environmental pressures. In this study, a typical benthic fish - Cynoglossus joyneri from three artificial habitats (artificial reef area (ARA), oyster reef area (ORA) and kelp cultivation area (NCA)) and a natural habitat (natural area (NA)) of Haizhou Bay (Lianyungang, Jiangsu Province, China) was selected as the research object, of which four otolith characters (length, width, perimeter, and area) were used to detect FA based on the squared coefficient of asymmetry variation (CVa2). The results showed that the CVa2 of otolith in C. joyneri tended to decrease as their body length increased. In terms of indicating environmental pressure, the CVa2 of otolith length in NA was significantly higher than those in the other area (P < 0.05); the CVa2 of otolith width in NA was significantly higher than those in ARA and ORA (P < 0.05), and those in NCA were significantly higher than those in ORA (P < 0.05); and the CV(a )(2)of otolith area in NA was significantly higher than those in ARA (P < 0.05), and those in NCA were significantly higher than those in ORA (P < 0.05). Generally, the otolith FA of C. joyneri in artificial habitats has lower CVa2 than that in natural habitats, indicating that the environmental pressure in artificial habitats is lower than that in natural habitats. We believe that C. joyneri can serve as an indicator species for environmental pressure between different habitats, which could be considered as a groundbreaking milestone in the study of otolith FA in fish. The findings not only advance the ability to assess environmental pressure in sedentary fish, which provide new insights into evaluating environmental pressure in artificial and natural habitats.

In the past two decades, there has been a growing interest in the ecological benefits and construction effects of marine ranching. As a result, the distribution of certain benthic fish species with limited swimming abilities is often used as a basis for assessment. This study focused on Chaeturichthys stigmatias in the Haizhou Bay marine ranching area of Jiangsu Province, China, and analyzed the seasonal variations in its population resources and the environmental factors influencing them. The findings revealed distinct seasonal changes in spatial distribution. During spring and autumn, the biomass of C. stigmatias was primarily concentrated in coastal waters (31.75 and 32.43 kg/km(2)), while during summer, it was mainly distributed in the northern waters of the marine ranching area (95.57 kg/km(2)). The generalized additive model (GAM) analysis identified the main environmental factors influencing changes in C. stigmatias biomass for each season. In spring, these factors included latitude, silicate (SiO3--Si), phosphate (PO43--P), chlorophyll-a concentration (Chla), dissolved oxygen (DO), suspended matter (SS), and salinity. In summer, the main factors were biochemical oxygen demand (BOD5), DO, pH, Chla, chemical oxygen demand (COD), depth, and water temperature. In autumn, the main factors were Chla, COD, SiO3--Si, BOD5, SS, depth, and water temperature. We find that Chla is consistently recognized as an environmental factor that influences the biomass of C. stigmatias. However, it is important to acknowledge that the effects of nutrients, DO, water temperature, and salinity should not be disregarded. To identify the key environmental factors impacting the biomass of C. stigmatias, it is necessary to consider the biological characteristics at different stages of its life history. Additionally, it is crucial to examine the potential interactive effects and dynamic relationships among various environmental parameters. This study aims to enhance our understanding of the ecological and physiological traits of C. stigmatias, provide guidance for population conservation efforts, and offer a scientific foundation for the management of fishery resources in marine ranching areas.

Plastic products are widely distributed worldwide and continue to have a negative impact on the environment and organisms. Intertidal regions, which interface between upland and marine ecosystems, are regions of high ecological importance and serve as repositories for a variety of plastic wastes. However, ecological risk assessments of microplastics (MPs) in these transitional environments are still scarce. In this study, the morphological characteristics and spatial distribution of MPs in the intertidal surface sediments of Haizhou Bay were analyzed, and an ecological risk assessment framework for MPs was developed. Overall, the average abundance of MPs in the sediments was 2.31 +/- 1.35 pieces/g dw. The size of the MPs was mainly less than 1 mm, and the main shape, color and polymer type of the MPs were mainly fibrous (58%), blue (30%), and PVC (22%), respectively. Cluster analyses showed that the sites could be well distinguished by size and polymer type but not by MP shape and color. According to the hazard scores, most of the sites in this area belonged to a risk level of IV, while the pollution loading index (PLI) showed that most of the sites belonged to a risk level of II. The ecological toxicity risk from the species-sensitive distribution (SSD) model showed that one-third of the sites had ecological MPs toxicity risks to marine organisms. We believe that normalized and standardized assessment methods should be implemented to monitor and manage the risk of MPs in the intertidal sediments. Particularly, the multiple dimensions, standard abundance of MPs, as well as MPs ingestion in the intertidal organisms, should be fully considered in the next step.

Plankton are an important component of marine protected areas (MPAs), and its communities would require much smaller interpatch distances to ensure connection among MPAs. According to the survey from MPAs dominated by artificial reefs and adjacent waters (estuary area (EA), aquaculture area (AA), artificial reef area (ARA), natural area (NA) and comprehensive effect area (CEA)) in Haizhou Bay in spring and autumn, we analyzed phyto-zooplankton composition, abundance and biomass, and correlation with hydrologic variables to gain information about the forces that structure the plankton. The results showed that the dominant zooplankton were copepods (spring, 98.9%; autumn, 94.2%), while the phytoplankton were mainly composed of Bacillariophyta (spring, 61.8%; autumn, 95.6%). The RDA results showed that temperature, salinity and depth highly associated with the distribution and composition of plankton species among the habitats than other factors in spring; temperature, Chla and DO had the strongest influence in autumn. The zooplankton in the ARA and AA ecosystems basically contained the same species as those in other habitats, and each habitat also exhibited a relatively unique combination of plankton species. The structures of the EA zooplankton in spring and the EA phytoplankton in both seasons were much different than other habitats, which may have been caused by factors such as currents and tides. We concluded that there exists similarity of the plankton community between artificial reef area and adjacent waters, whereas the EAs may be relatively independent systems. Therefore, these interaction between plankton community should be considered when designing MPA networks, and ocean circulations should be considered more than the environmental factors.

Marine ecosystems are facing numerous environmental challenges due to global climate change. In response to these challenges, the establishment and growth of marine ranching has emerged as a pivotal solution. Chlorophyll a concentration (Chla) is recognized as a valuable indicator for the ecological assessment of marine ranching. This study focused on the spatiotemporal distribution of Chla and its response to environmental factors according to the dataset in the marine ranching area of Haizhou Bay (Lianyungang, Jiangsu, China) from 2003 to 2022. The results showed that Chla had a significant cycle of summer > spring > autumn and was distributed evenly in the central area of the marine ranching. During interannual changes, Chla patches were centered in the central region during 2014, 2015, and 2016. The Chla patches predominantly focused on the eastern area in 2018-2019, shifting to the western area in 2020-2021. The generalized additive model (GAM) indicated that salinity, depth, temperature, biological oxygen demand (BOD5) and SiO3--Si were the main environmental factors affecting Chla during spring, summer and autumn. However, during El Ni & ntilde;o events, salinity, depth, temperature, BOD5 and transparency became the main environmental factors. We concluded that salinity, depth and temperature consistently played a crucial role in determining Chla under various climate conditions, and SiO3--Si and transparency will no longer be an environmental factor limiting Chla. In addition, The effect of interannual variability on upwelling and vertical mixing of water layers may potentially alter the spatial distribution pattern of Chla. These findings can offer ideas into predicting the variation of Chla in marine ranching under global interannual events in the future. Furthermore, this can contribute to the comprehensive assessment of ecological benefits and the in-depth construction of marine ranching. Ultimately, it can provide essential data and scientific references for offshore ecological environment assessment and ecosystem restoration.