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 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.