In recent years, harmful algal blooms have frequently occurred in coastal waters of China. Among the microcystins produced by these blooms, paralytic shellfish toxins (PST) are the most widely distributed and harmful, leading to significant concerns. When marine organisms ingest PST, they are passed up the food chain and accumulate, eventually posing a serious threat to human health, the environment, and the ecosystem.Therefore, this paper primarily introduces the definition, distribution, harm, toxicity mechanism, enrichment, and transformation of PST. It also discusses the methods used to detect PST, including biological, chemical, and biochemical approaches. The paper expounds on research trends and regulatory recommendations for PST. Its aim is to serve as a reference for the improvement of research, detection, and prevention of PST.

Biochar has gained significant attention in the field of sewage treatment, both domestically and internationally, due to its favorable adsorption capabilities and low cost. While ordinary biochar does exhibit certain adsorption effects, its performance is less effective when dealing with high concentrations or specific pollutants. However, the performance of modified biochar in sewage treatment shows significant improvement compared to unmodified biochar. Modification processes result in a larger specific surface area, larger pores, and a higher concentration of functional groups. These modifications not only enhance its adsorption capability, but also enable the specific adsorption of organic pollutants, making it highly valuable in the treatment of aquaculture wastewater. This paper provides a review of the recent research status of biochar at both domestic and international levels, highlighting several common methods of biochar preparation and modification, as well as discussing their respective advantages and disadvantages. The mechanisms of action of biochar and its application in the treatment of aquaculture wastewater are explained, while also exploring the factors that have hindered the development and adoption of biochar. Countermeasures and suggestions are proposed, along with a prospect of its application prospects in the field.

Yolk immunoglobulin (IgY), a polyclonal antibody, has garnered considerable attention for its role in conferring passive immunity against bacterial and viral diseases. This paper comprehensively reviews the current research on the fundamental structure and physicochemical properties of IgY. Additionally, the paper emphasize the diverse applications of IgY in preventing and treating bacterial and viral diseases, offering valuable insights for future research and the broader utilization of IgY in aquaculture.

Mantis shrimp (Oratosquilla oratoria), the main catches of stow net fishing vessel in Zhangpu, Fujian Province, were followed and sampled monthly from August 2022 to April 2023. A total of 368 samples were used to determine the body length and body mass, to characterize the feeding intensity and female ovarian development, and to calculate the ratio of males to females in the catch, in order to analyze the fishery biology of O.oratoria. The results showed that the ratio of female to male was 1∶1.115 in the catch of O.oratoria, the dominant body length group was 110-130 mm, the dominant body mass advantage group was 15.0-25.0 g,and there was no significant difference in average body length and average body mass between male and female samples. The relationship between body length and body mass was W = 2.140×10^-5L^2.882 (R² =0.946, n=368). The gonadal maturity of female O.oratoria was between stage Ⅰ-Ⅲ, and stage III individuals mainly appeared from February to April. The average feeding grade of O.oratoria was 1.44, of which grade 1 was the most. The average annual condition factor index of O.oratoria was 1.226, and the male was slightly larger than the female.

In this study, COⅠgene fragments were used as DNA barcodes for the molecular identification in fish larvae and juvenile from Xuwen Jiaowei coral reef sea areas in summer and autumn of 2018—2020, and its applicability to the identification in the early stages of fish was investigated. A total of 199 high quality COⅠsequences of fish larvae and juvenile were obtained, among them, 69 sequences matching to species were identified to the species level, and 110 sequences were identified to the genus, family and order level. In all, 32 taxa of 20 genera in 6 orders and 19 families were successfully identified. Among them, 17 taxa were identified to the species level, 5 taxa to the genus level, 9 taxa to the family level, 1 taxa to the order level, and another 9 taxa were not identified. Gobiidae had the most species and quantity in family level, accounting for 17.07% and 31.16%, respectively, followed by Leiognathidae with 7.31% and 8.04%, respectively. The present study indicated that the proportion of species identification based on DNA barcoding for fish larvae and juvenile in the Xuwen coral reef sea area was relatively low, and the gap of DNA barcode sequences for adult fish species was an important factor. Therefore, it was necessary to develop a reliable DNA barcode database for local adult fish. Combined traditional morphological and molecular method might improve the accuracy in identifying fish larvae and juvenile.

The acute toxicity of povidone iodine, trichloroisocyanuric acid, and lambda-cyhalothrin on Cyprinus carpio Songhe [(118.8±5.63) cm in length, (72.75±15.11) g in body mass]was investigated at a water temperature of (20±1) ℃ using a static bioassay method. The results revealed that the median lethal concentration (LC₅₀) of povidone iodine was 870.551 mg/L at 24 h, 790.650 mg/L at 48 h, 694.959 mg/L at 72 h, and 654.692 mg/L at 96 h, with a safe concentration of 195.653 mg/L. For trichloroisocyanuric acid, the LC₅₀ was 23.076 mg/L at 24 h, 19.608 mg/L at 48 h, 15.674 mg/L at 72 h, and 13.871 mg/L at 96 h, with a safe concentration of 4.247 mg/L. The LC₅₀ of lambda-cyhalothrin was 4.620 mg/L at 24 h, 2.216 mg/L at 48 h, 1.205 mg/L at 72 h, and 0.847 mg/L at 96 h, with a safe concentration of 0.153 mg/L. The descending order of toxicity among the three substances to C.carpio Songhe was lambda-cyhalothrin > trichloroisocyanuric acid > povidone iodine. Based on toxicity evaluation criteria, povidone iodine and trichloroisocyanuric acid exhibited low toxicity for C.carpio Songhe and could be considered as the preferred choices in practical applications. However, lambda-cyhalothrin demonstrated high toxicity for C.carpio Songhe, requiring careful consideration and cautious use in practice.

In order to explore the tolerance of Glyptosternon maculatum to extreme temperatures at different stages, this study performed acute hyperthermic stress on the fry and adult fish, determined semi-lethal time at each temperature, and measured the respiratory rate of adult fish under hyperthermia. The results showed that the semi-lethal time (LT₅₀) of fry G.maculatum shortened with the increase of temperature, and there was a significant difference in the LT₅₀ of the different temperature groups (P<0.05), among which LT₅₀ was 13.53 h at 28 ℃ and 71.20 h at 24 ℃. The respiratory rate of adult fish under high temperature stress increased significantly, and the semi-lethal time (LT₅₀) of adult fish at 24 ℃ was 15.6 h, which was much lower than that of fry at this temperature. The results showed that there were differences in heat tolerance at different growth stages, and attention should be paid to water temperature control during the breeding process. The short-term lethal temperature of fry was 28 ℃, and the short-term lethal temperature of adult fish was 24 ℃. The results of this study can provide basic data for healthy breeding and further study of high temperature tolerance mechanism of G.maculatum.

The male and female gametophytes of Saccharina japonica ‘Dongfang No.7’ were cultured at different temperatures, photoperiods and nitrogen concentrations to observe the development of gametophytes and explore the optimum environmental conditions for the formation of gametophyte oogonium, ovulation and young sporophyte. The results showed that temperature, photoperiod and nitrogen concentration had significant effects on the development of gametophyte. The rate of gametophyte development at 12 ℃ and 15 ℃ (60%-70%) was significantly higher than that at other temperature groups. At 20 ℃, the gametophyte was in the vegetative growth stage without development. The rate of gametophyte development (80%) in 10L∶14D group was significantly higher than that in other photoperiod groups, followed by that in 6L∶18D group, but the length of young sporophyte in this condition was significantly lower than that in other photoperiod groups. When the concentration of N was 2 mg/L and 4 mg/L, the final development rate was more than 75%, and the sporophyte accounted for about 70%, which was significantly higher than other groups. This study provides theoretical basis and data support for artificial breeding of gametophyte of S.japonica ‘Dongfang No.7’.

To investigate the effects of Bacillus subtilis as water additive on gut microbiota in Spinibarbus caldwelli, Acrossheilus hemispinus and Hypophthalmichthys molitrix and its purification effect on aquaculture water, the gut microflora in the foregut, midgut and hindgut of three fishes were investigated through 16S rDNA sequencing and the pH, the levels of ammonia nitrogen and nitrite in the aquatic water were measured. The results suggested B.subtilis could reduce the contents of ammonia nitrogen by 46.39% in water stably since the 11th day and nitrite by 84.61% in water stably since the 19th day. The gut microflora in each intestinal site between experiment and control group were significantly different overall and the abundance of intestinal flora decreased in the experiment group. On the whole,in experiment group, the abundance of intestinal microbiota decreased and the phylum abundance of Actinobacteria and Planctomycetes increased and decreased, respectively. The genus levels of Bacillus increased while pathogenic bacteria Aeromonas and Vibrio decreased. The KEGG signal pathways showed that the metabolic functions of the H.molitrix were enhanced. This study showed that B.subtilis could reduce the level of ammonia nitrogen and nitritein in the aquatic water and purify the aquatic wate, while inhibiting the propagation of harmful intestinal microbiota and improving the metabolic level of intestinal microbiota in H.molitrix.

To investigate the changes in digestive enzyme activities in the intestine and stomach, as well as the activities of non-specific immunoenzymes in the liver of juvenile Sebastiscus marmoratus under salinity stress, and to assess the ability of the juveniles to adapt to sudden changes in salinity, a salinity experiment was conducted. The experiment comprised four groups, representing different salinity gradient levels: 6, 8, 10, and 20 (control). These groups were referred to as S6, S8, S10, and S20, respectively. Results indicated that at the acute stress period of 96 hours, the activities of trypsin, pepsin, amylase, and lipase in S10 and S20 were significantly higher compared to those in S6 and S8 (P<0.05). Conversely, the activities of glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase were significantly higher in S6 and S8 compared to S10 and S20 (P<0.05). There was no significant difference in the activities of ACP and AKP between S6 and S8 (P>0.05). Additionally, the activities of ACP and AKP increased initially and then decreased over time in S10 and S20. These activities in S10 and S20 peaked at 12 hours, signifying a significant increase compared to other salinity levels. These findings suggest that the optimal salinity for breeding juvenile S.marmoratus ranges from 10 to 20.

To investigate the changes in oxygen consumption rate and suffocation point of Eleutheronema tetradactylum under different water temperature conditions, the experiment compared the effects of different temperatures (22,27,32 ℃) on the oxygen consumption of E.etradactylum with an average length of (4.5 ± 0.5) cm and an average body mass of (1.5 ± 0.5) g.The experimental results show that: 1) Under the conditions of this experiment, the higher the water temperature, the shorter the time for all juvenile fish to die, and the higher the mass concentration of dissolved oxygen (DO) in the water. The suffocation point at 22 ℃ is 1.39 mg/L, the suffocation point at 27 ℃ is 1.54 mg/L, and the suffocation point at 32 ℃ is 1.76 mg/L; 2) The oxygen consumption rate of juvenile fish in each temperature group showed a decreasing trend with the extension of experimental time, and the higher the temperature, the faster the decrease rate of oxygen consumption rate. When the oxygen consumption rate decreased from 1.418, 2.346, and 4.243 mg/(g·h) at the beginning of the experiment to 0.4-0.5 mg/(g·h), all juvenile fish died, and the changes in different temperature groups slowed down. The concentration difference between adjacent observation points was not significant (P>0.05), while the survival rate of juvenile fish in the control group was 100%; 3) During the experiment, when the DO content of each temperature group was 2.53, 2.90, and 3.10 mg/L, the juvenile fish began to exhibit disorderly movement, restlessness, occasional jumping out of the water, and gill opening. As the experiment continued, the frequency of the juvenile fish jumping out of the water increased, and the amplitude of gill cover vibration increased accordingly. After intense stress, they lay still at the bottom of the water, twitching and suffocating to death.

In order to develop high quality scallop mince products, this paper took frozen Argopecten irradians scallops as the raw material, and selects soybean isolate protein, hydroxypropyl cassava starch, carrageenan, and egg albumen to be added to the A.irradians mince, which explored the effects of exogenous additives on the gelatinization characteristics and nutritional quality of A.irradians mince.The results showed that 5% soybean isolate protein (Group B) and hydroxypropyl cassava starch (Group C) were effective in improving the textural properties when added to A.irradians mince respectively, and the latter was able to significantly improve the water-holding capacity of A.irradians mince products, but 8% egg albumen (Group D) or 0.6% carrageenan (Group E) decreased the hardness, cohesiveness, springiness, and water-holding capacity of A.irradians mince. The combination of exogenous additives (Group F: 7% hydroxypropyl tapioca starch, 1.0% carrageenan,Group G: 8% hydroxypropyl cassava starch+1.5% carrageenan+5% egg albumen+4% soybean isolate protein) had a lesser effect on the fabrication structure of the A.irradians mince and was able to improve the water-holding capacity. Group F A.irradians mince products had higher sensory ratings in terms of flavor, color and histomorphology. The A.irradians mince products from groups C, F and G all had superior amino acid and fatty acid ratios, with significant differences in amino acid composition, and significantly higher unsaturated fatty acid contents than saturated fatty acids. The content of EPA+DHA accounted for 45.04%, 44.74% and 30.87% of the total fatty acids, separately. It could be seen that the type and proportion of exogenous additives significantly affect the gelatinization behavior and nutritional quality of minced scallop meat in A.irradians, providing theoretical data for the subsequent development of scallop mince products with different textural structures and cost levels.

Enterocytozoon hepatopenaei (EHP) is a specialized intracellular parasite that has caused huge economic losses in shrimp aquaculture due to its large outbreaks,and no specific drugs have been found to effectively treat EHP infection.Histopathology and molecular biology are the main methods used to detect EHP.The isothermal amplification method,a key technique in molecular biology,has gained significant attention as a potential field detection method owing to its simplicity,cost-effectiveness,high sensitivity,and specificity.This paper provides a comprehensive review of conventional detection methods for EHP,including loop-mediated isothermal amplification (LAMP) and recombinase isothermal amplification (RPA),and discusses their applications in EHP detection.The aim is to offer valuable insights for the early detection,efficient prevention,and control of EHP infection,ultimately promoting the sustainable development of shrimp aquaculture.

With the acceleration of China’s ecological civilization construction,the fishery has entered a new era of high-quality development.Eel,as one of the main freshwater aquaculture species of Fujian Province,the problem of its breeding tail water discharge has become increasingly prominent.Four primary treatment modes for eel culture in Fujian Province are currently employed.These modes include the conventional chemical treatment,the improved chemical treatment in industrial circulating water eel culture,the ecological comprehensive planting and breeding treatment,and the double circulation zero discharge eel culture treatment.This paper elucidates the primary technical processes and mode characteristics of eel culture tail water treatment.It also analyzes the key advantages and disadvantages of these processes and modes,and presents recommendations to promote future advancements in eel culture tail water treatment.The findings of this study serve as a valuable reference for enhancing aquaculture tail water treatment technology in Fujian Province,as well as nationwide.

In September 2021,the goldfish (C.auratus) cultured at two adjacent ornamental fish farms in Tongzhou District of Beijing suffered from sporidiosis,and displayed dorsolateral humps or swollen abdomen,which lost their ornamental value and caused a small number of deaths.In order to identify the specie of parasite and enrich its epidemiological data,the lesion tissues from dorsolateral humps and hepatopancreas of diseased fish were collected.Morphological observation and spores measurement were carried out.18S rDNA gene of the parasites was then cloned,sequenced and analyzed.The results showed that the morphological characteristics of the spore was pyriform in shape,and two polar capsules arranged in an octagonal shape at the front which accounts for about half of the entire length of the spore.The measured data of the spores were 17.58 μm and 18.09 μm in average length,11.02 μm and 11.82 μm in average width,and there were 7-9 loops of polar filaments,which were similar to those of M.wulii. The partial sequences of 18S rDNA gene of the parasites had the highest homology with M.wulii based on blast from GenBank,and the similarity was more than 99%.In addition,in the constructed phylogenetic tree by 18S DNA gene,the isolated spore was also clustered with the M.wulii.Therefore,it was confirmed that the parasites caused goldfish sporidiosis in these two cases were both M.wulii,and this was the first report that M.wulii parasitized in goldfish muscle.

In light of the beam trawl survey conducted in the Xiamen sea area during April (spring) and November (autumn) of 2021,this study delves into an analysis of the community structure and biodiversity of nekton within this marine region.The findings unveiled a diverse array,encompassing 176 nekton species,categorized into 18 orders,71 families,and 124 genera.This encompassed 107 fish species,18 shrimp species,35 crab species,8 Stomatopoda species,and 8 Cephalopoda species.Regarding the quantitative aspects,the recorded biomass and abundance of nekton were determined as 281.40 kg·km^-2 and 14.49× 10³ ind·km^-2,respectively.Notably,marked spatial and temporal variations were observed across the surveyed stations.Specifically,the resource density exhibited notable disparities,with the eastern waters and Tong’an Bay of the Xiamen sea area displaying relatively higher concentrations.Moreover,the resource density in autumn significantly surpassed that in spring.The relative importance index (IRI) highlighted distinct dominant species across the seasons.Parapenaeopsis hardwickii,Parapenaeopsis cultrirostris,and Chiloscyllium plagiosum were dominant during spring,whereas Johnius belengerii and Leiognathus brevirostris took precedence in autumn.These dominant species primarily comprised groups characterized by small individuals,abbreviated life cycles,and comparatively lower nutritional levels.Analysis of nekton indices revealed substantial variability in richness,with relatively significant fluctuations.Conversely,diversity and evenness indices displayed minor alterations.Notably,spring exhibited significantly lower values than autumn,positioning the biodiversity at a moderate level.Furthermore,noteworthy interdecadal alterations in the nekton community structure were evident.Through these observations,this study contributes valuable insights into the dynamic composition,seasonal variations,and structural changes within the nekton community in the Xiamen sea area,offering a comprehensive understanding of its biodiversity and ecological dynamics.

To monitor fish resources and biodiversity in the headwaters of Chishui River,a comprehensive investigation was conducted using both traditional catch methods and environmental DNA (eDNA) technology from 2020 to 2021.A total of 48 fish species were identified,representing 4 orders,10 families,and 41 genera.Traditional fishing methods captured 23 fish species,spanning 2 orders,5 families,and 22 genera,while eDNA technology expanded the detection to encompass 4 orders,8 families,38 genera,and 40 species.In the analysis of fish species composition,the relative importance index (IRI) highlighted Schizothorax grahami,Acrossocheilus yunnanensis,Zacco platypus,and Semilabeo prochilus as the dominant species in the river section of the reserve.The Shannon-Wiener index registered at 2.99,indicating relatively rich overall fish resources and a relatively stable community structure.The catch Margalef index (D) reached 3.31,affirming the richness of fish species in the monitoring area,with a stable composition and population structure.Further assessment revealed a catch evenness index of 0.66,indicating a uniform distribution of population structure.Notably,differences in fish resources between the main river and tributaries were observed.Based on these findings,future conservation efforts should prioritize the core protection zone of the main stream,enhancing measures for fish diversity protection.Additionally,targeted interventions to restore tributary resources should be progressively implemented to elevate the overall resource level.This study provides valuable insights into the diverse fish species,their distribution,and recommendations for effective conservation strategies in the headwaters of Chishui River.

Microplastic pollution is widespread worldwide and can enter organisms by ingestion or inhalation.In this study,an experimental group (with microplastics) and a control group (no microplastics detected) were set up,and a non-targeted metabolomic analysis was performed on K.pelamis muscle tissue from the Eastern Pacific Ocean using liquid chromatography-mass spectrometry to investigate the potential effects of microplastic contamination on their metabolites.The results showed that a total of 34 metabolites were significantly different,of which 19 differential metabolites were up-regulated and 15 differential metabolites were down-regulated.The differential metabolite analysis showed that methylmalonic acid and propionic acid were up-regulated to induce neurological disorders and may be responsible for the abnormal swimming pattern of K.pelamis.The metabolite content of 20-hydroxyarachidonic acid in the metabolites of K.pelamis muscle tissue was significantly upregulated (P=0.003) and the difference multiplier was 6.002-folds.Arachidonic acid metabolism was closely related to hepatic disorders of glycolipid metabolism and its abnormal metabolism may affect disorders of glycolipid metabolism.Malic acid downregulation might put K.pelamis at risk of bacterial infection.In contrast,glycerol-3-phosphate,creatine phosphate and hydroxy cumene glycosides were up-regulated as a self-protective mechanism for K.pelamis in response to microplastic accumulation.Metabolic pathway enrichment analysis showed that different metabolites were mainly enriched in metabolism,bile secretion,propionate metabolism,proximal tubular bicarbonate recycling,ethylbenzene degradation,glycerophospholipid metabolism,and cholesterol metabolism.Among them,cholesterol metabolism and glycerophospholipid metabolism were involved in building biofilms and maintaining the basic life activities of the organism;while ethylbenzene degradation and propionate metabolism were used to alleviate toxicity in vivo;and proximal tubular bicarbonate recycling was responsible for mediating blood pH.The results of the study provided some reference significance for the toxicology of microplastic pollution on marine fish.

To study the effect of carotenoids on the body color of red,yellow and blue strains of N.denticulata sinensis,this study used TLC (thin-layer chromatography) to analyze the main pigment compositions of 3 strains of N.denticulata sinensis.According to the results,the effects of carotenoids on the body color of 3 strains of N.denticulata sinensis were tested.The TLC analysis was used to separate the dermis and extract the pigment of 3 strains of N.denticulata sinensis.The feeding trials were conducted in light and dark,while 300 shrimps from each strain were divided into thirty groups,with three replicates in each group.The control group was fed with basic feed,while the other four groups were fed with basic feed added Spirulina,lutein,natural-astaxanthin and artificial-astaxanthin.The results showed that the pigment substances of red,yellow,and blue strains of N.denticulata sinensis contained β-carotene and astaxanthin;the pigment substances of blue N.denticulata sinensis contained a combination of crustacyanin and astaxanthin.The feeding trials showed that in yellow strain and blue strain,natural-astaxanthin had the most obvious effect on the body color promotion.Under the dark condition,lutein,natural-astaxanthin and artificial-astaxanthin had certain promotion and maintenance effects on the body color of red strain and yellow strain.The four carotenoid additives had no effect on the body color in blue strain.This study provided a theoretical basis for improving body color of N.denticulata sinensis.

Artemia is an important biological feed for aquatic animals.In this study,Saccharomyces cerevisiae,powder of Chlorella pyenoidosa,and fermented shrimp flake were fed to new hatched Artemia nauplii to evaluate the effects of different diets on the growth,survival,and nutritional composition of Artemia nauplii.Results showed that after 6 days feeding,the fermented shrimp flake feed group had the largest average body length,which were significantly larger than that of the S.cerevisiae group and the powder of C.pyenoidosa group (P<0.05).The survival rate of Artemia nauplii fed with S.cerevisiae was the lowest,but there were no significant differences between the powder of C.pyenoidosa group and the fermented shrimp flake group (P>0.05).After 6 days feeding,the crude protein content of Artemia nauplii significantly increased,but the crude fat content significantly decreased compared to Artemia nauplii (P<0.05).The protein content of Artemia nauplii in the powder of C.pyenoidosa group and the fermented shrimp flakes group was significantly higher than that in the S.cerevisiae group (P<0.05).Furthermore,the highest crude fat content was obtained in Artemia nauplii that were fed with the fermented shrimp flakes.The fermented shrimp flakes group had the highest total amino acid (TAA) content and essential amino acid (EAA) content.All experimental groups contained high levels of eicosapentaenoic acid (EPA),but the docosahexaenoic acid (DHA) was undetectable.The total fatty acid content and polyunsaturated fatty acid content in the fermented shrimp flakes group were significantly higher than those in the powder of C.pyenoidosa group and the S.cerevisiae group (P<0.05).However,the Artemia nauplii fed with powder of C.pyenoidosa had significantly higher high unsaturated fatty acid (HUFA) content and EPA content than the fermented shrimp flakes group as well as the S.cerevisiae group (P<0.05).The outcome of this study provided that fermented shrimp flakes and powder of C.pyenoidosa had advantages in enhancing the nutrition of Artemia,and could be used for Artemia production and nutrient enhancement.

In order to obtain the heritability of growth traits in juvenile T.rubripes,and to exert the important role of heritability in guiding breeding work,the body mass,body length and total length of 2 900 juvenile T.rubripes at 1,2 and 4 months old were measured using the whole sib family of T.rubripes constructed in 2022.The heritability of these three growth traits was estimated by the whole sib correlation method and its formula.The phenotypic correlations among these three growth traits were calculated by Pearson coefficient.The genetic correlation of these three growth traits was calculated by sib covariance method.The results showed that the heritability of the 1-month-old juvenile T.rubripes was 0.54 (body mass heritability),0.39 (body length heritability) and 0.36 (full length heritability),respectively,all of which belonged to the high heritability.The genetic correlation between body length and body mass was 0.889 and the phenotypic correlation was 0.851.The genetic and phenotypic correlations of body mass were 0.873 and 0.864,respectively.The genetic correlation between body length and total length was 0.947 and the phenotypic correlation was 0.894.Heritability of body mass,body length and full-length at 2 months old were 0.28,0.23 and 0.25,respectively,all belonging to the medium heritability.The genetic correlation between body length and body mass was 0.828 and phenotypic correlation was 0.917.The genetic correlation and phenotypic correlation were 0.820 and 0.932,respectively.The genetic correlation between body length and total length was 0.897 and the phenotypic correlation was 0.952.At 4 months old,the heritability of body mass,body length and full length were 0.23,0.29 and 0.29,respectively,which belonged to the medium heritability.The genetic correlation between body length and body mass was 0.769,the phenotypic correlation was 0.779,the genetic correlation between body mass and body length was 0.726,and the phenotypic correlation was 0.801.The genetic and phenotypic correlations between body length and total length were 0.912 and 0.941,respectively.The results of this study can provide reference for the subsequent breeding of T.rubripes.

This study aimed to understand the gonadal development and reproductive characteristics of the black scraper (T.modestus) before and after spawning.From November 2021 to March 2022,the parent fish were collected for five times,with three males and three females at each time.The total length,body weight,hepatopancreas index and gonadosomatic index were measured every time.At the same time,paraffin-embedded sections and hematoxylin-eosin staining were used to observe the gonadal development.The results showed that under artificial temperature control,the gonad weight and gonadosomatic index of the female and male parental T.modestus reached the maximum in February,and entered the peak period of sexual maturity,which was significantly higher than that in other months (P<0.05),suggesting that the parent fish reached the peak of maturity in February under the condition of artificially controlled water temperature.The spawning type of T.modestus was asynchronous and batch spawning,and the ovarian development of T.modestus could be divided into six phases,which was peri-nucleolus,yolk vesicle,primary yolk,secondary yolk,teritary yolk,and ripe stage,respectively.The testis development of T.odestus could be divided into five phases,which was spermatogonium,primary spermatocyte,secondary spermatocyte,spermatid and spermatozoa,respectively.In conclusion,this study investigated the morphological characteristics,organizational structure and developmental rules at different gonadal development stages of T.modestus,which may enrich the basic data of reproductive biology and provide scientific basis for artificial breeding and seed production of T.modestus.

In this study,juvenile A.japonicus (experimental group) were purchased from northern China and reared in southern China under natural water temperature for one year.The same age seedlings of juvenile A.japonicus (control group) were directly collected from northern China to compare their thermal resistance with those of the experimental group.The study of thermal limits showed that the sublethal temperature of A.japonicus in the experimental group was 32 °C,significantly higher than the 30 °C in the control group.The ULTs₅₀ of A.japonicus in the experimental and control groups were 33.1 °C and 31.9 °C,respectively.These results demonstrated that the thermal history influenced the upper thermal limit of A.japonicus,and A.japonicus undergoing continuous thermal shock would possess stronger thermal resistance.Additionally,the expression patterns of HSP90a,gp96,HSP70,HSP26,and proeintl(2)efl genes after heat shock for 1,2,and 3 hours between the experimental and control groups were analyzed using qRT-PCR.The expression patterns of HSP90a,gp96,HSP70,HSP26,and proeintl(2)efl genes were different between the experimental and control groups.At 30 °C heat shock,the gene expressions of HSP90a,gp96,HSP70,and HSP26 in the control group did not noticeably increase after stimulation for 1 and 2 hours but were significantly up-regulated at 3 hours,with expression values reaching (9.801±1.303),(2.508±0.910),(8.649±1.936),and (34.787±4.978),respectively.However,all of the HSP90a,gp96,HSP70,and HSP26 gene expressions in the experimental group were dramatically up-regulated at 1 hour at 30 °C,with expression values reaching (42.000±8.798),(20.019±6.224),(218.750±78.701),and (93.710±5.674),respectively.These four temperature-tolerant related genes detected in the present study in the experimental group were up-regulated earlier than those in the control group,indicating a higher ability of A.japonicus in the experimental group to respond adaptively to heat shock than that in the control group.Therefore,the research showed that A.japonicus undergoing high temperature acclimation could respond earlier to external environmental heat conditions.

Deeper offshore aquaculture plays a crucial role in mitigating the ecological pressures in nearshore waters, expanding the aquaculture industry’s development space, and offering high-quality green aquatic products. In Fujian Province, the deeper offshore aquaculture is still in its early stages, and it has introduced the “Fujian Province Pilot Work Plan (2021—2023) For Deepsea Equipment Breeding Project” to research and tackle the technological challenges related to this industry. The plan aims to establish a complete industry chain, enhance the industrial service system, and explore novel fields, mechanisms, and models for deeper offshore aquaculture. This paper is centered around the developmental requirements of the deep-sea aquaculture industry and follows a problem-oriented approach. It presents an industry development service system for deeper offshore aquaculture that consists of three main links and six systems,including infrastructure construction services and financial support services during the pre-production stage, production technology services and industrial supply chain services during the mid-production stage, and brand building services and processing and circulation services during the post-production stage. Moreover, it provides strategies and suggestions for constructing a service system, aiming to establish a comprehensive support system that enables the sustainable development of the deep-sea aquaculture industry.

Carbon peaking and carbon neutrality are important measures to address climate change in China. Carbon emission reduction in aquaculture is crucial to achieving the dual carbon target. Therefore, studying and exploring low-carbon aquaculture technology has important practical significance. Based on the concept of low carbon development and the background of dual carbon goals, the present study analyzed the current situation and trends of low carbon aquaculture technology development at home and abroad, discussed the urgent issues to be solved in the development of low carbon aquaculture technology in China, and proposed relevant countermeasures in terms of innovation of low carbon technology, improvement of policies and regulations, and construction of professional personnel in combination with China’s national conditions, aiming at effectively reducing greenhouse gas emissions from China’s aquaculture industry,promoting high-quality green transformation of aquaculture industry to provide scientific reference and contribute to the realization of China’s dual carbon vision.

Chlorella is a unicellular microalga that could grow and accumulate biomass through photosynthesis using sunlight and carbon dioxide. It is widely used to produce biofuels and other high-value products in fields like aquaculture, food, energy, and the environment. With the development of genetic engineering technology, research and applications of Chlorella at the molecular level have received increasing attention, making specific genetic modification possible. In this paper, we summarized and discussed the application of Chlorella in genetic engineering and protein production from four perspectives: transformation system, transformation methods, factors affecting transformation and expression of exogenous proteins. The aim of this review was to provide theoretical support and references for high-value products production of Chlorella.

The kelp knots are the main product for exporting and earning foreign exchange in Chinese kelp culture provinces, but there are no mechanical processing devices. Therefore, the kelp knots are usually tied manually. Based on the principle of bionics, this paper offered an automatic knotting machine which could make the kelp forming a circle and passing through it to form a knot with the logic circuit. The test verified that this knotting machine was able to complete the operational requirements for kelp knotting accurately, which showed that this design was reasonable and feasible, and had the value of promotion and application after further optimization. It could also provide certain reference for the design and application of relevant knotting equipment.

This article focused on the typical processing by-products of sea cucumber (A.japonicus), including intestines and ovum, to explore their nutritional composition and conduct a comprehensive evaluation by comparing them with body walls. The results showed that the crude protein, crude fat, ash, and total sugar contents in sea cucumber intestines and ovum were 68.85%, 13.53%, 9.96%, 0%,and 58.18%, 12.24%, 19.01%, 2.36%, respectively. In comparison to the body walls, the by-products exhibited higher crude protein and fat contents, but lower ash and total sugar contents. The intestines and ovum were found to contain 18 different amino acids, constituting 68.15% and 51.38% of the total amount, respectively. The ratio of essential to non-essential amino acids was 65.17% and 61.37%, respectively, with essential amino acids accounting for 39.46% and 38.03% of the total amino acids. The essential amino acid index was 94.85 and 67.73, respectively, suggesting that both the intestines and ovum possessed high nutritional value as they exhibited a good balance effect of amino acid components, identifying them as ideal protein sources. The unsaturated fatty acids constituted a similar proportion of total fatty acids, with 80.82% and 80.74%, respectively. Notably, EPA and DHA were the major components of these fatty acids. Additionally, five macro elements and five trace elements were detected, with sodium and iron being the primary elements. This study serves as a foundation for the high-value utilization of sea cucumber by-products and the development of active substances.

To figure out the different nutritional quality of S.scherzeri muscle from different habitats, this study determined and compared the nutritional compositions, as well as fatty acids composition and content of S.scherzeri. The results showed that there was significantly higher crude fat content in the muscle of S.scherzeri in upstream area than that in the muscle of S.scherzeri in downstream area (P<0.05), without significance in content of moisture, crude protein and ash between these two groups (P>0.05). There are 16 kinds of fatty acids in the muscle of S.scherzeri in upstream area and 17 in downstream area. The saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids occupied 35.886%, 34.184% and 29.922% in the muscle of S.scherzeri in upstream area, occupied 34.913%, 34.895% and 30.181% in the muscle of S.scherzeri in downstream area, respectively. And for the composition of fatty acid, the essential fatty acid occupied 11.735%, the ratio of ω-6/ω-3 was 0.919,EPA and DHA was 11.672% in the muscle of S.scherzeri in upstream area. The essential fatty acid occupied 9.571%, the ratio of ω-6/ω-3 was 0.781,EPA and DHA was 12.939% in the muscle of S.scherzeri in downstream area. In conclusion,the nutritive value of fatty acid in the muscle of S.scherzeri in upstream area was better than that of S.scherzeri in downstream area.

In order to investigate the potential ecological risks of heavy metals at cage farming in surface sediments, 5 samples were collected from Zhanghu reservoir bay in Shuikou reservoir and the acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) were studied. The results indicated that the AVS concentrations ranged from 0.57-2.13 μmol·g^-1, and the SEM concentrations ranged from 1.66-6.35 μmol·g^-1. Among heavy metals, Zn, Cr and Cu were the dominating metals, accounting for over 80% of SEM. By comparing the ratio of SEM to AVS, the values of annual average were ranged from 1.65-9.11. If Cr was not included in the calculation, the values were ranged from 1.42-7.75, and the value of (SEM-AVS) were mainly smaller than 5. These indicated that heavy metals were associated with the AVS phase in the sediments, while metals in surface sediments could not cause toxicity to benthic organism. Compared with the threshold of toxic effects, the most toxic metal was Pb in terms of individual heavy metals. According to the present study, the potential toxic effects of heavy metal release and hydrogen sulfide (H₂S) production from sulfides on cage aquaculture should be on the alert.