Abstract:To investigate the status of germplasm resources and the level of genetic diversity of American shad (Alosa sapidissima) breeding populations in southern Jiangsu, a total of 210 individuals from seven different populations including Zhenjiang Dantu (Dtq), Suzhou Zhangjiagang (Zjg), Suzhou Xiangcheng (Xcq), Nantong Zhongyang (Zyq), Zhenjiang Yangzhong (Yzq), Changzhou Gehu (Ghq) and Changzhou Wujin (Czq) were analyzed using 15 microsatellite markers and mitochondrial D-loop sequences in this study. With the exception of Asa-12, the findings revealed that all 15 SSR loci exhibited high polymorphism (PIC > 0.5). Among them, the expected heterozygosity (H_e) of the seven populations ranged from 0.615 to 0.758, and the polymorphic information content PIC ranged from 0.568 to 0.723, both of which were highest in the Zjg population. A total of 32 mutation loci and 20 haplotypes were defined for the D-loop sequence analysis, with the Zjg population having the most haplotypes (11). The haplotype diversity and nucleotide diversity indices for the seven populations ranged from 0.618 to 0.945 and from 0.003 to 0.008, respectively. The genetic distance of Nei's (0.058) and the genetic K2P distance (0.003) between the Ghq and Zyq populations, determined by genetic distance analysis using SSR and D-loop sequences, were the lowest and were lower than the genetic distances between other populations (0.073-0.397 and 0.003-0.006, respectively). We conducted a thorough investigation and discovered that genetic variation among the seven populations was low, despite the fact that they were genetically diverse. The gene flow N_m > 1 and the mosaic arrangement of the different evolutionary trees supported the strong connectivity of the seven groups. This study provides a theoretical basis for further breeding efforts and a preliminary understanding of the status of American shad germplasm in southern Jiangsu Province.

Abstract:Sex steroid hormones are closely related to biological reproduction, gamete emission and gonadal development. And Srd5a1 plays an important role in the synthesis of sex steroid hormones. In order to investigate the effect of the sex steroid hormone synthesis-related enzyme gene Srd5a1 on ovarian development in female Hyriopsis cumingii, Srd5a1 was obtained from the gonads of H.cumingii by RACE (Rapid-amplificiantion of cDNA ends). The expression characteristics of Srd5a1 were investigated by real-time fluorescence quantification (qRT-PCR), in situ hybridization and in vitro induction of 17β-estradiol (E2) and 17α-methyltestosterone (MT) at different concentrations for 24 days. The results showed that the full-length cDNA of Srd5a1 was 2 224 bp, including ORF 825 bp, 3'-UTR 953 bp, and 5'-UTR 446 bp, encoding 274 amino acids. The expression of Srd5a1 in the gonad was bimodal, with higher expression in the ovary than that in the testis; Srd5a1 had the highest expression level in the ovarian discharge period, which was extremely significantly higher than that in all other periods. In situ hybridization results showed that Srd5a1 detected positive signals in ovarian oocytes and follicles as well as spermatocytes of the testis. The expression of Srd5a1 was changed after 24 days of treatment with different concentrations of E2 and MT. In conclusion, Srd5a1 may play a role in the developmental maturation of the ovary oocyte and gamete emission in the female H. cumingii. This study is important for exploring the gonadal growth and development of H. cumingii, and also provides a theoretical reference value for the realization of monogamous breeding of H. cumingii.

Abstract:In order to investigate the tetrodotoxin(TTX) content in the tissues of Takifugu obscurus and the expression characteristics of voltage gated sodium channel genes in toxic tissues, this study used enzyme-linked immunosorbent assay (ELISA) to determine the TTX content in 8 tissues, including the liver and heart of Takifugu obscurus. Real time fluorescence quantification (RT-qPCR) was used to detect the relative expression of voltage gated sodium channels α subunit gene family, including scn1aa, scn1ab, scn4aa, scn4ab, scn5aa, scn5ab, scn8aa, and scn8ab in various tissues. The results showed that the TTX content in various tissues ranged from high to low, including brain (9.521 ±2.816) μg/g, heart (4.271 ±1.129) μg/g, gills (1.586 ±0.527) μg/g, muscle (1.494 ±0.938) μg/g, liver (0.913 ±0.206) μg/g, skin (0.902 ±0.235) μg/g, intestine (0.894 ±0.215) μg/g, and eye (0.864 ±0.287) μg/g. Brain and heart tissues were weakly toxic, while liver, skin, muscle, eye, intestine, and gill tissues were slightly toxic. The RT-qPCR results showed that the relative expression levels of scn1aa, scn1ab, scn4ab, scn5aa, scn5ab, scn8aa, and scn8ab genes were the highest in liver tissue. The scn4aa gene was only expressed in muscle tissue, and only the scn4ab gene was expressed in skin tissue. Moreover, the scn4ab gene was expressed in all detected tissue types, indicating widespread expression. It is discovered that there are differences in the expression characteristics of sodium channel genes between zebrafish and Takifugu obscurus tissues.

Abstract:This study investigated the significance of aldh3a2a in zebrafish pigment cell development and its impact on aldehyde metabolism and liver health.Using CRISPR/Cas9 technology,we successfully generated aldh3a2a knockout homozygous mutant lineages,resulting in reduced numbers of melanocytes, xanthophores and iridophores,csf1ra, pnp4a and itk were downregulated, and key genes in the melanin synthesis pathway,including mitfa,tyrp1b and kita,were also downregulated.Transcriptome analysis revealed changes in gene expression profiles,with downregulation of differential genes scd, lpla and aox5 in the steroid biosynthesis pathway, indicating the critical role of aldh3a2a in steroid biosynthesis. Transcriptomic analysis and qPCR combined study on the retinol metabolism pathway revealed that aldh3a2a can regulate raldh2, rxrab and aox5, indicating its certain influence on the signaling transduction of retinoic acid receptors.Additionally, aldh3a2a can regulate potassium channel protein kcns3b, suggesting its association with melanocyte function and potassium ion signaling. GO and KEGG enrichment analysis found widespread effects on pathways such as the cell cycle, homologous recombination, RNA degradation, RNA transport, p53 signaling pathway, eukaryotic ribosome biogenesis, DNA replication, base excision repair, aminoacyl-tRNA biosynthesis, cytoplasmic DNA sensing pathway, steroid biosynthesis, mismatch repair, steroid hormone biosynthesis, and aldarate metabolism in the mutant. Moreover, knockout of the aldh3a2a gene leads to significant accumulation of aldehydes in the body, causing cytotoxicity and resulting in abnormal enlargement of the liver, appearance of vacuoles within the liver, and characteristic weight gain, resembling symptoms of Sjögren-Larsson syndrome. This reveals the role of aldh3a2a in zebrafish and its relevance to human genetic diseases, which will contribute to a deeper understanding of its function and potential therapeutic targets in both zebrafish and humans.

Abstract:In this study, the differences in feeding behavior of juvenile crab, early stage of adult, sub-adult and adult Chinese mitten crabs (hereafter referred to as "river crabs") were firstly investigated by culture experiments and camera techniques. The feeding behavior, feeding response time, and feeding rate of Chinese mitten crabs with different genders at different developmental stages were then evaluated. The feeding selectivity of river crabs at different stages of development on trash fish, formula feed, corn, and snails was further compared. The results showed that:(1) The feeding behavior of Chinese mitten crabs included four stages:exploration, orientation, testing and feeding. Among them, exploration and feeding took a long time. (2) In terms of time consumed during exploration stages and feeding response, females consumed significantly more time than males in the juvenile crab and early stage of adult stage, while males consumed significantly than females in the sub-adult and adult stage. (3) In terms of feeding, females consumed more time than males at all developmental stages. (4) In terms of the feeding rate, the feeding rate of Chinese mitten crabs tended to decrease significantly with increasing developmental stages, but there was no significant difference between females and males. (5) In terms of the selective results of feeding on different feeds, the frequency of first feed of different feeds by Chinese mitten crabs at different stages of development was ranked from highest to lowest as follows:trash fish>formula feed>corn >snail. (6) There was no significant difference in the feeding response times of male and female crabs to trash fish and formula feed, but both were significantly lower than those to corn and snail. In summary, the feeding behaviors of Chinese mitten crabs were significantly different between developmental stages and genders, and the sub-adult stage was an important developmental stage in which the feeding behavior of female and male crabs changed. Additionality, Adult crabs preferred to feed on trash fish and formula feed.

Abstract:To investigate the alkali resistance of the hybrid of Leuciscus and its parent Leuciscus waleckii (female parent) and Leuciscus idus (male parent) of the Irtysh River in Xinjiang, the alkalinity stress experiment of 50 mmol/L NaHCO₃ was carried out on three experimental fish for 7 days. Several physiological indexes and corresponding gene expressions involving osmotic pressure regulation and ammonia metabolism and significantly related to alkali resistance were compared and studied. The results showed that the Na⁺/K⁺ ATPase (NKA) activity and gene expression (ATPase α1-like and ATPase α3) of the gill tissues of the female parent with strong alkali resistance were higher than those of hybrids, and significantly higher than those of the male parent. The serum alkaline phosphatase (AKP) activity and the gene expression amount (alpl) of gill tissue were significantly lower than those of the other two fish, indicating that the female parent may regulate NKA enzyme activity through AKP dephosphorylation and participate in osmotic pressure regulation under high alkaline stress. The detection of ammonia metabolism related indexes showed that the blood ammonia (Amon) and urea nitrogen (BUN) contents of the female parent were extremely significantly lower than those of the other two fish, while the serum glutamate dehydrogenase (GDH) and glutamine synthetase (GS), as well as the expression of related genes in the gill tissue (glud, glul, Rhbg and Rhcg1) were mostly higher than those of hybrids, and significantly higher than those of the male parent, indicating that the female parent consumed ammonia in the body by synthesizing ammonia intermediate metabolites and increasing the activity of ammonia transporters. In summary, these physiological indexes were significantly related to the female parent's strong alkali resistance, and were well inherited to its hybrid offspring. The results of this study provide a theoretical basis for the comprehensive evaluation of the alkali resistance of fish, and lay a working foundation for the selection and breeding of new varieties of alkali resistance and the declaration of improved varieties of Leuciscus.

Abstract:Short-term Artemia enrichment is an efficient approach for improving the desired nutritional value of live feed Artemia nauplii. To investigate the optimal enrichment conditions, newly-hatched Artemia nauplii were enriched with commercially produced dry powder of microalgae Phaeodactylum tricornutum and Isochrysis zhanjiangensis, and fugus Schizochytrium aggregatum in this study. And the n-3 HUFA enrichment with the above products was compared with two commercially important Artemia strains from Great Salt Lake, USA (GSL) and Aral Lake, Uzbekistan. Higher Artemia survival percentages (85%-90%) were obtained when Artemia nauplii were enriched with I. zhanjiangensis under the following conditions:enrichment dose (0.05, 0.1, 0.15 and 0.2 g/L), enrichment duration (12, 18 and 24 h) and Artemia density (150, 200 and 250 ind./mL). And the individual body length and total biomass of Artemia increased with prolongedduration and increased dose. Considering the Artemia size preference and easy operation in the hatchery, the optimal enrichment parameters were proposed with Artemia nauplii density of 150-200 ind./mL, enrichmentdose of 0.1-0.2 g/L, and enrichment duration of 12-24 h. Fatty acid analysis showed that fatty acid profile of the enriched Artemia was closely related to the enrichment agent and Artemia strains. For GSL Artemia, P. tricornutum and I. zhanjianggensis enrichment remarkably increased the EPA contents (7.39 and 3.20 mg/g dw, respectively) in Artemia when compared with newly-hatched Artemia nauplii (1.63 mg/g dw); whilst for Aral Lake Artemia, slight increase of EPA content could be observed between the enriched-Artemia (17.59 mg/g dw and 17.26 mg/g dw, respectively) and newly-hatched Artemia nauplii (14.35 mg/g dw), showing that the enrichment effect closely linked to the original EPA content of Artemia strains. On the other hand, the DHA contentin two Artemia strains did not show remarkable improvement when enriched with microalgae, but S. aggregatum enrichment remarkably improved the DHA content of Aral Lake Artemia (2.31 mg/g dw), which should be attributed by the high DHA content of S. aggregatum (115 mg/g dw). The results of this study will support development of microalgae enrichment agent and application of Artemia nutrition enrichment in hatcheries.

Abstract:This study conducted diallel hybridization experiments on three excellent populations of Procambarus clarkii, namely Gehu, Jiangsu; Jianhu, Jiangsu; and Wuhu, Anhui, with high genetic diversity and fast growth. Six hybrid groups were obtained[Gehu ♀×Jianhu ♂ (GJ), Jianhu ♀×Gehu ♂ (JG), Gehu ♀×Wuhu ♂ (GW), Wuhu ♀×Gehu ♂ (WG), Jianhu ♀×Wuhu ♂ (JW), Wuhu ♀×Jianhu ♂ (WJ)], and three self crossing groups[Gehu ♀×Gehu ♂ (GG), Jianhu ♀×Jianhu ♂ (JJ), Wuhu ♀×Wuhu ♂ (WW)]. A comparative analysis was conducted on the growth performance and ecological adaptability of 9 combinations. The results showed that:(1) During the breeding cycle, the weight gain and weight gain rate of both male and female individuals in the WW and JJ combinations were significantly higher than those in the other combinations (P<0.05); Except for GJ and JG, the weight gain and growth rate of male individuals in all combinations were significantly higher than those in females. From March to May, no heterosis was observed in the growth traits of each hybrid group; (2) With the increase of breeding time, there were significant changes in the length/body length of the head and chest armor, as well as the length/body length of the abdomen in the 9 populations of crayfish. The length/body length of the head and chest armor gradually increased, while the length/body length of the abdomen gradually decreased. In May, there was differentiation between male and female individuals, and the proportion of female abdomen length was significantly higher than that of male. The ratio of head to chest armor width/body length, abdominal width/body length, and tail segment length/body length only showed a significant increase in April; (3) After 24 hours of dry dew, each group of shrimp began to die, and at 48 hours, the survival rate of each group showed significant differentiation. At 48 hours, the survival rate of the WW combination was significantly higher than that of the other combinations. The GJ and JG cross groups showed heterosis in terms of dry dew tolerance. This study found that the mixed germplasm of crayfish limited the heterosis of growth traits to a certain extent, but showed heterosis in stress resistance. Proper hybridization and re-selection are important breeding strategies. The growth and abdominal length ratio of crayfish showed obvious male and female dimorphism, and single sex breeding is also an important direction for future research.

Abstract:A doubled haploid (DH) population consisting of 240 strains of Pyropia haitanensis was constructed using the heterozygous filament derived from the cross between the wild-type strain (W, ♀) and the red mutant (R, ♂) in the experiment. The correlation of blade color with the five quantitative traits of length, width, blade thickness, protoplast size and cell wall thickness of gametophytic blades was subsequently analyzed. The results showed that the phenotypic values of the five traits were normally distributed in different color groups (the wild-type group and the red-type group). The variation coefficient of each trait ranged from 10.02% to 43.73%, and the variation coefficient of length was the largest. The phenotypic values of each trait showed significant differences among different color groups (P < 0.01). Compared with the wild-type group, the blades of red-type group had longer length, narrower width, thinner blade, smaller protoplast and thinner cell wall. The correlation degrees between color and each trait were ranked in the order of blade thickness > cell wall thickness > protoplast size > length > width. In addition, the heritability order of each trait was presented as length > protoplast size > blade thickness > cell wall thickness > width, and the heritability in the wild-type group was higher than that in the red-type group. The genes controlling the same economic trait were different in different color groups, and the genes controlling the length trait were the most different. This study provides reference for developing new varieties with compound economic traits in P. haitanensis.

Abstract:In order to screen probiotics that can inhibit the growth of Streptomycetes spp. that produces geosmin (GSM) and 2-methylisobcamol (2-MIB) in aquaculture, Streptomyces thermocarboxydus, S. cyaneofuscatus and S. roseoflavus were used as test strains to carry out inhibition experiments, and the screened strains were identified. The results showed that eight strains of probiotics had inhibitory effects on the growth of S. spp., 2 strains of them could inhibit the growth of S. thermocarboxydus and S. roseoflavus, meanwhile, the other 6 strains affected the growth of S. thermocarboxydus. 2 strains belonged to Bacillus licheniformis and 6 strains belonged to B. subtilis.The 8 screened strains can serve as probiotics for preventing and controlling off-flavor, providing theoretical reference and practical basis for biological control and removal of off-flavor in aquaculture.

Abstract:Tropomyosin (TM) is considered to be a major allergen of crustaceans and shellfish. To address the increasing risk of crustacean and shellfish allergy, in this study, TM enrichment from shrimp (Litopenaeus vannamei) was used as the immunogen of BALB/c mice. A monoclonal antibody (Mab) cell line 2F8 against TM allergen of Litopenaeus vannamei was obtained by hybridoma cell fusion techonology. The immunological properties of Mab 2F8 including titer, specificity, antibody isotype and binding region were characterized using ELISA, Western Blot and bioinformatics. Moreover, its application feasibility was discussed using a sandwich colloidal gold test strips constructed by Mab 2F8 and rabbit polyclonal antibody specific for TM. ELISA and Western Blot results showed that the antibody subtype of Mab 2F8 was IgG1, with an antibody titer of 1.28×10⁵ and an IC₅₀ value of 20.21, indicating a high affinity to TM. It was found that the purified Mab 2F8 had specific reaction with the TMs in crustaceans, shellfish and squid. Three potential binding regions in amino acid sequence AA_0-31, AA_38-43 and AA_58-67 of TM were found according to bioinformatics analysis techniques. Detection results by test strips showed that 5 ng/mL TM (equivalent to 12.5 μg/kg) of white prawn shrimp could be visually detected within 10 min, showing that the obtained Mab 2F8 could be used for the detection of TM in the muscle of crustaceans and shellfish. Our study indicated that the purified 2F8 Mab had high affinity and good application value, which could be used for identification and detection of allergen TM in shrimps, crabs, shellfish and squid. This study provides important biological materials for the identification or detection of allergen TM and technical support for the development of rapid detection kit of TM in the future.

Abstract:In order to study the temporal and spatial distribution characteristics of large aquatic organisms in Suzhou urban rivers, this study began in May 2020, monitored the large aquatic organism indexes and water quality indexes of 23 sections of the main rivers in Suzhou ancient city area for one year, analyzed the temporal and spatial distribution differences of physical and chemical factors, and discussed the influencing factors related to large aquatic organisms to reflect the restoration degree of Suzhou rivers. The results showed that water temperature, pH, TDS, conductivity, dissolved oxygen, transparency and ammonia nitrogen had significant differences in different months, and total nitrogen and total phosphorus had extremely significant differences in different months. During the study period, a total of 5 species of submerged plants, 10 species of macrobenthic invertebrates and 7 species of fish were detected in the urban rivers of Suzhou. Among them, the Simpson index of submerged plants was the highest and the structure was the most uniform. In each section, the margalef index of canglangting bridge was the highest and the species were the most abundant. There were significant differences in flow rate, total nitrogen and ammonia nitrogen between groups with and without submerged plants. According to the presence or non-absence of macrobenthic invertebrates, there were very significant differences in velocity, water depth, transparency and dissolved oxygen; According to the presence or non-absence of fish, there was no significant difference in water quality indicators. The results of redundancy analysis (RDA) also showed that ammonia nitrogen, water temperature, dissolved oxygen and transparency were the main water quality indicators affecting the distribution of large aquatic organisms in urban rivers.

Abstract:In order to carry out the study on the evolution of Shanghai coastal zone and the change of ecosystem service value, the experiment analyzed the characteristics of shoreline length change in Shanghai coastal zone based on Landsat remote sensing image data in 1990, 2000, 2010 and 2020; combined the data of Globe Land 30 with spatial analysis to explore the land change and land transfer in three periods from 1990-2000, 2000-2010 and 2010-2020; and on this basis, constructed the ESV model of Shanghai coastal zone to clarify the spatial and temporal characteristics of ESV in Shanghai coastal zone from 2000 to 2020. The results show that, between 1990 and 2020, the shoreline of Shanghai mainland displayed a trend of increasing, then slowly decreasing, and finally increasing due to human activities and natural factors, with the shoreline of Chongming Island decreasing and the shoreline of Changxing Island and Hengsha Island increasing. Meanwhile, due to the intensity of human activities and increased coastal engineering, the land use area of the coastal zone changed significantly, with an increase in arable land and construction land. In addition, due to land expansion, the Shanghai coastal zone showed an increasing trend of ESV during the study period, but its wetland ESV decreased by 28.59% between 2010 and 2020. In terms of spatial distribution, the ESV of Shanghai coastal zone gradually shifted from medium to high value areas to low and very low areas, and by 2020, areas with very high ESV per unit area had largely disappeared. The development of construction land in urban process and the reduction of coastal wetland ecosystem are the main reasons for the change of ESV in Shanghai coastal zone. This study can provide scientific basis and decision support to guide the environmental management of coastal zone as well as sustainable development in Shanghai.

Abstract:Based on the fishery resource survey data collected in Haizhou Bay and its adjacent waters in spring and autumn from 2013 to 2022, we evaluated the statement and change trend of the ecosystem health of Haizhou Bay using the fish-index of biotic integrity (F-IBI), considering many ecological parameters and attributes such as fish species composition, tolerance, trophic guild, and reproductive guild. The results showed that eight metrics were retained as F-IBI of Haizhou Bay in each season. The F-IBI scores of Haizhou Bay in spring and autumn ranged from 18 to 51 and from 24 to 54, respectively. The ecosystem of Haizhou Bay was basically at "fair" or above levels in spring, while fluctuating around "fair" level in autumn. Generally, the health statement of Haizhou Bay ecosystem in spring was better, and the F-IBI scores showed a gradually decreasing trend in fluctuation. The condition of fishery resources in Haizhou Bay were poor, with an increased proportion of tolerance and omnivorous fish species. Fishery resources in Haizhou Bay were under various pressures such as overfishing and climate change, and scientific and reasonable measures should be taken to protect and restore the ecosystem of Haizhou Bay.

Abstract:Study on how related species coexistence in community is a central objective in ecology. However, knowledge of coexistence pattern of Sagitta bedoti and S. enflata in the Sanmen bay and adjacent waters remains poorly known. Two speciesof S. bedoti and S. enflata with environmental factors were sampled, aiming to elucidate relationships that drive theircoexistence, on August and November of 2019, April and December of 2020, respectively. The Generalized Additive Models(GAMs) was used to analyze the relationships between species and environmental influences. The results indicated that S.bedoti was significantly correlated with temperature, the density of copepods and the density of phytoplankton. And S. enflata was significantly correlated with temperature, the density of copepods, water depth and salinity. The null model was used to test the coexistence pattern between S.bedoti and S. enflata. It showed that the observed Pianka indexes have no significant difference with simulated values between S.bedoti and S. enflata communities. It was suggested that there was a random distribution between S.bedoti and S. enflata communities, and competition and habitat filtering effects restricted their distribution. In addition, ecological niche differentiation of S.bedoti and S. enflata happened occurred in both time and space. Whether there was difference in food composition still needs further study.

Abstract:In 2020, China's first fisheries total allowable catch system (TACs) pilot project of Acetes chinensis during the summer moratorium of marine fishing was successfully launched in Haizhou Bay of the Yellow Sea.The project continued to be extended to the Bohai Sea in 2021.Therefore, it is crucial to explore the resource distribution of A. chinensis in Haizhou Bay in summer for the refined management of TACs project. In this study,the position and fishing effort of each netting based on the BeiDou vessel monitoring system (VMS) data during the TACs project of A.chinensis in Haizhou Bay in 2021 were firstly extracted.Then we used the Density-Based Spatial Clustering of Application with Noise (DBSCAN) algorithm to further identify the netting positions with production to investigate the resource distribution pattern of A.chinensis. The results showed that the DBSCAN algorithm could accurately identify the netting positions with production and its recognition rate was 97.18%. There were 898 netting positions with production during the TACs project, presenting an aggregated spatial distribution pattern. Moreover, it was found that the resource distribution of A.chinensis were mainly distributed in 120°00'E-120°15'E,34°43'N-34°48'N and 119°47'E-119°53'E,34°36'N-34°43'N based on the fishing effort of all the vessels. This study can be used as a scientific reference for using BeiDou VMS date to extract the netting positions with production in other fishing activities.

Abstract:In order to explore the energy accumulation of somatic tissues and their impacts on reproductive investment in Argentine shortfin squid (Illex argentinus), one of the most important commercial cephalopod species in the world, the energy density of soma tissues including the mantle, head-arms and fins of the squid was determined using the technique of tissue energy density. The relative energy accumulation of each soma tissue was analyzed between sexes, and was also regressed on the squid's gonadosomatic index (GSI) to justify the potential sex-specific differences in the process of soma energy accumulation and allocation to reproduction. The results showed that the maximum energy density was detected in the fins for both female and male individuals, with an average of (21.32±1.13) and (21.56±0.97) kJ/g, respectively. The energy density of mantle tissue was determined (21.15±0.69) kJ/g for females and (21.13±0.79) kJ/g for males, respectively. For the head-arms, the energy density was detected at the minimum value, with an average of (20.64±0.73) kJ/g for females and (20.66±0.70) kJ/g for males, respectively. For the females, the relative energy accumulation was estimated an average of 51.37%±4.77% for mantle, 37.42%±4.44% for head-arms and 11.21%±1.62% for fins, respectively. The relative energy accumulation of mantle of male squids was estimated the maximum value, with an average of 46.80%±5.42%, followed by head-arms with an average of 42.67%±6.05% and fins with an average of 10.53%±2.03%. Significant differences were only found in the relative energy accumulation between maturity stages for the mantle and head-arms of female squid. In addition, the results of linear mixed-effects models showed that the relative energy accumulation of mantle and head-arms was significantly correlated with the GSI for the female squid, while there were not any significant relationships between the relative energy accumulation of each soma tissue and the GSI for the males. Cumulatively, these findings revealed that the fins exhibit the greatest energy density among the soma tissues, and the mantle accumulates the largest energy reserve among the soma tissues. The energy reserve of the mantle was probably mobilized to support gonadal development in female I. argentinus, contrasting to the fitness maintenance of soma tissues for the males.

Abstract:Global warming is expected to have a profound impact on the driving mechanism of the Zhoushan coastal upwelling, and then affect the changes in the ecological environment and fishery resources in the sea. Using the three-dimensional numerical ocean model FVCOM, we simulated and studied the distribution characteristics of summer hydrodynamics and environmental factors in the upwelling zone of Zhoushan coast under the changes of heat flux, wind field and other climatic and environmental factors. The effect of global warming on the summer sea surface temperature in Zhoushan and its neighboring waters over the past three decades was assessed by introducing a transition test, and it was found that a significant leapfrog occurred around 2016, and the sea surface temperature increased by about 1℃ after the transition compared with that before the transition; the results of heat flux analysis showed that the increase of seawater heat content due to the decrease of cloudiness and the increase of short-wave radiation in spring was an important reason for the warming of seawater in summer; the spatial and temporal variations of wind speed show that the wind speed in Zhoushan sea area in July had a tendency to weaken in recent decades.The results show that the enhanced stratification of seawater caused by the increased heat absorption of surface seawater and increased advective heat transport caused by the increased heat flux of sea air makes the bottom seawater difficult to uplift; the reduced wind stress in summer weakens the offshore expansion of the low-salinity tongue of the Changjiang Diluted Water, resulting in a weakening of the stratification of seawater upper layer in the upwelling zone, thereby strengthening the ascent of the middle and lower layers of seawater towards the shore and increasing the intensity of coastal upwelling.

Abstract:Based on the trawl survey data along the Bering Sea slope in 2002, 2004, 2008,2010,2012 and 2016, all the cephalopods species were selected in this study. With the cephalopods data, we analyzed the cephalopods community composition, determined the dominant species and their spatial distribution in relation to environmental factors in the Bering Sea slope based on the generalized additive model, and quantified the distribution of cephalopods abundance (indicated by catch per unit effort, CPUE) in latitude and longitude. The diversity of cephalopods community was further evaluated according to the ecological methods. The results showed that a total of 20 cephalopods species were identified belonging to 3 orders, 9 families and 15 genera. The highest CPUE of the cephalopod species in latitude was 0.78 kg/km² at 55^oN. The CPUE in longitude fluctuated between 0.3 and 0.7 kg/km² except that the value exceeded 1.0 kg/km² around 166.5^oW, 171.5^oW and 177.5^oW. The dominant cephalopod species in the survey area were Berryteuthis magister, Enteroctopus dofleini, Opisthoteuthis californiana, Benthoctopus leioderma, and Rossia pacifica. Among them, there were significant spatial differences in the distribution of dominant species. In the stations east of 172^oW, species were mainly dominant species, and there were few other species. In the stations west of 172^oW, the CPUE of other cephalopods was relatively high except for Berryteuthis magister and Enteroctopus dofleini. GAM model analysis showed that longitude, latitude, bottom depth, bottom temperature and surface temperature were important factors affecting the CPUE of the most dominant species. The results of cluster analysis showed that there were two main clusters in different regions, and great differences were found in the community diversity index among different clusters.

Abstract:The marine food web constitutes a core mechanism within marine ecosystems, with its complexity and multidimensional stability ensuring the maintenance of ecological balance, promoting energy flow and material cycling, and playing a critical role in preserving biodiversity. Human activities such as overfishing and pollution discharge may disrupt the structure of the food web, consequently impacting the productivity and service functions of the entire marine ecosystem. Concurrently, under the progression of global changes like climate warming and ocean acidification, the structure and functionality of the food web are likely to undergo alterations, which not only affect the current dynamic equilibrium of ecosystems but also bear upon the adaptability and resilience of future marine ecosystems.Thepaper employs ecological network analysis to systematically review and organize the concepts of food web structural stability across various dimensions, elucidating the intrinsic relationship between stability and complexity. Through an extensive overview of how different types of disturbances act on the marine food web, the paper uncovers the adaptive mechanisms at play from perspectives including network reconfiguration, species substitution, and community evolution. Finally, the paper highlights existing limitations in current research on marine food webs, such as the difficulty in acquiring data, insufficient modeling of dynamic processes in food web models, and inadequate precision in defining population functions. These insights provide directions for improvement in future studies of marine food webs, aiming to gain a more comprehensive understanding of their responses to environmental changes.

Abstract:To conduct research on hydrodynamic characteristics of the plane netfixed on steel frame, a finite element model of the plane net was established with member elements to calculate hydrodynamic loads based on SACS. Comparing the previous calculation results of the truss model and those of the beam model, it is found that the simulation results are similar, which proves that the member model is accurate. This preliminarily study proves the feasibility of simulating the integrated structure that is consists of fixed offshore wind turbine and large steel aquaculture cage in SACS.Furthermore, the member model was used for hydrodynamic loads calculation of the plane net under wave and current. The results show that current velocity, wave height and wave period have a significant effect on the hydrodynamic loads on the plane net.Within the decrease of current velocity, wave height and the increase of wave period, the hydrodynamic load on the net decreases. The influence of wave period is particularly significant, with the certain nodal force difference of up to 80%.For the hydrodynamic load on the net under the action of wave and current, the maximum load appears on both sides of the top position of the plane net, and the wave height has a greater influence on the load at the upper position. These results are expected to provide theoretical basis and technical support for the design of large steel cage in the integrated structure.