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Nutritional components and safety evaluation of fermented mandarin fish
Yingying SHEN, Yanyan WU, Laihao LI, Shanggui DENG
Second Proofread  doi: 10.12131/2090247
[Abstract](562) [FullText HTML](271) [PDF 912KB](3)
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In this paper, the nutritional composition (crude protein, amino acids, crude fat, fatty acids, mineral elements, etc.) and safety index [total volatile basic nitrogen (T-VBN), thiobarbituric acid (TBA), nitrite and biogenic amines, heavy metals, etc.] in fermented mandarin fish (Siniperca chuatsi) muscle were tested. The results show that the contents of water and crude protein in the two fermented mandarin fish were lower than those of fresh ones, and the contents of ash, crude fat, umami amino acids (aspartic acid, glutamic acid and alanine), essential amino acids, total unsaturated fatty acids, sodium and calcium were all higher than those of fresh mandarin fish. The amino acid composition of the two fermented mandarin fish was similar. The contents of ash, crude fat, sodium and calcium in No.1 fermented mandarin fish were higher than those in No.2, while the contents of polyunsaturated fatty acid and crude protein were lower than those in No.2. In terms of safety, neither of the two fermented mandarin fish had excessive heavy metals, but the contents of TBA, T-VBN, nitrite and biogenic amines were higher than those of fresh mandarin fish. The contents of T-VBN and histamine in No.1 fermented mandarin fish were higher than those in No.2, while the contents of TBA, nitrite and total biogenic amines were lower than those in No.2. In general, fermented mandarin fish is a kind of fermented fish products with rich nutrition and high nutritional value. Besides, quality control technology should be used to improve the quality of fermented mandarin fish.
Study on food web of grass carp (Ctenopharyngodon idellus) push-water aquaculture ecosystem by stable isotope analysis
Kai ZHANG, Jun XIE, Deguang YU, Guangjun WANG, Wangbao GONG, Zhifei LI, Ermeng YU, Jingjing TIAN, Yun XIA
Second Proofread  doi: 10.12131/20190217
[Abstract](877) [FullText HTML](396) [PDF 1239KB](3)
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Push-water aquaculture ecosystem is a kind of production mode which integrates recycling aquaculture, high efficiency sewage collection, biological purification and automatic control technology. However, the fate of nutrients in this system is not clear, which results in the waste of food resources and the improper regulation of aquaculture. Therefore, in this study, Ctenopharyngodon idellus push-water aquaculture ecosystem was used as the treatment group, and common pond aquaculture system as the control group. Stable isotope (δ13C, δ15N) technology was used to investigate the bio food composition and system food web structure of the two aquaculture systems. The results show that the stable carbon isotope δ13C were (−25.76±0.23)‰−(−22.26±0.20)‰ and (−25.83±0.24)‰−(−22.38±0.15)‰ in the treatment and control groups, respectively. The stable carbon isotope δ15N were (6.73±0.08)‰−(12.34±0.11)‰ and (6.73±0.08)‰ to (12.14±0.11)‰ in the treatment and control groups, respectively. The stable isotope mixing model reveals that the artificial feed of grass carp and the sediment detritus were the main food sources for consumers in these two groups. To be specific, the artificial feed of grass carp was the main food source for grass carp; the artificial feed of grass carp and the macrozooplankton were the main food source for bighead carp; and the sediment detritus was the main food source for crucian carp. The contribution rate of forage to the food composition of grass carp in push-water aquaculture ecosystem was higher than that in common pond system. Therefore, the adoption of the former can promote the feed intake of cultured organisms and improve the efficiency of feed utilization.
Study on immunoprotection of eukaryotic expression plasmids of Streptococcus iniae simA and pgmA in Oreochromis niloticus
Li MA, Jinying WU, Songze GAO, Caiyun SUN, Wensheng LI
Second Proofread  doi: 10.12131/20190163
[Abstract](814) [FullText HTML](336) [PDF 1315KB](1)
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Nile tilapia (Oreochromis niloticus) is an important commercial fish in aquaculture in the world. However, it is easy to be infected by Streptococcus iniae in the breeding production. The use of vaccine is a relatively ideal anti infection measure. In this study, eukaryotic expression vectors (DNA vaccine) were constructed by taking the simA and pgmA gene of S. iniae as the target genes. Then protective efficacy was evaluated by intramuscular injection of tilapia. Two target genes were detected in the injected fish at DNA and RNA levels after immunization. Besides, 7−28 after the first immunization, the expression levels of interleukin-1 (IL-1β) and Tumor Necrosis Factor (TNF-α) in the gill, liver, kidney and head kidney of the vaccinal group were higher to some extent than those in the PBS control group. The antibody titer and antibacterial activity of immunized groups were significantly higher than that of control groups (P<0.05). Two weeks after being challenged with S. iniae, the relative protective rates of mixed vaccines of pcDNA3.1-pgmA, pcDNA3.1-simA and pcDNA3.1-pgmA, with pcDNA3.1-simA were 60.7%, 49.9% and 75.0%, respectively. It is revealed that the vaccine prepared in this paper has immune protection effect and can be used as a candidate vaccine.
Acclimation training of captive Spinibarbus denticulatus juveniles
Kaiyuan REN, Xiujun SHEN, Mingyun WANG, Xiaotao SHI, Guoyong LIU
Second Proofread  doi: 10.12131/20190205
[Abstract](572) [FullText HTML](274) [PDF 831KB](5)
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We investigated the life skills of Oreochromis mossambicus juveniles after chasing training. By using a mandarin fish model-chasing treatment, the fish were provided with 5 min of chasing training twice a day for 7 and 15 d, respectively, then the indices (escape time for avoiding simulated predators, critical swimming speed, feeding rate, specific body mass growth rate) were compared with those in the control group. The results show that after 7 and 15 d of chasing training, the escape time and feeding rate were significantly lower than those of the control group (P<0.05). There was no significant difference in critical swimming speed between the control group and the chasing training group after 7 d (P>0.05), but the critical swimming speed of the chasing training group after 15 d was significantly higher than that of the control group (P<0.05), and there was no significant difference in specific body mass growth rate between the two groups after 15 d (P>0.05). The results show that 15 d of training can improve the abilities related to survival in the wildness such as anti-predatory ability and swimming ability for juvenile O. mossambicus, but do not reduce the growth of body mass. The effect of 15 d of chasing training is better than that of 7 d.
Study on 17β-estradiol induced feminization of Pelteobagrus fulvidraco
Chenglong WANG, Wenzhi GUAN, Yongqiang LI, Feng LIU
Second Proofread  doi: 10.12131/20200001
[Abstract](327) [FullText HTML](200) [PDF 788KB](3)
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In this study, we compared the feeding method and feeding time of 17β-estradiol to explore the feminization method of XY Pelteobagrus fulvidraco, and then established three families (XY♀×XY♂) to compare the survival rate and sex reversal rate with sex molecular. The results show that the females in Artemia group could not be induced to develop well on the 5th day of opening, but the induced reversal rate was 75.20% on the 1st day of opening, the survival rate induced by the feed group from the 1st day of opening was not significantly different from that of Artemia group, while the sex reversal rate was significantly higher than that of Artemia group; the combination of molecular markers Y1 and Y2 could identify the genetic sex of Pelteobagrus fulvidraco accurately; there was no significant difference in the survival rate and sex ratio of each genotype among the three families in the control group, and the survival rate was 51.00%−56.67%. The proportion of XX female and XY male individuals were 90.91%−97.44%, 94.56%−95.96%, respectively, there was no significant difference in the survival rate and sex reversal rate among the three families in the induction group. The result shows that using 50 mg·kg−1 E2 mixed with micro pellet feed to induce 30 d from the 1st day of opening can screen out well-developed female XY/YY P. fulvidraco effectively by combination of genetic and phenotypic sex identification.
Variation of DOC, nutrients and chlorophyll a contents in shrimp ponds of Minjiang River Estuary
Guanghui ZHAO, Ping YANG, Chen TANG, Zhixian HAN, Chuan TONG
Second Proofread  doi: 10.12131/20190208
[Abstract](804) [FullText HTML](373) [PDF 1244KB](5)
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In order to reveal the spatiotemporal dynamic changes of DOC, nutrients, chlorophyll a and their eco-chemical metrological characteristics of land-based shrimp ponds in the Minjiang River Estuary, Fujian Province, from May to October 2018, we have analyzed the water temperature, pH, salinity, dissolved oxygen index and water samples of different depths from three land-based shrimp ponds in that area, and the soluble organic carbon (DOC), soluble inorganic nitrogen (DIN), PO4 3−P and chlorophyll a mass concentration were 5.73−16.79 mg·L−1, 0.04−1.80 mg·L−1, 0.03−0.16 mg·L−1 and 15.02−443.08 μg·L−1, respectively, all with obvious characteristics of spatio-temporal changes. The concentrations of DOC, nutrients and chlorophyll a were affected by the water environment parameters, human activities and cultured organisms. The water nutrient composition of carbon, nitrogen and phosphorus was similar with that of plants and soil, showing carbon surplus and nitrogen limitation. In summary, In the process of aquaculture, it is very important to strengthen the monitoring of the dynamic changes of nutrients and chlorophyll a in shrimp ponds, and artificially adjust the ratio of carbon, nitrogen and phosphorus, so as to prevent eutrophication of shrimp pond and promote the green and sustainable production of ecosystem of shrimp ponds.
Research progress on color transformation of red meat during storage
Hui HUANG, Shenyu SUN, Ya WEI, Laihao LI, Xianqing YANG, Shuxian HAO, Jianwei CEN, Yongqiang ZHAO, Shengjun CHEN, Zhi LIN
Second Proofread  doi: 10.12131/20190170
[Abstract](822) [FullText HTML](390) [PDF 627KB](2)
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Meat color is the most direct index of meat quality, and the correlation between its changes during storage and quality has been a hotspot in recent years. The paper reviews the relationship between myoglobin and meat color change, discusses the main influencing factors, and investigates the mitochondrial regulation of meat color by affecting the presence of myoglobin. The review provides a theoretical basis for the preservation technology of meat color during storage.
Variation characteristics of phytoplankton community in polyculture ponds of Scylla serrata and Penaeus monodon
Si CHEN, Yitong LI, Wengui CAI, Haigang CHEN, Fei TIAN, Linbao ZHANG, Zhe ZHANG, Zhixun GUO
First Proofread  doi: 10.12131/20190233
[Abstract](320) [FullText HTML](211) [PDF 1084KB](0)
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To understand the variation characteristics of phytoplankton population structure in the polyculture ponds of Scylla serrata and Penaeus monodon, we have conducted a monthly survey on the phytoplankton in three cultured ponds in Panyu District, Guangzhou from March to November 2018, and discussed the relationship between phytoplankton and environment factors based on redundancy analysis (RDA). The results show that a total of 29 species in five Phyla were identified, of which the most abundant group was Bacillariophyta, with 19 species accounting for 65.5% of the total species, followed by Cyanophyta (5 species, 17.2%), Pyrrophyta (3 species), Chlorophyta (1 species) and Euglenophyta (1 species). Navicula directa, Nitzschia delicatissima, Gyrosigma acuminatum, Ceratium macroceros and Oscillatoria tenuis were the dominant species during the investigation. The abundance of phytoplankton cells varied from 2.56×103 to 189.2×103 cells·m−3. The variation of the Shannon-Weaver diversity index ranged from 0.468 to 2.597. RDA reveals that nutrients, salinity and pH were the primary environmental factors influencing phytoplankton community.
Aquaculture of Strongylocentrotus intermedius in Fujian coastal areas
Yaqing CHANG, Chong ZHAO, Fangyuan HU, Jian SONG, Xiaofei LENG, Xiujin LIAO, Jia LUO, Mingtai LIU, Weijie ZHANG
Third Proofread  doi: 10.12131/20190156
[Abstract](1474) [FullText HTML](652) [PDF 13715KB](3)
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In order to explore the feasibility of Strongylocentrotus intermedius of seasonal breeding in Fujian coastal areas, we moved a new breed of S. intermedius ‘Dajin’ southward to Fuzhou sea area in November 2018. The tested S. intermedius was divided into two types: large-size (3 cm test diameter) and small-size (1 cm test diameter). Using the existing abalone breeding facilities, we regularly fed Laminaria japonica and Gracilaria lemaneiformis. After six months of breeding, the test diameter of large-size S. intermedius bred in Fuzhou had reached (55.90±2.63) mm, while the body weight had reached (56.30±6.92) g and the gonadal index reached (15.02±1.5) %. The gonadal development entered the stage of premature (Stage III) with good quality, which was significantly greater than the test diameter (40.97±4.01) mm and body mass (18.60±4.27) g for S. intermedius bred in Dalian in the same period (P<0.05). Besides, the test diameter of small-size S. intermedius in Fuzhou had reached (40.97±0.97) mm, while the body mass had reached (23.18±0.37) g and the gonadal index had reached (9.64±1.00)%. Thus, it is suggested that seasonally breeding S. intermedius in the coastal areas of Fujian Province in winter and spring is feasible. Feeding with local fresh algae on basis of existing facilities and abalone cages leads to higer growth rate of S. intermedius than those bred in Dalian in the same period. The important way to meet the increasing market demand of S. intermedius is to move the breeding southward along Fujian coast.
Effects of acute ammonia nitrogen stress on enzyme activities of gills and digest tract in juvenile mandarin fish (Siniperca chuatsi)
Weidong DING, Liping CAO, Zheming CAO, Xuwen BING
Third Proofread  doi: 10.12131/20190188
[Abstract](1529) [FullText HTML](871) [PDF 799KB](11)
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We investigated the effects of ammonia stress on the enzyme activities in gills and digestive tract of juvenile mandarin fish (Siniperca chuatsi) with body mass of (13.31±0.49) g and body length (9.73±0.46) cm to reveal their physiological changes at temperature of (22.0±0.5) ℃ and ammonia concentration of 48.65 mg·L−1. The results show that juveniles under acute ammonia nitrogen stress had undergone significant changes in the activity levels of Na+/K+-ATPase, respiratory metabolic enzymes and digestive enzymes. The Na+/K+-ATPase activity was significantly different from that of the control group, which first increased and then decreased with time. The activity of respiratory metabolism enzyme increased under stress. Digestive enzymes in the stomach and digestive tract were significantly affected too. AMS activity first decreased and then increased, while pepsin and LPS increased first and then decreased. The results suggest that ammonia nitrogen stress can cause a variety of impairments in the fish body, including deterioration of antioxidant system, physiological metabolism, gill tissue, respiratory function and detoxification function. In order to keep impairment less, the digestive and anaerobic metabolism enzyme activities should be activated to higher level to produce energy for the body's resistance to stress response.
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2020, 16(2).  
[Abstract](3) [PDF 938KB](0)
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Comparison on morphology and body spots characteristics between backcross progenies and their parents of mandarin fish
Lei WEI, Shuqin ZHU, Wei LIU, Jinliang ZHAO, Yezhou QIAN, Chao WU, De QIAN
2020, 16(2): 1-7.   doi: 10.12131/20190219
[Abstract](1570) [FullText HTML](816) [PDF 1327KB](3)
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Since morphology and body spots characteristics are important breeding traits in mandarin fish crossbreeding, we analyzed the difference in quantifiable morphological traits of the backcross progeny [S. scherzeri ♀× (S. scherzeri ♀×S. chuatsi ♂)] and parental offspring (S. scherzeri, S. scherzeri ♀×S. chuatsi ♂) by multiple comparison, hybrid index, principal component analysis and discriminant analysis, and observed the body spots of the backcross. The results show that the average hybrid index of the backcross was 38.73. The morphometric difference analysis and hybrid index indicate that the backcross progenies were biased toward S. scherzeri. Principal component analysis and discriminant analysis reveal that the main differences lay in head angle, body height/body length, head height/head length, and C (the length from the back of the angle bone to the beginning of the ventral fin)/body length between the backcross progenies and their parents. The three-dimensional spatial distribution of the backcross, S. scherzeri and the hybrid on the first three principal components did not overlap and were distinguished from each other. Discriminant analysis can clearly classify the three groups in two-dimensional. The body spots of the backcross included back saddle spots and trunk spots which can be classified into four different combinations. 45.5% of the individuals had back saddle spots, and 72.8% had hollow spots. The results can provide data for cross breeding and hybrid identification of mandarin fish.
Identification and isolation of parasite Branchiomma in ground-based culture of Euthynnus affinis
Zhenhua MA, Shengjie ZHOU, Rui YANG, Wang ZHAO, Qia'er WU, Gang YU
2020, 16(2): 8-14.   doi: 10.12131/20190259
[Abstract](1162) [FullText HTML](716) [PDF 1097KB](21)
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Parasites were observed during land-based farming of the small tuna (Euthynnus affinis) in Tropical Fisheries Research and Development Center, Sanya, Hainan. In this study, the parasite was isolated and morphologically observed, and 18S and 28S rRNA molecules were identified. The 18S rRNA showed 99.12% similarity to Branchiomma sp. (EF116223.1) and 28S rRNA showed 100% similarity to B. nigromaculatum. The parasite was found on the surface of the posterior margin of gill arch and middle and posterior part of pectoral fin of E. affinis. The body of the worm was dark green, brownish yellow or reddish brown, with a gill crown, and the total length was 30–90 mm. The parasite consisted of gill crown, chest and abdomen, but calcareous canal was not found. Its digestive tract included mouth, pharynx, intestine and anus. Therefore, the parasite might belong to Branchiomma and B. nigromaculatum, but further verification is needed. The infected fish reduced food intake significantly, accelerated the swimming speed, and were easily frightened. Formalin immersion had a good removal effect, and the survival rate of the fish after cure was 75.9%.
Feasibility study on recycling of grass carp feces by Pomacea canaliculate
Fang OU, Di WU, Min YIN, Zhijian WANG, Li JIN
2020, 16(2): 15-20.   doi: 10.12131/20190179
[Abstract](2160) [FullText HTML](1255) [PDF 7736KB](9)
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In order to study whether apple snail (Pomacea canaliculate) can utilize the feces produced by grass carp (Ctenopharyngodon idellus) effectively after being fed with water hyacinth (Eichhornia crassipes), we analyzed the growth index, body composition, digestive enzyme activity and accumulation of nitrogen and phosphorus in grass carp feces group and water hyacinth bait group, respectively. The results show that: 1) The body mass in the two groups increased very significantly after 35 d (P<0.01). Both the specific growth rate (SGR) and food conversion rate (FCR) in water hyacinth group were very significantly higher than those in feces group (P<0.01). There was no significant difference in the survival rate (SR) between the two groups (P>0.05). 2) The difference in body composition between the two groups of snails was not significant (P>0.05). 3) The activity of gastric amylase in water hyacinth group was significantly higher than that in feces group (P<0.05), and there was no significant difference in cellulase and lipase activity between the two groups (P>0.05). 4) Apple snail accumulated nitrogen and phosphorus elements in both groups without significant difference (P>0.05). In summary, the feces of grass carp can meet the basic growth requirements of apple snails and reduce the nitrogen and phosphorus contents in water indirectly. It is suggested that apple snails can be used to reduce the pollution brought by grass carp feces in "water-water hyacinth-grass carp" farming mode.
Selection of artificial fish nest material and influencing factors of implementation effects
Yuefei LI, Weitao CHEN, Yuguo XIA, Jiping YANG, Shuli ZHU, Xinhui LI
2020, 16(2): 21-28.   doi: 10.12131/20190198
[Abstract](1995) [FullText HTML](1233) [PDF 858KB](13)
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To determine the optimal artificial fish nest material, and to promote the restoration technology of spawning grounds for fish species with adhesive eggs, we had made fish nests with six kinds of materials (Arundo donax, Miscanthus sp., Pennisetum purpureum, Livistona chinensis, simulation aquatic plants and nylon mesh) at Zhaoqing section in Xijiang River from March to May in 2019, and studied the effects of materials and environmental factors on the implementation of fish nests. Common carps (Cyprinus carpio) had strong preference for adhesion medium, and Arundo donax was the best material for making fish nests, since the eggs adhesion ratio and the number of eggs in each nest were significantly higher for A. donax than for the other materials (P<0.05). The eggs adhesion ratio and the number of eggs decreased with the increase of days of entering water. The principal component analysis reveals that days of entering water are the most important influencing factor on the implementation effect. The increase of discharge and rise of water level can promote common carps to gather to nests and lay eggs, but weather condition had little effect. Besides, we discussed the effects of implement time and location.
Effects of multiple environmental factors on molting death of Procambarus clarkii and countermeasures
Dongliang LIU, Jianhua HUANG, Lishi YANG, Liqi TAN
2020, 16(2): 29-35.   doi: 10.12131/20190128
[Abstract](1567) [FullText HTML](727) [PDF 816KB](4)
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In order to study the cause of molting death of Procambarus clarkii and its preventive measures, we raised and stressed the crayfish of different sizes by different environmental factors. The results show that the survival rate and decidua rate of P. clarkii were highest in groups of 30 mg·L−1 Ca2+ and 15 mg·L−1 Mg2+, significantly higher than those in the contol (P<0.05), but their decidua mortalities were significantly lower than those in the control (P<0.05). When the pH value was 9.23 or the dissolved oxygen concentration was 4.5 mg·L−1, the survival rate and decidua rate were significantly lower than those in the control (P<0.05), but the decidua mortality was significantly higher than that in the control (P<0.05). The molting mortality of P. clarkii was highest when the salinity was 21 (P<0.05). Environmental factors and many other factors are the important causes of molting death of P. clarkii.
Effects of chronic ammonia stress on growth, antioxidative and immunity indices in liver of juvenile Acipenser schrenckii
Min GUAN, Dezhi ZHANG, Daming TANG
2020, 16(2): 36-42.   doi: 10.12131/20190191
[Abstract](1616) [FullText HTML](923) [PDF 658KB](3)
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To preliminarily reveal the physiological response of juvenile Acipenser schrenckii to chronic ammonia-nitrogen stress, we exposed the juveniles to different ammonia nitrogen concentrations (0.01, 0.5, 1.0, 2.0 and 4.0 mg·L−1) for 60 d, and investigated their growth, antioxidative and immunity indices. The results show that the weight gain rate (WGR), specific growth rate (SGR), viserosomatic index (VSI) and hepatosomatic index (HSI) of the juveniles decreased significantly with the increase of ammonia concentration (P<0.05). However, there was no significant change in condition factor (CF). Among the antioxidative indexes, the superoxide dismutase (SOD) , catalase (CAT) , total antioxidant capacity (T-AOC) activity and glutathione (GSH) content in liver decreased gradually with the increase of ammonia concentration, while malondialdehyde (MDA) content increased gradually. Among the immune indices, lysozyme (LZM) activity and immunoglobulin M (IgM) content in the liver decreased significantly (P<0.05). The results suggest that the chronic ammonia stress inhibits the growth, antioxidative and immunity capacity of the juveniles significantly. Thus, in the actual breeding process of A. schrenckii, the ammonia concentration in water should be controlled at ≤0.5 mg·L−1 to avoid the adverse effects of ammonia stress.
Construction of knock-out mutant of vhh in Vibrio harveyi and its related biological characteristics analysis
Yaqiu ZHANG, Yiqin DENG, Juan FENG, Can MAO, Jianmei HU, Youlu SU
2020, 16(2): 43-53.   doi: 10.12131/20190211
[Abstract](1648) [FullText HTML](806) [PDF 1403KB](8)
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Vibrio harveyi is an important pathogen of aquatic animals. In order to study the biological characteristics of the strain after the absence of hemolysin gene vhh, the knock-out mutant of vhh in V. harveyi was constructed by homologous recombination technique. Moreover, the biological characteristics of the wild type strain and the mutant strain were compared. The results show that the deletion of vhh gene did not affect the growth of the strain, neither the secretion of extracellular protease, the stress response to H2O2 and Cu2+, the uptake and utilization of iron, and the 15 antibiotics resistance and biofilm formation, but it caused the strain to swim and surge significantly. In addition, although vhh was highly expressed in the wild type strain, the strain did not show hemolytic activity. The results indicate that vhh negatively regulates the bacterial motility. The study provides novel information for understanding the function of vhh gene in V. harveyi.
Spatio-temporal distribution and eutrophication assessment of nutrients in Daya Bay during 2009–2015
Wenchao YANG, Daojian HUANG, Jixin CHEN, Xiaoyan CHEN, Yushan WANG
2020, 16(2): 54-61.   doi: 10.12131/20190244
[Abstract](1548) [FullText HTML](817) [PDF 858KB](3)
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We investigated the spatio-temporal distribution characteristics and eutrophication of nutrients in Daya Bay in April and May 2009, May and June 2010, February 2012, as well as January and February 2015. Generally speaking, the contents of DIN and PO4-P increased first and then decreased. The spatio-temporal distribution of DIN and PO4-P was affected by terrestrial pollution, marine aquaculture, etc.. The nutrient concentration decreased from coastal area to open sea. The evaluation of potential eutrophication indicates that the seawater in Daya Bay experienced a process from poor nutrition to moderate nutrition and then to poor nutrition. The seawater in the functional areas of Class I had been always in a state of poor nutrition. The average N/P ratio was lower than the Redfield value (16) in the monitoring period.
Spatio-temporal variation of Ommastrephes bartramii resources (winter & spring groups) in Northwest Pacific under different climate modes
Jiajia LI, Jintao WANG, Xinjun CHEN, Lin LEI, Changtao GUAN
2020, 16(2): 62-69.   doi: 10.12131/20190175
[Abstract](2277) [FullText HTML](1344) [PDF 1598KB](6)
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Ommastrephes bartramii is an oceanic species with short life cycle, whose life history and biomass are affected by environmental and climatic factors significantly. Based on the fishery data, sea surface temperature (SST), chlorophyll a (Chl a) and Pacific decadal oscillation (PDO) from 2004 to 2015 in the Northwest Pacific, we applied patial autocorrelation statistics, hot spot analysis and wavelet analysis to study the spatio-temporal variation of O. bartramii in that area under two PDO models with cold and warm periods. The results show that the PDO index was positively correlated with the catch per unit effort (CPUE) and the CPUE lagged PDO for eight months. However, the conjugate period was 2−4 months under the influence of CPUE and PDO index. The distribution of fishery hotspots under two PDO modes is characterized by the fact that the gravity centers of fishing ground is obviously distributed in high and low latitude direction with strong and weak spatial agglomeration in warm and cold periods, respectively. PDO index affects the spatio-temporal distribution of O. bartramii in different periods significantly, which has positive implications for the sustainable development of O. bartramii in the Northwest Pacific Ocean.
Variation of fishing ground gravity of tuna free-swimming school caught by purse seiner in Western and Central Pacific Ocean and its relationship with Southern Oscillation Index
Peng LI, Liuxiong XU, Cheng ZHOU, Xuefang WANG, Hao TANG, Wei LIU
2020, 16(2): 70-76.   doi: 10.12131/20190158
[Abstract](2255) [FullText HTML](1339) [PDF 1033KB](15)
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Based on the data of fishing positon, fishing date and catch of free-swimming school from the logbooks of Chinese tuna purse seine fishing fleet operating on the Western and Central Pacific Ocean during 2013 and 2017, we analyzed the relationship between monthly and yearly variation of fishing grounds gravity of free-swimming school and the South Oscillation Index (SOI) obtained from the US Climate Analysis Center. The results show that more catch was found in the fishing areas with sea surface temperature (SST) above 29.5 ℃. The fishing ground gravity was mainly distributed between 160°E and 175°W. The gravity center had an eastward tendency from 2013 to 2015 without evident monthly variation. The "warm pool" and the gravity center of the Western and Central Pacific Ocean moved towards the west when SOI was positive, while the gravity center moved eastwards when SOI was negative. Correlation analysis shows a significant negative correlation between SOI and fishing ground gravity (the correlation coefficient was −0.27, P<0.05), indicating that there was a close relationship between the change of fishing ground gravity center and climate change. The study helps understand the variation law of fishing ground of tuna purse seine fishery in the Western and Central Pacific Ocean.
Application of grey topological prediction model in water quality prediction of artificial reef area in Haizhou Bay
Yuxin SHEN, Shuo ZHANG, Lizhen WU, Jikun LU, Guanghui FU
2020, 16(2): 77-86.   doi: 10.12131/20190171
[Abstract](1478) [FullText HTML](731) [PDF 829KB](0)
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In this study, we applied residual modified GM (1,1) model and grey topological prediction method to establish water quality prediction models based on the monitoring data of dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and dissolved inorganic nitrogen (DIN) of the artificial reef area in Haizhou Bay in spring (May) and autumn (October) of 2007−2017. Then we selected the model with higher accuracy to predict the variation trend of water concentration during 2018−2022. Finally, we verified the forecast results with the meaured data of 2018. The results indicate that the grey topological model has better prediction accuracy for water quality data than the residual correction GM (1,1). The predicted results are consistent with the actual values in 2018, so the model is reliable. According to the prediction results, the DO and COD can maintain good values in 2018−2022. It is shown that the construction of artificial reef has a certain restoration effect on the water environment of the sea area, but BOD5 and DIN have a risk of exceeding the standard; and improvement of grey topology model should be further explored.
Hydrodynamic performance and around flow field of biplane-type otter board with different working positions
Zhiqiang LIU, Liuxiong XU, Hao TANG, Fuxiang HU, Cheng ZHOU
2020, 16(2): 87-98.   doi: 10.12131/20190221
[Abstract](757) [FullText HTML](360) [PDF 1673KB](10)
Abstract:
Otter board, an important accessory for net expansion in the single trawl, whose stability directly determines the degree of expansion of the trawl mouth and affects the catch efficiency and economic benefits. In this study, the hydrodynamic performance of the biplane-type was investigated by using the flume tank experiment and numerical simulation (Computational fluid dynamics, CFD) at different heel angles (inward, outward and tilt) and angles of attack, and the flow field and surface pressure around otter board was visualized. The results show: 1) At heel angle of 0° and angle of attack of 25°, both the lift coefficients of otter board for flume tank experiment and numerical simulation reached the maximum values (1.69 and 1.88, respectively), while both drag coefficients decreased with increasing heel angle. 2) Both the lift-to-drag ratios of model experiment and numerical simulation decreased with the increase of heel angle, and both reached the maximum values (3.27 and 3.69, respectively) when the heel inward angle was 5°. 3) The pressure center coefficient (Cpb) almost maintained stable with the change of heel angle; Cpc increased and decreased with increasing heel angle when the otter board was set to forward and backward tilting states, respectively. 4) CFD results show that the vortex at the rear of the center surface of otter board decreased with increasing heel angle. When the otter board was in inward and outward inclination states, the front end flow velocity reduction zone increased with increasing heel angle gradually. The pressure center moved toward the end chord of otter board as the heel angle increased in forward tilting state, but moved toward the lower end chord in backward tilting state. The results can provide scientific references for the studies on the stability of otter board and adjustion of fishing strategy.
Extraction and antioxidant activity of protein from Grateloupia livida
Miaomiao CAI, Shengjun CHEN, Xianqing YANG, Haixia MA, Jianchao DENG, Chunsheng LI, Xiao HU, Bo QI
2020, 16(2): 99-106.   doi: 10.12131/20190232
[Abstract](1487) [FullText HTML](787) [PDF 721KB](8)
Abstract:
With Grateloupia livida as the raw material and protein extraction rate as the index, we explored the effect of different wall-breaking techniques on their protein extraction, and optimized the ultrasonic-assisted water extraction by single-factor analysis and orthogonal test. The antioxidant activity of the crude protein that was purified by ammonium sulfate salting-out was evaluated. Results show that the highest protein extraction rate of the swelling method, freeze-thawing method and bead milling method was (29.66±0.86) %, (24.52±0.04) % and (26.52±0.79) %, respectively, all lower than those of ultrasonic-assisted water extraction method. The best optimal conditions of extracting protein from Grateloupia livida by ultrasonic assisted water extraction (the protein extraction rate could reach 58.16%) are as follows: liquid-to-solid ratio of 160 mL·g−1, total ultrasonic time of 60 min, ultrasonic power of 1440 W and pH of 6.0. The crude protein had strong antioxidant activity at the concentration of 1−8 mg·mL−1 (its reducing power at 8 mg·mL−1 was 0.43±0.01), and the IC50 of DPPH free radicals and ABTS free radicals are 4.00 mg·mL−1 and 3.96 mg·mL−1, respectively.
Anti-hepatic injury effect of enzymatic hydrolysate from soft tissue of Pinctada martensii
Jiajia ZHONG, Chaohua ZHANG, Jialong GAO, Xiaoming QIN, Wenhong CAO, Huina ZHENG, Haisheng LIN
2020, 16(2): 107-114.   doi: 10.12131/20190239
[Abstract](449) [FullText HTML](285) [PDF 818KB](8)
Abstract:
In order to analyze the anti-hepatic injury effect of enzymatic hydrolysate from Pinctada martensii (EP), we seperated EP by membrane ultrafiltration into three molecular size fractions [MW> 10 kD (EP-Ⅰ), MW=3–10 kD (EP-Ⅱ) and MW < 3 kD (EP-Ⅲ)], and then measured the effects of three ultrafiltration fractions on the anti-ALD in vitro and liver-protection on mice. The results of experiments in vitro show that EP-III could activate alcohol dehydrogenase (ADH) significantly (P<0.01), and three fractions demonstrated different antioxidant capacities (EP-Ⅲ>EP-Ⅱ>EP-Ⅰ). The results of mice experiment show that compared with the alcohol model group, the activities of ALT and AST in serum, liver index, the levels of MDA and TG in liver decreased in each ultrafiltration fraction group significantly, while the activities of SOD, ADH and ALDH and the levels of GSH in liver increased significantly. Therefore, the ultrafiltration fractions of enzymatic hydrolysate from soft tissue of P. martensii showed good protective effect on alcoholic liver damage, and the effect of EP-Ⅲ with low molecular mass was the best. Its mechanism may be related to accelerating ethanol metabolism and slowing down the oxidative damage caused by ethanol.
Effects of dietary microalgae on growth and survival of larval development of sea urchin (Anthocidaris crassispina)
Shigai XI, Chuanxin QIN, Zhenhua MA, Gang YU, Jinhui SUN, Wanni PAN, Tao ZUO, Hongmei MA, Wentao ZHU
2020, 16(2): 115-120.   doi: 10.12131/20190209
[Abstract](1665) [FullText HTML](924) [PDF 1185KB](10)
Abstract:
To investigate the growth and survival of sea urchin (Anthocidaris crassispina) larvae, we fed six microalgal diets [Dicrateria zhanjiangensis, Chaetoceros gracilis, Pavlova viridis, Platymonas subcordiformis, Chlorella vulgaris, and mixture of C. gracilis and D. zhanjiangensis (1∶1)]. The results show that different diets had different effects on the growth and development of the planktonic larvae of sea urchin. D. zhanjiangensis was the optimal microalgal diet. C. gracilis was the second, and then were P. viridis, C. vulgari, and mixture of C. gracilis and D. zhanjiangensis. However, P. subcordiformis was not suitable to be used as the opening bait for sea urchin larvae rearing. In terms of baits, D. zhanjiangensis was the best, since the survival rate of the larvae could reach (23.12 ±1.8)%, significantly higher than those of other unicellular algae (P<0.05). In terms of growth rate, mixture of C. gracilis and D. zhanjiangensis was the best, since the average length of the larvae could reach (885.25±30.49) μm, significantly higher than those of the other five treatments (P<0.05). The growth of the larvae fed with P. viridis was slow at early stage with body length of (337.98±24.56) μm, but it grew faster than the other unicellular algae at later stage with body length of (580±32.95) μm, so P. viridis is the suitable bait for planktonic larvae of A. crassispina at later stage.
Research progress of mechanical property of tuna longline gear
Liming SONG, Yiting LI
2020, 16(2): 121-127.   doi: 10.12131/20190183
[Abstract](2337) [FullText HTML](1378) [PDF 494KB](10)
Abstract:
The mechanical property of longline gear affects fishing efficiency and energy consumption directly. The paper summarizes relevant research methods and progress on the mechanical property of tuna longline gear, including the initial measurement at sea, the model test in the flume tank, and the numerical simulation. Results show that: 1) the theoretical analysis of mechanical property of longline gear have developed from static analysis to dynamic analysis; 2) the model test of longline could only be carried out on a small scale in order to verify the accuracy of numerical simulation analysis under specific circumstances; 3) the perpendicular drag coefficient (CN90) and inertia coefficient (Cm) were determined to be 1.12 and 3, respectively. It is suggested that the future studies on longline gear mechanical property should: 1) foucus on the effects of the stiffness and damping of fishing gear materials on the numerical simulation accuracy; 2) combine the behavioral characteristics of tuna to study the hydrodynamic force after hooking and take it into account in the model, so that the model can match the actual operation state; 3) further numerically simulate the interaction among the fishing gear, current, fishing boat, line hauler and catches.
Display Method:
Distribution of structure of macrobenthic communities in coastal waters of Jiangmen, Guangdong
Zilin CHEN, Chunhou LI, Yayuan XIAO, Yong LIU, Lin LIN, Jiujiang WANG, Qiumei QUAN
Latest Accepted  doi: 10.12131/20190248
[Abstract](154)
Abstract:
Based on the data collected from four-season investigations in Jiangmen coastal waters of the South China Sea in 2016, we examined the ecological characteristics and biodiversity of the macrobenthic community. A total of 56 species were identified, including 21 Mollusks, 18 Annelids, 7 Arthropods, 3 Echinoderms, 2 Nemerteans, 2 Coelenterates, 1 Sipunculan, 1 Chordate and 1 Echiuran. The density and biomass values varied from 10 to 920 ind·m−2 and from 0.2 to 267.7 g·m−2, respectively. The spatial distribution of density was generally higher in the waters outside the bay than inside. In the macrobenthos community, Pseudopolydora kempi and Aglaophamus sinersis were most widely distributed, and Aglaophamus sinersis was a the common dominant species that appeared in four seasons. The evaluation results of abundance and biomass comparison curve show that the overall stability of the community in this area is general, while the macrobenthic community in spring and autumn is moderately disturbed with poor community stability. The correlation analysis shows that the tempo-spatial differences of the macrobenthic community are mainly affected by water depth, salinity, temperature, phosphate, sediment type, predation pressure and so on.
Research on catchable size and resource protection of Squaliobarbus curriculus in Xijiang River Fengkai section based on length-frequency data
Shuli ZHU, Yuefei LI, Zhi WU, Jie LI, Yuguo XIA, Jiping YANG, Xinhui LI
Latest Accepted  doi: 10.12131/20190231
[Abstract](82)
Abstract:
We conducted an eight-month catch survey in 2014 and collected 526 individuals of Squaliobarbus curriculus. Based on the body length and mass data of these samples, we estimated the biological stock characteristics (growth and mortality parameters) and assessed the stock size and status of S. curriculus. The length-mass relationship was fitted by a power function (a=0.028 8, b=2.858 2). The von Bertalanffy growth parameters were estimated: the asymptotic length Linf was 74 cm; the growth coefficient K was 0.1; the natural mortality coefficient M was 0.19; the total mortality coefficient Z was 1.51; the fishing mortality rate was as 1.32; the exploitation rate was 0.88. In 2014, the size of the stock in numbers and biomass were 2 234 652 individuals and 428.558 t, respectively. Results of the Yield per recruit modeling shows that the current length at first capture was 12.3 cm; the fishing mortality rate was 1.32; the current yield per recruit was 1.89 g. The length at first capture was 27.8 cm; the fishing mortality rate was 0.45; the yield per recruit was 7.76. The current stock of S. curriculus is over-exploited. We suggest that the length at first capture should be 27.8 cm, and the fishing mortality rate should be 0.45.
Effects of anesthetic MS-222 and eugenol on oxygen consumption rate and ammonia excretion rate of Sinogastromyzon szechuanensis
Xiaojiang CHEN, Liling XIONG, Jiangu WU, Lu QI, Quan WANG
Latest Accepted  doi: 10.12131/20190261
[Abstract](87)
Abstract:
In order to improve the survival rate of Sinogastromyzon szechuanensis in the process of production, breeding and transportation, we measured the anaesthetic effects of MS-222 and eugenol at different mass concentrations on S. szechuanensis with body mass of (2.029±0.26) g at water temperature of (18±0.5) ℃ by the method of closed respirometry, and explored the effects of MS-222 and eugenol on oxygen consumption rate, ammonia excretion rate and oxygen nitrogen ratio (O/N). The results show that when the mass concentration of MS-222 and eugenol reached 1.5 mg·L−1 and 24 mg·L−1 respectively, it could reduce the oxygen consumption rate and ammonia excretion rate significantly (P<0.05). With the increase of mass concentration of MS-222, the oxygen consumption rate and ammonia excretion rate continued to decrease. With the increase of mass concentration of eugenol, the oxygen consumption rate and ammonia excretion rate of the S. szechuanensis first increased and then decreased. Under the stress of two kinds of anesthetics, the oxygen consumption rate, ammonia excretion rate and oxygen-nitrogen ratio of S. szechuanensis increased with increasing water temperature at water temperature of 14–26 ℃ (P<0.01). The oxygen-nitrogen ratio was 8.0~19.4. In conclusion, the MS-222 with a mass concentration of 1.5 mg·L−1 or eugenol with a mass concentration of 24 mg·L−1, which make S. szechuanensis enter the stage of anaesthesia II (sedation), can be recommended as the anesthetic dosage for the transportation of live fish, and low temperature is appropriate.
Study on respiratory metabolism changes of juvenile Penaeus monodon after exercise of exhaustion
Zicong CHEN, Pimao CHEN, Huarong YUAN, Xue FENG, Fei TONG, Haoming ZHANG
Latest Accepted  doi: 10.12131/20200017
[Abstract](122)
Abstract:
In order to provide scientific basis for the breeding and releasing of Penaeus monodon, we investigated the respiratory metabolic recovery of the juveniles after exhaustion exercise. With different recovery times after exhaustive exercise, there were significant changes in the total protein content (TP) and lactic acid (LA) concentrations as well as the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase(LDH) and succinate dehydrogenase (SDH) in the hepatopancreas of the juveniles (P<0.05). There was significant difference in the LA concentration and LDH activity in abdominal muscles. The TP concentration in hepatopancreas was significantly higher than that of the control group after 4 h of exhaustive exercise, and returned to the control level at 48th hour. The LA concentration of hepatopancreas reached the maximum value at 12th hour, significantly higher than that of the control group, and returned to the control level at 24th hour. The activities of AST, LDH, SDH and ALT in hepatopancreas increased significantly during the 8th to 12th hour, peaked at 12th hour, significantly higher than those of the control group, and returned to the control level at 48th hour. The glycogen concentration (GLY) in the muscle decreased significantly after exhaustive exercise and returned to the control level at the 12th hour. The LA concentration increased significantly after exhaustive exercise and decreased to the control level at 8th hour. The LDH activity increased significantly after exhaustive exercise, and continued to increase during 1st to 12th hour, and remained significantly higher than that of the control group at 72th hour. The anaerobic metabolism of the juveniles was significantly enhanced after exhaustive exercise, and exhaustive exercise could be performed again after 8 h; heaptopancreas was the place where the juveniles cleared metabolites, and began to deal with internal environment imbalance after exercise.
Effects of vertical distribution and soaking time of tuna longline fishing hooks on catches in North Pacific
Yingchao DANG, Xiaojie DAI, Feng WU
Latest Accepted  doi: 10.12131/20190252
[Abstract](139)
Abstract:
We investigated the relationship between vertical distribution and soaking time of hooks and catches collected in the North Pacific (150°W−164°W, 30°N−37°N) from September to December 2018 by the Chinese Longline Fisheries Observer Programme. The results show that the depth ranges of 11 main species were different. The species with the shallowest and deepest depths were Katsuwonus pelamis and Prionace glauca, respectively. Except for Prionace glauca and Alepisaurus ferox, the mean depth and depth distributions of bycatch species were significantly different from those of the targeted Thunnus obesus. With the increase of soaking time, the total catch rate firstly increased and then decreased. Besides, it was higher in 10~14 h, which reached the maximum value at 10th hour [1.44 ind·(1 000 hooks·h)−1]. The catch rate of bigeye tuna was higher in 10~16 h, which reached the maximum value at 11th hour [0.45 ind·(1 000 hooks·h)−1]. The results provides references for the fishing strategy and catch per unit effort (CPUE) standardization as well as formulating effective management measures to reduce the bycatch species.
Status of shrimp peeling and pretreatment technology for facilitating peeling
Shuxian HAO, Xiaojie YANG, Hui HUANG, Laihao LI, Chuang PAN, Xianqing YANG, Jianwei CEN
Latest Accepted  doi: 10.12131/20190229
[Abstract](291)
Abstract:
Rapid peeling is a key technology in deep processing of shrimps, but it is a harsh problem that has restricted the industrialization of shrimp processing industry. This paper reviews the status of shrimp peeling industry and the characteristics of tight connection in shell-meat, discusses the application and the potential utilization of traditional pre-treatment methods and novel high-tech as HP (High pressure), ultrasound, enzyme treatment and microwave in shrimps peeling. Furthermore, we propose the future trends of shrimp peeling industry,. which provides references for solving the bottleneck problem of shrimp shelling and improving the technical level of shrimp processing industry.
A preliminary study on identification of age of Portunus trituberculatus by gastric mill
Chenxing WANG, Zhenyu NI, Bilin LIU, Jian ZHANG
Latest Accepted  doi: 10.12131/20190258
[Abstract](269)
Abstract:
Portunus trituberculatus is an important economic species in China, and age identification is beneficial to its population resources assessment and management. We discussed the feasibility of gastric mill age identification by gastric mill of P. trituberculatus. The gastric mill was composed of five parts (propyloric ossicle, explyloric ossicle, urocardiac ossicle, zygocardiac ossicle and pterocardiac ossicle). According to the results of previous studies, we selected the explyloric ossicle and urocardiac ossicle for section observation. The results show that the gastric mill microstructure of P. trituberculatus consisted of four parts: wax layer, exocuticle, calcified layer and membranous layer. The growth lines that can be used for research mainly existed in endocuticle. We used seven growth equations to fit the relationship between biological data and the number of growth lines of gastric mill. Combining with AIC method, it is concluded that there are a linear function relation between carapace length and carapace width and a power function relation between carapace width and body mass; the relationship between body mass and the number of growth lines in the gastric mill is applicable to the Gompertz growth model, while the relationship between carapace length, carapace width and the number of growth lines in the gastric mill is more applicable to the v-B growth model. Thus, the growth lines of gastric mill can be used as the material for Crustacean age identification. However, due to the fact that the samples tend to be miniaturized, the time span needs to be extended for further verification.