Abstract:Mussel farming habitat distributed in Shengsi archipelago has been growing in scales since the last century and playing key roles as marine ranching. Fully understanding of habitat use strategies of rock fishes in mussel farming area can be important reference for design of marine ranching programs. A monthly survey targeted on juvenile rockfish Sebastiscus marmoratus was carried out from May to July, 2018 in the northern area of Zhoushan archipelago, in order to explore the habitat use characteristics of juvenile rockfish in mussel farming area, as well as its reference value for marine ranching projects. Self-designed nets were applied to collect juvenile rockfish. Inhabitant density and its spatial distribution characteristics, habitat selection strategies, food selection characteristics based on stomach contents analysis, and early life cycles based on otolith rings, were discussed. The inhabitant density for juvenile rockfish from May to July was respectively (10±6) inds/string, (7±5) inds/string and (5±5) inds/string, showing a monthly decline trend. Juvenile individuals distributed widely during early month and then moved from offshore side of mussel farming area toward inshore side till its complete disappearance in offshore sites. However, sites with the greatest densities were always located beside shoreline area. Positive correlation was detected between juvenile densities and void volume as well as macroalgae biomass from hanging mussel strings based on correlation analysis, although not at significant level. High feeding intensity lasted all three months with zero rate of empty stomachs, and was revealed by stomach content analysis. The average feeding degree was higher in mussel farming area than that in the rocky reef habitat. The juvenile rockfish mainly fed on Amphipoda represented by Caprellidae sp.and Gammaridea sp., which accounted for 99.2% together by weight among its total diet composition. Its early stage inhabited in mussel farming habitat lasted about two to three months with average daily growth ring equal to (57±12) d for juvenile rockfish. Comparison of homogeneousness and regularity on otolith rings revealed that individuals inhabited in mussel farming area showed much more consistence than those from rocky reef habitats. It indicated that hanging strings in mussel farming waters around Gouqi Island supplied ideal habitats to juvenile rockfish by offering much more stable physical environment and abundant food sources, which in turn made great contributions to its stock enhancement and population conservation effects in local areas. It is suggested that local government should pay close attention to habitat use strategies of dominant reef fishes such as rockfish by means of applying suspended structures on proper scales in local marine ranching programs.

Abstract:Seaweed is one of the most important coastal ecosystem-engineers, and the habitat formed by it plays an important role in supporting ecological behaviors (e.g. feeding, growth and recruitment, etc) of marine organisms. However, seaweed beds are declining around the world due to the environmental changes and human activities, which makes non-negligible impact on organisms inhabited there. China suffered severely from this situation. To achieve the goal of sustainable utilization of marine resources, the restoration of seaweed beds is becoming an important assignment of China's ecological environment protection in coastal areas. However, the lack of understanding of ecological function of seaweed and seaweed-formed habitat makes the objectives and methods of the seaweed beds restoration unclear. In this paper, we summarized the ecological function of seaweed and seaweed-formed habitat, such as seaweed beds and seaweed farming area in the context of ecological restoration of seaweed beds. Furthermore, we put forward some thoughts about whether it's suitable for the seaweed farming to be incorporated into the construction of sea ranching. We also suggested some quantitative measures of ecological function in seaweed-formed habitat. Our analysis may provide references for restoring seaweed beds reasonably and efficiently, and sustainable development of seaweed farming industry in the future.

Abstract:Abundance of Liza haematocheila has declined rapidly since the 1980 s in Bohai Sea, due to the increasing fishing pressure caused by the change of fishery methods. Furongdao artificial reefs (ARs), located in Laizhou Bay, has provided a good habitat for L. haematocheila, making it one of the major fish resources in the AR area. In order to explore the response of L. haematocheila to environmental factors, the effect of environmental factors, artificial reefs, food abundance on CPUE and mean standard length of L. haematocheila were analyzed using GAM model. L. haematocheila were collected by trammels survey of Furongdao ARs during 2014-2017. The results showed that there was no significant difference between average CPUE values of artificial reef area and natural area in spring (P=0.362), however, the CPUE in AR area is 3.53 times CPUE in the control area in the autumn. Three-way ANOVA showed that CPUE is significantly affected by year, month, artificial reefs and interaction effect of year and month (P < 0.01). Average length was affected by year (P < 0.01). Results of Delta GAM showed that the probability that L. haematocheila occurs was significantly influenced by temperature and whether the site is in the AR area. The probability of presence is higher in AR area than in the natural area. As temperature increases, probability of presence decreases. CPUE increases when temperature is below 8℃ and then decreases. Mean standard length of L. haematocheila is influenced by abundance of Bacillariophyta and zooplankton. When abundance of Bacillariophyta is smaller than 3×10⁵ cells/m³, mean standard length decreases with the increase of the abundance of Bacillariophyta, and then tends to stabilize change. Mean standard length decreases with abundance of zooplankton rises. In conclusion, L. haematocheila is mainly distributed in the AR area at low temperature, and large fish is mainly distributed in the area with low abundance of Bacillariophyta and zooplankton.

Abstract:Artificial reefs (ARs) are an important part of marine ranching, which are installed in seabed to protect and cultivate marine life systems. After ARs are deployed, changes in seabed conditions may intensify local scouring of seabed nearby ARs and influence the stability of ARs. Therefore, it is necessary to investigate the scouring characteristics. In this study, a physical model experiment was conducted in an experimental sink to investigate the local scouring of an artificial reef at different water flow velocities, which was placed on silty sand bed. The experiment results show that the scouring response of the silty bed to the 0.11 m/s flow velocity is not significant. The depth of the scouring hole behind the reef model is 0.5 mm, and there is no obvious scouring hole on both sides. When the flow velocity increases to 0.22 and 0.27 m/s, sand scales are uniformly distributed on the surface of sand bed. The depth of the scouring hole behind is 1.0 and 1.5 mm respectively. The maximum depth of the scouring holes on both sides is 4.5 mm and the width is 4.0 cm and 7.5 cm respectively. Combined with the experiment results, the numerical simulation method was introduced to analyse the mechanism of scouring phenomenon nearby ARs. According to the simulation, the flow field, shear force and vortex distribution are similar to the scouring pattern of silty sand bed in the experiments. The numerical simulation results show that the holes in the surface and multi-legs of reef increase the flow and scouring strength. The high value area of above three parameters corresponds to the area with stronger scouring. It is concluded that the scouring strength of ARs in the silty sand bed increases with flow velocity, but it is not strong enough to influence the stability of reef model. The structure of ARs does have effects on the local scouring. Flow field, stability and scouring pattern should be taken into consideration during the design of ARs.

Abstract:The artificial reefs are an important part of the marine ranching. Sebastes schlegelii which occurs in the coastal waters of China, including Yellow Sea and East China Sea, is a delicious seafood and has great economic value. We studied the resource status of S. schlegelii in different reef areas, such as growth, mortality and utilization of resources assessment, based on the cage questionnaire data in Weihai artificial reef area, Shandong province, from 2016 to 2018, by the means of ELEFAN Ⅰ, length-converted catch curve, Y_w/R curve and the biologic reference points. And uncertainty was incorporated into the estimation of the biological reference points F_0.1 and F_max by Monte Carlo simulation. The results of the first study on the resources of reef areas at different depths showed that the average body length, average weight, asymptotic body length and asymptotic weight of the S. schlegelii in shallow water areas were greater than those in the middle waters, and the deep water areas were the smallest, indicating that the artificial reefs in shallow water areas were more conducive to the protection of fishery resources. The fishing mortality coefficient and the natural mortality coefficient in the middle water area were greater than the deep water area, the shallow water area was the smallest. It is the first time to apply biological reference points F_0.1, F_max and uncertainty analysis to the resource assessment of different depths of reef area. The result showed that the judgment results of F_BRP at the three uncertainty levels were consistent with the none uncertainty, but the value of F_max was far greater than F_0.1, making it more difficult to judge the amount of reef resources as overexploitation. Therefore F_0.1 is more suitable for the evaluation of S. schlegelii. In combination with Gulland's theory, biological reference points and yield per recruitment, reef resources were under the mild exploitation, and fishing intensity can be appropriately enhanced to increase catch yield. Shallow waters can be increased to F=0.39, and Y_w/R=25.60, corresponding fishing age is 1.83 a. The middle water area can be increased to F=0.46,Y_w/R=23.89 and fishing age 0.93 a, respectively. Deep water area can be increased to F=0.42, and Y_w/R=16.74 corresponding to a fishing age of 1.12 a.

Abstract:The throwing scale of artificial reefs is one of the core issues in the construction of reefs. The throwing amount and disposal spacing of artificial reefs not only characterize the range and density, but also determine the efficiency of artificial reefs flow field effects. In our study, the flow field characteristics of seven disposal spacing (0 l, 0.5 l, 1.0 l, 1.5 l, 2.0 l, 3.0 l and 4.0 l) that is the multiple of the length of the single artificial reefs, with four throwing amounts of Mi-zi artificial reefs (2×2, 3×3, 4×4 and 5×5) were simulated using the large eddy simulation model based on the ANSYS software. Then, the relationships between the characteristics (including the relative volume, relative height and relative length) of different flow fields and the throwing amounts and disposal spacing and the target velocity ratio were studied. The results showed that when the upwelling target velocity ratio is less than 0.10, 0.10 to 0.15 and greater than 0.15 times, the maximum disposal spacing is 4.0 l, 3.0 l, 2.0 l, respectively, and there was a synergistic effect on the upwelling area. And the maximum disposal spacing is 3.0 l at all the back eddy target velocity ratios. The larger the reefing amount is, the higher the relative volume both the upwelling and the back eddy are, and the lower the average relative volume growth rate. At the disposal spacing of 0.5 l, the relative upwelling volume and the relative volume of the single artificial reefs are the largest, but the back eddy relative volume and the relative volume of the single artificial reefs are the largest at 1.5 l. The upwelling's relative height increased at a rate of 1.01 times with the laying amount increasing and decreased at a rate of 0.90 times with the disposal spacing increasing, while the relative length of the back eddy would increase firstly and then decrease with the disposal spacing and the maximum at 1.0 l. The study provides the theoretical planning guidance for the artificial reef placement in different construction modes.

Abstract:With the aim of understanding the impact of artificial reef deployment on the distribution of fish eggs and larvae, a horizontal trawl survey using large plankton nets in Ma'an Archipelago from January 2018 to October 2018 was carried out on four voyages. According to the species composition, quantity distribution and other community structure characteristics of fish eggs and larvae, their resource distribution in reef areas and natural areas were studied.The results showed that a total of 5 642 fish eggs and 1 013 larvae were collected, which belonged to 10 orders, 21 families and 49 species. Harpodonle sueur, Cynoglossus joyneri and Larimichthys polyactis were dominant fish eggs; Sebastiscus marmoratus, Lateolabrax japonicus and Stolephorus sp. were the dominant fish larvae. The dominant species of fish eggs and larvae in the reef area and the natural area were almost the same, while the community structure was significantly different. The reef areas had significant differences with the natural areas in the biodiversity, and the diversity index, richness index and evenness index of the reef area were highest in spring. Cluster analysis indicated that the community structure of fish eggs and larvae were the most stable in spring, the simplest in winter, and the summer had the higher similarity with autumn. Comprehensive analysis suggested that artificial reefs in Ma'an Archipelago have certain aggregation and shelter effects on fish eggs and larvae, and the marine physical environmental factors such as temperature (T), salinity (S), water turbidity (Turb.) and so on have significant effects on the distribution of fish eggs and larvae.

Abstract:The trend of artificial reefs construction in China has following two aspects:using large-scale artificial reef construction project to enhance the ecological effect of hard substrate, and using offshore artificial reef construction to extend the stock enhancement function of hard substrate. Static accumulation experiment was conducted to analyse the stacking effect and performance of regular frame reef monomer and HUT reef monomer, which are commonly used for offshore reef pile construction in China. In view of the structure and shape of reef monomer, the index of coefficients, such as the volume growth rate, the volume ratio and stack slope angle of the two monomers (regular frame reef monomer vs. HUT reef monomer) models in the experiment were compared. Also, we compared the change of efficiency in different quantity between two monomers. The results showed that:①using the same quantity monomer condition model, the volume growth rate of the regular frame reef monomer is higher than that of the HUT reef monomer, and the scale and bottom area of the artificial mound are relatively higher. regular frame reef:7.799±0.057. This result demonstrated that regular frame reef monomer is more appropriate for artificial reef construction in slow current and shallow waters. While the volume ratio of the HUT monomer forming-mound structure is higher than that of the regular frame reef forming-mound structure. This result showed that HUT reef monomer forming mound is relatively taller and more permeable, which is more appropriate for offshore artificial reef construction project. ② From the perspective of the height contribution rate of two types of monomer mound, and the difference of the characteristics of the two monomers is fully demonstrated in our study. Specifically, to achieve effective physical effect of artificial reef mound, the minimum number of regular frame reef units is 28 while that of the HUT reef unit is 40.

Abstract:Marine ranching is a long-term and world-widely used marine fishery development measure. This paper reviewed the development of marine ranching around the world as well as the existing definitions and classifications. Abroad, fishery resources enhancement is generally regarded as marine ranching. Since the 1940s, the artificial reef has expanded from the simple fish aggregation to the protection and restoration of marine ranching habitat, and aimed to the increase and utilization of fishery resources. In northeast Asian, such as Japan and South Korea, the objective of constructing artificial reefs is to increase, aggregate and catch fishery resources on large scales; and many countries in Europe and America build artificial reefs to increase and protect fishery resources and develop recreational fishery. Overall, the overseas marine ranching construction with fishery resources enhancement as the main purpose has both successes and failures, whereas the successful experience is worth our learning. The overseas definitions and classifications of marine ranching are in small number, the definition is presented and used in a more rigorous way. China paid much attention to the development of marine ranching in recent years, and supported it as an important means for aquatic biological resources conservation, fishermen industrial upgrading, and marine ecology civilization construction. Great progress has been made in the construction scale, output effect, technical level and development mechanism of marine ranching. However, the industry and sci-technology are still in the initial stage, and facing a series of problems to be solved urgently due to the late start. From 1960s to 1970s, Chinese scholars put forward the concepts of marine ranching and marine farming and ranching, and made a distinction between the two definitions. Subsequently, many scholars equated the enhancement of fishery resources with marine ranching. Recently, the development of marine ranching is rapid in China, but the definition of marine ranching is non-standard, such as numerous definitions, meaningless definitions, and lacking precise definitions. Finally, this paper summarized and prospected the development trend, development concept, target positioning, construction content, research support and other aspects of marine ranching. Grasping the development philosophy, positioning, content and goal of marine ranching rationally and practically, we should strengthen the publicity of the existing marine ranching industry standards, especially the definition and classification, and guide the orderly development of marine ranching research and construction work, which is the key for effectively supporting the healthy development of marine ranching.

Abstract:In order to understand the characteristics of speciation and vertical distribution of heavy metals in the sediments, columnar sediments were collected in surrounding waters of Ma'an Archipelago in June 2018. Seven heavy metals (Cd, Cu, Zn, Pb, Cr, As, Ni) were analyzed, with the improved European Community Bureau of Reference (BCR) method, by measuring the grain size composition of columnar sediments, and the vertical distribution characteristics and sources of heavy metals in the sediment of Ma'an Archipelago, by combining the analyzing method, I_geo, correlation and potential ecological risk index, were explored. The results showed that fine silt (D[3,2]) was dominant in the columnar samples; the content of heavy metals in the columnar samples fluctuated serratedly with depth. The total amount of seven heavy metals reached the peak at 0.5 m and 2.0 m; all of them reached the class I standard of marine sediment quality in China; Cd was dominated by secondary phase, which was composed of the exchangeable and carbonate fractions (F1)、iron-manganese oxide states (F2) and organic matter and sulfide fractions (F3), The proportion of three fractions was similar; the mode of occurrence of Cu, Zn, Pb, Cr, As, Ni was residual state, and the trend of effective state of seven heavy metals was periodic and consistent. Take Ni as a reference, with three analytical methods,results showed that Cu, Zn, Pb, Cr, As and Ni are mainly natural deposition, and whether Cd is a threat to the environment still remains for further study. Through three analytical methods, we can observe the content and morphology changing by years of heavy metals by means of isotope dating, aiming to determine the historical records and influencing factors of heavy metal pollution. The pollution degree of heavy metals in surrounding waters near Ma'an Archipelago is much lower, and the ecological environment is totally well protected, and the environment is less affected by human factors, reflecting the results of local sediment background values.

Abstract:The apparent diurnal vertical migration of zooplankton leads to diurnal vertical migration of certain fishes that feed on zooplankton. In order to investigate the effects of an artificial reef on diurnal vertical migration of micro-and meso-zooplankton, we obtained 14 zooplankton samples from diurnal sampling in and outside an artificial reef area in the coastal Fangchenggang City, Guangxi Autonomous Region in November, 2018. The analysis showed that zooplankton compositions were quite similar between the artificial reef site and the control site, with the low species replacement rate and the same dominant species, indicating that the zooplanktons came from the same faunal assemblage. However, influenced by the flow-field effect of an artificial reef, zooplankton abundance and diversity were higher at the reef site than those at the control site. At the control site, zooplankton abundance showed apparent diurnal changes following a sinusoidal trend, with the highest abundance at 16:00 and the lowest at 08:00. There was apparent vertical migration between 4:00 and 20:00, while zooplankton abundance was quite stable from 20:00 to 4:00. At the reef site, due to the effect of horizontal fast flow field above the reef, zooplankton abundance fluctuated with time and no apparent diurnal vertical rhythm was observed. It is believed that higher zooplankton abundance above an artificial reef would enhance the reef's fish-aggregating effect and promote the conversion of zooplankton productivity to fish. Cluster analysis and ordination of the 14 zooplankton samples identified one sample group for the reef site, but two sample groups for the control site, one being mainly composed of phytoplankton feeders following the upward shifts of phytoplankton during the daytime, the other being mainly composed of carnivorous species during nighttime after the phytoplankton feeders migrating downward.

Abstract:This paper reviews the marine ranching researches in China since its construction, including introduction of the background and necessity of marine ranching construction in China, and summarizes research process, research content and current basic state of the marine ranching in China. At the same time, we reviewed the research content and development process of marine ranching in foreign countries, especially summarized the research experience of marine ranching in Japan. From their research on marine ranching, researchers of foreign countries concluded that the ultimate goal of marine ranching construction was to restore its natural ecosystem. The current researches of marine ranching in China were focused on their own construction of marine ranching and the population restoration of the enhancement and releasing species. Although there were some researches about the ecological system of marine ranching in China, most of them stayed in the primary research stage, without depth and accuracy. Many research parameters of these researches were introduced from the results of other research works, with no consideration of the differences between natural and artificial sea areas, and the regional differences among marine ranching. The future focus of research work about marine ranching in China should be concentrated on the food web and energy flow of marine ranching's ecosystem, in order to promote the production of marine ranching,and to provide a scientific basis for the study of natural nutrient channels between artificial reef areas and surrounding waters for ecosystem construction.

Abstract:In order to establish a marine ranching demonstration area in the Xiangshan Bay for an effective restoration of biological resources and maximum output of fisheries resources in natural waters, habitat for biological resources was built, suitable proliferation species were screened and applied, ranchable species were multiplied and harvested, and a series of assessment and management techniques were applied. Seven groups of reefs consisting of 15 hexagons and 1 000 roundtable frame-type induction reefs were constructed with an area of 25 hm² and space of 53 810 m³. Large algae such as Laminaria japonica, Porphyra haitanensis and Gracilariopsis lemaneiformis were transplanted. Artificial ranch of 80 hm² for algae, floating plane algae beds as majority and three-dimensional floating algae beds as assistance, were built. Twenty million shellfish including Scapharca subcrenata and Atrina pectinata were cultured by bottom sowing;1.6 million fish such as Pseudosciaena crocea, Sparus macrocephlus, Nibea albiflora and Sebastiscus marmoratus were released annually; and ten million shrimps such as Fenneropenaeus chinensis, Marsupenaeus japonicas were released annually. Survey results show that the degree of eutrophication in ranch demonstration area has decreased, primary and secondary productivity improved significantly, with algae biomass 18 000 kg/hm². Fishery resources exhibited positive response to the marine ranching. Nineteen months after reef deployment, species richness, the total biomass and abundance of demersal nekton assemblage in the impact area were 1.32, 2.04 and 1.49 times higher, respectively, than those in the control areas.

Abstract:At present, there is no clear principle and basis for the structural design of artificial reefs. This paper expounds the basic principle of artificial reef structure design from the point of view of flow field effect, biological effect and shelter effect, illustrates the relevant basis and methods with examples, and summarizes and analyses the construction mode and future development of artificial reef area suitable for different types of sea area, in order to provide reference for the structural design of artificial reefs and the planning of marine ranching.

Abstract:The integrated development of marine ranching and recreational fishery is one of the development directions of marine ranching in China. At the present stage, the marine ranching leisure industry is small in scale and single in type, mainly for recreational fishing and diving, and its landscape ornamental function needs to be further explored and developed. The research on the landscape pattern of marine ranching mainly focuses on the formation and distribution of marine ranching landscape resources as well as their layout and arrangement in landscape space, aiming to understand the specific embodiment of the variation degree of its ecosystem or spatial attributes. Taking the marine ranching demonstration area in Zhelin Bay in eastern Guangdong Province as the research case, this paper used landscape pattern analysis method to calculate the characteristic index of landscape elements and the heterogeneity index of landscape. The results showed that the natural landscape in the marine ranching demonstration area in Zhelin Bay in eastern Guangdong Province is the landscape matrix, however, because of the largest patch area in the semi-natural landscape and the the highest fragmentation index, it is most affected by human activities, therefore the protection of biodiversity and the maintenance of landscape habitat should be strengthened. In addition, the large degree of separation between cultural landscape and the overall landscape leads to the poor connectivity of the overall landscape, affecting the landscape effect; The coastal landscape patches are few and the richness is not high, however, according to the survey, the surrounding tourism resources are abundant, so there is a lack of integrated development and utilization with marine ranching in Zhelin Bay, eastern Guangdong Province. In short, by analyzing the distribution and interaction of different landscapes in the pattern space of marine ranching landscape, this paper can provide data support for the next step of landscape ecological planning, and provide support for the development and utilization of marine ranching recreational fisheries and ecological landscape sustainable development, comprehensively enhancing the ecological, economic and social values of marine ranching.

Abstract:Golden cuttlefish, Sepia esculenta, was one of the largest economic cephalopods in Chinese northern seas, with an annual yield of more than 1 000 tons until the 1970 s. Since then, with the continuous expansion of fishing activities and dwindling of spawning field, this species has greatly reduced its local abundance compared with the previous condition due to its biological sensitivity to the environment (one-year life cycle and low fecundity). For this situation, many measures have been adopted to boost the population to meet the needs of human consumption, such as the release of artificially hatched juveniles and restoration of spawning habitats. The primary objective of this study is to optimize the existing conservation strategies and methods of cuttlefish by exploring the structural characteristics of the cuttlefish population in Qingdao coastal waters. The brood amount and size of egg cells of adult cuttlefish in 2017 were calculated. The distribution of body length and spatiotemporal migration process of juveniles were analyzed by using continuous monitoring methods. Results showed a decreasing trend in the specification of golden cuttlefish that arrived at different stages during the grouping period (May-July). The brood amount and size of egg cells of breeding cuttlefish in the early-stage were significantly higher than those of middle-and later-stages. The fertilized eggs of cuttlefish are characterized by sinking and stickiness, thus attaching to the attachment, such as algae or reefs. For juvenile cuttlefish, they grow rapidly, and the dispersion level of body specifications increases with sampling time due to the long grouping period and spawning in batches habits of breeding cuttlefish. This behavior might be a reproductive strategy for avoiding intraspecific feeding competition and promoting the differentiation of spatial niche. Therefore, according to the actual brood amount and the quality of eggs in the collection periods of breeding cuttlefish, it is suggested that the utilization rate of the early-stage population should be increased to improve breeding efficiency and guarantee the supply of large-size juveniles. The placement of spawning substrates in the spawning ground (slow-flowing area, 15-20 m) of adult cuttlefish from May to July is an important measure of resource restoration. Based on the reproductive habits of breeding cuttlefish, background survey in food abundance of release's water for juvenile cuttlefish is indispensable. To reduce the intraspecific predation pressure and improve the survival rate of released population during large-scale juveniles' release, juveniles' release in different periods should be taken into consideration. In order to further optimize the mode of resource restoration and reduce the cost of the proliferation of cuttlefish, we also suggest exploring the technology of releasing fertilized eggs.

Abstract:Marine ranching is an important measure to achieve marine environmental protection and efficient production of fishery resources. Based on the water environment data of Haizhou Bay marine ranching demonstration area in spring (May), summer (August) and autumn (October) of 2014, selecting permanganate index (COD_Mn), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), biochemical oxygen demand (BOD) as evaluation indexes, neural network models were developed using BP (back propagation) to evaluate the water environmental carrying capacity of the area. The results showed that the average water environmental carrying capacity index of Haizhou Bay marine ranching in 2014 was higher than 0.6, indicating an ideal level of the carrying status. Water environmental carrying capacity varied seasonally as follows:summer > spring > autumn. The water environmental carrying capacity of marine ranching area was obviously better than that of the control area. The high concentrations of COD_Mn and DIN were the main cause for the slight overload of some stations, which might be related to land-based pollution. In addition, shipping also had a certain negative impact on the water environment. BP neural network model has the advantages of convenient construction, objective and reasonable evaluation results, which could be applied to the study of water environmental carrying capacity in marine pastures and other sea areas.