Abstract:To investigate the ossificational process of intermuscular bones in Cyprinus carpio haematopterus, the modified bone clearing and staining experiment were conducted to study the number, morphology, distribution of intermuscular bones in C.c.haematopterus. It was reveled that the initial intermuscular bones were ossified at 14 dpf (day post fertilization) with the standard length of 11.29 mm, in which period the other types of bones had already showed up completely. The first appeared intermuscular bones were located in the tail region and then turned toward the head. When the larvae were 40 dpf with the standard length of 15.60 mm, all the intermuscular bones basically appeared and were equally distributed from the tail to the head. The number of intermuscular bones in C.c.haematopterus ranged from 93 to 104 with an average of 98. The average number of epineurals in each side of the body was 34, and the epipleurals was 15. Seven types were included: non-forked, one-end-unequal-bi-fork, one-end-equal-bi-fork, one-end-multi-fork, two-end-bi-fork, two-end-multi-fork, and tree-branch types. Generally,the morphological complexity of most intermuscular bones in anterior body was greater than that in posterior body. These results will be helpful for us to further understand the molecular mechanism underlying intermuscular bone development as well as the breeding of C.c.haematopterus with fewer or even no intermuscular bone.

Abstract:This study tries to gradually reduce the addition of carbon source to zero,and to explore the effect of domesticating nitrifying bio-flocs on water quality,bacterial community dynamics of bio-floc and the growth performance of shrimp in high-intensive culture system. Experiment was carried out in three runway aquaculture systems at stocking density of 685 shrimp/m³.Water quality results showed that daily addition of glucose at 100%-150% of feed,which can decrease the concentration of TAN,but the concentration of NO₂^--N was not decreased obviously.When the addition of glucose dropped to zero,TAN can be maintained at lower level,and the NO₂^--N concentration decreased significantly.The bacterial community structure was analyzed by using high throughput sequencing technology.At the phylum level,experiment results showed that both the main advantage microflora of heterotrophic bioflocs and nitrifying bioflocs are Proteobacteria and Bacteroidetes.At the class level,dominant microflora of heterotrophic biofloc is Alphaproteobacteria,and dominant microflora of nitrifying bioflocs are Alphaproteobacteria,Flavobacteria and Gammaproteobacteria.After 65 d,study found that without adding carbon source,nitrifying bio-flocs can limit the abundance of heterotrophic bacteria,nitrospira was rising,and developing into dominant bacteria.At the end of the experiment, glucose which is 41.03%±7.86% of feed was added throughout the culture period.The survival rate and harvest of Litopenaeus vannamei respectively were 43.35%±7.57% and (3.03±0.59) kg/m³.The domestication of nitrifying bio-flocs not only saved cost, but also effectively optimized the structure of bacterial communities, and contributed to better water environment which results in the higher growth and survival of shrimp.

Abstract:This study was conducted to investigate the effects of different fish oil replacement levels on reproductive performance, egg diameter, individual egg wet weight and dry weight, proximate composition and fatty acid composition in the eggs produced by Chinese mitten crab (Eriocheir sinensis). Five isonitrogenous and isolipidic fattening diets were formulated by the blending vegetable oils(soybean oil: rapeseed oil = 1:1) to replace 0, 25%, 50%, 75% and 100% of fish oil(defined as feed 1#, 2#, 3#, 4# and 5#,respectively).Each experimental diet was fed to three replicates and each replicate consisted of 25 females and 25 males.After 60-day feeding, four females and two males from each replicate were randomly transferred into the brackish water tanks for the mating, and the reproductive performance and egg biochemical composition were further studied for the evaluation of effects of fish oil replacement. The results showed that: (1) Feed 3# treatment started to spawn only after 10 days of post-mating, while there were 15 days of post-mating for the other treatments; the final ovigerous rate was 100% for the treatments of feed 1#, feed 3# and feed 5#, while the final ovigerous rate of feed 2# and feed 4# was around 80%; although feed 4# treatment had the highest egg production, fecundity and reproductive effort among five treatments, no significant differences were found among the five treatments(P>0.05). (2) As for the egg quality, feed 1# had the slightly higher egg diameter than the others,but no significant differences were found on egg diameter, individual egg wet weight and dry weight among the five treatment (P>0.05). (3) As for the egg biochemical composition, no significant differences were found for the moisture, crude protein, crude lipid and fatty acid composition in the eggs among the five treatments (P >0.05); the percentages of 18:2n6, and the ratio of n-6 polyunsaturated fatty acids/n-3 polyunsaturated fatty acids (∑n-6PUFA/∑n-3PUFA) increased with increasing the replacement levels of dietary vegetable oils, while the decreasing trend was found on the percentage of 22:6n3 in the eggs. In conclusion, dietary fish oil replacement have no significant effect on reproductive performance, egg quality, proximate composition, and fatty acid composition of eggs for feeding E. sinensis at middle stage of gonadal development. Therefore, the appropriate replacement level of dietary fish oil is around 75% in consideration of egg production and fecundity.

Abstract:This experiment was conducted to investigate the effect of astragalus polysaccharides (APS) on nonspecific immunity of grass carp (Ctenopharyngodon idellus). 600 healthy grass carps were randomly divided into Group Ⅰ-Ⅳ, fed with the basal diet added with 0, 10.0, 30.0, 50.0 mg APS per kilogram body weight everyday respectively. Phagocytic percentage (PP), phagocytic index (PI) of leukocytes in blood and the activities of total superoxide dismutase (T-SOD), catalase (CAT) and lysozyme (LSZ) in serum were determined on D0, D8, D15, D22 and D29. On the 29th day of feeding, 20 grass carps of each group were infected by Aeromonas hydrophila and mortalities were recorded. The results indicated that APS added in diets can increase PP and PI of leukocytes, and enhance the activities of serum T-SOD, CAT, LSZ. The mortality rate of grass carps infected by A. hydrophila was significantly decreased when fed by APS (P<0.05) and the protective rate of Group Ⅱ-Ⅳ were 54.3%±6.4%, 52.9%±12.5% and 44.2%±4.8% respectively. It suggested that APS can enhance nonspecific immunity function of grass carp, and the effect of low dose was superior to high dose. The recommended dose of APS added to the diet applying in aquaculture was 10-30 mg/d per kilogram body weight.

Abstract:Based on investigation data obtained from January to December in the enclosed Fengxian bay throughout 2015, water quality and eutrophication conditions were evaluated on the basis of organic pollution index (A) and eutrophication index (E) and the species composition, biomass as well as bioremediation abilities of benthic algae community were analyzed. The results of water quality indicate that this mariculture area has been in serious eutrophication state. Dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) complied with the Grade inferior Ⅳ and Ⅲ, respectively. The annual average values of A and E were 1.88 ±0.21 and 29.95±1.18, respectively. The results also show that the dominant species of green algae is Ulva flexuosa, accounting for 97.3%. From March to December in 2015, the biomass of U. flexuosa increased by 1497.3 tons. The average N and P contents of algae were 3.50% ± 0.02% and 0.13%±0.01% and (4354.90±46.78)kg of N and (161.75±1.74)kg of P could be removed by this seaweed. The population of U. flexuosa has certain bioremediation abilities by assimilating nutrients generated by human aquaculture activities. However, the biomass of U. flexuosa stocked on hand could not completely remove all excess nutrients. Establishing an integrated multi-trophic level system co-cultured with macroalgae showed high bioextraction efficiencies on nutrients and could balance the nutrient produced by marine aquatic animal farming in the enclosed bay.

Abstract:Pinghu oil and gas field submarine pipeline has ruptured in 2012 near Daishan, but related toxic test of Pinghu crude oil is less. In order to investigate the toxic effect of Pinghu crude oil and its water-accommodated fractions(WAF), the acute toxicity effects of Pinghu crude oil and its WAF on Mugil cephalus, Palaemon carincauda, Sinonovacula constricta and Ruditapes philippinarum were studied,respectively. The results showed that both of Pinghu crude oil and its WAF had significant dose-effect relationship on tested marine organisms. The 96 h LC₅₀ values of Pinghu crude oil for Mugil cephalus, Palaemon carincauda, Sinonovacula constricta, Ruditapes philippinarum were 865 mg/L, 343 mg/L, 2 441 mg/L and 5 221 mg/L, respectively. The 96 h LC₅₀ values of WAF for Mugil cephalus, Palaemon carincauda, Sinonovacula constricta, Ruditapes philippinarum were 1.697 mg/L,0.645 mg/L, 4.535 mg/L, 5.783 mg/L, respectively. The order of the 96h LC₅₀ for four test organisms did not change between Pinghu crude oil and its WAF, but WAF was more toxic than crude oil.

Abstract:The contents and distributions of heavy metals Cu, Zn, Pb, Cd, Hg, As in fishes were investigated with the samples collected from the Qiantang River in 2015.Then we evaluated the pollution degree and assessed the food safety based on the single factor pollution index(P_i) and the provisional tolerable weekly intake(PTWI),respectively. Results showed that the contents of Cu, Zn, Pb, Cd, Hg in the muscle of fishes in Qiantang River were rather low. However, compared with the limit values of the safety requirements for non-environmental pollution aquatic product, the contents of As were somehow higher with the exceeding rates of 3% than the standard limit and reached ‘Light Pollution’. The statistics results showed that although there was no significant difference among Cu, Zn, Cd, Hg and As(p> 0.05), the contents of Pb had obvious variation with sampling areas, which may be mainly caused by the waste water and atmospheric deposition of nearby factories. Assessment results showed that the dietary exposures of heavy metals in the muscle of fishes in Qiantang River were lower than PTWI, indicating overall in a safe range of the fish meat, namely no harm to health. However, we found that the Hg intake of a minority of fish species exceeded the PTWI value, suggesting possible risk to health. Therefore, more attention should be paid to the heavy metal Hg.

Abstract:We conducted a series of conditional experiments to explore the changes in cell densities, volume and phosphorous uptake kinetics of Karenia mikimotoi at three different inorganic phosphorus levels. The results showed that the growth of K. mikimotoi was significantly affected by inorganic phosphorus levels, the cell densities in high-phosphorous (HP) group were significantly (P<0.05) higher than those in medium-phosphorous (MP) and low- phosphorous (LP) groups starting from the 12th day until to the end of experiment. On the contrary, the cell volume of K. mikimotoi which grew in LP group was significantly (P<0.05) greater than those in MP and HP groups from the 6th day, however, it was non-significantly different between MP and HP group (P>0.05). The relationship between inorganic phosphorus absorption rate and initial phosphorus concentration was preferably fitted by the Michaelis-Menten equation. According the equation, the maximum inorganic phosphorus absorption rate of K. mikimotoi (ρ_max) was 18.587 fmol/(cell·h) and the half-saturation constant (K_s) was 0.490 μmol/L. Given the fact that inorganic phosphorus content was low (approximately 0.10 μmol/L) in the East China Sea when dinoflagellates red tides occurred, and K. mikimotoi have strong affinity for inorganic phosphorus and continuous growth potential in low phosphorus condition indicate that dinoflagellates have more competitive nutriment absorption ability than diatom, which may promote the succession of the diatom and dinoflagellates red tides in the East China Sea.

Abstract:Macroalgae detritus is known as an important material basis of both detritus productivity and water productivity cycle. The divergence of environmental factors, for example, dissolved oxygen concentration has significant effects on macroalgae detritus decomposition and releasing rate. To study the Sargassum vachellianum detritus degradation processes, specifically, degradation and mineral nutrition rate of nitrogen, phosphorus, silicon in dissolved oxygen concentration gradients, lab-based experiments were conducted under controlled conditions of hypoxic (1-4 mg/L) and aerobic (5-9 mg/L). The results showed that compared with hypoxic condition, the Sargassum vachellianum had higher decomposition rate (k=0.110/d, weight loss=84.699%) during the first 0-7 days, while aerobic treatment had lower decomposition rate(k=0.041/d). Similarly, hypoxic treatment had higher nitrate and nitrite release rate than aerobic treatment. Conversely, aerobic treatment released more ammonia and dissolved inorganic nitrogen (3.811 mg/g) than hypoxic treatment (1.511 mg/g), while ammonia is known as the dominant nutrient of dissolved inorganic nitrogen. For active phosphate, under different dissolved oxygen gradient, hypoxic treatment(10.143 mg/g)had 2.4-9 times contribution compared with aerobic treatment(1.091-4.777 mg/g). In a word, dissolved oxygen concentration in the waters have significant effects on Sargassum vachellianum detritus decomposition process, thus changed the nitrogen, phosphorus, silicon nutrient contribution of detritus, even the materials and energy flow in the water.

Abstract:The main fish resources of Qingcaosha Reservoir were detected and evaluated by dual-frequency identification sonar (DIDSON) in September, 2015. The data collected by DIDSON are analyzed and processed by Fishery Acoustic Data Processing Software Echoview. The fish in the image is counted and the accuracy of software counting is verified by the artificial visual counting. The amount of major fish stocks in the reservoir was further evaluated based on the number of fish collected by DIDSON and the information on the fish length and weight of fish collected by the catch. The results show that the number of reservoir fish is about 1.16×10⁷～1.24 ×10⁷, and the proportion of small fish (length <20 cm) is 78.3%, while the medium and large fish (length> 40 cm) accounted for a small proportion (8.5%). From the relationship between the average body weight and body weight in the reservoir area,it can be concluded that the reservoir fishery resource is about 4 620～4 980 t. The spatial distribution of fish body weight in reservoirs was given by GIS method. The spatial distribution of fish weight in the route was analyzed by GIS. The results showed that there were more resources in the deep-water region on the southeast side of the reservoir, while the resources on the northwest side of the reservoir were generally less. The innovative applicability of DIDSON in assessing fishery resources of Qingcaosha Reservoir is discussed, and some suggestions and prospects are put forward.

Abstract:Crocodile shark (Pseudocarcharias kamoharai) is a common bycatch species in tropical Atlantic tuna longline fishery. This species is mostly distributed at the topmost parts of the marine ecosystem and plays a very important role in the stability and diversity of the marine ecosystem. A total of 1 561 ind. crocodile sharks were recorded according to the biological data collected by Chinese longline fishery observers in the tropical Atlantic Ocean from 2010 to 2015 and the preliminary analyses about its resource information and spatial distribution were made. The results were summarized as follows: In the study area (6.33°S-17.43°N,18.25°W-42.03°W), the highest concentration of the CPUE area was in the zone 5°N-10°N, 20°W-30°W; the CPUE value was in the range: 0.00-3.94, and the average was 0.83. From 2010 to 2015, CPUE showed a variation trend, but the upward trend was not significant. The Chondrichthyes percentage in total proportion of the catch decreased; the total number of crocodile sharks accounted for 5.8% of total number of fish caught, accounting for 22.5% of the total number of Chondrichthyes bycatch. The higher average CPUE values of the tropical Atlantic crocodile sharks were recorded in December, and from January to March. The largest fork length class (fork length range of 85-90 cm) of the crocodile sharks were distributed in the regions 5°N-7.5°N, 27.5°W-37.5°W and 5°N-0°,25°W-30°W.Crocodile shark hook depth ranges between 140-313 m, the average observed depth was 221 m.The frequency of 1-3 hooks (140-212 m) is the largest, accounting for 55.59% of the total catch rate. There was no significant difference in the hook position of the crocodile shark in different months from October to April. Crocodile sharks were obviously distributed in the shallow water layer during pregnancy. There was no significant difference between feeding level and hook position of crocodile sharks.

Abstract:According to the data of shrimp obtained from the fishery resources survey conducted in the coastal waters of Zhoushan in November 2015 (autumn) and in May 2016 (spring), the catch was used as the quantitative index of the distribution of shrimp resources. The composition of shrimp species,the temporal and spatial distribution of quantity, the alteration trend of population and the relationship with the environmental factors were studied in this sea area.The research results: (1) 21 species of shrimp were identified in the investigation sea area, belonging to 8 families and 15 genera. The quantity distribution was obvious in spring and autumn, in general,the number in Autumn was greater than that in Spring. (2) There were significant differences between dominant species and common species in different seasons. Compared with the previous survey, small shrimp replaced large shrimp and became dominant species. (3) The temperature at the bottom and salinity had no significant effect on the distribution of shrimp catches in Zhoushan coastal waters. However, according to the analysis of depth classification, shrimp catches showed different variation with water depth. (4) The ABC curve shows that the catch curve and the abundance curve were staggered, indicating that the shrimp community in the survey area was strongly affected by human beings, and was in serious disturbance state, and the ecological sensitivity was high. Therefore, the shrimp biological resources in Zhoushan coastal waters were strongly affected by human activities and the community structure was in obvious succession. The main catch displayed miniaturization and low production trend.

Abstract:According to the four cruises of fisheries survey conducted in south Haizhou bay, eastward of Lianyungang in Jiangsu Province, all the catch fish species from bottom trawl of 24 stations were identified to species level, and the spatial and temporal distributions of species composition were analyzed. The results showed that 98 species were collected from the south Haizhou bay, involving 2 class, 15 orders, 47 families and 77 genera. Most of the fish species belong to Perciforme, Scorpaeniforme, Pleuronectiformes and Clupeiforme. More than 50% of the total species belong to Perciforme in different seasons except for winter, different stations also showed different patterns in species composition, although difference was not tested in statistical analysis; the dominant species were less than four species in every season, pelagic species dominated in spring and winter, and commercial species were commonly dominated in summer and autumn. The highest weight density occurred in spring, then summer and autumn, winter is the lowest; however, the highest individual density occurred in winter, followed by spring and summer, and autumn was the lowest. The density differences between near-shore and off-shore were also revealed in this study without any statistical difference. Margalef diversity index was analyzed with highest value in spring, followed by summer and autumn, winter had a relatively low species composition. The value of indices showed different patterns in different stations without significant difference. The protection of fisheries resources in Haizhou bay has been kept at a stable level. Closed fishing system should be maintained and the minimum net size should also limited. Sustainably developing some novel fisheries should be considered to better utilize the marine resources.

Abstract:The common cuttlefish, Sepia officinalis Linnaeus 1758, is mostly found in the eastern Atlantic and in the Mediterranean Sea, and constitutes an important fishery resource in the world cephalopod fisheries by attaining high market value in the Mediterranean and Asian markets. Herein,the individual fecundity of S.officinalis was studied based on the samples collected from the pelagic fisheries outside Mauritania during the fishing season of July to August in 2015. In addition, the relationship between individual fecundity and the biological indices of each individual, including mantle length, mantle width, fin length, fin width, head width, body weight, eviscerated weight, and head weight, was analyzed by using mathematic regression equations. The results showed that the frequency distribution of mantle length, mantle width, fin length, fin width, head width, body weight, eviscerated weight, and head weight was unimodal respectively. The potential fecundity (PF) was 13 06~3 375 oocytes, with an average of 2 466±545 oocytes, and increased significantly with sexual maturation (P<0.05); the relative fecundity by mantle length (PF_ML) was 8.70~18.56 oocytes/mm, with an average of 14.17±2.12 oocytes/mm; while the relative fecundity by body weight PF_BW was 2.72~7.81 oocytes/g, with an average of 5.18±1.23 oocytes/g. Based on the comparison of variance, PF_BW was more stable than PF_ML (δ_PFBW²< δ_{PFM L}²).There was a significant relationship between F and PF_BW and the biological indices(P<0.05), while PF_ML showed little evidence to correlate with the biological indices due to the low value of correlation coefficient (P>0.05). Furthermore, a multiple regression analysis revealed that the potential fecundity was significantly correlated with fin length, while relative fecundity by body weight was significantly correlated with body weight.This finding showed that fin length was the reliable index to estimate the potential fecundity, while body weight was appropriate to estimate the relative fecundity by body weight for S. officinalis.

Abstract:Data in November 2012, February 2013, May 2013 and August 2013 of Dongshan Bay zooplankton were analyzed by primer statistical software. Results indicate that zooplankton were clearly divided into the outer bay community, Zhangjiang community, estuarine community and inner bay communities. Different zooplankton communities varied in abundance composition, seasonal variations of species and seasonal variations diversity. Zhangjiang communities were most affected by the diluted water, species are mainly Oikopleura dioica,Oikopleura rufescens,Paracalanus parvus and Tortanus dextrilobatus; Estuarine communities in the brackish region, Acartia pacifica is the main species with little seasonal change in number and diversity; The inner bay community was dominated by Acartia pacifica,Paracalanus aculeatus and Calanus sinicus; Sagitta enflata,Subeucalanus subcrassus and Paracalanus aculeatus constitute the most important species abundance in bay communities. Throughout the four seasons' changes of dominant zooplankton species in different communities, the difference of dominant species in four communities in November 2012 and February 2013 is not obvious. In May 2013 and August 2013,in four communities, the dominant species were significantly different.

Abstract:The fishing activities and administrative management are important historic grounds for Chinese sovereignty over the Nansha Islands according to 'effective occupation' in the international law.Effective occupation is the key step for a nation to acquire territorial sovereignty based on the occupation principle in the international law. In the remote or harsh areas, the requirements of effective occupation could be reduced appropriately, if only the occupying state exercises and demonstrates the sovereignty which is appropriate to the territory situation. The Nansha Islands of China is far away from the mainland, and the natural conditions are adverse. Since the ancient times, fishery is one of the most important ways for the development and management of the Nansha Islands. The fishery history of the Nansha Islands in China not only proves that China discovered the Nansha Islands firstly for the navigation and fishery development, but also confirms that China has implemented jurisdiction over them on account of the administrative management over fishery activities which is corresponding to the Nansha Islands and its adjacent waters, and occupied the Nansha Islands effectively, and therefore has owned the sovereignty over them.

Abstract:Water flowing is the basic condition for the water purification of pond. High efficient water hydrodynamic forming and control are of great value. The eccentric hydrodynamic equipment provides a good balance between the oxygenation and hydrodynamic forming. Based on the requirement of pond fine ecological factor regulation, the control system hardware system including sensor, data processing, storage, output and wireless communication components is constructed. Control algorithm based on oxygenation and hydrodynamic parameters is developed, which also contains the low-voltage sub-system self-detection and high-voltage sub-system checking function. By real time supervision of the dissolved oxygen and combined with the covering range in different power conditions, the control system achieves adaptive power output control and reaches a comprehensive effect from the view of oxygenation, hydrodynamic and energy cost. Based on the pond ecological factors and the requirement of meeting the pond oxygen demand, the practical experimental comparison results between the eccentric hydrodynamic equipment with the designed control system and other oxygenation equipments show the power flow in the new equipment decreases more slowly, and the hydrodynamic effect of the same area is dramatically increased. It can save about 24% of energy cost. The above results lay a solid foundation for the wide application of eccentric water power equipment.

Abstract:Microwave-assisted extraction combined with solvent assisted flavor evaporation(MAE-SAFE) was applied to extract the volatiles from two edible parts of Chinese mitten crab, abdomen meat and gonad part. The volatiles were quantitatively analyzed by the comprehensive two-dimensional gas chromatography/high resolution-time of flight mass spectrometry (GC×GC/HR-TOFMS), and identified by the retention index with an aid of the NIST11 library. A total of 122 volatile compounds were identified, which is the largest identification number among similar researches of same material, and 60 compounds were double identified by the accurate mass (AM) determination. More aldehydes, ketones, nitrogen-containing compounds in gonad part with total of 108 compounds were identified, while only 75 volatiles were identified in abdomen meat. MAE-SAFE has a better effect on the extraction of polar thermo-sensitive volatile compounds than other volatile enrichment method, and 20 ketones, 27 alcohols, 7 nitrogen-containing compounds, 4 sulfur-containing compounds were identified. The gentle and rapid heating method ensures the authenticity of the aroma components. GC × GC/HR-TOFMS with high resolution and high peak capacities enabled isomeric compounds like (E) -2-penten-1-ol and (Z)-2-penten-1-ol to achieve full separation. Compounds like formamide (ammonia flavor), maltol (baking-like flavor) and its precursor 4H-2,3-dihydro-3,5-dihydroxy-6-methylpyran-4-one were first detected in Chinese mitten crab. Therefore, this study provides comprehensive and reliable volatile component information for subsequent screening of key aroma compounds.