Table of Content

25 February 2020, Volume 42 Issue 1

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Study on using BP artificial neural network model for chlorophyll-a concentration in Pingtan Thirty-six Feet Lake

2020, 42(1):  1-9. 

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We collected the meteorological and water quality data of Pingtan Thirty-six Feet Lake from January 2016 to May 2017 and developed a model based on the BP artificial neural network. Environmental factors were used as input indicators to run the model, while the chlorophyll-a concentration was used as an output index. 80% historical data were randomly extracted from the sample data for model calculating, and others were used for model verification. The results showed that the fitting degree of chlorophyll-a concentration and monitoring data reached R2=0.97, RMSE=0.05 μg/L, RSR=0.17, and the error was small when the temperature, conductivity and water temperature were taken as input factors. We sampled the lake for five times from March 13th to April 26th, 2019 by comparing the measured chlorophyll-a concentration with the predicted chlorophyll-a concentration. It showed that the RSR was 0.24, the deviation between measured and predicted values was small. The results showed that the model was expected to be applied to the prediction of chlorophyll-a concentration and early warning of water blooms in the area of Pingtan Thirty-six Feet Lake, which would provide a reference for the prevention and control of eutrophication.

The continuous observation of ichthyoplankton species composition and diversity in summer in Yangtze River estuary

2020, 42(1):  10-21. 

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To clarify the relationship between species composition of ichthyoplankton and tides in the Yangtze River estuary，we set 2 survey stations, L1 and L4, respectively on July, 2017. The sample was collected continuously for 24 hours. A total of 19 fish eggs and 201 juveniles were collected at the L1 station and a total of 17 fish eggs and 92 juveniles were collected at the L4 station. We totally obtained 70 mtCOI, sequences 26 species were identified, of which 19 were identified to the species level, 1 was identified to the genus level, and 6 were identified to the level of the genus, the average genetic distance within the species is 0.007. The results of species diversity analysis based on DNA barcode showed that:There are 14 species at L1 station and 21 species at L4 station. Tide has a great influence on the abundance of ichthyoplankton in the Yangtze estuary, but has little to do with species composition. The abundance of inshore station decreases at flood tide and so does that of offshore station. Inshore station havs higher abundance than off-shore station, but offshore station has higher species richness. The results show the reliability of DNA barcode technology in the study of fish eggs and larvae diversity, and reveals the influence of tidal waves on the species composition of fish eggs and larvae in the Yangtze River estuary.

The detection and analysis of acute hepatopancreatic necrosis disease (AHPND) and Vibrio in water or in Fenneropenaeus chinensis

2020, 42(1):  22-28. 

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In recent years, acute hepatopancreatic necrosis disease (AHPND) has broken out in all over the world and led to significant economic losses to shrimp farms. To gain further information of the outbreak of AHPND and Vibrios in Fenneropenaeus chinensis ponds, nPCR method and TCBS selective medium culture were used to detect samples collected from April to September 2018, respectively. The nPCR products revealed that the positive detection rate was higher in July and August, reached 15.6% and 25.0% respectively, whereas no positive samples were detected in other months. The TCBS selected medium results showed that Vibrios were controlled within 0~8.6×103 cfu?mL?1 between April and September, under the measures of water transfer and material control, and peaked in July and August. Furthermore, the black colony found in this experiment was detected by 16S rRNA colony PCR, while the neighbor-joining method in Mega 6 was used to construct phylogenetic tree. In this paper, based on the basic information of this disease and combined with the research progress in recent years, we proposed a series of control measures, which provided a basis for further controlling the occurrence of the disease.

Residue elimination of enrofloxacin and its metabolite ciprofloxacin in Larimichthys crocea at multiple dosages

2020, 42(1):  29-35. 

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The current study investigated the residue elimination of enrofloxacin and its metabolite ciprofloxacin in Larimichthys croceaat multiple dosages to provide a reasonable dosing plan and withdrawal period for the aquaculture industry of L. crocea. The concentration of enrofloxacin and its metabolite ciprofloxacin in the plasma, muscle and liver of L. crocea after a 5 days consecutive dose of 25 mg/kg body weight at water temperature of (20±3)℃were detected by high performance liquid chromatography tandem mass spectrometry method. The results showed that the peak concentration of enrofloxacin in L. crocea was fast reached after dosage, while the peak time of enrofloxacin in plasma, liver and muscle were 8 h, 12 h and 12 h, respectively. The peak concentration of enrofloxacin in plasma, liver and muscle were 3.068mg/L, 3.446 mg/kg and 4.089 mg/kg, respectively. The peak time of ciprofloxacin in plasma, liver and muscle were 8 h, 12 h and 8 h, respectively, and the peak concentration of ciprofloxacin were 0.104 mg/L, 0.753 mg/kg and 0.355 mg/kg, respectively. Enrofloxacin metabolized less ciprofloxacin in L. crocea. The withdrawal time of enrofloxacin in L. crocea should not be less than 18 days under this experimental condition.

Effect of three drugs on the survival rate of Obelia genicutata Linnaeus

2020, 42(1):  36-41. 

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Obelia genicutata Linnaeus grow and breed well with the right temperature, salinity, bait and other conditions. On the one hand, they directly poison and kill the tender seedlings, and on the other hand, jellyfish compete for baits with seedlings. At present, researches on jellyfish at home and abroad mainly focused on the classification of marine jellyfish and freshwater jellyfish, the embryonic development, effects of ecological factors on their growth and the outbreak mechanism. How to control the outbreak of jellyfish in seedling water has not been reported. In order to explore the inhibitory effect of potassium permanganate, copper sulfate and available chlorine on O. genicutata Linnaeus, the lethal effect of potassium permanganate, copper sulfate and available chlorine to O. genicutata Linnaeus were detected respectively at (28.8±0.7)℃ and with a salinity of (7.4±0.7). The results showed that when the concentration of potassium permanganate was 2.0 mg/L, the average survival rate of O. genicutata Linnaeus at 3 hours was 80.0%, while the average survival rate of O. genicutata Linnaeus at 24 hours was 40.0%. When the concentration of potassium permanganate was 2.9 mg/L, the average survival rate of O. genicutata Linnaeus at 3 hours was 43.3%, while the average survival rate of O. genicutata Linnaeus at 24 hours was 0. When the concentration of copper sulfate was 0.3 mg/L, the average survival rate of O. genicutata Linnaeus at 3 hours was 100%, while the average survival rate of O. genicutata Linnaeus at 24 hours was 56.7%. When the concentration of copper sulfate was 0.6 mg/L, the average survival rate of O. genicutata Linnaeus at 3 hours was 63.3%, while the average survival rate of O. genicutata Linnaeus at 24 hours was 0. When the concentration of sodium hypochlorit was 260 mg/L, the average survival rate of O. genicutata Linnaeus at 3 hours was still 93.3%. When the concentration of sodium hypochlorit was 104 mg/L, the average survival rate of O. genicutata Linnaeus at 24 hours was rapidly decreased to 36.7%. In conclusion, when the concentration of copper sulfate was 0.6 mg/L, O. genicutata Linnaeus were restrained after 24 hours. The effect will be more pronounced, if combined lowdown. The test results were obtained under the condition of good water quality and low organic content. In practical production, various drugs will be degraded by organic components in water especially in seeding water, which contained a lot of organic matter. Therefore, small water test is needed in the process of use.

The growth analyses of the hybrids between Haliotis discus hannai and Haliotis fulgens

2020, 42(1):  42-49. 

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In order to find out the discipline of abalone hybrids, fertilization rate and hatching rate were studied in abalone hybrids between Haliotis discus hannai and Haliotis fulgens. Then, the survival and growth performance were compared in abalone hybrid juveniles to evaluate the heterosis. In the same culture conditions, the growth differences and corresponding advantages were studied. This study provided a theoretical basis for making full use of the heterosis of abalone.

The study on the reservoir area cage-culture of Murray cod, Maccullochella peelii peelii

2020, 42(1):  50-56. 

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The Murray cod, Maccullochella peelii peelii (Mitchell), were reared in the reservoir area under the condition of cage-culture. The initial average body weight of juvenile Murray cod was (20.41±3.81) g, and the average total length was (13.30±1.21) cm. The water temperature ranged between 7.4℃ and 27.6℃ during the experiment. The fish was fed with customized artificial formula feed, whose crude protein content was 48.9%. After 26 months of cultivation, the average body weight and total length reached to (1618.04±24.33) g and (46.30±5.26) cm, respectively, and the feed coefficient was 1.53. The optimal regression equation for the body weight and total length of Murray cod was W=0.003L3.394. According to the Von Bertalanffy's non-linear growth model, the growth inflection point of body weight was 756.7 g, the growth inflection point of total length was 13.7 cm, the test time of the growth inflection point was 12.1 months and 1.4 months, respectively. The results showed that reservoir area cage-culture can be adapted to Murray Cod.

Nursery culture for commercial Manila clam (Ruditapes philippinarum) spat in subtidal zoon

2020, 42(1):  57-62. 

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In order to improve the nursery culture technique of Ruditapes philippinarum, a survey for the juvenile growth and environmental parameters was carried out at Weitou Bay of Jinjiang, Fujian Province, China. From January to April, 2019, the water temperature increased while the salinity gradually decreased, both were within the suitable range. Diatoms dominated the phytoplankton, with a density of 5 100 cells/L in January and 8 300 cells/L in April. The shell length of juveniles increased from (2.33±0.75) to (11.14±2.52) mm, but the survival rate was 30.30%. Comprehensive analysis showed that the high death rate might be caused by predators.

Study on extraction technology of Antarctic krill oil rich in phospholipid

2020, 42(1):  63-69. 

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Using Antarctic krill as raw material, the pretreatment process of krill was studied by Sodium citrate solution immersion method. Through comprehensive analysis on the most important four aspects of manufacturing cost and product quality of krill oil from extraction rate, phospholipid, acid value and fluidity, the optimum technological conditions were confirmed as follows: the treatment concentration of Sodium citrate solution was 1.0%, the ratio of material-solvent was 1:5, and the soaking time was 3 hours. Under these conditions, krill powder was extracted with 95% ethanol, and the separated extract was distilled under vacuum after solid-liquid separation. After removing ethanol, the phospholipid content and acid value of krill oil can reach 50.15% and 10.33 mg KOH/g respectively, and the extraction rate of krill oil was 14.9%, while its fluidity was excellent. The process was simple in operation, safe and practical, while the extracted krill oil had high phospholipid content, low acid value, good fluidity and stable quality. Therefore, the comprehensive utilization rate of krill was greatly increased, which had important practical application value.

Study on changes of quality of salted carp flesh during storage

2020, 42(1):  70-75. 

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In this paper, carp was taken as the experimental object, and the quality indexes (texture, color difference and volatile basic nitrogen) of the flesh of carp and salted carp were measured at intervals of one day during the 1～7 days' refrigeration at 4℃, respectively, so as to study the quality changes of salted carp during the storage process. Combined with the analysis of texture, color difference and volatile basic nitrogen, the flavor of fresh carp was the best，the time of salted and refrigerated was longer than that of refrigerated. Further researches were required.

Countermeasures and suggestions for developing Euphausia superb industry in Fuzhou City

Jian-jie LIN

2020, 42(1):  76-82. 

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Euphausia superba is the largest, single global oceanic biological resource, and is a huge protein reservoir for humans. Under the general global environment of “enclosure blue” and more and more resource occupation, in Fuzhou City bigger and stronger fishing, driving the development of ocean fishery whole industry chain has strategic significance. By expounding the background of E. superba resources, investigating the development of E. superb industry at home and abroad, analyzing the basic status quo and basic advantages of the development of E. superb industry in Fuzhou, we discussed about the problems and difficulties in the development of E. superb industry in Fuzhou, and put forward countermeasures and suggestions for accelerating the development of E. superba industry in Fuzhou.

Comparison on the development of shrimp seedling industry between Hainan Province and Fujian Province

2020, 42(1):  83-89. 

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Fujian is a major province of the shrimp seedling industry in China, which has a long history of shrimp breeding. But, with the development of this industry, some problems have become emerging gradually. This article compared the industry scale, marketing situation, breeding techniques as well as technology supports of Fujian Province's shrimp seedling industry to Hainan Province's, hoping to provide some advices for the further development of Fujian Province's shrimp seedling industry.

Progress on application of phlorotanninsin cosmetic

2020, 42(1):  90-96. 

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The present review summarized the source, types and chemical structure of phlorotannins. The research progress of cosmetic efficacy of phlorotannins, such as whitening, anti-aging, anti-oxidation, anti-inflammatory and anti-allergic activities of phlorotannins,was also pointed out. Moreover, the market prospect of developing new cosmetics withphlorotannins was reported in order to provide references to further research and their potential use in functional cosmetics.