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Relationship of hepatopancreas colours with lipid and mineral contents in cultured grass carp during winter
Chunhong HUANG, Jiali LI, Yanju LEI, Zhongguo XIE
Third Proofread  doi: 10.12131/20190073
[Abstract](862) [FullText HTML](423)
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To clarify the relationship between hepatopancreas colours and lipid and mineral contents of grass carp (Ctenopharyngodon idella), we analyzed the moisture, total lipid and minerals contents of hepatopancreas with different colours during winter. Results show that the average moisture and lipid contents in kermesinus, spot, white and yellow hepatopancreas were 77.78%, 70.98%, 67.91%, 64.01% and 2.06%, 2.85%, 4.24%, 5.28%, respectively, which were significantly different (P<0.05). Compared with kermesinus hepatopancreas, the Ca, Cr, Zn and Se contents in spot, white and yellow hepatopancreas all increased significantly (P<0.05). Cu and As contents in spot hepatopancreas, and Mg, Fe, Cu contents in white hepatopancreas were lower than those in kermesinus hepatopancreas. However, all the detected minerals in yellow hepatopancreas were higher than those in kermesinus hepatopancreas. Briefly, there was less lipid in hepatopancreas of grass carp during winter, but when the hepatopancreas colours changed from kermesinus to spot, white and yellow, the moisture contents gradually decreased but the lipid gradually increased. Compared with kermesinus hepatopancreas that had lower lipid content, the contents of Ca, Cr, Zn and Se in hepatopancreas with the other colours which had higher lipid contents significantly increased (P<0.05).
Calcium ion binding ability of tilapia skin hydrolysate and its antioxidant activity
Ruijie LI, Xiao HU, Laihao LI, Xianqing YANG, Shengjun CHEN, Yanyan WU, Wanling LIN, Hui RONG
Third Proofread  doi: 10.12131/20190102
[Abstract](895) [FullText HTML](434)
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By digesting tilapia (Oreochromis mossambicus) skin with neutral protease, Protamex1.5L and alkaline protease, we studied the binding ability of different enzymatic products to calcium ions (Ca2+), compared the antioxidant capacity of enzymatic hydrolysates and their combinations, and analyzed the Fourier infrared spectrum of the conjugate. The results show that the enzymatic hydrolysate of Protamex1.5L hydrolyzed tilapia skin had the highest calcium ion binding rate of 87.79%. All the three tilapia skins hydrolysates had antibacterial properties, and the DPPH free radical scavenging rate, OH radical scavenging rate and reducing power of the products of Protamex1.5L enzymatically tilapia skin were 51.46%, 17.26% and 0.09, respectively. After the tilapia skin hydrolysate (TSH) was combined with calcium ions, the DPPH free radical scavenging rate and hydroxyl radical scavenging rate of calcium ion chelate (TSH-Ca) decreased, but the reducing power was enhanced. Fourier transform infrared spectroscopy reveals that calcium ion had combined with amino nitrogen atom and carbonyl oxygen atom in TSH.
Comparation of nutritional composition of Pyropia haitanensis from different sea areas of China
Shaoling YANG, Bo QI, Xianqing YANG, Wanling LIN, Jianchao DENG, Yanyan WU, Haixia MA, Hui RONG
Third Proofread  doi: 10.12131/20190066
[Abstract](996) [FullText HTML](451)
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We compared the nutritional composition of Pyropia haitanensis from six breeding sea areas in China. The results show that the moisture content of P. haitanensis was 9.68%−12.31%, and the moisture contents of sun-dried samples in Guangdong were significantly higher than those of the machine-dried samples in the other areas (P<0.05). The contents of crude fat were all lower than 0.5% (dry mass, same as below). The ash contents ranged from 7.85% to 9.55% (Xiapu highest, Dongshan lowest). The contents of protein were 33.40%‒36.38% (Xiapu highest, Laiwu lowest). The contents of total amino acids and essential amino acids were 30.15%‒32.41% and 11.52%‒12.27%, respectively, both relatively high. However, the nutritional value score, chemical score and essential amino acid index of P. haitanensis from all the areas were all low. The essential amino acid index of Dongshan samples was the highest. Methionine+cysteine was the first limiting amino acid of P. haitanensis. The mineral elements contents were rich in P. haitanensis and varied greatly from area to area. The contents of K, Ca, Fe, Zn, Cu, Co and V in Xiapu samples, the contents of Na and Se in Nan'ao samples, the Mg content in Dongshan and Mn content in Wenzhou were the highest.
Optimization of multi-enzymatic extraction of polysaccharide from Gelidium amansii by response surface methodology
Ruonan PEI, Honglei ZHAI, Bo QI, Xianqing YANG
Third Proofread  doi: 10.12131/20190081
[Abstract](959) [FullText HTML](440)
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To optimize the multi-enzymatic extraction process of polysaccharides from Gelidium amansii, we designed a three-factor and three-level Box-Benhnken center-united experiment based on single factor test, and conducted a regression analysis. The optimum technological parameters of enzymatic extraction of G. amansii polysaccharide were: enzymes addition 2.30%, enzymatic hydrolysis temperature 60.43 ℃, ratio of material to water 1∶32 (g·mL−1). The extraction yield of polysaccharide was up to 15.98% after 120 min of enzymatic hydrolysis under these conditions.
Effect of precooling before slaughter on quality of Micropterus salmoides during ice storage
Ya WEI, Hui HUANG, Laihao LI, Xianqing YANG, Honglei ZHAI, Wanling LIN, Shuxian HAO
Third Proofread  doi: 10.12131/20190003
[Abstract](902) [FullText HTML](447)
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In order to investigate the effect of precooling before slaughter on the quality of fish fillets during ice storage, we treated fresh Micropterus salmoides at different precooling temperatures (15 ℃, 10 ℃ and 5 ℃) for 0.5 h, and then killed and preserved them in ice. The physicochemical (pH, TVB-N, K value and TBA value) and microbial (TVC) indices were measured on 0th, 3rd, 6th, 9th, 12th, 15th, 18th and 21st day, respectively. The results indicate that precooling treatment at 15 ℃ could better retain the quality of M. salmoides during ice storage and stabilize the sensory quality of its muscle. Besides, it could inhibit the growth of bacteria and the increase of TVB-N, K value and TBA value. The precooling extended the shelf life of M. salmoides fillets up to 3 d during ice storage comparing with the control group.
Preparation and immunogenicity of Lactococcus lactis vaccine expressing Sip-Pgk fusion protein of Streptococcus agalactiae isolated from tilapia
Yumei YUAN, Cunbin SHI, Jiafa TAO, Defeng ZHANG, Chengwen SUN, Hua GONG, Zhibin HUANG, Yingtiao LAI
Third Proofread  doi: 10.12131/20190092
[Abstract](607) [FullText HTML](435)
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In order to develop a more effective Oreochromis sp. oral vaccine of Streptococcus agalactiae, we constructed a recombinant plasmid pNZ8148-sip-pgk which expressesd Sip-Pgk fusion protein of S. agalactiae by using homologous recombination, and Lactococcus lactis NZ9000 pNZ8148-sip-pgk was obtained by electrotransformation of L. lactis NZ9000. The Sip-Pgk fusion protein was induced by nisin and tested by Western blot so that a Sip-Pgk fusion protein Lactobacillus oral vaccine was prepared. The tilapia was vaccinated orally by gavage with recombinant L. lactis NZ9000 pNZ8148-sip-pgk for twice or three times. ELISA was used to detect the level of serum antibody after immunization, and the relative immune protection rate was obtained by intraperitoneal injection of S. agalactis on the 18th day after immunization. The results show that the inducible protein size of the constructed recombinant Lactobacillus was 92 kD, which was consistent with the size of the target protein. Compared with the second immunization, the third immunization with the fusion protein Lactobacillus vaccine could significantly improve the serum antibody level of tilapia and the immune protection against S. agalactiae. The serum level of Lactobacillus vaccine immunized with three times Sip-Pgk fusion protein was significantly higher than that of single protein group and PBS group, with the highest relative immune protection rate of 45.56%.
Molecular characterization and expression pattern analysis of a defensin (HdDef1) from small abalone (Haliotis diversicolor)
Tuo YAO, Jie LU, Lingtong YE, Huasheng CHEN, Jiangyong WANG
Third Proofread  doi: 10.12131/20190045
[Abstract](649) [FullText HTML](349)
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Defensin is one of the most important antimicrobial peptides (AMPs) that participates in invertebrate innate immunity against invading pathogens. In the present study, a novel defensin was identified in small Haliotis diversicolor (denoted as HdDef1) using RNA-seq and RACE techniques. The HdDef1 cDNA contained a 201 bp open reading frame (ORF) encoding 66 amino acids including a signal peptide of 18 amino acids and a mature peptide of 48 amino acids. The mature peptide of HdDef1 shared common features of AMPs, such as lower molecular mass, net positive charge (+1) and high hydrophobic residue ratio (45%). In addition, six cysteines in the mature peptide were arranged in the pattern of C-X16-C-X3-C-X9-C-X4-C-X1-C and stabilized the α-helix/β-sheet motif (CSαβ) with three disulfide bonds (C1-C4, C2-C5 and C3-C6) in the predicted tertiary structure. Moreover, by comparision with the similar three-dimensional structure of Anopheles gambiae defensin and phylogenetic analysis, it is suggested that HdDef1 might be a new member of the arthropod defensin family. Quantitative real-time PCR analysis reveals that HdDef1 transcripts were expressed constitutively in intestine, head, gill, hepatopancreas, mantle and foot, with the highest level in hepatopancreas. After being challenged with Vibrio harveyi, HdDef1 transcripts were induced significantly in hepatopancreas. The results indicate that HdDef1 might have an important function in host defense against invasive pathogenic bacteria, but its antimicrobial activity at protein level needs further study.
Population genetic structure of brushtooth lizardfish (Saurida undosquamis) based on mitochondrial cytochrome b gene sequences
Min LI, Zirong HUANG, Youwei XU, Zuozhi CHEN
Second Proofread  doi: 10.12131/20190123
[Abstract](655) [FullText HTML](366)
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We examined the population genetic structure of brushtooth lizardfish (Saurida undosquamis) from the coastal waters and continental shelf of China based on the complete cytochrome b gene sequences. A total of 142 haplotypes have been derived from 266 individuals at eight sampling sites. Genetic diversity analysis shows that the S. undosquamis samples were characterized by rather high haplotype diversity (0.925 1−0.992 9) and relatively low nucleotide diversity (0.003 145−0.003 852). Median joining network shows that the haplotypes were connected in a star-like manner with four dominant haplotypes without clades of samples corresponding to sampling localities. Analyses of molecular variance suggest that nearly all the genetic variation (99.79%) was from individuals within population rather than from the populations. The pairwise FST reveals no genetic differentiation among different populations. A high rate of gene flow between populations implies a panmixia for S. undosquamis among the sampling sites. Neutrality tests show significant deviation of population historical dynamics from stable population model, and mismatch distribution analysis indicates a late Pleistocene expansion in S. undosquamis. The expansion time was estimated to be 40−100 thousands years ago. The results reveal that S. undosquamis from the coastal waters and continental shelf of China belong to the same population and can be managed as a unit in fisheries.
Effect of dietary protein level on digestive enzyme activity and histological structure in intestine and liver of juvenile Schizopygopsis younghusbandi
Jian WANG, Benhe ZENG, Zhaoli XU, Bianbian ZHANG, Haiping LIU, Wanliang WANG, Jinlin WANG, Jianshe ZHOU, Liping HUANG
Second Proofread  doi: 10.12131/20190107
[Abstract](867) [FullText HTML](448)
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To explore the effects of different feed protein levels on the digestive enzyme activity and histological structure in the intestine and liver of juvenile Schizopygopsis younghusbandi, we designed six kinds of equal-energy experimental feeds with different protein levels (20%, 25%, 30%, 35%, 40%, 45%) to feed the juveniles with initial body mass of (22.42±0.56) g for 60 d. The results show that with the increase of feed protein level, the protease activity in intestine and liver increased first then declined. The protease activity in 35% protein group was significantly higher than that in the other groups (P<0.05). The lipase and amylase activities reduced significantly (P<0.05). The wall thickness and villus height of foregut, midgut and hindgut all increased and then decreased (P<0.05). The wall thickness of foregut and midgut were the highest in 30% group, while the wall thickness of the hindgut was the highest in the 35% group. The villus height of foregut, midgut and hindgut in 30% group were the highest. Feed protein level higher than 35% may damage liver tissue structure. Under this condition, considering the digestive enzymes activity and histological structure of intestines and liver, the optimum protein level of juvenile S. younghusbandi should be 30%.
Comparison of quality and volatile components among five brands of cod sausages
Fan YE, Kang CHEN, Meijie TAO, Simin LI, Yalun CAO, Zhiyuan DAI
Second Proofread  doi: 10.12131/20190120
[Abstract](643) [FullText HTML](361)
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Five brands of cod sausages were evaluated for their gel properties, fatty acid composition and volatile components. Their gel strengths were 3 394.39 g·mm, 3 109.18 g·mm, 2 790.72 g·mm, 3 204.49 g·mm, 3 742.91 g·mm, respectively, while the whiteness was 69.61, 66.63, 63.88, 76.46 and 76.78, respectively. A total of 17, 15, 22, 19 and 15 fatty acids were detected. The contents of oleic acid, linoleic acid and palmitic acid were relatively high, while the relative contents of polyunsaturated fatty acids were 17.87%, 26.42%, 16.92%, 59.56% and 59.27%, respectively. The total amount of EPA and DHA in Brand B was the highest (18.00%). A total of 83 volatile components were identified, including six aldehydes, five ketones, six acid-phenols, 25 hydrocarbons, eight alcohols, 22 esters and 11 other components. Acid-phenols were the most in Brand A (61.12%) but only 7.66% in Brand B. The relative content of esters in Brand B was higher than those of the other components, reaching 50.68%. The volatiles were mainly composed of acid-phenols and esters in Brand C. In Brand D and Brand E, esters were the most, reaching 43.12% and 38.48%, respectively.
Zooplankton community structure in Hailing Bay and its relationship with primary environmental factors
Yuyan GONG, Yayuan XIAO, Shannan XU, Yong LIU, Yutao YANG, Zirong HUANG, Chunhou LI
Third Proofread  doi: 10.12131/20180220
[Abstract](638) [FullText HTML](378)
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Based on the data obtained from four voyages in February (winter), July (summer), November (autumn) in 2015 and April (spring) in 2016, we investigated the structure of zooplankton community, including species composition, abundance, biomass, dominant species and species diversity in Hailing Bay. A total of 132 zooplankton species and 14 types of pelagic larvae were identified. The most dominant group of zooplankton was Copepoda (54 species). There was no similar dominant species between two adjacent seasons, indicating that the zooplankton community in Hailing Bay had obvious seasonal variation. Abundance and biomass of zooplankton were highest in winter but lowest in summer. Zooplankton abundance was greater in autumn and spring than in winter and summer except for Noctiluca scintillans. Both Shannon-Wiener diversity index (H′) and Pielou's evenness index (J′) were higher in autumn and summer than in winter and spring. N. scintillans appeared in winter and spring with mass propagation since the temperature was low, but disappeared in summer and autumn. Correlation analysis shows that there is a significant negative correlation between N. scintillans-dominated Protozoa and water temperature, indicating that water temperature is one of the main factors affecting the growth and reproduction of N. scintillans in Hailing Bay.
Economic and ecological benefits of annually two-cycle farming method of GIFT tilapia with in-pond raceway system
Qinglang YIN, Zhifang WANG, Zhongbao GUO, Pengfei BI, Yi ZHOU, Zhanyang TANG, Yongju LUO
Second Proofread  doi: 10.12131/20190085
[Abstract](635) [FullText HTML](331)
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To achieve an efficient utilization of pond aquaculture system and reduce the risk of cultivation, we investigated the annually two-cycle farming method of GIFT tilapia (Oreochromis niloticus) with in-pond raceway system. In the first breeding production, we kept the fish [(36.6±2.8) g] in two raceway for 122 d with the density of 183 ind·m−2 and 274 ind·m−2, respectively. In the second breeding production,we kept the fish [(185.2±15.8) g] in two raceway for 100 d with the densities of 154 ind·m−2 and 215 ind·m−2, respectively. Meanwhile, Macrobrachium rosenbergii, Hypophthalmichthys molitrix and Aristichthys nobilis were cultured around the pond. Then we evaluated the water quality, aquaculture results and breeding benefits in the aquaculture process. The results show that the survival rate of GIFT tilapia was 83.38%; the feed coefficient was 1.12; the aquaculture yield was 24 107 kg in the first breeding production. While in the second breeding production, the survival rate was 93.35%; the feed coefficient was 1.17; and the aquaculture yield was 25 730 kg. The yields of M. rosenbergii, H. molitrix and A. nobilis were 2 012 kg, 1 789 kg and 801 kg, respectively. For the breeding benefits, the average investment and income were 452 566 Yuan per square hectare and 655 099 Yuan per square hectare, respectively, with a profit of 202 533 Yuan per square hectare and a return rate of investment of 44.75%. It is indicated that the annually two-cycle farming method with in-pond raceway system is effective for GIFT tilapia breeding, which can reduce the incidence of Streptococcus and improve the breeding efficient utilization.
Correlation and path analysis of quantitative traits of clam (Callista erycina)
Haijun WEI, Zhenghua DENG, Mingqiang CHEN, Jijin WANG, Youning LI, Yu WANG
Second Proofread  doi: 10.12131/20190126
[Abstract](659) [FullText HTML](377)
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In order to study the relationship between morphological traits and body mass, 477 clams (Callista erycina) were randomly selected form Beihai, Guangxi Province to measure their shell length, shell height, shell width, anterior length, posterior length, number of growth lines and body mass by correlation analysis, path analysis and multiple stepwise regression analysis. The results show that there was extremely significant correlation among all the phenotypic traits (P<0.01), among which the correlation coefficient of shell length and anterior length was the highest (0.886), and that of posterior length and stripe number was the lowest (0.180). The correlation coefficient of body mass with shell width was the highest (0.865), and that of body mass with posterior length was the lowest (0.474). We established a regression equation of morphological traits for body mass (R2=0.812). The shell width influenced the body mass most with a path coefficient of 0.665, followed by the shell length (0.154) and shell height (0.117). The anterior length had the greatest indirect effect on the body mass (0.586), followed by shell height (0.580) and shell length (0.504). The shell width was the most important determinant of body mass.(0.442), followed by the shell length (0.024). The results suggest that breeding of C. erycina with body mass as breeding objective should mainly select shell width, and the synergistic breeding of anterior length and shell height should be strengthened at the same time.
Comparative study on credibility of fishing information of electronic fishing logs of trawlers and fishing information acquired by Beidou position data
Fei FENG, Yanbo ZHOU, Sen CHEN, Enge XIE, Qia'er WU
Second Proofread  doi: 10.12131/20190110
[Abstract](405) [FullText HTML](265)
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To analyze the accuracy and credibility of electronic fishing log data, we extracted and analyzed the fishing time, hauls and fishing area of five trawlers ('Yuexinhui fishing 01282', 'Yuexinhui fishing 01240', 'Yuexinhui fishing 01286', 'Yuexinhui fishing 01239', 'Yuemaobin fishing 47239', 'Yuexinhui fishing 02163', 'Yuemaobin fishing 42278', 'Yuexinhui fishing 00070' and 'Yuexinhui fishing 01268') from August 17, 2018 to April 30, 2019 by Beidou position data, and then ccompared them with relevant information of electronic fishing logs data. The repetition rates of five trawlers extracted from the electronic fishing logs data and Beidou position data were 36.7%, 64.8%, 71.4%, 81.5%, 24.7%, 46.7%, 66.7%, 79.6% and 68.9%, respectively. The repetition rates of fishing areas were 80%, 86.9%, 65.7%, 74.7%, 75.3%, 85.6%, 71.6%, 56.9% and 65.2%, respectively. The repetition rate of fishing hauls were 65%, 86.4%, 60%, 70%, 75.3%, 67.1%, 54.4%, 62.1% and 35.4%, respectively. The correlation analysis between fishing time and catches shows that the fishing time of 'Yuexinhui fishing 01282', 'Yuexinhui fishing 01240', 'Yuexinhui fishing 01239' and 'Yuemaobin fishing 47239' correlated with catches very significantly (P<0.01); the fishing time of 'Yuemaobin fishing 42278' correlated with catches significantly (P<0.05); the fishing time of 'Yuexinhui fishing 01282', 'Yuexinhui fishing 01286', 'Yuexinhui fishing 00070' and 'Yuexinhui fishing 01268' had no significant correlation with catches (P>0.05), which reflects that the accuracy and feasibility of electronic fishing logs data still need to be improved.
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2019, 15(5).  
[Abstract](570) [PDF 1941KB](15)
Abstract:
Assessment of allowable catches and exploitation state of marine fishery resources in Pakistani coastal waters
Kui ZHANG, Ping GENG, Dengfu SHI, Youwei XU, Panhwar SHER KHAN, Zuozhi CHEN
2019, 15(5): 1-8.   doi: 10.12131/20190065
[Abstract](1627) [FullText HTML](539) [PDF 1561KB](38)
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According to the catch statistics data during 1950−2015, we applied a Catch-MSY model to estimate the allowable catches and maximum sustainable yields (MSYs) for 24 commercial fish groups and total allowable catch (TAC) in Pakistani coastal waters. Results show that MSY and TAC in Pakistani coastal waters were 40.53×104 t and 36.47×104 t, respectively. The total catches in 2015 were less than MSY, suggesting that the fisheries are not overfished. The MSY results show that eight fish groups (cobia, Barracudas, Groupers, Butterfishes, common dolphinfish, dorab wolf-herring, crevalle jack and largehead hairtail) have been overfished at present since the catches in 2015 exceeded MSY. At present, the marine fishery resources in Pakistani coastal waters are fully exploited. Most commercial fish groups are overfished or recovering after collapse and their development potential is relatively small. It is recommended to exploit oceanic fishery resources such as Sthenoteuthis oualaniensis in Arabian Sea in future fisheries development.
Study on carbon and nitrogen stable isotopes of main fishery species in typical gulf, southern China
Wenbo ZHANG, Honghui HUANG, Chunhou LI, Yong LIU, Zhanhui QI, Shannan XU, Huaxue LIU
2019, 15(5): 9-14.   doi: 10.12131/20180173
[Abstract](1268) [FullText HTML](513) [PDF 779KB](14)
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In order to understand the characteristics of trophic structure of main fishery in typical gulf of southern China with significant habitat difference, we analyzed the ratio of carbon and nitrogen stable isotopes (δ13C and δ15N) of major fishery species collected in Hailing Bay and Lingshui Bay in wet season of 2015, and calculated several quantitative metrics based on the δ13C and δ15N ratios so as to quantitatively characterize the trophic structure in community-wide aspect. The results show that the average δ13C [−15.36±0.62)‰] and δ15N [(15.53±0.94)‰] values of main fishery species in Hailing Bay were significantly higher than those in Lingshui Bay [(−17.44±1.21)‰ and (13.78±1.31)‰, P<0.01]. However, the NR and TA values of Hailing Bay were lower than those of Lingshui Bay, showing longer food chain length and higher diversity in Lingshui Bay. Calculated by 3.4‰ as a nutrient grade of nitrogen stabilized isotope enrichment, the grade distance of Lingshui Bay fishery was only 1.37, lower than 1 of Hailing Bay, indicating that both Lingshui Bay and Hailing Bay have relatively less high trophic organisms and the food webs are often disturbed.
Difference analysis of trace elements in statolith of Sthenoteuthis oualaniensis in South China Sea
Yu LIU, Xuehui WANG, Feiyan DU, Bilin LIU, Peng ZHANG, Mengna LIU, Yongsong QIU
2019, 15(5): 15-24.   doi: 10.12131/20190039
[Abstract](1404) [FullText HTML](507) [PDF 1359KB](39)
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Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to measure the concentration of trace elements in the otolith of the South China Sea squid (Sthenoteuthis oualaniensis). The composition of trace elements in the otolith and the change of the ratio of trace elements to calcium (Ca) were analyzed. The differences and the relationship between the otolith and habitat were discussed. The results show that the main trace elements are Ca, Sr, Na, Fe, Ba and Mn. Analysis of variance (ANOVA) reveals no significant difference between populations and genders (P>0.05). There was significant difference in the ratio of trace elements to calcium among different regions of statolith (P<0.01) except for Fe/Ca. The Sr/Ca ratio was the highest in the nucleus and then decreased. There was no significant difference in Sr/Ca ratios among different spawning groups and geographical regions (P>0.05). There was a positive relationship between Sr/Ca and temperature, and a negative relationship with salinity at the larval stage. Sr/Ca can be used as a good temperature indicator. Na/Ca first increased and then decreased, highest at the dark zone. Na/Ca is significantly different among different spawning populations at the nuclear and post nuclear zones (P<0.01). Mn/Ca and Ba/Ca, which first decreased and then increased (lowest in the dark region), increased at the edge zone and peripheral zone. There was a positive relationship between Ba/Ca and salinity at adult stage, and Ba/Ca can be used as an indicator of vertical movement. Fe/Ca was significantly different among different spawning populations and geographic areas (P<0.01). It is shown that Na/Ca and Fe/Ca are suitable for distinguish of different groups of squid, and Sr/Ca and Ba/Ca can be used to estimate the habitat environment of squids in the South China Sea.
Water quality evaluation of Pearl River Delta based on environmental factors and phytoplankton
Xin LI, Zini LAI, Wanling YANG, Chao WANG
2019, 15(5): 25-34.   doi: 10.12131/20190020
[Abstract](1531) [FullText HTML](542) [PDF 1045KB](20)
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In order to select asuitable method for water quality evaluation in the Pearl River Delta (PRD), we accessed and analyzed the water environment factors and phytoplankton data in PRD in 2015. Four phytoplankton indices, including Shannon index, evenness index, richness index and biomass index, were selected from six common phytoplankton indices based on similarities by using self-organizing map (SOM). Then, we compared the water quality evaluation results of the above indices and environmental factors. The results based on dissolved oxygen and ammonia nitrogen could reflect the spatial differences between city centers and other regions, but total nitrogen and total phosphorus were not suitable for water quality evaluation. However, the results based on Shannon and biomass indices could reflect the differences between city centers and other regions, but evenness and richness indices were not suitable for water quality evaluation. Except for total nitrogen and total phosphorus, the evaluation results of other environmental factors and four phytoplankton indices show that the water quality of the survey area was generally good, but the water quality of stations around the city was slightly poor. Thus, issolved oxygen, ammonia nitrogen, Shannon index and biomass index are suitable environmental factors and phytoplankton index for water quality evaluation.
Physiological response of Sargassum hemiphyllum to cadmium stress
Penghao YE, Tingting HAN, Guiquan FU, Yangguang GU, Honghui HUANG
2019, 15(5): 35-40.   doi: 10.12131/20190032
[Abstract](1501) [FullText HTML](480) [PDF 768KB](8)
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Sargassum hemiphyllum, a common species in coastal waters of Guangdong Province, was selected to study its physiological response to different concentrations of heavy metal (Cd2+) stress and its tolerance to Cd2+ stress in laboratory semi-static experiments, so as to provide a basis for remediation of heavy metal pollution in that area. The results show that chlorophyll a (Chl a), carotenoid (Car), soluble protein (SP), soluble sugar (SS) and antioxidant enzyme activity (SOD and CAT) of S. hemiphyllum at Cd2+ concentration of 0.1 mg∙L−1 had no significant difference with the control (P>0.05). The contents of Chl a, Car, SP, SS, SOD and CAT at ρ(Cd2+) of 0.5−12.5 mg∙L−1, were significantly higher than those of the control (P<0.05); there was no significant change in MDA contents under Cd2+ concentration of 0.1−0.5 mg∙L−1 (P>0.05), and significant increase at Cd2+ concentration of 2.5−12.5 mg∙L−1 (P<0.05). Therefore, S. hemiphyllum had stronger stress resistance at Cd2+ concentration of ≤0.5 mg∙L−1, while excessive Cd2+ stress of >0.5 mg∙L−1 will be harmful for its photosynthesis and antioxidant function.
Biological study of reproductive characteristics of Acanthopagrus schlegeli in Daya Bay
Defang CHEN, Teng WANG, Yong LIU, Yayuan XIAO, Jiujiang WANG, Chunhou LI
2019, 15(5): 41-47.   doi: 10.12131/20190051
[Abstract](1555) [FullText HTML](534) [PDF 1037KB](13)
Abstract:
We collected 721 individuals of Acanthopagrus schlegeli in Daya Bay in January, March, April, August−December, 2018, and then investigated the annual variation of reproductive characteristics of A. schlegeli in Daya Bay so as to provide a theoretical basis for its artificial breeding and conservation. The results show that: 1) the spawning period falls between November and March. The total length ranged 175−487 mm for females [averge (297.92±56.61) mm]. The body mass ranged 90.96−1 907.12 g for females [average (511.36±307.53) g]. The total length ranged 110−440 mm for males [average (237.61±61.05) mm]. The body mass ranged 21.92−1 370.00 g for males [average (277.76±210.33) g]. The full lengths of females were significantly longer than those of males (P<0.001). 2) The gonad maturity coefficient and gonad development indicate that the reproductive period of A. schlegeli in Daya Bay was from November to March. 3) The existence of androgynous individuals indicates that the species will undergo sexual reversal, and the males will mature first and then change to females. 4) The total lengths (TL) at 50% sex maturity for females and males were 248.52 mm and 148.03 mm, respectively. 5) A. schlegeli is a multiple spawner with indeterminate fecundity by oocyte size-frequency distributions. The number of the individual fertility ranged from 84 100 to 2 655 168 granules (average 728 732±499 547). The relative fertility of total length was 380.54−8 271.55 eggs·mm−1 [(2 731.44±1 630.93) egg·mm−1]. The relative fertility of body mass was 277.58−3 592.83 eggs·g−1 [average (1 443.87±766.82) eggs·g−1]. There was a linear correlation among absolute fecundity and total length, body mass and gonadal mass.
Investigation of Grateloupia on floating raft in Nan'ao, Shantou of Guangdong Province and Dongshan of Fujian Province
Bin FENG, Ting LI, Bo Zhang, Changbo ZHU, Jiaqi SU, Suwen CHEN, Xianqing YANG
2019, 15(5): 48-54.   doi: 10.12131/20190050
[Abstract](2057) [FullText HTML](791) [PDF 12442KB](16)
Abstract:
In order to promote the development and utilization of Grateloupia and provide reference for its food and processing, we investigated the species composition, biomass, growth environment and mouthfeel of Grateloupia on floating rafts in Nan'ao, Shantou, Guangdong Province and Dongshan, Fujian Province once a month from January to April 2018. The results show that the water velocity and temperature were 0.039−0.985 m·s–1 and 19−23 ℃, respectively, and the water velocity in Dongshan was greater than that in Nan'ao. By morphology, cross-section and rbcL sequence analyses of the samples collected from the floating raft, we found eight Grateloupia species (G.lanceolata, G. turuturu, G.taiwanensis, G.carnosa, G.livida, G. haimensis, G. prolongata and G. sparsa). The dominant species were G. lanceolata and G. turuturu whose highest biomass were 901.26 g·m–1 and 352.9 g·m–1, respectively. G. lanceolata that grew with higher water velocity had longer body length that could reach 142 cm. The mouthfeel of G. turuturu and G. prolongata was the worst but that of G. lanceolata and G. livida was the best. G. lanceolata and G. livida had better mouthfeel in January to March than in April. It is worth developing G. lanceolata as marine vegetable for its bigger biomass, size and its better mouthfeel.
Effects of two breeding methods on growth and bacterial structure of Nitzschia closterium f. minutissima
Yapeng TANG, Ruixuan WANG, Jianhua HUANG, Lishi YANG, Shigui JIANG, Heizhuo LIN, Guofu WANG
2019, 15(5): 55-62.   doi: 10.12131/20190011
[Abstract](1429) [FullText HTML](523) [PDF 1152KB](8)
Abstract:
We compared the density, pH, dissolved oxygen and colony structure of Nitzschia closterium f. minutissima bred in negative pressure photobioreactor and open bucket, respectively. It is shown that the algae grew fast in negative pressure photobioreactor with the highest density of 1.33×107 cells·mL–1, significantly higher than that in open bucket (8.36×106 cells·mL–1). The pH in algal solution increased with increase of algal density, and there was a significant positive correlation between them (P<0.01). The highest pH values in negative pressure photobioreactor and open bucket were 10.3 and 9.3, respectively. Oppositely, in negative pressure photobioreactor, the dissolve oxygen of algea decreased with increase of algal density, which finally stabilized at about 6.5 mg·L–1. The decline of dissolved oxygen might be related to the fact that Roseobacter had become the dominant bacteria. Results of 16S rDNA gene high-throughput sequencing show that the bacterial diversity decreased significantly (P<0.05). Proteobacteria and Bacteroidetes were dominant bacteria at early stage of breeding. However, the dominant bacteria were Cyanobacteria and Roseobacter at late stage in negative pressure photobioreactor, which was obviously different from that in open bucket.
Estimation of genetic parameters for ammonia nitrogen and freshwater tolerance traits in Penaeus monodon
Falin ZHOU, Qibing YANG, Jianghua HUANG, Shong JIANG, Lishi YANG, Tangsheng ZHANG, Shigui JIANG
2019, 15(5): 63-68.   doi: 10.12131/20190091
[Abstract](1385) [FullText HTML](506) [PDF 760KB](12)
Abstract:
Taking lethal time of high ammonia nitrogen and freshwater tolerance as indices, we estimated the heritability of ammonia nitrogen tolerance and freshwater tolerance of Penaeus monodon. We established 27 full-sib families including five half-sib families of P. monodon based on two breeding populations of P. monodon from Nanhai No.1 and African strain. Besides, we estimated the variance components and genetic parameters for ammonia nitrogen tolerance and freshwater tolerance by using one trait animal model and ASReml software. Then we calculated the estimated breeding values of all animals and families with best linear unbiased prediction. The heritability for ammonia nitrogen tolerance and freshwater tolerance were 0.11±0.04 and 0.29±0.08, respectively (P<0.05). The family phenotypic value correlation coefficients between ammonia nitrogen tolerance and freshwater tolerance was 0.15, showing low linear positive correlation and statistically insignificant difference. The family breeding value correlation coefficients between ammonia nitrogen tolerance and freshwater tolerance was 0.57, showing moderate linear positive correlation and statistically significant difference (P<0.01). Thus, the resistance to freshwater stress can also be improved to some extent with selection of characteristics of ammonia tolerance of P. monodon.
Effects of desiccation and resubmersion on oxidative stress response of crayfish (Procambarus clarkii)
Haifeng WANG, Yongxu CHENG, Jinghao LI, Yewen XI, Jiayao LI
2019, 15(5): 69-76.   doi: 10.12131/20190059
[Abstract](1518) [FullText HTML](514) [PDF 1073KB](13)
Abstract:
In order to study the effects of desiccation stress on crayfish (Procambarus clarkii) during crayfish seedling transportation, we investigated the antioxidant stress ability and survival rate of crayfish to desiccation stress (6 h, 12 h, 18 h, 24 h) and resubmersion in water (1 h, 6 h, 12 h) at (20±1) ℃ and with (50±5)% relative humidity (RH). The results show that the desiccation time should not exceed 18 h; the mortality rate at 24th hour was 53.3%, but no juveniles died during the resubmersion. During desiccation, no significant difference was observed in total antioxidant capacity (T-AOC, P>0.05); the superoxide dismutase (SOD) significantly reduced; the catalase (CAT) activity increased with time; the malondialdehyde (MDA) content reached the maximum value after 24 h (P<0.05), and the blood sugar and muscle lactic acid increased significantly with time (P<0.05). During the resubmersion period, the SOD and CAT activities fluctuated without an obvious rule; the MDA content restored to normal level after 12 h but the T-AOC maintained a high level. The lactate contents of 6 h and 12 h groups restored to the control level after resubmersion for 1 h. The blood sugar contents of all treatment groups were always higher than that of the control group (P<0.05). It is shown that the MDA content and SOD activity which can be regarded as immune indices are more sensitive to desiccation stress. The MDA, blood sugar and lactate contents can reflect the physiology of crayfish during resubmersion period.
Diet feeding, oxygen consumption rhythm and gastrointestinal evacuation time of Trachinotus ovatus
Xinyi SUN, Xiaolin HUANG, Zhong HUANG, Xiaocong CAO, Ting ZHOU, Heizhao LIN, Hu SHU, Wei YU, Yukai YANG, Tao LI
2019, 15(5): 77-83.   doi: 10.12131/20190072
[Abstract](1399) [FullText HTML](866) [PDF 883KB](10)
Abstract:
In order to determine a scientific feeding strategy for Trachinotus ovatus, we investigated the day and night diet feeding, oxygen consumption rhythm and gastrointestinal evacuation time of the fish in laboratory. The diet feeding rhythm was invstigated by a continuous feeding with fixed interval (feeding once every two hours day and night for three continuous days). The oxygen consumption rhythm was measured by flow-water breathing method (measuring once every two hours day and night for 24 h). The gastrointestinal evacuation time was measured by a full feeding method (sampling once every two hours day and night for a day). Results show that T. ovatus had a daytime feeding pattern with two extremely obvious feeding peaks (10:00 and 14:00−16:00, P<0.05), and the peak periods of oxygen consumption appeared at 08:00 and 16:00, respectively (P<0.05). The stomach digesta ratio of T. ovatus decreased sharply after feeding (P<0.05), nearly 50% at 7th hour, and reached to zero after 19 h. However, the bowel digesta ratio of T. ovatus increased sharply after 1−3 hours of feeding, and reached the maximum at 11th hour and the minimum at 21st hour. Thus, it is suggested that the optimal feeding periods of T. ovatus are 09:00−10:00 and 14:00−16:00 with strong light, oxygen consumption and peak feeding. The feeding frequency is 2−3 times per day and the feeding interval is 7−9 h.
Genetic diversity analysis of Sillago japonica based on mitochondrial DNA ND2 gene
Deyu ZHENG, Yijia GUO, Tianyan YANG, Tianxiang GAO, Yao ZHENG, Donghao YUAN, Shujin SI
2019, 15(5): 84-91.   doi: 10.12131/20190042
[Abstract](1484) [FullText HTML](507) [PDF 744KB](13)
Abstract:
A total of 119 individuals of Sillago japonica were collected from six sampling sites (Laizhou, Jiaonan, Zhoushan, Xiamen, Shantou and Beihai). The length of 450 bp NADH dehydrogenase subunit 2 (ND2) gene fragment was amplified and sequenced. No base insertion or deletion mutations occurred and 77 mutation sites were detected, including 30 parsimony informative sites and 28 singleton polymorphic sites. Sixty-one haplotypes were defined in 119 sequences. The average haplotype diversity (Hd) and nucleotide diversity (π) were 0.945 3±0.015 5 and 0.009 718±0.005 445, respectively. The average genetic distance among the six populations was 0.008 3, and the genetic differentiation index FST value was less than 0.05, indicating no significant genetic differentiation among the populations. Analysis of molecular variance (AMOVA) shows that genetic variation of S. japonica mainly resided among individuals within populations (99.96%). The neutral tests (Tajima's D and Fu's Fs) were both negative and deviated from the neutral significantly. Besides, the nucleotide mismatches distribution showed a unimodal distribution, indicating that S. japonica had experienced population expansion in history. The estimated expansion time was about 0.12−0.29 million years ago in late Pleistocene.
Effect of enzymatic hydrolysis from mantle of pearl oyster on skin wound healing
Faming YANG, Haisheng LIN, Xiaoming QIN, Chaohua ZHANG, Wenhong CAO, Jialong GAO
2019, 15(5): 92-98.   doi: 10.12131/20190079
[Abstract](1197) [FullText HTML](546) [PDF 1777KB](16)
Abstract:
In order to promote the high value utilization of pearl oyster (Pinctada martensii), we were determined explore the antibacterial activity and procoagulant activity of enzymatic hydrolysis from its mantle (EHM), and the effects of EHM on open wound healing of skin of mice. Results showed that EHM possessed of procoagulant activity in mice but had no antibacterial activity against 13 tested strains. Compared with the negative control group, the healing rate of wound of mice increased significantly after skin application with EHM for 6 d (P<0.05), but there was no significant difference with comparison with the positive control group (P>0.05). The healing rate was 100% on 14th day for the drug group, and the scar contraction rate was significantly higher than that of the negative control group (P<0.05). Biochemical indicators test indicated that EHM had significant inhibitation effect on inflammatory factor IL-6 (P<0.05); compared with the negative control group, it could promote IL-10 secretion in wound tissues significantly (P<0.05), but there was no significant difference in FGF-2 content in skin tissue of the drug groups (P>0.05), and EGF content in the positive control group was significantly higher than that in the other groups (P<0.05). Howerer, there was no significant difference in the contents of FGF-2 and EGF between the drug groups (P<0.05). In summary, EHM has procoagulant, anti-inflammatory and promotional effects, which can accelerate the open wound healing of soft tissue in mice and has a certain inhibitory effect on superficial scar hyperplasia.
Optimization of ratio of refrigerants for quick liquid freezing of aquatic product by response surface methodology
Tao ZHANG, Yanyan WU, Laihao LI, Xianqing YANG, Wanling LIN, Shaoling YANG, Shuxian HAO
2019, 15(5): 99-108.   doi: 10.12131/20190038
[Abstract](1523) [FullText HTML](479) [PDF 4017KB](15)
Abstract:
In order to develop a safe food-grade quick-freezing liquid formulation suitable for rapid freezing of aquatic products, we designed a low-temperature quick freezing liquid which composed of ethanol, oligofructose, citric acid, calcium chloride and propylene glycol. Then, we analyzed the variation of freezing point with different mass fractions of that composition by single factor test. Based on that, taking the freezing point and viscosity as response values, we optimized the addition amount of the refrigerants in the quick freezing liquid by Box-Behnken response surface method. The optimum formula of quick-freezing liquid was 19.9% ethanol, 9.5% fructooligosaccharide, 3% citric acid, 5% calcium chloride and 10% propylene glycol. The quick-freezing liquid prepared by the formula had a freezing point of –63.50 ℃ and a viscosity of 4.64 mPa·s, characterized by low freezing temperature, small viscosity, low formulation cost and convenient operation, suitable for rapid freezing of aquatic products and frozen convenience foods.
Changes of pigment-related enzyme activity and gene expression at early developmental stage of koi carp
Haoran YIN, Mingkun LUO, Lanmei WANG, Zaijie DONG, Wenbin ZHU, Jianjun FU
2019, 15(5): 109-117.   doi: 10.12131/20190023
[Abstract](1346) [FullText HTML](532) [PDF 3273KB](16)
Abstract:
We investigated the changes of tyrosinase and cystinase activities, as well as the expressions of tyr, mitf, agouti and mc1r mRNAs at the early developmental stage of Kohaku and Hi-Utsuri koi carp (Cyprinus carpio) by using histological observation, enzyme-linked immunoassay and quantitative reverse transcription-polymerase chain reaction methods. The results show that the hatched carps became light yellow and translucent. The melanocytes occurred on 8 dph (day-post-hatching). The activity of cystinase increased with the koi carp development, and no significant difference was observed between Kohaku and Hi-Utsuri groups before 7 dph (P>0.05), while Hi-Utsuri group showed significantly higher enzyme activity than Kohaku group at the same stages after 7 dph (P<0.05). Tyrosinase activity showed an up-regulation trend with slight fluctuation during the development of koi carp, and peaked at the ocular pigment stage and on 23 dph (P<0.05). The enzyme activity was significantly higher in Hi-Utsuri group than in Kohaku group at each developmental stage (P<0.05), which indicates that tyrosinase and cystinase activities were closely associated with pigment cell development of koi carp. The expressions of agouti, mc1r, mitf and tyr mRNAs peaked in gastrula and blastula periods (P<0.01), then decreased. Thus, agouti, mc1r, mitf and tyr mRNAs might play an important role in the formation of body colors in early embryonic development.
Bacteriostasis and safety evaluation of two lactic acid bacteria
Kai CHEN, Ludan ZHU, Hongliang TAN, Dongyu HUANG, Bingwen XI, Liangkun PAN, Jun XIE
2019, 15(5): 118-125.   doi: 10.12131/20190012
[Abstract](1357) [FullText HTML](514) [PDF 1008KB](14)
Abstract:
In this study, two strains of lactic acid bacteria [Lactobacillus casei (S60) and L. plantarum (S72)] were tested by aseptic technique, including routine biochemical detection, susceptibility test, in vitro bacteriostasis test and animal experiment. Their feasibility and safety as probiotics for fishing were also verified. Results show that the two lactic acid bacteria could tolerate acid (pH 4.0) and bile salt (0.1%), and exhibit different antibacterial activities against six pathogens including Aeromonas hydrophila. The results of antimicrobial substances analysis shows that the effective antimicrobial substances were related to the organic acids produced in metabolic process. The results of safety evaluation shows that the two strains of lactic acid bacteria had no ability to decompose gelatin and hemolysis. The results of death statistics and blood biochemical indicators show that the intraperitoneal injection of live bacteria as high as 1.0×109 CFU·mL−1 did not cause serious death and body injury in experimental fish. It is included that the two strains of lactic acid bacteria have high safety as oral probiotics. Drug resistance studies show that the two strains of lactic acid bacteria had strong tolerance to aminoglycosides and sulfamethoxazole, and were sensitive to ampicillin, enrofloxacin, florfenicol and doxycycline. Therefore, the application of the two strains of lactic acid bacteria should pay attention to the selection of drugs in management process.
Advance in marine algicidal bacteria research
Honghui HUANG, Beibei HAN, Shufei ZHANG, Fengxia WU
2019, 15(5): 126-132.   doi: 10.12131/20190040
[Abstract](1132) [FullText HTML](519) [PDF 568KB](17)
Abstract:
As a notorious environmental issue, harmful algal blooms (HABs) severely threat the marine ecosystem, aquaculture and human health around the world. Therefore, it has been a research hotspot to develop a more environment-friendly and effective agents to control the HABs. In recent years, a lot of marine bacteria have been found to inhibit algal growth or lyse the algae through direct or indirect attacking. Utilizing marine algicidal bacteria to control HABs can maintain balance of water ecosystem. The algicidal bacteria show broad application prospects in HABs control because of its secure and high efficiency. In this paper, the development of algicidal bacteria, algicidal mechanism and their applications are summarized, and the future prospects in theoretical research and application fields are discussed.
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Analysis of fish community structure and environmental effect of West River
Yingqiu ZHANG, Daotian HUANG, Xinhui LI, Qianfu LIU, Jie LI, Yuefei LI, Jiping YANG, Shuli ZHU
Latest Accepted  doi: 10.12131/20190142
[Abstract](310) [FullText HTML](211)
Abstract:
From 2016 to 2018, we had seasonally collected fish and monitored the environmental factors at the six sites from Guiping to Zhaoqing in the West River, the main stream of the Pearl River. In total, we collected 99 species belonging to 12 orders and 29 families. The species number collected for each sampling ranged from 10 to 45, while the Shannon-Weiner index ranged from 0.90 to 2.93, and the evenness index ranged from 0.30 to 0.89. The species variation was agreed with patterns of seasonal turnover and spatial turnover. As revealed by the index of relative importance, Cirrhinus molitorella, Megalobrama terminalis and Squaliobarbus curriculus were the most dominant fish species. The permutational multivariate analysis of variance indicates that the fish community structure varied significantly among seasons and sites. The significant difference between summer and winter was mainly caused by the weight percentage variation (W%) of Cyprinus carpio, C. molitorella, M. terminalis and S. curriculus. The significant difference between Guiping and lower reaches of Wuzhou and Zhaoqing was mainly caused by the number percentage (N%) variation of C. molitorella, M. terminalis and Squalidus argentatus, and W% variation of C. molitorella, M. terminalis, C. carpio, Hypophthalmichthys molitrix and Oreochromis niloticus. Redundancy analysis explains 49.92% variation of fish N% and 49.61% of fish W%; the most important influencing variables are distance to estuary, water temperature, water transparency and runoff; C. molitorella distributes in water of low transparency and high temperature; M. terminalis and H. molitrix distributes in lower reach; S. curriculus distributes in middle and upper reach; C. carpio distributes in water of high transparency and low temperature.
Beak microstructure and its application in age and growth study of Dosidicus gigas in open sea of Chile
Bilin LIU, Na LIU, Jianhua LI, Xinhao ZHANG
Latest Accepted  doi: 10.12131/20190116
[Abstract](312) [FullText HTML](239)
Abstract:
In this study, Dosidicus gigas age and growth were investigated by analyzing the microstructure of upper beak rostrum sagittal section (RSS), based on 148 specimens collected from the open sea of Chile. The results show that its RSS was composed of hood and crest, where periodic growth bands including one light and one dark increment were distinct. The increments of hood and crest met together at the region of internal rostral axis, showing a pattern of ‘<’. The stress marks and aberrant structures might relate to special ontogenetic events or external accident. The back−calculated hatching date was deduced from March to November, mainly from June to July in 2009. The relationship between mantle length (ML) and age can be described as power function. The average IGR (instantaneous growth rate) and AGR (absolute daily growth rate) of ML of female D.gigas were 0.14 %˙d−1 and 0.60 mm˙d−1, respectively, and the average IGR and AGR of ML of males were 0.11 %˙d−1 and 0.47 mm˙d−1, respectively. The results can provide not only a new method for age and growth study of squid but also important references for Chinese scientists to perform relevant researches.
Effects of nitrogen, phosphorus and carbon on growth of seven marine microalgae
Zuoyi LIU, Shibin QI, Ning HE, Jiefeng KOU, Kaifeng SUN
Latest Accepted  doi: 10.12131/20190089
[Abstract](379) [FullText HTML](236)
Abstract:
In order to screen fine algae species (strains) for in situ treatment of aquaculture tail water, we investigated the effects of nitrogen (nitrate, ammonium and urea), phosphorus (phosphate) and carbon (carbonate) on the growth of seven marine microalgae (Cochlodinium geminatum, Karenia mikimotoi, Skeletonema costatum, Chaetoceros muelleri, Phaeocystis globosa, Platymonas subcordiformis, Nannochloropsis oculata) in batch cultures. The results reaveal that the growth rates of microalgae were positively correlated with nutrients concentration. Compared with the control, the enhancements on the specific growth rate were 35%, 19% and 19% in C. geminatum, S. costatum and N. oculata under carbonate treatments. The enchancements on the specific growth rate under phosphate, nitrate, ammonium and urea were 25.01%−446.60%, 16.54%−77.52%, 15.79%−88.82% and 25.16%−71.43%, respectively. In general, the maximal specific growth rates (highest in P. globosa) of seven marine algae under carbon, nitrogen and phosphorus were negatively correlated with cell size, while those of P. subcordiformis and N. oculata were not significantly different with red tide microalgae except P. globosa. The nitrate and phosphate uptake rates were positively correlated with cell size, but the utilization efficiency of nitrogen/phosphorus per cell was negatively correlated with cell size. The N:P ratios in all culture medium increased. The phosphorus uptake rates were higher than nitrogen uptake rates. P. subcordiformis and N. oculata could be used in algal absorption of nitrogen and phosphorus in aquaculture tail water.
Correlation among growth performance, morphological traits and body weight of Eleutherollema tetradactyuulum cultured in indoor circulating aquaculture system and aquaculture pond
Junwei LI, Youjun OU, Jiufu WEN, Ruiping HU, Changbo ZHU, Junnan LAN, Jia’er LI, Hui ZHOU
Latest Accepted  doi: 10.12131/20190155
[Abstract](124) [FullText HTML](126)
Abstract:
We applied correlation analysis and path analysis to explore the relationship between the body weight and the 12 morphological traits of Elentheronema tetradactylum cultured in indoor circulating aquaculture system and aquaculture pond, which had significant correlation (P<0.05), and the correlation among the morphological traits of E. tetradactylum in the two systems was very significant (P<0.01). The descending order of morphological traits which affected on the body weight of E. tetradactylum in indoor circulating aquaculture system and aquaculture pond were fork length>body length>head length>caudal peduncle height>total length, and total length>caudal peduncle height>fork length>body length>body height, respectively. The path analysis reveals that the body length, body height, head length, body width and eye diameter had significant direct effects on the body weight of E. tetradactylum in indoor circulating aquaculture system (P<0.05). The total length, caudal peduncle height, body height, trunk length and head length had significant direct effects on the body weight of E. tetradactylum in aquaculture pond system (P<0.05). Besides, the total decision coefficients of those morphological traits to the body weight were 1.418 and 0.968 in indoor aquaculture system and aquaculture pond, respectively. The results reveal that the larger variation coefficient of fish in aquaculture pond is conducive to the breeding of improved species, while the more uniform specification of indoor circulating water culture is conducive to production. In different aquaculture environment, the correlation analysis of morphological traits and body weight of E. tetradactylum can provide theoretical basis for its large-scale cultivation and breeding technology optimization.
Comprehensive rating quantitative assessment on aquaculture environment of subtropical bay of southern China
Xiuli LIAO, Honghui HUANG, Zhanhui QI, Ming DAI, Huaxue LIU
Latest Accepted  doi: 10.12131/20190067
[Abstract](156) [FullText HTML](94)
Abstract:
According to the ecological environment survey data of three subtropical aquaculture bays (Maowei Sea, Dapeng cove and Baisha Bay) along the northern coast of the South China Sea from 2011 to 2012, and by appling methods of comprehensive grading evaluation of aquaculture area as well as river comprehensive water quality index (Iwq) evaluation, we compared the advantages and disadvantages of ecological environment of the same level quantitatively on the basis of the classification of marine environment. The results show that only two of the 12 voyages in three bays (autumn and winter in Dapeng cove) have a good environmental rating, and the other 10 are medium. In spring, the rating of the three bays is medium and the index is similar. In summer, autumn and winter, the environmental quality of Baisha Bay is the worst. In the past two years, five water environmental factors had been alarmed, and the three surveyed bays were at risk of eutrophication. The influence of seasonal change on the bay environment increased with the increase of latitude. It is found that the improved Iwq index is more efficient in comparing the environmental conditions of the same level, but its comparability among different levels is uncertain.
Comparison of development and growth of hybrid Chromileptes altivelis () × Epinephelus tukula ()
Zhentong LI, Yongsheng TIAN, Meiling CHENG, Yuping WU, Jingjing ZHANG, Ziqi LI, Linna WANG, Wenhui MA, Zunfang PANG, Lijuan SUN, Jieming ZHAI
Latest Accepted  doi: 10.12131/20090168
[Abstract](116) [FullText HTML](83)
Abstract:
We performed breeding experiments with Chromileptes altivelis as the female parent and Epinephelus tukula as the male parent by artificial fertilization to breed new species of groupers with excellent traits. Besides, we observed and compared the embryonic development and growth characteristics of C. altivelis (♀) ×E. tukula (♂) and C. altivelis by microscope (Nikon E200) and anatomic microscope (Olympus). The results show that the fertilized eggs of hybrid and C. altivelis took 24 h 50 min and 25 h 8 min to accomplished the embryo development under the conditions of water temperature 27 ℃, salinity 30, pH 8.1 with the micro-flowing water and micro-inflated. The post-embryonic development of the hybrid had experienced four stages of early larva (0−3 d), late larva (4−40 d), juvenile (41−60 d) and young fish stages (after 61 d). At 330 days of age, the total lengths of the hybrid and C. altivelis were (23.57±0.94) cm and (18.35±0.72) cm, respectively; and the body weights were (220.5±25.3) g and (142.6±0.58) g, respectively. The total length and body weight of the hybrid were 1.28 and 1.55 times that of the C. altivelis, respectively. Compared with C. altivelis in the external morphological traits, the hybrid was slender and the head was larger, the black spots on the body surface was distributed disorderly, and the fins of each part was relatively small. Based on our continue observation on embryo and larval development of hybrid, it is confirmed that the distant hybridization combination of C. altivelis (♀) ×E. tukula (♂) is feasible, and the hybrids show the merit of heterosis, which provides scientific basis for distant hybridization and the cultivation of new varieties of groupers.
Development and identification of SSR markers based on RNA-seq data of Diodon hystrix
Jun MA, Jiaxin LIU, Zhijing JIANG, Yongsen ZHOU, Zhenhao YU, Haishan WANG, Yan CHEN, Pan CHEN, Hai HUANG
Latest Accepted  doi: 10.12131/20190147
[Abstract](251) [FullText HTML](184)
Abstract:
The transcriptome sequences of Diodon hystrix were obtained by RNA-seq technology, and a total of 221 762 Unigenes were generated by de novo assembly with N50 of 2 240 nt and GC% of 46.20%. By using MISA software, 106 221 SSR loci were detected from the RNA-seq data of D. hystrix, and these loci distributed in 62 451 Unigenes with a frequency of 28.16%. The dominant repeat units were mononucleotide, dinucleotide and trinucleotide, which accounted for 48.99%, 32.57% and 14.72% of the total SSR loci, respectively. The A/T was the main repeat unit in mononucleotide, accounting for 46.21% of the total SSR loci, while the AC/GT and AGG/CCT were the dominant repeat units in di- and thinucleotides, accounting for 21.90% and 2.70% of the total SSR loci, respectively. The 17 563 pairs of primers were designed by selecting SSR loci with length greater than 20 bp. Then 160 pairs of primers were randomly selected for amplification and identification, and 95 pairs of effective amplification primers were screened, accounting for 59.38%. The 30 pairs of stable and repeatable polymorphic primers were obtained from the effective amplification primers by polymorphism verification (31.58% of the effective amplification primers). Among them, 15 pairs of primers showed high polymorphism (PIC>0.5) which were benefit for assessing the diversity for D. hystrix population. These results indicate that the transcriptome data of D. hystrix can be used as an effective source for the development of stable SSR markers, and the obtained polymorphic SSR loci can provide foundation for the further study of genetic map and genetic diversity of D. hystrix.
Anatomy and histological observation of digestive system in Schizothorax eurystomus
Jie WEI, Xiquan CAO, Yongli REN, AIKEBAIER Rehemana, Zhulan NIE
Latest Accepted  doi: 10.12131/20180262
[Abstract](310) [FullText HTML](219)
Abstract:
Anatomy, paraffin section and HE staining were used to observe the anatomical characteristics and tissue slice in the digestive tract of Schizothorax eurystomus. The results show that the wall of digestive tract included mucosa, submucosa, muscularis and serosa from inner to outer. The main difference lies in mucosa and muscular layers. The mucosa layer of esophagus was covered with stratified epithelium and abundant goblet cells. The mucosae in the foregut and midgut were obviously lined by a simple columnar epithelium with abundant goblet cells, brush border and lymphocytes. The mucosa of hindgut was composed with pseudostratified columnar epithelium, goblet cells and lymphocytes. From front to back, the number of goblet cells of intestine increased gradually. The muscularis of esophagus and foregut consisted of internal-circular muscle layer and external-longitudinal muscle layer. However, the skeletal muscle and smooth muscle were distributed in muscularis of esophagus and foregut. The muscularis of midgut and hindgut consisted of internal-spiral and external-longitudinal smooth muscle layers. The digestive gland was composed of liver and pancreas, and the pancreas is diffuse in the liver. The hepatic lobule was unconspicuous. In conclusion, the histological structure of digestive system of S.eurystomus was related with its function and feeding habit.
Evaluation on carrying capacity of fishery resources in coastal waters of Dapeng Peninsula, Shenzhen
Xinling LONG, Pimao CHEN, Huarong YUAN, Xue FENG, Jing YU, Liming SHU, Xiaoguo LI, Wenjing CHEN, Zicong CHEN
Latest Accepted  doi: 10.12131/20190024
[Abstract](1204) [FullText HTML](451)
Abstract:
To explore the carrying capacity of fishery resources in the coastal waters of Dapeng Peninsula, Shenzhen, in consideration of the actual situation of that sea area, we established an evaluation index system by referring to the Resource and Environmental Carrying Capacity Monitoring and Early Warning Technology Method (Trial) and the evaluation methods of fishery resources carrying capacity at home and abroad. Based on the survey data of fishery resources in that waters every autumn in 2012 to 2016, we applied two methods [comparing the data between 2016 and the previous three years (2013 to 2015) and comparing the data between 2016 and the previous four years (2012 to 2015)] to evaluate the carrying capacity. The results of both methods show that the swimming animal index had a downward trend. The fish spawn and larvae index decreased significantly. The fishery resources carrying capacity was almost overloaded. Therefore, it is recommended to strengthen the monitoring and investigation of fishery resources as well as the evaluation and early warning of fishery resource carrying capacity, so as to provide technical support for promoting the restoration and protection of fishery resources as well as proliferative maintenance.