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.

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.

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.

This study was performed to explore the distribution and resources of natural sea cucumbers in the inshore aquaculture area in Pingtan District (Fujian Province, China). The study conducted surveys to collect information on species, biology, resource amount, fishing amount, and fishing output value of sea cucumbers in the coastal aquaculture area of Pingtan in April, May, and June 2023. Moreover, the samples of sea cucumbers (n=242) were sampled and used for classification. The results showed that all samples were identified as Apostichopus japonicus. Biological measurement results showed that sea cucumbers collected in April, May, and June reveal average body lengths of (131.7±44.3), (150.1±40.6) and (114.9±28.3) mm, average body weights of (52.2±41.6), (108.3±55.9), (56.1±32.2) g, feeding levels of 3~4, 1~4, and 0~3, respectively. Furthermore, the questionnaire survey results of six fishing boats showed that the average sea cucumber catch per boat in April, May, and June was 1 050.0, 683.3, and 233.3 kg, respectively.This is the first report on the possible existence of a self-propagating population of sea cucumber in Pingtan sea area,which provides information on the resources of sea cucumber in Fujian Province.

To evaluate the culture performance of triploid Crassostrea angulata cultured in inner and outside Huangqi Bay,9 month ages oysters rope-cultured were sampled randomly in Huangqi Bay,Lianjiang,Fujian Province.The shell length(X_L),shell width(X_W),and shell height(X_H),as well as the total weight(TW) and meat weight(MW) were measured for 85 individuals respectively.One-way analysis,multiple regression analysis and path analysis were used for investigating the morphological variation.One-way ANOVA showed that besides shell height,all morphological parameters of the oysters cultured outside the bay were significantly larger than those in the bay.The oysters cultured outside the bay were more round at shape and higher in meat condition.The optimum multiple regression equations were obtained though stepwise multiple regression analysis.As path analysis,the direct effects of morphological parameters on total weight were in order of shell length>shell width>shell height.Shell length had the maximum direct effect on the total weight,and was the major factor.The correlation indices (R²) of morphological parameters against the total weight was less than 0.850,indicating some other factors associating total weight,besides shell length,shell width and shell height,such as meat condition and shell weight.

Microalgae is a kind of unicellular photosynthetic autotrophic eukaryotic plant, which grows rapidly and processes high photosynthetic efficiency.It can provide a lot of high value products, such as protein, polyunsaturated fatty acids and bioactive compounds which are important sources of health care, aquaculture and biofuels.In order to improve productivity, microalgae breeding technology has been developed to explore the strains which have larger biomass, more lipid, and the ability of stress resistance.The article summarized the advantages and disadvantages of various breeding technologies and research advanced, in order to provide a reference for the development of microalgae breeding.