Abstract:The southern coastal waters of Wenzhou is in the mid to southern parts of the East China Sea. This area is influenced by the high temperature and high salinity conditions of the Taiwan Warm Current, the low salinity of the Zhejiang Coastal Current, and the southern coastal upwelling. These waters are rich in nutrients and baitfish and are highly diverse with fish species. The area is a typical ecological region of the East China Sea shelf. Cluster analysis, non-metric multidimensional scaling, and a diversity index was used to analyze the patterns of community composition, diversity, and community structure based on data from two fishery resources investigations conducted in May (spring) and September (autumn) 2015 in the area. The results identified 47 species in the southern coastal waters of Wenzhou, which belonged to 41 genera, 27 families, nine orders, and two classes. Warmwater and warm temperate species were dominant, and Perciformes were the most abundant, with 26 species, followed by Clupeiformes, with six species. The third most frequent group was Tetraodontiformes, with four species. The dominant species in spring were Amblychaeturichthys hexanema, and , accounting for 49.3% of the total catch. The dominant species in autumn were Polynemus sextarius, accounting for 50.8% of total catch. , were typically found at all stations in both seasons, and they were the major divergent species causing community differences among stations. Pearson's correlation analysis indicated that the richness index () were positively correlated with dissolved oxygen, salinity, and temperature. A canonical correspondence analysis suggested that the main environmental factors affecting the spatial patterns of fish assemblages were pH, depth, and salinity. pH represents the sum of some of the chemical properties in water and is the result of interactions among factors. pH can be affected by salinity and temperature. The canonical correspondence analysis results showed a division in the fish community in spring, which was likely due to influx of the high temperature and high salinity water in the Taiwan Warm Current. This current forms an obvious salinity gradient in the local coastal strip, which further affected the division of the spring fish community. The Taiwan Warm Current retreated in autumn, and the lower temperature and lower salinity of the Zhejiang and Fujian Coastal Currents gradually carried a large amount of silt into the study area. Therefore, whether temperature, salinity, and suspended particles affected the fish community structure requires further investigation.

Abstract:The effects of changes in temperature on physiological and biochemical activities of Ino were studied in the laboratory to better understand the thermal tolerance mechanisms of abalone. Abalone were transferred abruptly from a rearing temperature (15℃, control temperature) to 5℃, 10℃, 20℃, or 25℃. Other groups of abalone were acclimated to different experimental temperatures (5℃, 10℃, 20℃, and 25℃) by gradually increasing or decreasing seawater temperature (0.5℃/12 h). Then, oxygen consumption and ammonia excretion rates of Ino were measured, the activities of superoxide dismutase (SOD), catalase, acid phosphatase and lysozyme (LSZ) in the digestive gland were determined, and Cu/Zn-SOD gene expression levels in hemocytes and muscle were determined. The results showed that oxygen consumption and ammonia-N excretion rates of Ino increased gradually with an increase in water temperature and peaked at 20℃. The rates of oxygen consumption and ammonia-N excretion in the 25℃-acute temperature change treatment were significantly higher than those in the gradual treatment (<0.01). Moreover, significant differences in the abalone O/N ratio were observed between the acute and gradual temperature change treatments at 5℃ and 10℃ (<0.01). SOD, catalase, acid phosphatase, and LSZ activities increased significantly in abalone exposed to high temperature (25℃) for 72 h and reached the maximum at 3 h or 6 h (<0.01). However, a significant decrease in LSZ activity was found in abalone in the 5℃-acute temperature change treatment and reached the lowest level after 9 h (<0.01). Significantly up regulated Cu/Zn-SOD gene expression was also observed in hemocytes and muscle in abalone from the different temperature treatments (H. discus hannai Ino were significantly affected by temperature. These data provide valuable insight into the possible mechanisms of abalone summer mortalities and will serve as a theoretical basis for healthy breeding of abalone.

Abstract:The estuarine tapertail anchovy () is widely distributed in the Yangtze River, the coastal waters of China and Korea, and the Ariake Sound of Japan. It is a commercially important species because of its nutritive value and popularity. However, excess fishing and changes in aquatic ecology have almost caused extinction of this species in the middle reaches of the Yangtze River. In recent years, several studies have been performed on pond breeding and artificial propagation, and larval rearing techniques have been established. Thus, the threat to is very sensitive to stress, which often results in death and huge economic losses. Little is known about the mechanism by which loading stress causes death in fish. Pro-opiomelanocortin (POMC) is synthesized in the corticotrophs and melanotrophs of the anterior and intermediate lobes of the pituitary, respectively, as well as in peptidergic neurons in the arcuate nucleus of the hypothalamus. It is post-translationally cleaved into peptide hormones, including adrenocorticotrophic hormone, -melanocyte stimulating hormone (MSH), N-POMC, and -LPH) in tissue- and cell dependent manners. These peptides exhibit different physiological functions, such as promoting ovarian maturation, lipolysis, inhibiting fat accumulation, regulating osmotic pressure, and reacting to stressors. We cloned the and determined that the full-length cDNA is 1212 bp long, with a 699 bp open reading frame that encoded a 232 amino acid protein. The POMC protein is predicted to contain the typical POMC domains of a signal peptide sequence, the N-terminal region, and the adrenocorticotrophic hormone, -EP domains. Gene expression patterns were detected in different tissues by quantitative reverse transcription-polymerasechain reaction. was expressed strongly in the brain and relatively highly in the gill, kidney, and testis, whereas it was expressed at low levels in the liver, spleen, intestine, head kidney, muscle, and ovary. <0.05) and was significantly up regulated 4 h and 6 h after transport ( expression returned to the control level before stress. The gene plays an important role regulating fat metabolism and stress. Our results provide important clues for breeding and stress control studies in .

Abstract:17β-Estradiol (E₂) is among the most important sex steroid hormones during ovarian development and vitellogenesis in crustaceans. In this study, an immunofluorescence assay was used to identify the immunopositive distribution and variations in E₂ in the ovary, hepatopancreas, thoracic ganglia, brain ganglion, and the mandibular organ during ovarian development in the swimming crab, was mainly distributed in the follicular cells and the cytoplasm of late-stage oocytes (II-V). Follicular cells stained strongly positive for E₂ at all ovarian stages; the immunoreactivities of E₂ in the oocyte cytoplasm and nucleus trended as "low-high-low", and maximum positive staining appeared during ovarian stage IV and stages II-III, respectively. In the hepatopancreas, E₂-positive staining was mainly distributed in F cells and R nuclei, and E₂ immunoreactivity in the R nucleus tended to decrease from stages III to IV. However, strong positive E₂ immunoreactivity was always detected in F cells at all ovarian stages. E₂ was mainly distributed in neurons, the nerve medulla of thoracic ganglia, and cell nuclei of cerebral ganglion nerve cells during the early stages of ovarian development (I-II). E₂ immunore activity in the nerve medulla of the thoracic ganglion was moderately positive, where as neurons were always weakly positive. Strong positive E₂ staining was always distributed in the nuclei of mandibular gland cells and the cytoplasm around mandibular gland cellnuclei. These results suggest that E₂ is widely distributed in the ovary, hepatopancreas, thoracic ganglion, cerebral ganglion, and mandibular gland of immunoreactivity and ovarian developmental stage. E₂ may act through multiple target organs to regulate ovarian development in

Abstract:Saline-alkaline water resources are plentiful in China, but fisheries production in these waters is relatively low due to the lack of suitable culture species adapted to different saline-alkaline water characteristics. (Order Cypriniformes and Family Cobitidae) lives in Dali Lake where salinity reaches 6% and alkalinity is as high as 53.57 mmol/L. This species has a high tolerance to high salinity and alkalinity and could be a good aquaculture species for high salinity-alkalinity water. However, little is known about the tolerance limits of cobitid fish compared with those of other freshwater fish species. Thus, the tolerance of three cobitid fish species, such as T. dalaica, to salinity and alkalinity were investigated by 96 h one-way acute toxicity tests and a uniform orthogonal test in this study. The results showed that the 24 h-and 96 h-LC₅₀values for salinity in were 15.64 g/L, 13.58 g/L, and 15.43 g/L and 14.18 g/L, 14.00 g/L, and 11.57 g/L, respectively, with safe concentrations of 4.12 g/L, 4.03 g/L, and 3.74 g/L respectively. The degree of salinity tolerance was The 24 h-and 96 h-LC₅₀values for carbonate-alkalinity in were 117.1 mmol/L, 72.62 mmol/L, and 128.4 mmol/L and 88.83 mmol/L, 155.2 mmol/L, and 120.0 mmol/L, respectively, with safe concentrations of 18.77 mmol/L, 23.66 mmol/L, and 36.30 mmol/L respectively. The degree of carbonate-alkalinity tolerance was The joint effect of salinity and alkalinity was coordinated in and the coordination coefficients increased first and then decreased, but reached the maximum at 48 h. However, the combined effect was coordinated within 0-48 h in whereas it was antagonized during 48-96 h, and the coefficient of antagonism increased gradually with exposure time. These results provide a theoretical basis for promoting breeding and culture of cobitid fish in high salinity-alkalinity water in the future.

Abstract:Hybrid abalone () have been cultured in southern China for many years. Two experiments were performed (high temperature stress and culture in a southern sea area) to study whether a southern population (hybrid population) of Pacific abalone has different high temperature tolerance and is more adapted to that environment than a northern population (inbred population). After a 30℃ stress or in the high temperature stress experiment, relative expression of heat shock protein (HSP) 70 in the southern population at 0h of the recovery phase was significantly higher in the foot, mantle, gill, and hepatopancreas than those in the northern population (<0.05). At the same time, relative expression of HSP90 in the southern population was significantly higher in the mantle and hepatopancreas than that in the northern population. The relative expression levels of HSP70 and HSP90 in the southern population after the 33℃ stressor were significantly higher in the foot, mantle, and hepatopancreas at 0 h in the recovery phase than those in the northern population (<0.05). In another experiment, the most rapid growth period in the northern population occurred from December to February;abalone in the northern population grew faster than those in the southern population and water temperature was no higher than 17.11℃ at this time. Water temperature eventually exceeded 20℃ in March, when the northern population grew slower than the southern population and mortality increased. Less than 30 abalone in the northern population remained in July. Taken together, we conclude that because hybrid abalone have been cultured for many generations in southern China, they became better adapted to higher water temperature. The relative expression levels of HSP70 in the two populations were positively correlated with heat resistance after the 30℃ stressor. These data could be useful for assisted selection in an abalone high temperature resistance breeding program.

Abstract:A 56-d feeding experiment was conducted to investigate the effects of replacing fish meal in the diet with soy protein concentrate (SPC) on growth, body composition, serum biochemical indices, and liver histology of juvenile large yellow croaker, (initial weight 10.50 g±0.04 g). The basal diet contained 40% fish meal, and five isonitrogenous (crude protein 45%) and isolipidic (crude lipid 10%) diets were formulated by replacing 0%, 25%, 50%,75%, and 100% of the fish meal with SPC and were designated the FM, R25, R50, R75, and R100 groups, respectively. All diets were supplemented with the appropriate amounts of crystalline lysine and methionine, based on lysine and methionine contents in the control group. Each diet was assigned randomly to triplicate groups of 60 ind/cage. All larvae were stocked into experimental cages (1.5 m×1.5 m×2 m) at Xihugang, Xiangshan County, Ningbo city, Zhejiang Province, China. As results, none of the experimental diets had a significant effect on the weight gain rate, specific growth rate, survival rate, or feed conversion ratio compared with those of fish fed the FM diet (>0.05). Whole-body, muscle, and crude lipid contents decreased as the SPC replacement level was increased, and fish fed the R100 diet had the lowest contents. However, whole-body and muscle moisture contents increased as the SPC replacement level was increased. No differences in any of the serum biochemical indices were observed among the groups (>0.05); briefly, serum total protein and albumin contents decreased, and fish fed the R100 diet had the lowest contents. Cholesterol and triglycerides tended to increase initially, and then decreased. Liver histology revealed serious damage to hepatocytes when SPC reached 75% (R75), as large cytoplasmic vacuole-like spaces were present, indicating excess fat accumulation, and nuclei had dissolved gradually or were absent in many of these cells. These results suggest that protein from SPC can substitute for up to 75% of the fish meal protein in the diet without affecting growth of .

Abstract:Stable carbon and nitrogen isotope ratios (N) provide a predictable method to evaluate the contribution of food sources to bighead carp (δ¹⁵N of bighead carp in four treatments, such as fertilization (group A), fertilization + 1/2 feeding (group B), fertilization feeding (group C), and feeding (group D) to analyze variations in the stable isotope ratios and the contribution rates of different food sources. The results showed that the N values in group A tended to be higher than those in the other groups[(−23.8±0.1)‰ and (10.8±0.4)‰, respectively, <0.05]. Zooplankton, particulate organic matter, and artificial feed were the food sources used in the different treatments, and their N values were lower than those of bighead carp. Zooplankton was a major food source for bighead carp in group A, with a mean contribution rate of (65.6±3.2)%, whereas artificial feed was the main food source in the other three groups, of which the contribution rate in group B was relatively higher (82.1%). These results suggest that artificial feed was absorbed well by bighead carp. However, fertilizing the cultured plankton effectively improved the contribution by artificial feed, decreased the amount of feed, and reduced the pollution caused by residual feed. The present study provides a theoretical basis to invest and culture bighead carp.

Abstract:An 8-week feeding trial was conducted to determine the effects of different carbohydrate sources on growth performance, body composition, and physiological and biochemical parameters of juvenile Dabry's sturgeon (). Six isonitrogenous and isoenergetic semi-purified diets were prepared with dextrin, wheat starch, corn starch, α-starch, saccharose, and glucose as carbohydrate sources. Mean initial body weight of the study fish was (68.05±1.63) g. The results indicated that feed efficiency and the protein efficiency ratio values of the dextrin, wheat, starch, corn starch, and α-starch groups were significantly higher than those in the saccharose and glucose groups (<0.05). Fish fed the diet containing corn starch had the highest weight gain ratio, specific growth rate, and feed efficiency. No effect of the different carbohydrate sources on condition factor was observed (>0.05). However, the hepatopancreas somatic index (HSI) and visceral somatic index (VSI) were significantly affected by the different carbohydrate sources (<0.05). The highest HIS and VSI were seen in the glucose group, whereas the lowest HIS and VSI were observed in the wheat starch group. The wheat starch group had the highest crude protein content in whole body, muscle, and liver. The glucose group had significantly lower whole-body and muscle crude protein contents than those in the other groups (<0.05). Whole-body, muscle, and crude lipid contents in the dextrin, saccharose, and glucose groups were significantly higher than those in the other groups (<0.05). Hepatic glycogen content was significantly higher in the α-starch group than that in the other groups (<0.05). Muscle glycogen contents in the α-starch and glucose groups were significantly higher than those in the other groups (<0.05). Triglyceride and total cholesterol levels in the liver and serum were positively correlated with whole-body and serum glucose contents. The different carbohydrate sources had significant effects on enzyme activities in the digestive tract and those of pyruvatekinase and phosphoenolpyruvate carboxy kinase in the liver (<0.05). However, hexokinase and phosphoenolpyruvate carboxylase activities in the liver were not significantly affected by the different dietary carbohydrate sources (>0.05). These results indicate that corn starch was the optimal carbohydrate source for juvenile Dabry's sturgeon.

Abstract:The effects of five water temperatures (15.8℃, 21.0℃, 26.6℃, 30.9℃, 36.5℃) on respiration and excretion in three sizes (27.4 g±0.8 g, 276.5 g±17.3 g, and 575.4 g±18.8 g) of hybrid grouper () were investigated using ecological methods in the laboratory. The experimental results showed that both water temperature and body weight had significant effects on oxygen consumption and ammonia excretion rates of hybrid grouper (<0.05). Under controlled laboratory conditions, oxygen consumption and ammonia excretion rates increased initially in all sizes of hybrid grouper, then decreased and increased again as water temperature was increased. These rates were highest at 26.6℃, such as (1.510±0.124) mg/(g·h), (0.306±0.007) mg/(g·h), and (0.161±0.010) mg/(g·h) and (47.739±21.048) μg/(g·h), (13.956±1.783) μg/(g·h), and (6.811±1.882) μg/(g·h), respectively. The regression equations between oxygen consumption rate and ammonia excretion rate and water temperature were quadratic (=1.000). Oxygen consumption and ammonia excretion rates within the temperature range of 15.8-6.5℃ decreased roughly with an increase in body weight at the same water temperature, and the regression equations for oxygen consumption rate mg/(g·h) and ammonia excretion rate μg/(g·h)and body weight were quadratic ( values for the oxygen consumption and ammonia excretion rates in all sizes of hybrid grouper peaked at water temperatures of 21.0-26.6℃ and were at their minimum at 26.6-30.9℃. The mean O/N ratios of the small- and medium- and large-sized hybrid grouper were 21.535, 15.713, and 12.097 to 113.541, 32.193, and 27.094, respectively, indicating that protein, fat, and carbohydrate wereconsumed by the small-sized hybrid grouper for energy, and that protein and fat were consumed by medium-and large-sized hybrid grouper.

Abstract:This experiment was conducted to evaluate different artificially formulated feeds on promoting gonadal development in broodstock during the nutrient enrichment stage. Three kinds of formulated feeds, numbered diets no.1 (without krill meal), no.2 (10% krill meal), and no.3 (20% krill meal) were used as the experimental groups, with two replicates, and natural polychaete worm bait was used as the control group. The purpose of the experiment was to determine the appropriate formulated feed to enhance gonadal development in broodstock. The four treatment groups were fed the four different feeds for 60 d, and whole-body, hepatopancreatic, and gonad weights were determined. In addition, the fatty acid profiles of the four feeds and those of the hepatopancreas and gonads were analyzed in the four treatment groups. Fatty acid profiles of feed are important for gonadal development and reproduction in brood stock, as they can affect the hepatopancreatic and gonadal fatty acid profiles, as well as gonadal development. Eicosapentaenoic acid (EPA) docosahexaenoic acid (DHA), and arachidonic acid (AA) are three kinds of polyunsaturated fatty acids (PUFAs) that play significant roles in gonadal development. T he results showed that female broodstock in the control group had the significantly highest weight gain rate, which was (78.10±6.38)% (<0.05), compared with that of the others. No difference in weight gain rate (>0.05) was observed between female broodstock in the three formulated feed groups. Weight gain rate of male broodstock was lower than that of females. Males in the control group had the highest weight gain rate, but no difference (>0.05) was observed between males fed diets no. 3 and no. 2. Fish fed diet no.2 had the lowest hepatopancreatic index at (2.37±0.02)%; the hepatopancreatic index was not different (>0.05) from that in the control group, but was significantly different (<0.05) from that in the other two treatment groups. Fish fed diet no. 2 had a significantly higher (<0.05) gonadosomatic index (GSI) than that in the other groups, but no difference (>0.05) in GSI was observed between fish fed diet no.3 and the control group. The fatty acid profiles differed among the four feeds. More ∑PUFA was detected in than those in the artificially formulated feeds, and EPA, DHA, and AA contents in were higher than those in the formulated feeds. Diet nos. 2 and 3 had significantly more (>0.05) ∑PUFA as well as more EPA, DHA, and AA than those in diet no.1, indicating that the fatty acid profiles in diet nos. 2 and 3 were closer to those in . These results show that the fatty acid profiles in gonads were correlated with the fatty acid profiles in the brood stock feeds.

Abstract:Eight iso-nitrogenous and iso-energetic (crude protein, 48% and gross energy, 18.5 MJ/kg) diets (L5, L10, Z5, Z10, X5, X10, M5, and M10) were formulated with 5% and 10% waxy corn starch (L), high-amylose corn starch (Z), wheat starch (X), and cassava starch (M) to determine a suitable starch source and supplementation level for a largemouth bass, , diet. Fish (initial body weight, 23.46 g±0.19 g) were fed to apparent satiation twice daily for 45 d. The results showed that the supplemented dietary starch level and starch source had significant effects on growth, feed utilization, body composition, and non-specific immunological indices of largemouth bass. Significant decreases in specific growth rate and feed intake were observed with increasing content of the same starch from 5% to 10%. However, feed and protein efficiency increased significantly in the L10, X10, and M10 groups, compared with those in the L5, X5 and M5 groups, whereas no differences were detected in these parameters between the Z5 and Z10 groups. Hepatosomatic index, viscerosomatic index, and liver glycogen concentration increased significantly in the L10, X10, and M10 groups, compared with those in the L5, X5, and M5 groups, but no difference was found in the viscerosomatic index between the Z5 and Z10 groups Whole-body and liver lipid contents, as well as liver protein content decreased significantly when any of the supplemented starches were increased from 5% to 10% in the diets. Blood erythrocyte count and hematocrit in the L10 group, serum triglyceride content in the Z10 group, and hematocrit and serum triglyceride content in the X10 group decreased significantly, compared with those in the L5, Z5, and X5 groups. Serum 50% hemolytic complement (CH₅₀) activity was significantly lower in the Z10 group than that in the Z5 group. Serum glucose concentrations from 3 to 12 h after a meal in the L5, Z5, X5, and M5 groups were lower than those in the L10, Z10, X10, and M10 groups. Apparent digestibility of the dietary starch and hepatosomatic index were significantly lower in the Z5 group compared with those in the L5, X5, and M5 groups, whereas whole-body lipid deposition rate increased significantly. Apparent digestibility of dietary protein was significantly lower in the M5 group than that in the L5, Z5, and X5 groups. Apparent digestibility of dietary starch, hepatosomatic index, viscerosomatic index, and liver glycogen concentration decreased significantly in the Z10 group compared with those in the L10, X10, and M10 groups, whereas whole-body lipid deposition rate increased significantly. Apparent digestibility of dietary protein was significantly lower in the M10 group than that in the L10, Z10, and X10 groups. Significant interactions were detected between feeding rate, specific growth rate, protein digestion rate, lipid deposition rate, hepatosomatic index, glycogen content, erythrocyte count, serum triglyceride level, and serum CH₅₀ activity between the dietary starch supplementation level and starch source. In conclusion, the starch source and supplementation level in the largemouth bass diet exerted different effects on growth performance, body composition, hematological parameters, non-specific immunological indices, and serum glucose. Adding 10% high-amylose corn starch was the most appropriate supplement in the diet for largemouth bass.

Abstract:This study was conducted to provide basic information for a comprehensive evaluation of nutritional components in the muscle tissues of five cultured fish species and to guide commercial-scale manufacturing of fish feed. Four-year-old originally from Dali Lake (DL) and Songhuajiang River progeny (SHJ), from the Ertix River (GT), and two hybrids, such as hybrids DS (DL♀×SHJ♂) and DG (DL♀×GT♂), were held in a low saline-alkaline pond. Fifteen fish from each genetic group were divided into three replicates, and their nutrient components and muscle amino acid and fatty acid contents were measured and analyzed. The results showed significant differences in ash, crude protein, and crude fat contents among the five genetic groups except that of water (<0.05). Ash content (1.77%) was significantly higher in DS than that in the other four genetic groups (1.16%-1.22%), and crude fat content (7.23%) was significantly higher than that of DL (4.31%), SHJ (4.22%), and the hybrid DG (3.32%). Eighteen amino acids were detected in the five genetic groups, and total amino acid contents were 73.06%-79.29%.The total amino acid components were significantly higher in DG and DL than those in the other three species (<0.05). In addition, the DG and DL groups had higher amino acid, chemical, and essential amino acid index scores than those of the others, which coincided with the higher crude protein content in DL, indicating that the higher crude protein in DG was inherited from DL, and was evidence of hybrid vigor. Twenty-three fatty acids were detected in the five genetic groups, and the saturated fatty acid (SFA), mono-unsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) contents were 15.03%-19.06%, 49.15%-53.92%, and 27.54%-29.40%, respectively. The PUFA to SFA ratio was 1.53-1.83. GT and DL had relatively higher SFA and PUFA contents, and the DG and DS hybrids had higher MUFA contents. Taken together, the five cultured genetic groups had balanced nutrient components in muscle and could be excellent protein sources for human consumption. Nutrient quality was improved effectively through hybridization; thus, satisfying market requirements with higher lipid and protein contents from DS and lower lipid but higher protein contents from DG.

Abstract:This study applied headspace solid phase microextraction combined with comprehensive two-dimensional gas chromatography-time of flight mass spectrometry to analyze the volatile flavor compounds in the skin and scales of cultured in small cages (X), submersible cages (S), and purse seines (W). A total of 118 volatile components were detected in skin and scales of fish from X, S, and W. In addition, aldehydes, alcohols, ketones, and hydrocarbons were the dominant compounds. Significant differences were observed between the volatile components in the skin and scales of X, S, and W (<0.05). In particular, carbonyl compound and alcohol contents were highest in scales of W fish, followed by scales of those in S, and lowest in scales of fish from X. The carbonyl compound and alcohol contents in skin of fish in W were significantly higher than those in skin of fish from X and S, but no differences were detected between skin from fish in X and S. Differences in carbonyl compound and alcohol contents were directly related with polyunsaturated fatty acid (PUFA) content in the bodies of cultured using different methods. PUFA content accumulated gradually in the body of as physical activity and natural food intake increased. Therefore, the carbonyl compounds and alcohols produced by PUFAs increased accordingly. Among the volatile compounds in scales of fish held in all three enclosures, 5, 15, and 13 kinds of compounds (ROVA≥1) were selected as key odorants with relative odor activity value. The number of key odor compounds (ROVA≥1) in scales of fish from W and S were more than that in scales of fish from X. In addition, more key odor compounds were detected in scales of fish from W and S than from the other. Nine, 10, and 16 key odor compounds (ROVA≥1) were selected in skin from fish in the X, S, and W. More key odor compounds (ROVA≥1) were detected in scales from fish in W than those in skin from fish in X and S. Similarly, more key odor compounds were detected in scales of fish from W than the others. We concluded that carbonyl compound and alcohol contents in W was higher than those in X and S. In addition, the flavor composition in W was optimal. The number and variety of key odor compounds were greater in W than those in X and S, and, flavor in W was richer than that in X and S.

Abstract:The Bleeker is mainly distributed throughout the tropical and subtropical coastal seas of the Indo-Pacific region. The specie is one of the heavily traded and expensive materials in traditional Chinese medicine (TCM) and has been cultured for generations in public and private aquaria, its conservation status is listed by the International Union for the Conservation of Nature (IUCN) as vulnerable. In order to meet the demand from Chinese traditional medicines, increased trade of seahorses has occurred. However, seahorse culture is a relatively new industry, and many culture problems have been encountered which need to be studied and solved. Feeding behavior is an important index of an animal's suitability to their living environment. Study on the feeding behavior has significance to the strategy of seahorse resource enhancement. In order to provide a theoretical reference for the feeding technology and culturing condition of , we examined the effect of varying water temperatures on the growth rate and feeding behavior. The experiment included four different water temperatures (18℃, 23℃, 28℃ and natural temperature CT) in the laboratory for 28 days, with three replicates per treatment. Results revealed that the growth rate was significantly different among the four treatment groups, and the fastest growth appeared at 23℃ treatment. The seahorses feeding behavior was observed more frequently at the treatment of 28℃ as compared with those at other treatments. At 18℃ and CT treatment groups, the seahorses were more entangled in the attachment, clustered distribution and insensitive to food. At 23℃ and 28℃ treatments, seahorses were more sensitivity and more frequently active feeding. In conclusion, variation in water temperature produced significant differences in seahorse growth and feeding behavior. Present study has provided the results that will be useful in rearing.

Abstract:Cryptocarioniasis, which is caused by , is difficult to control in cultured large yellow croaker, and dozens of other marine fish species and is seriously threatening development of the aquaculture industry. To investigate the effects of the Chinese herbal compound (HD-2)[Dryopteris crassirhizoma, (Burm. f.) Nees] for treating cryptocarioniasis, were collected and fed different doses of HD-2 to compare changes in non-specific immune indices, such as lysozyme (LZM), total superoxide dismutase(T-SOD), alkaline phosphatase (AKP), and acidic phosphatase (ACP) activities. The results showed that HD-2 promoted LZM, T-SOD, AKP, and ACP activities, and maximum activities were observed 14-21 d after feeding 2% HD-2. No . However, 20%, 54%, and 89% of the theronts were killed at concentrations of 80 mg/L, 100 mg/L, and 200 mg/L HD-2, respectively; all theronts were killed by 400 mg/L HD-2. The median lethal concentration for 50% (LC₅₀) of the theronts was 109 mg/L. A 15-d indoor therapeutic experiment was performed in which fish were assigned randomly into groups A-C and a control. Fish in group A had a survival rate of 50% after being fed 20 g/kg HD-2 in feed and dipped in a 100 mg/L HD-2 bath. Fish in group B had a survival rate of 50.67% after being fed 20 g/kg HD-2 in feed and dipped in a 50 mg/L HD-2 bath. Fish in group C achieved a survival rate of 42.67% after being fed 20 g/kg HD-2 in feed. The survival rates of the three treatment groups were significantly higher than that of the control group (2.67%). The number of trophontson the pectoral fins of was significantly lower than that in the control group. The number of trophonts on gill filaments declined during the three treatments. In contrast, the number of trophonts in the control group increased significantly, where as the number of tomonts in the treated groups decreased significantly. The numbers of tomonts in groups A, B, and C decreased by 100%, 91.1%, and 77.7%, respectively, on day 12 and were significantly different from those in the control group. In conclusion, simultaneous oral administration and a medicated bath in HD-2 was the most efficacious treatment for cryptocarioniasis. The 2% HD-2 oral treatment added to feed for 6-14 d is recommended to guarantee higher survival rates of based on availability and cost considerations. These results provide a theoretical reference and technical support for preventing and controlling cryptocarioniasis, and will be useful for fish culture in future.

Abstract:Kinetic parameters were determined for the biological accumulation and release of lead (Pb) in muscle, the hepatopancreas, and exoskeleton of to assess the enrichment and release characteristics of Pb in seawater, feed, and tissues using a two-compartment bioconcentration model. Shrimp were exposed to seawater with Pb concentrations of 0.0015 mg/L(B0), 0.0080 mg/L(B1), 0.0466 mg/L(B2), and 0.2302 mg/L(B3). Shrimp were provided a diet with Pb concentrations of 2.089 mg/kg(A0), 2.750 mg/kg(A1), 6.103 mg/kg(A2), and 14.520 mg/kg(A3). The heavy metal uptake rate constant (), bioconcentration factor (BCF), biological half-life(in vivo () were obtained by non-linear curve fitting. The results showed that muscle, exoskeletal, and hepatopancreatic tissue contents were less <0.5 mg/kg after feeding Pb. Pb in all tissues increased to >0.5 mg/kg after exposing shrimp to the two lower Pb concentrations in seawater as the Pb concentration in feed was increased in shrimp in the B3 seawater treatment. The Pb release rate by the hepatopancreas was higher than that by muscle or the exoskeleton. A three factor repeated-measures analysis of variance with feed concentration, seawater concentration, and enrichment time as the factors showed that all three factors had significant effects in the different tissues. In addition, the Pb accumulating effect in the exoskeleton based on feed concentration was marginally significant (=0.071). A feed, seawater, and time interaction effect analysis resulted in a significant interaction among the three factors. An analysis of Pb feed and seawater concentrations, as well as Pb duration in different tissues showed that the contribution of Pb concentration in seawater was greater than that in feed during Pb enrichment in each tissue. At steady state, the Pb concentrations in muscle of shrimp in the A0 and B0-B3 groups were 0.128-2.981 mg/kg, and those in the hepatopancreas were 0.399-4.765 mg/kg. The values for Pb in the muscle and hepatopancreas were 2-7 d and 3-7 d, respectively. The Pb concentrations in muscle of shrimp from the A2 and B0-B3 groups were 0.380-1.000 mg/kg, and in the hepatopancreas were 0.288-5.355 mg/kg. The values for Pb in muscle and hepatopancreas were 2-7 d and 2-5 d. The steady state concentration of Pb in the hepatopancreas was higher than that in muscle.

Abstract:Slow growth of farmed has been reported throughout shrimp growing areas of Zhoushan since 2013, resulting in severe economic losses for high density farmers. Bacterial culture, histopathology, and polymerase chain reaction analyses were conducted to identify the pathogenicity of these slow growing, multiple infections. Infectious hypodermal and hematopoietic necrosis virus (IHHNV) and the microsporidian (EHP), which are typical slow-growing pathogens, were analyzed by polymerase chain reaction in 270 samples collected from high-density, slow-growing Zhoushan shrimp in farm ponds. The results showed a high incidence of EHP (230/270, 85.19%), but no evidence of IHHNV infection. Bacteria were not consistently isolated from the diseased shrimp, and EHP and IHHNV were not detected in any normal appearing shrimp. A BLAST analysis of the sequenced product revealed 99.55% similarity with the matching region of small subunit rRNA from EHP (KF362130). Histopathological sections showed microsporidial spores only in the cytoplasm of hepatopancreatic tubule epithelial cells from diseased shrimp. Based on the ultrastructural features of the family and the cytoplasmic location of the plasmodia, the pathogen causing slow growth syndrome in Zhoushan was EHP. EHP is a microsporidian parasite that was first isolated and characterized from the giant or black tiger shrimp . Although EHP does not appear to cause mortality, shrimp farmers have reported that it is associated with severely retarded growth in compared with their unaffected counterparts. No specific signs were observed in shrimp at the early stage of pathogenicity, which differs from the most common microsporidian reported previously from cotton shrimp. Further studies are required to understand the interaction between this host and pathogen.

Abstract:is a rapidly maturing fish and an important aquaculture species in China. A comprehensive analysis of the genetic structure of a germplasm resource is an essential prerequisite for their effective protection and utilization. The genetic diversity and structure of six populations-Donggang (DG), Qingdao (QD), Qinhuangdao (QHD), Suizhong (SZ), Zhuhai (ZH), and Zhoushan (ZS), inhabiting the Chinese coast were determined using eight microsatellite DNA markers. A medium level of genetic diversity was detected among the six populations but no significant differences were observed. Population SZ had the least genetic diversity, whereas ZS had the most. Most populations, except QHD, had a significant loss of heterozygosity (<0.01), which was also revealed by the global Hardy-Weinberg equilibrium (<0.01) between the Lama18 and Lama42 markers. The analysis of molecular variance results detected a significant difference in variance between populations, between individuals, and between individuals within populations (<0.01); the pair-wise Fst between groups and genetic distance results showed that maximum genetic differentiation and genetic distance occurred between ZS and the other five populations. No significant genetic differentiation was detected among the SZ, DG, QHD, and QD populations. A cluster analysis showed that ZS, ZH, and QHD were clustered with SZ, DG, and QD. Three genetic compositions were observed in the six populations. The genetic information in ZS was intact and was not mixed. The other five populations had a similar genetic composition and were significantly mixed genetically. Approximately 40% genetic similarity was detected between QHD and ZH. These results indicate that genetic differentiation has occurred between the ZS population and the other five populations analyzed. The genetic diversity among the five populations (DG, QD, QHD, SZ, and ZH) of inhabiting the Chinese coast has decreased and has become more homogeneous due to interactions with escapees from local aquaculture operations.

Abstract:We evaluated variations of in fish community structure in the Bohai Sea using data collected during trawl surveys in August 2010-2014. The dominant species, individual mean body weight, relative resource, Jaccard's similarity coefficient, an abundance biomass comparison curve and multivariate statistical analyses were used to evaluate the data. The results showed that the abundance of all fish species decreased from 2010 to 2013, the abundance of a few species increased in 2014, but the abundance of all warm-temperate species decreased from 2010 to 2014. The dominant fish species changed drastically from 2010 to 2014, and the dominant demersal fish species changed from sp., whereas the dominant pelagic fish species changed from phytoplankton, to Engraulis japonicus, >0.05) among mean station resource were observed for any of the fish during 2010-2014, and the mean station resource data had hetero generous variances (<0.05) during 2010-2014, except data of all fish between 2013 and 2014, and those of demersal fish between 2010 and 2014. The abundance biomass comparisons and statistical W values showed that the fish community was stable in 2010, relatively stable in 2012, but disturbed in 2014, and seriously disturbed in 2013.The annual relative resource and distribution of the five fish species with the highest contribution rate to similarity in the groups and differences between groups changed significantly. Mean weight of all fish decreased from 2010 to 2014, as the sizes of all fish in the Bohai Sea has tended to decrease in recent years. In conclusion, the fish community in the Bohai Sea changed dramatically from 2010 to 2014 and remains in a disturbed state.

Abstract:This review introduces the development and applications of germ cell transplantation (GTC) (also called as surrogate production) as a newly emerging biotechnology. It is achieved by inducing germ-line chimerism between different species. Primordial germ cells (PGCs) and spermatogonial (or oogonia) are the key material of this technique. During the last decade, several different approaches have been developed for germ cell transplantation in fish, using different type of germ cell and recipients of various ages and life stages, such as blastula-stage embryos, newly hatched larvae and sexually mature specimens. All of these achievements give it advantages for application in many aquaculture research fields. (1) It has opened up new scenarios for the study of germ cell and niche biology and the possibility of generating transgenic fish. (2) Combined with the technique of cryopreservation of germ cell, whole testes and even whole fish, it could be a powerful tool for preserving valuable fish strains with desirable genetic traits and endangered species. (3) It presents a unique sex-selective breeding system that is superior to traditional endocrine sex control strategies. (4) It could serve as a novel and efficient method of producing fish seeds with increased genetic diversity for use in stock enhancement.