Abstract:The American shad (Alosa sapidissima) is an anadromous fish species with ecological importance along the east coast of North America. At present, it has a potential for aquaculture in China because of its commercial importance and high market value. To evaluate and compare the growth regularity and difference of young fish A. sapidissima cultured in outdoor and shaded ponds, the standard length and body mass of young fish A. sapidissima (n=600) cultured in outdoor and shaded ponds were measured. The results showed:The relationship of body length and mass of young fish cultured in outdoor and shaded ponds could be described by the power function (W=aL^b, R²>0.99, P<0.01,n=300), the values b were close to and slightly less than 3 (2.786 4 and 2.843 1, respectively), and the body length grew slightly faster than the body mass. A leap-style compensatory growth reaction was found in young fish at the beginning of the culture experiment (0-15 d), and then the body length and mass specific growth rates (SGR) of young fish steadily declined with increasing culture time. The relationships between the body length of young fish cultured in outdoor and shaded ponds and culture time could be described by the linear function (L=at + b, R²>0.97, P<0.01, n=9), the intersection point of two straight lines appeared at 73.25 d (September 29); Nevertheless, the relationships between the body mass and culture time could be described by the quadratic function (W=at²+bt+ c, R²>0.97, P<0.01, n=9), the intersection point of two curves appeared at 61.92 d (September 18); at the earlier stage of culture experiment, before 57 d (September 13), young fish of outdoor pond grew faster than shaded pond; at the later stage, after 79 d (October 5), the reverse is true. The food coefficient of outdoor pond (1.22) was lower than that of shaded pond (2.04). The coefficient of variations of young fish body length and mass in outdoor pond was smaller than that of shaded pond. Therefore, the adaptive capacity for high temperature of young fish A. sapidissima is better than adult fish. It is suggested that:the young fish A. sapidissima should be cultured in outdoor pond, and then adult fish should be cultured in shaded pond.

Abstract:In order to investigate the effects of Sr²⁺ and boric acid (H₃BO₃) on the development of Macrobrachium rosenbergii, 25 days of nursery experiments with 7 groups of Sr²⁺ and H₃BO₃ water were conducted to analyze the abnormal development and survival of juveniles and the effect of metabolic enzyme activity in larval shrimp. The results of nursery experiments showed that the high and low concentrations of Sr²⁺ and H₃BO₃ in the nursery water significantly affected the survival rate and the emergence rate of the juveniles. The high concentration effect was stronger than the low concentration and was not suitable for nursery. When the mass concentration of Sr²⁺ ≥ 6.53 mg/L and the mass concentration of H₃BO₃ ≥ 155.60 mg/L, the survival rate and seedling emergence rate of juveniles were significantly lower than those of C control group (P<0.05). When the mass concentrations of Sr²⁺ and H₃BO₃ in water were close to 0, the larvae still had 11.7% and 11.3% emergence rate, respectively.The range of suitable nursery seedlings was 0.72-3.90 mg/L and 2.38-9.66 mg/L, corresponding emergence rate of 12.3%-16.0% and 12.1%-16.3%, The optimal concentration was (2.80±0.05) mg/L and (9.66±0.14) mg/L, respectively,which were similar to the Sr²⁺ and H₃BO₃ mass concentrations obtained by converting the ratio of salinity to oceanic water and artificial rearing water.Sr²⁺ had a significant effect on alkaline phosphatase (AKP) activity (P<0.05) and had no significant effect on Ca²⁺-ATP activity (P>0.05). However, when the mass concentration of Sr²⁺ was 1.29-3.90 mg/L, both AKP and Ca²⁺-ATP showed higher viability, and the activity was lower at low mass concentrations (less than 0.72 mg/L). H₃BO₃ had a significant effect on AKP and SOD activity (P<0.05). At 9.66-49.50 mg/L, AKP activity was significantly higher than that of low mass concentration group (P<0.05) in the control group; when mass concentrations were 5.60-9.66 mg/L, SOD activity is low. The result of metabolic enzyme showed that the metabolic enzyme had good vigor when the mass concentration of Sr²⁺ and H₃BO₃ was 1.29-3.90 mg/L and 5.60-49.50 mg/L, respectively.This experimental result provides a practical guidance for the optimization of artificial seawater formula of Macrobrachium rosenbergii.

Abstract:In order to study the circadian rhythm of juvenile Nile tilapia (Oreochromis niloticus), constant photoperiods were designed with 12 h in the light following 12 h in the darkness (12L:12D), 6 h in the light following 6 h in the darkness (6L:6D) and 2 h in the light following 2 h in the darkness (2L:2D), respectively. The results showed that:(1) when the photoperiod was 24 h, the Nile tilapia showed circadian rhythm, and its circadian rhythm was (24.3±0.2) h; (2) the circadian rhythms of the Nile tilapia still existed under sustained darkness and illumination, which were (25.1+1.1) h and (25.6+1) h respectively; (3) when the photoperiod was 12 h, the Nile tilapia still showed an obvious circadian rhythm that was (12.6±0.5) h; (4) when the photoperiod was 4 h, the swimming behavior of Nile tilapia still had an obvious circadian rhythm, the rhythm was (4.0±2.0) h. These results indicated that the Nile tilapia had endogenous circadian clock with 24 h cycle, however, compared with exogenous light regulation, endogenous circadian clock is relatively weak in tilapia. Exogenous light cycle is the main factor regulating the circadian rhythm of juvenile Nile tilapia.

Abstract:Since an appropriate initial feed for Anguilla japonica larvae is still the bottleneck of eel artificial reproduction, the nutritional analysis of its eggs could provide knowledge to study the initial feed. The contents of common nutritional components, trace elements, amino acid and fatty acid were detected using conventional analytical methods. The results showed that the contents of crude protein, crude fat, moisture and ash in fresh eggs of Anguilla japonica were 10.54%, 7.24%, 82.28% and 0.78%, respectively. Seventeen amino acids including 7 essential amino acids (EAA) and 10 nonessential amino acids (NEAA) were found in Anguilla japonica eggs. The contents of total amino acids (TAA), EAA and NEAA were 8.07%, 3.19% and 4.88%, respectively. According to the FAO/WHO standard of amino acid score (A_AAS) and chemical score (C_CS), the first limiting amino acid was valine, and the second limiting amino acid was isoleucine. Essential amino acid index (EEAAI) of Anguilla japonica eggs was 7.79%. There were 27 fatty acids detected in eggs, including 9 saturated fatty acids (SFA), 8 mono-unsaturated fatty acids (MUFA), and 10 polyunsaturated fatty acids (PUFA). The composition of SFA, MUFA and PUFA were 41.14%, 18.19% and 40.69%, respectively, with EPA+DHA taking the 30.25% of total fatty acids. The potassium (K) and calcium (Ca) of the Anguilla japonica eggs were 1 698.676 mg/kg and 121.268 mg/kg, respectively. The high level of DHA is commonly found in marine fish, and the limited content of amino acids might cause the short survival time of larvae.

Abstract:Aging is a series of complex life processes that occurs in living organisms and usually leads to a series of degenerative manifestations in reproduction, metabolism, stress, and exercise behavior. In this experiment, the model organism zebrafish was used as an experimental animal. The characteristics of 6-month and 30-month zebrafish were distinguished based on the body morphology and reproductive ability, and the circadian rhythm, stress behavior and respiratory metabolism of 6-month and 30-month zebrafish were compared, in order to investigate the effects of aging on metabolism and behavior of zebrafish. The results showed that the spine of 30-month zebrafish was curved and the reproductive performance of old fish was lower than the 6-month zebrafish in terms of fecundity, fertilization rate, hatching rate and survival rate, showing obvious aging characteristics. The swimming behavior of the 6-month zebrafish dispalys an obvious circadian rhythm. Compared with the 30-month zebrafish, 6-month zebrafish is active in the daytime, and always rest at night. The swimming behavior in the daytime and nighttime is significantly different. When 6-month zebrafish suffered from chase-stress, their large movement distance, large movement time and average swimming speed were higher than those of 30-month zebrafish (P<0.05). When exposed to light-stress, the large movement distance and average swimming speed of 6-month zebrafish were higher than those of 30-months zebrafish (P<0.05). The results of stress behavior showed that the stress response ability in aging zebrafish is significantly weaker than that of young zebrafish. The standard metabolic rate (SMR), maximum metabolic rate (MMR), and metabolic space (MS) of 30-month zebrafish were lower than those of 6-month zebrafish (P<0.05), which was consistent with the difference in stressed swimming behavior. Reproduction, metabolism and stress behavior are important physiological activities of fish, and investigating these physiological responses and behaviors in aging and young zebrafish can help to understand the effects of aging on the physiological functions of organism, and furthermore, the molecular mechanism of metabolism and behavior associated with aging.

Abstract:Aspiorhynchus laticeps belongs to Osteichyes, Cyprinformes, Aspiorhynchus Kessler, and was mylopharyngondon piceus. A. laticeps was national level to protect animals, so it had very important economic and scientific values. Because 2-phenoxyethanol was easy preparation, low price and rapid action, it acts as a general anaesthetics in fish. This paper regarded anaesthetics concentration(50, 100, 200, 400, 600, 800, 1 000 μL/L), exposure duration(2, 4, 8, 12, 16, 32 min) and dissolved oxygen concentration(4, 8, 12, 16, 18, 22 mg/L) as reference indices, and the effects of 2-phenoxyethanol were focused on as anaesthetics on juvenile A. laticeps(9.91±0.31g). Result showed that induction time and anaesthetics concentration were negative correlation, however recovery time and anaesthetics concentration were positive correlation. Respiratory rate of A. laticeps would decrease when concentration under 200 μL/L in initial period, but would be 11times/10s at mid-late period. Opercular movement frequency decreased with increasing doses of anaesthetics when concentration was equal or greater than 400 μL/L, and at last. juvenile A. laticep would cease respiration. Juvenile A. laticep could be anaesthetized in less than 3 min, with recovery in less than 5 min at 800 and 1 000 μL/L, so effective anaesthesia range was from 800 to 1 000 μL/L. In high concentrations, recovery time decreased with increasing exposure time. Juvenile A. laticep could recover in (100.51±10.60) seconds(P<0.05. Because of different dissolved oxygen concentration, there were differences between recover time:12 mg/L would recover in less than (129±36.50) seconds, which was lowest. 22 mg/L would recover in (406.33±53.20) seconds, which was highest. The highest group was 3.15 times higher than the lowest group (P<0.05).

Abstract:Path analysis was performed on eight morphometric attributes to determine for body mass of Macrobrachium nipponense, which were closed cultured for five years in ponds. The direct and indirect effects of eight attributes included total length, body length, carapace length, carapace width, carapace height, abdomen length, second uromere width and height. Results showed that body mass still had the greatest selection potential. And body mass was significantly correlated with the traits of total length, body length, abdomen length, carapace height and carapace width in female, and with traits of the total length and carapace height in male. Furthermore, body length and total length had substantial direct effects on body mass in female and male respectively. The regression equations were established between the selected traits to body mass for the male and female and the regression coefficient of equations reached the extreme significant level. The multiple correlation coefficients of the five attributes in female prawn and two attributes in male prawn to body mass reached 0.933 and 0.930 respectively, which indicated that the selected traits were the main variable index of body mass. Results suggest that body length in female and total length in male are primary selection criteria for improving body mass in M.nipponense.

Abstract:The present study was conducted to determine the activity of enzymes in intestine, stomach, and hepatopancreas of puffer (Fugu obscurus) and whether corn gluten meal(CGM) partially replaced fish meal could affect the activity of trypisn, chymotrypsin, carboxypeptidase A, carboxypeptidase B, pepsin, aminopeptidases, lipase and amylase. Five isonitrogenous and isoenergetic experimental diets were formulated. Diets contained corn gluten meal from 0% to 20%. After 60 d, the activities of the enzymes were measured. The results showed that:(1) The enzymes activity in the intestine were significantly higher than those in stomach and hepatopancreas except pepsin. The enzymes activity of stomach were lower,except pepsin; (2) The corn gluten meal impacts the enzymes activity of Fugu obscurus. Trypsin activity was highest in 10% treatment. The activity of chymotrypsin, carboxypeptidase A and aminopeptidases were linearly decreased with increasing CGM percentage from 5 to 20%, and it was significantly lower than that of the control in 20% treatment. Pepsin activity of 10% treatment was significantly higher than that of other groups. Lipase and amylase activities were increased in the trial groups, and it is significantly higher in 10% treatment than that of the others(P<0.05). It was concluded that the activity of digestive enzymes was highest in intestine, and the upper limit of corn gluten meal for optimal digestive enzymes activity in puffer feed was 10%.

Abstract:From June 2008 to May 2009, the phytoplankton community structure characteristics of the net-pen closing area and three corresponding points in Yangcheng Lake were investigated, the relationship between the phytoplankton community structure and environmental variables was analyzed, and multiple parameters were used to evaluate water quality. A total of 275 species, belonging to 116 genera of 8 phyla, were identified. In net-pen closure area, Microcystis incerta, M.aeruginosa and Pseudoanabaena sp. were the dominant species, while Microcystis incerta, Merismopedia aeruginosa,Pseudoanabaena sp. and M.densa were dominant in lake area. The annual mean value of density[(3 143.38±3 660.84)×10⁴ cell/L] and biomass[(3.71±2.31)mg/L] of phytoplankton in the lake area were lower than the average value of density[(3 830.77±4 296.56)×10⁴ cell/L] and biomass[(5.24±4.10)mg/L] in net-pen closure area. The results of redundancy analysis(RDA)suggested that temperature was the main environmental factor affecting the community structure of phytoplankton, and it had a significant positive correlation with the density of phytoplankton. Water quality analysis indicated that the water in the net-pen closure area and lake area was all meso-eutrophicated, and there was no significant difference among the 3 groups.

Abstract:Three stocking densities from 300 ind/m³ to 900 ind/m³ were applied under the conditions of non-drug use, adding probiotics and zero water exchange during the construction of nitrifying biofloc system, and the effects of stocking densities on water quality and growth of Litopenaeus vannamei and the suitable density of culture were analysed by ninety day period of indoor seawater culture. The results show that:In the process of constructing nitrifying biofloc system, the water quality of gradually declined with increasing density. For example, the DO of the BFT900 group dropped from 8.21 mg/L to 3.34 mg/L, pH from 8.24 to 6.75, TAN rose from 0.08 mg/L to 1.64 mg/L, NO₂^--N from 0.10 mg/L to 10.80 mg/L, NO₃^--N from 0.54 to 153.70, rose the differences of the above indexes in each group were significant(P<0.05). After the transformation of nitrifying biofloc system was successful, the water quality indexes of each group were in the suitable range for shrimp growth; The survival rate decreased with increasing density. The survival rates of the three treatment groups (BFT300, BFT600 and BFT900) were 84.59%±8.83%, 74.26%±6.66% and 54.95%±4.23% respectively, and there was a significant difference among the three groups(P<0.05); At the end of culture, the average length and weight of shrimp decreased with increasing density. The average length and weight of shrimp in group BFT300 were significantly higher than those in groups BFT600 and BFT900(P<0.05); The highest yield of BFT600 groups was (5.45±0.48) kg/m³, but there was no significant difference with group BFT900 (P>0.05), but the yield was significantly higher than that in group BFT300[(4.08 + 0.63) kg/m³], and the feed coefficient rate increased with the increase of density, and there was no significant difference between BFT300 and BFT600 groups(P>0.05), but they were significantly lower than those in group BFT900 (1.82 + 0.62)(P<0.05). According to the comprehensive effects of culture and the benefit of production, 300-600 ind/m³ could be the reference density range for Litopenaeus vannamei indoor seawater culture based on practical situation during the construction of nitrifying biofloc system.

Abstract:Raising the carbon/nitrogen ratios of Biofloc technology(BFT) aquaculture system by providing carbohydrates can promote the growth of heterotrophic bacteria, and reform bioflocs with feces and lures in cultured water, so as to improve the utilization rate of feed protein and purify the aquaculture water. However, there is no uniform view on how to add carbohydrates. In order to prevent the aquaculture animals from being poisoned by ammonia nitrogen and nitrite nitrogen during the construction of BFT system, it is necessary to set the start-up stage of the BFT system. Therefore, a 60 days experiment was carried out to investigate three strategies of carbohydrates providing at the start-up stage of the biofloc system with salinity of 30 ppt, aiming at optimizing the adding strategy of glucose, so as to shorten the formation period of the biofloc system and stabilize the water quality quickly. The first method is to add glucose to the biofloc technology (BFT)system (group A) at a one-time to make the C/TN (total nitrogen) be 15(group A). The second is 10% total glucose of group A was added every day from 1st to 10th day, after that, if the total ammonia nitrogen (TAN) increased to above 1 mg/L, the glucose was added according to C/TAN of 6. The third is to add glucose every day according to C/TAN of 6. The results showed TAN in A and C treatment groups was generally at a low level during the experiment period. TAN in B group reached a peak value of (16.36±3.02)mg/L on the 31st days, nitrite nitrogen(NO₂^--N) and nitrate nitrogen(NO₃^--N) had a significant accumulation, but dropped to the lowest level on the 59th day. The three treatment groups both had assimilation and nitrification, but the nitrification was obviously inhibited in the system with continuous addition of carbohydrates. The extracellular polymeric substances (EPS) and crude protein of bioflcos in the three treatment groups showed the trend of decreasing during the experiment period, and the settling velocity of bioflocs of the three treatment groups becomes better. The bacterial community of bioflocs was analyzed by high-throughput sequencing. The results showed that, at the phylum level the main dominant microflora of the 3 different groups were Proteobacteria. Besides,Bacteroidetes and Planctomycetes were also found in group C. At the class level, the main advantage microflora in group A and group B were mainly Gammaproteobacteria, while the main dominant microflora in group C are Gammaproteobacteria,Alphaproteobacteria, Flavobacteria and Phycisphaerae. Thus, continuous addition of carbon sources can enrich microbial species. The experiment shows that the three carbohydrates additions can stabilize the water quality in about 55 days in a seawater aquaculture system using bioflocs technology.It can be concluded that the best method for the start-up of seawater BFT system is maintaining C/N 15 initially, then adding carbon source to 6 of C/N when TAN was up to 1 mg/L.

Abstract:The performance of phosphate removal by magnetic iron/zirconium-modified zeolite (FeZrZeo) using batch experiments and the efficiency of sediment capping with FeZrZeo to control phosphorus (P) release from river sediments were tested using incubation experiments. The results showed that the as-prepared FeZrZeo exhibited a high phosphate adsorption capacity. P in river sediments could be released into the overlying water under natural and anoxic conditions. However, sediment capping with FeZrZeo can greatly reduce the releasing flux of SRP from the sediment to the overlying water, resulting in a very low level of SRP in the overlying water (0.007-0.031 mg/L). When FeZrZeo-based barrier layer was destroyed, the mixing of FeZrZeo with sediment not only led to the reduction of SRP concentration in the overlying water, but also resulted in the transformation of the mobile P (sum of the NH₄Cl extractable P (NH₄Cl-P) and Na₂S₂O₄/NaHCO₃ extractable P (BD-P)) to the more stable phosphorus such as the NaOH extractable P (NaOH-rP) and residual P (Res-P). Furthermore, the mixing of FeZrZeo with sediment led to the transformation of bioavailable P including anion resin extractable P (Resin-P), water soluble P (WSP), readily desorbable P (RDP), NaOH extractable P (AAP) and NaHCO₃ extractable P (Olsen-P) to the non-bioavailable P in the sediment, resulting in the decrease in the P bioavaiability of the sedidment. Results of this study show that FeZrZeo is a promising capping material for the control of SRP release from river sediments.

Abstract:Macrobenthos were collected in the subtidal waters of the wetland of the north branch of the Yangtze River estuary. The changes of macrobenthos community before and after the release of shellfish in the area were analyzed. A total of 51 species of macrobenthos were collected in the shellfish released area adjacent to the subtidal zone. There are 15 species of mollusks, 17 species of arthropods, 4 species of annelids, 14 species of chordates, and 1 species of nemertea. Eight dominant species were found throughout the year. The annual average density was 0.265 ind/m², the annual average biomass was 0.06 g/m², the annual Shannon-Wiener index was 0.93, the annual Margalef index was 0.895, the Pielou index was 0.39. Compared with the macrobenthic community before release, the release of shellfish affects the composition of benthic communities and dominant species in the adjacent waters of the released area.

Abstract:In recent years, tidal flat reclamation has been carried out outside Pudong airport of Yangtze River Estuary. Considering the particularity of pudong airport location, it is planned to use method of pole reef ecological restoration to restore the tidal flat. The results showed that small water bodies could be formed at the base of pole reef after the implementation of the installation. The length of the overground of pole reef was correlated with the volume of water body (P=0.035), the water content of the sedimentary soil sample was about 45.62%. Through the comparative analysis of the water content of the sedimentary soil samples inside and outside the restoration area in different ways, it is shown that the restoration time affects the water content of the sedimentary soil samples. The water content of the area with a long restoration time of 0 m(48.41%), which is higher than that of the area with a short restoration time of 0 m, which is 40.73%. The water content of the sedimentary soil sample was also affected by the spatial distribution. The water content of the nearshore side of the restoration area was 50.56%, much higher than that of the far shore side, which was 38.22%. The water content of surrounding habitats in the restoration area is affected by the restoration area, which is shown as the water content of the vertical shoreline sample (longitudinal sample) extending outside the restoration area is higher than that of the parallel shoreline sample (transverse sample) extending outside the restoration area. Through the comparison and analysis of the water content of the sedimentary soil samples inside outside the restoration area, the above results show that the electric pole reef ecological restoration technology can have a certain positive impact on the beach habitat, surrounding sedimentary soil and its ecological environment of water content.

Abstract:ENSO are the largest coupled ocean-atmosphere phenomena. ENSO has enormous effects on marine fisheries. Spatial-temporal changes and abundance index of Chilean jack mackerel (Trachurus murphyi) are analyzed, according to the statistical data of fishing yield of Chilean jack mackerel of Chinese fleets, and data of Niño 3.4 region sea surface temperature anomaly (SSTA) from 2003 to 2016. The result shows that there is significant correlation between ENSO and the fishing ground gravity of Chilean jack mackerel. The correlation degree between SSTA of the Niño 3.4 region and longitudinal gravity, latitude gravity, monthly change of CPUE and interannual change of CPUE are 0.700, 0.726, 0.520 and 0.703. During EI Niño occurrence, fishing ground gravity moves northwest, the CPUE higher than the CPUE of normal month, while during La Niña occurrence, fishing ground gravity moves southeast, the CPUE lower than the CPUE of normal month.

Abstract:Schaefer form and Fox form of surplus production model are widely used in fishery stock assessment. However, the two models are two special cases of the generalized surplus production model, i.e. Pella-Tomlinson model, with two special values of the shape parameter. Because the shape parameter has a close relationship with the age structure and reproductive capacity of the population and directly affects the modeled population productivity, fixing the shape parameter at some special values would raise doubts about the results of the stock assessment models of the model. The impacts of shape parameter on stock assessment results were analyzed based on Indian Ocean yellowfin tuna (Thunnus albacares) data. The results showed:1) the shape parameter was difficult to be estimated and its best value range would be greatly different with different data sets from different time periods; 2) the shape parameter had obvious impacts on the estimate of carrying capacity and the intrinsic rate of population increase; 3) the depletion levels of the stock and the overfished or overfishing levels were enhanced with the value of the shape parameter increasing and accordingly the shape parameter had important impacts on the inference of stock status and overfished and/or overfishing levels.

Abstract:The compound peptide was used to digest the Euphausia superba to obtain the shrimp powder polypeptide, which was separated and purified by ultrafiltration separation and high-speed countercurrent chromatography to test its antioxidant activity in vitro. The results showed that the peptides isolated by ultrafiltration had the best antioxidant activity when the molecular weight ranged from 5 to 10 ku. When the concentration was 10 mg/mL, the superoxide anion radical scavenging rate reached 21.28%, and the DPPH free radical scavenging rate was 86.52%, the hydroxyl radical scavenging rate was 53.49%, and the Fe²⁺ chelation rate was 85.35%. High-speed countercurrent chromatography was carried out on peptides with a molecular weight ranging from 5 to 10 ku, using chloroform-butanol-methanol-water=4:0.75:3:2 as the two-phase solvent system, the lower phase as the stationary phase and the upper phase as the mobile phase; As for inversion, the speed was 900 r/min, the constant temperature water bath temperature was 25℃, the flow rate of the mobile phase was 1.5 mL/min, and the five components were separated under the injection concentration of 20 mg/mL. It was determined that when the concentration was 5 mg/mL, the ability of P3 component to scavenge superoxide anion radicals and Fe²⁺ chelation ability were significantly higher than the other four components, which were 37.18% and 92.33%, respectively. The free radical scavenging rate of P2 was the highest, which was 90.33%, and the P5 component had the highest hydroxyl radical scavenging rate of 70.11%. Antioxidant activity was significantly enhanced compared to the control group not isolated by HSCCC.

Abstract:In order to dynamically detect the hydrological data of oceans and lakes, an unmanned semi-submersible vehicle was designed. Based on the design idea of modularization, the unmanned semi-submersible vehicle is divided into four functional modules:submergence main hull, surface floating body, control module and lifting mechanism. The main hull structure was designed into a catamaran, composed of left, right submarines, according to the functional requirements, each submarine is divided into five functional modules:dome, sensor module 1,battery module, sensor module 2 and electric motor module; The surface floating body is the shape of the ship, the control module is embedded in it; The lifting mechanism adopts stepper motor and screw rod to adjust the depth of the main hull. Based on the main size of the unmanned semi-submersible vehicle, the unmanned semi-submersible vehicle is checked for stability. Using FLUENT software to analyze the model, calculate the required power, and select the appropriate motor. The experiment shows that the design of unmanned semi-submersible vehicle is stable in the water and has the function of advancing and changing the depth of the main hull.