Abstract:We analyzed the associations between the polymorphisms of the PRL (prolactin) gene and the growth traits and flesh components of the grass carp, . Six variable sites with mutation rates exceeding 30% were detected in 10 individuals by sequencing the full length of the gene. These included five single-nucleotide polymorphic loci and one insert mutation (-/CACTCACTA), designated > -/+, respectively. The polymorphisms at the variable sites were examined in 192 juvenile using allele-specific PCR and genotyping. The associations between the polymorphisms at these loci and the growth traits and flesh components of the fish were analyzed with general linear models. The polymorphisms at three loci () and one locus () were significantly associated with growth traits and the flesh protein content ( < 0.05), respectively. Multiple comparisons of the traits were made with the genotypes at each locus. The standard length and bodyweight of individuals with the mutant genotypes (-+ and ++) at ->+ were significantly higher than those of individuals with the wild-type genotype (- -) ( < 0.05). In contrast, the standard length and bodyweight of individuals with the mutant genotypes at (TG and GG) were significantly lower than those of individuals with the wild-type genotypes at < 0.05). For the, Individuals with the mutant genotype CC at had significantly higher flesh protein content than individuals with the other genotypes (GG and GC) ( < 0.05). Similar results were found in multiple comparisons for the traits of two loci groups. The standard length and bodyweight of individuals that contained mutant genotypes (-+ and ++) at ->+ were generally higher than those of individuals with the wild-type genotype (- -). The fat and protein contents of individuals that contained the mutant genotype CC at were generally higher than those of individuals with the other genotypes (GG or GC), and the protein contents were significantly different ( < 0.05). Overall, there were significant associations between the polymorphisms of the . Therefore, the different variable sites in the gene might have utility as markers for practical breeding programs for growth traits and flesh components in .

Abstract:The growth and development of the vertebrate skeleton is regulated by the bone morphogenetic proteins (BMPs), among which BMP4 is one of the most active osteoinduction factors. In this study, we cloned the ) and described its expression profiling. The cDNA sequence was 1680 bp, and contained a 5'-untranslated region (5'-UTR) of 419 bp, an open reading frame (ORF) of 1212 bp encoding a protein of 403 amino acids, and a 3'-UTR of 49 bp. Homology and phylogenetic analyses revealed that the deduced amino acid sequence of the BMP4 protein shares highest identity with those of Cichlidae species, and fish BMP4 forms a single lineage distinct from the BMP4 proteins of other vertebrates. The tissue expression distribution of the mRNA was predominantly expressed in the gill, and less in the dorsal fin, cartilage, etc. In the early developmental stages, mRNA was also detected at the egg, larval, juvenile, and fingerling stages, with the highest expression in the egg stage (cleavage and gastrula periods), and the second highest in the larval stage (3-4 days old). Whole-mount in situ hybridization showed that mRNA was firstly detected in head and anterior region in the early larval stage, and then appeared in the crown-like larval fin, jaw, and pectoral fin. mRNA was then predominantly expressed in all the fins and the operculum during the early juvenile stage. These results demonstrate the important role of BMP4 in the fin development of , and provide a theoretical foundation for investigating the mechanisms regulating fish bone development.

Abstract:The lack of a PepT1 antibody for fish has hindered analysis of PepT1 protein expression by immune tissue chemistry or western blot. We analyzed the expression and distribution of PepT1 in L. at the transcriptional and protein levels. The immunogenic cDNA of PepT1 was obtained by PCR and the fragments were inserted into a pET-32a (+) Vector and transformed into Rosetta. The target polypeptide was expressed after induction with 1‰ IPTG. The molecular weight of the recombinant protein was measured by SDS-PAGE electrophoresis. The purified PepT1 recombinant protein was used to immunize New Zealand long-eared rabbits by ear vein injection combined with subcutaneous injection for 38 d to obtain rabbit anti carp PepT1 polyclonal antibody. Enzyme-Linked Immuno Sorbent Assay (ELISA) was used to evaluate the antibody titers, immunohistochemistry was used to check the tissue expression of PepT1, and real-time fluorescent quantitative PCR was used to evaluate the expression of PepT1 at the transcriptional level. The molecular weight of the target polypeptide was ~28 kDa, and the antibody titer was 4×10⁵, suggesting that activity was high. The PepT1 protein was expressed in the foregut, midgut, hindgut, spleen, hepatopancreas, and kidneys. The level of expression was remarkably higher in the foregut and midgut than in other tissues, which may be due to their roles in absorption of peptides during digestion. The positive immune staining region in the renal tissue was obvious and clear, and consistent with short peptides being re-absorbed by PepT1 distributed on the renal tubular basement membrane. Additionally, the PepT1 transporter was also expressed in the hepatopancreas and spleen, both metabolically active tissues in carp. In conclusion, the rabbit anti-carp PepT1 polyclonal antibody prepared in this study can effectively identify PepT1 from different tissues of carp. The expression pattern of PepT1 is similar to that at the transcriptional level. Our results provide a foundation for study of the structure and function of PepT1 at both the molecular and protein levels in carp. Additionally, we provide a basis for analysis of the relationship between small peptide absorption and protein metabolism. The antibody described here will be an important tool for localization and quantitative research of PepT1 in related fish such as , that belong to the family Cyprinidae or even in Cypriniformes.

Abstract:Myogenin (MyoG) is a vital member of the myogenic regulatory factors (MRFs), and plays an essential role in regulating myocyte development and maturity. , one of the most economically important fish in China, displays sexual dimorphism in both size and growth. To characterize the , we cloned the full-length cDNA of this species with reverse transcription-PCR and the rapid amplification of cDNA ends. The cDNA included a 63-bp complete 5' untranslated region (5'-UTR), a 521-bp 3'-UTR, and a 762-bp open reading frame encoding a 253-amino-acid peptide containing a basic arginine-rich domain and the helix-loop-helix structural domain typical of MRFs. The amino acid sequence was more similar to that of (94.1%) than to those of other species. A phylogenetic analysis based on amino acid sequences showed that I. furcatus, and of the Siluriformes. These results indicate a high degree of conservation during gene evolution. An expression analysis of MyoG in the heart, brain, liver, kidney, muscle, stomach, intestine, and gill showed that it is only significantly highly expressed in muscle tissue ( < 0.05). Western blot analysis demonstrated that MyoG protein expression was higher in males than in females. We infer that MyoG plays an important role in the muscle development and growth of male and female based on its expression characteristics at the gene and protein levels. These results extend our understanding of MyoG function, clarify the growth and differentiation of male and female P. fulvidraco strains.

Abstract:, the most valuable prawn species, plays an important role in aquaculture in China, so protective measures must be taken to ensure its normal reproduction. In this study, we measured the genetic diversity and genetic structure of 135 individuals collected from a before-release population (FLQ), an after-release population (FLH), and hatchery postlarvae population (FLXX) by sequencing the 938 bp mitochondrial D-loop. D-loop is a non-coding sequence which locates in the noncoding region of the mitochondrial genome. Overall, we detected 237 variable sites, 177 parsimony-informative sites, and 100 haplotypes. The nucleotide diversity index (0.02480) and haplotype diversity index (0.993) of the before-release population were higher than the nucleotide diversity (0.02125) and haplotype diversity (0.960) of the hatchery postlarvae, and slightly lower than the nucleotide diversity index (0.02394) and haplotype diversity index (0.993) of the after-release population. The genetic distances within population of the three groups were 0.02598, 0.02504, and 0.02216, respectively. The genetic distance between the released postlarval and before-release populations was 0.02582; that between the released postlarval and after-release populations was 0.2524; and that between the before-release and after-release populations was 0.02567. Analysis of molecular variance showed that for the before-release population and after-release population was 0.00629 ( > 0.05), so that most variation was within each population, although the finding was not significant. Between the hatchery postlarvae and the after-release population, < 0.01), so the genetic variation coefficient between groups was 8.15% and the genetic variation within the populations accounted for 91.85%, indicating that most genetic variation occurred within the populations, and the genetic differentiation among the populations was low. In neutrality tests, the values of Tajima's were negative, with deviations from the neutral mode, indicating that has been subject to population expansion and natural selection. In summary, proliferation activity not only maintains resources, but also the genetic structure of a population, which ensures that the after-release population retains a high level of genetic diversity.

Abstract:The Manila clam, , which is widely distributed along the coasts of China, is an economically important marine bivalve species in China's aquaculture industry. The world production of this species was 3.6 million metric tons in 2010. As a country, China accounts for the largest proportion (~90%) of the total global production of Manila clams, producing about 3.0 million metric tons annually. This species includes several pedigree lines, such as White, Zebra, Liangdao Red, and Marine Red that are distributed in the coastal areas in North China. Microsatellite markers are a powerful tool because of their high level of polymorphism, stability, and co-dominance. As a result, they are used widely in studies of genetic diversity and population differentiation. In this study, 10 microsatellite markers were analyzed in three selected lines and one wild population of . The number of alleles per locus ranged from 3 to 12, and allelic richness range was 3.0-10.7. Among all SSR loci, the mean number of alleles breeding populations of white zebra strain was 4.4. Allelic richness was lowest in the breeding white clam population (4.267). The average number of alleles and allelic richness was highest in the wild population from Longwangtang (5.100 and 5.278, respectively). There was no difference in average allelic richness among all groups (Kruskal-Wallis test, d_{=0.412). Expected heterozygosity ranged from 0.307 to 0.757, and observed heterozygosity ranged from 0.208 to 0.583. The 77.5% inbreeding coefficient () was positive, indicating that there is a certain level of inbreeding within populations, resulting in varying degrees of loss of heterozygosity. The R. philippinarum were between 0.05 and 0.15, indicating a moderate level of differentiation. The values for comparisons between the Longwangtang population and the three shell colored lines were 0.15-0.25, indicating a greater level of differentiation. Our results suggest that genetic variation has not been significantly affected by mass selection and there remains high genetic variability in the mass selection lines, suggesting that there is still potential for increased gains in future selective breeding programs.}

Abstract:Two wild populations of the freshwater pearl mussel, , from Poyang Lake and Dongting Lake were selected as the base populations for breeding. The purple was included for its objective traits of purple shell nacre and a large body mass. To evaluate the effects of five generations of selection on , offspring families were established in the breeding group with the selected line and the control group with the ordinary population as parents. Comparisons were made of the shell nacre color (with CIELAB colorimetric measurements) and the growth traits of the two groups. The shell nacre color of the breeding group was deeper and richer than that of the control group. L^*, C^*, and dE^* of the breeding group were significantly different from those of the control group ( < 0.01), being 17.13% lower, 20.55% higher, and 22.56% higher than those of the control group, respectively. -L^* and dE^* gradually increased from the front to the back of the organism, indicating that the shell nacre color deepened gradually, whereas it did not change significantly in the control groups. The color parameters did not differ significantly at the same positions on the mussel shell ( > 0.05). The differences in the growth traits of the two groups were also highly significant ( < 0.01), and the shell length, shell height, shell width, and bodyweight of the breeding group were 12.30%, 9.95%, 8.60%, and 36.34% higher than those of the control group, respectively. A combined analysis of the shell nacre color parameters and the growth traits showed that B3, B2, B4, B5, and B6 displayed superior color and growth traits, and can be used for the further development of the stock. The correlation indices between the shell nacre color and growth traits were low, so that growth traits cannot be indirectly selected based on the shell nacre color. This study identified some offspring families with superior purple shell nacre or superior growth traits, and extends our research into germplasm resources for breeding of .

Abstract:The Tumenjiang River is an international river linking China, the Democratic People's Republic of Korea, and Russia. However, there has been little research into the mitten crab in this river. In this study, mitten crabs were sampled in the Tumenjiang River and their morphological traits were compared with other populations of Chinese mitten crab () sampled in the Yellow River and Liaohe River and with the Japanese mitten crab () collected on the Japanese mainland. Thirty-two morphological traits were examined with three kinds of multivariate analysis and a genetic cluster analysis. A discriminant analysis identified the lowest accuracy of discrimination among the Tumenjiang River crabs (83.30%). A principal components analysis revealed that the 12 largest differences in morphological traits in the Tumenjiang River population were between . A traditional clustering analysis showed the smallest differences between the Tumenjiang River crabs and the Japanese crabs. The results of a genetic clustering analysis also revealed that 60% of the individual crabs in the Tumenjiang River clustered with E. sinensis, and the remaining 30% of individuals may have been an introgression type. These results indicate that the mitten crab population in the Tumenjiang River comprises overlapping distributions or a genetically mixed population of , and that its morphological traits are closer to those of .

Abstract:Fish usually alter their swimming behavior to adapt to changes in food resources in their natural habitats. In this study, we investigated the effects of nutritional status on the preferred swimming behavior of the juvenile crucian carp (). Three experimental treatment groups with different nutritional status were established: the control group (fasted for 48 h), the feeding group (fed to satiation), and the starvation group (starved for 14 days). The experimental fish were videoed individually with a hand-made device for determining the preferred water velocity: a 1.5 m long conical raceway in which the water speed gradually increased from 11.86 cm/s to 65.45 cm/s at (25±1)℃. The water velocity of the 1st, 2nd, 3rd, 4th and 5th waster velocity intervals were 11.86-15.18 cm/s, 15.18-20.12 cm/s, 20.12-27.91 cm/s, 27.91-41.30 cm/s, 41.30-65.45 cm/s, respectively. The videos were analyzed with the Ethovision XT9 software, and several parameters were calculated in each water velocity interval: frequency(), and the percentage of time stayed( increased as the water velocity increased for both the control and feeding groups. showed no significant variation across different water velocity intervals in the fasting group, whereas the feeding group displayed the longest t, was significantly higher in the third and fourth water velocity intervals than in the other intervals in both the control and feeding groups, and the preferred swimming speeds of both the control and feeding groups were 20.12-41.30 cm/s. Two distinctly different preferred swimming behaviors were apparent in the starved group, which we arbitrarily designated the type I and type II preferred swimming behaviors. The type-I fish showed the largest values in the first water velocity interval, which were significantly higher than those in all other intervals. However, the of these fish showed extremely low values across all water velocity intervals, and was much lower than those of the other groups. Therefore, the preferred swimming speed of the type I fish from the starvation group was 11.86-15.18 cm/s. However, of the type II fish were similar to those of the control group, i.e., , of the type II fish was significantly higher in the third and fourth water velocity intervals than in the other intervals, and was significantly higher in the fourth water velocity interval than in the first, second, or fifth, but was not higher than that in the third water velocity interval. Consequently, the preferred swimming speed of the type II fish from the starvation group was 20.12-41.30 cm/s. This study shows that satiation feeding does not affect the preferred swimming speed of the crucian carp. However, during digestion, the crucian carp showed fewer traverses across different water speed intervals, but a longer period of stay each time they arrived at a given interval. Starvation may enhance the interindividual variations in energy reserves and hence the maintenance of swimming capacity, resulting in two distinctly different types of preferred swimming behavior in the fasting crucian carp. The type I fish showed a profoundly reduced preferred swimming speed, whereas the preferred swimming speed of the type II fish did not differ from that of the normally fed fish.

Abstract:Cobalt (Co) is one of the essential elements for fish, with various biological functions, including in growth promotion, blood production, reproduction, and immunity. In this study, we evaluated the effects of dietary cobalt methionine (CoMet) on growth performance, mineral deposition, and hepatic enzyme activities in the juvenile pearl gentian grouper ( ♀). Six extruded isonitrogenous and isoenergetic diets (51% crude protein and 13% crude lipid) were formulated by supplementing the basal diet with CoMet, providing actual Co contents of 0.30, 1.75, 3.42, 6.73, 12.56, or 25.50 mg/kg diet, which were fed to groups designated D1, D2, D3, D4, D5, and D6, respectively. Each diet was randomly assigned to triplicate groups of 20 juveniles (initial weight, 60.02±0.42 g). The experiment was conducted for 8 weeks in plastic cylindrical tanks in an indoor recirculated feeding system. The weight gain rate (WGR) and specific growth rate (SGR) of the juveniles both increased and then decreased with higher CoMet levels, and both were significantly higher in the D3 group than in the other groups ( < 0.05). The feed conversion rate declined with dietary CoMet level decrease but increased with dietatry CoMet increase, and the lowest feed conversion rate was observed in the D3 group. There were no significant differences in the moisture or ash contents of the muscle among the treatment groups ( > 0.05). The crude protein content of the muscle was clearly reduced by dietary CoMet, and was significantly lower in the D5 and D6 groups than in the other groups ( > 0.05). The muscle of fish fed the D6 diet had the highest crude lipid content ( < 0.05), and the muscle of fish fed the D4 diet had the lowest crude lipid content ( < 0.05). The Co contents of the liver, intestine, vertebrae, and muscle were significantly increased with CoMet supplementation ( < 0.05). The Co deposition rate in the whole body was markedly increased (from 0.30 mg/kg to 6.73 mg/kg diet) by dietary Co ( < 0.05), and then plateaued in the fish fed diets with Co contents of 12.56 mg/kg (D5) and 25.50 mg/kg (D6). The Fe, Cu, and Zn contents of the liver increased from group D1 to group D3 and then declined from group D4 to group D6 ( < 0.05). The Mn content of the liver was significantly reduced by dietary CoMet ( < 0.05). The glutathione peroxidase activity of the liver increased and then decreased as CoMet increased ( < 0.05). Fish fed the D5 or D6 diet showed significantly lower hepatic malondialdehyde contents ( < 0.05). The arginase activity in the liver was significantly increased by dietary CoMet ( < 0.05). The carboxypeptidase A activities in the livers of the D4, D5 and D6 groups were significantly higher than those in the D1, D2 and D3 groups ( > 0.05). In conclusion, under the experimental conditions used here, the optimum Co requirement for the juvenile pearl gentian grouper was 3.25 mg/kg diet (53.28 mg CoMet/kg diet) based on a broken-line regression of SGR.

Abstract:Seven isonitrogenous and isolipidic commercial diets with arginine contents of 2.13%, 2.42%, 2.71%, 2.95%, 3.20%, 3.48%, or 3.74%(dry matter) were formulated to investigate the effects of dietary arginine on growth performance, feed utilization, and serum total nitric oxide synthase in the juvenile orange-spotted grouper, . Triplicate groups of 30 fish with mean body weight of (7.52±0.02) g were randomly assigned to each treatment in separate tanks. The fish were fed the experimental diets for 8 weeks. The different levels of dietary arginine had no significant effect on the fish survival rate ( > 0.05). However, the weight gain rate and specific growth rate were significantly higher in the 2.95% arginine group than in the other groups ( < 0.05). The feed coefficient of the fish fed 2.95% arginine was significantly lower than that of the fish fed 2.13%, 2.42%, or 2.71% arginine ( < 0.05). The whole-body protein of the fish fed 3.20% arginine was significantly higher than that of the fish fed 2.13% arginine ( < 0.05). Serum glucose tended to decrease as dietary arginine increased, and was significantly higher in the fish fed 2.13% or 2.42% arginine than in those of the other groups ( < 0.05). Total protein and total nitric oxide synthase were significantly higher in the sera of fish fed 2.95% arginine than those in the sera of fish in the other groups ( < 0.05). These results indicate that dietary arginine not only promotes growth and body protein synthesis, but also improves the immunity of the grouper. A quadratic regression analysis of the specific growth rate against dietary arginine indicated that the optimum arginine level for the maximum growth of the juvenile grouper is 3.06%, corresponding to 6.07% of dietary protein on a dry weight basis.

Abstract:To investigate the bacterial species composition and distribution in the intestine of Boone and its aquacultural environment, we used Illumina MiSeq high-throughput pyrosequencing to analyze the composition of the bacterial communities in the gut of Boone and its aquacultural sediments and water, based on the 16S rRNA sequence. We detected 206, 265, and 270 genera in the gut of Boone, the aquaculture sediment, and the water, respectively. Ninety genera occurred in all three samples, 146 genera in the sediment and water, 128 in the sediment and intestine. This indicates the close interaction between the bacteria in the shrimp intestine and their aquacultural environment. Twenty, seventeen, and ten dominant genera with a relative abundance in the total sequences of > 1% occurred in the sediment, water, and intestine, respectively. Unclassified genera were the most abundant in all the samples, accounting for 23.08%, 37.13%, and 42.22% of the total sequences from the sediment, water, and Ohtaekwangia (4.79%), and Sediminibacterium (6.64%), (3.95%), and GPIIa (3.20%) were the dominant genera in water; and the predominant genera in the Acinetobacter (6.54%). Three, three, and six potentially pathogenic bacterial genera were also observed in the sediment, water, and Boone intestine, respectively, and the most abundant were (14.57%), respectively. Six, eight, and seven probiotic genera were also found in the sediment, water, and Boone intestine, respectively, and among these genera, five were shared by all three samples. A cluster analysis showed that the 20 most abundant operational taxonomic units in each sample (sediment, water, and Boone intestine) differed significantly. These results provide insight into the interactions between the microbiota in the intestine of Boone and those in its aquacultural environment, and provide new data for the development of probiotics.

Abstract:Formulated diets are an important factor in the sustainable development of aquaculture. However, no information is available on the growth performance or gonadal development of based on the formulated diets they are fed in pond culture. Therefore, in this study, we investigated the growth performance, survival, precocity rate of first-year crabs, gonadal development of second-year crabs, crab yield, size distribution, and feed conversion rate (FCR) of during the first and second years of pond culture when fed formulated diets. (1) During the whole juvenile crab culture stage (first year), no significant difference was detected in the growth performance of males and females, the average specific growth rate (SGR) was about 1.9%/d, and growth was rapid from June to September; the mean survival and precocity rates were around 10.0% and 4.9%, respectively, and females had significantly higher precocity rates than males; at the end of the first year of culture, the bodyweights of the precocious crabs and normal juveniles were around 19.8 g and 7.5 g, respectively, whereas the average yields of precocious crabs and normal juveniles were 229 kg/hm² and 2433 kg/hm², respectively; dietary consumption mainly occurred between July and October, which accounted for more than 80% of the total feed consumption, and the feed consumption was related to the crab biomass and water temperature; FCR was around 2.15 for the whole juvenile culture period. (2) During the whole adult crab culture stage (second year), the average SGRs of the female and male crabs were about 1.6%/d and 1.4%/d, respectively, and the males grew faster than the females after June; the final mean body weights of the adult males and females were around 126 g and 181 g, respectively; the survival rates of the females and males were 61.30% and 53.47%, respectively, and the overall survival was 58.4%, whereas the yields were around 412.20 kg/hm² (females), 536.10 kg/hm² (males), and 950 kg/hm² (overal); the highest dietary consumption by the adult crabs was recorded during the period from July to October, and FCR was 2.63 for the whole adult culture stage. (3) Pubescent molting predominantly occurred from August to September, and around 20 days earlier in females than in males; the rapid gonadal development of females occurred between September and October after the pubescent molt, whereas the gonadal development of the males took longer, and the gonadosomatic index reached around 0.8% before the pubescent molt; in both females and males, the hepatosomatic index tended to decline during the gonadal development period. In conclusion, feeding pond-reared a formulated diet ensures their normal growth and development during the first and second years in culture. This regimen could be extended to large-scale aquaculture practice to improve the productivity of the farming industry.

Abstract:Using a 1982 model of the Bohai Sea as the starting state, an Ecosim model was constructed for the Bohai Sea, including the 17 functional groups. Using time series of catch per unit effort (CPUE) and relative fishing effort as the driving factors, this model simulated the dynamic changes in different developmental stages of the Bohai Sea ecosystem and the impact of fishing on this ecosystem. The effects of climate change on the fishery resources of the Bohai Sea ecosystem were analyzed based on the environmental time series data. From 1982 to 2008, the biomass of Oratosquilla oratoria showed an increasing trend, and the biomasses of some species of high economic value showed decreasing trends, including Pseudosciaena polyactis, Scomberomorus niphonius, Engraulis japonicus, Lateolabrax japonicus, and Setipinna taty, and the biomasses of shrimp, crabs, and cephalopods were relatively stable. The mean trophic level of the catch clearly decreased from 1982 to 2008, and correlated significantly negatively with the total catch. The fishing-in-balance (FIB) index followed the same trends as the total catch, increasing after 1984. The Q-90 diversity index fluctuated slightly from 1982 to 1987, maintaining a growth trend in 1988-1994, followed by a rapid decline after 1994, from 2.5 to around 0.5, and the fishing biodiversity decreased. The surface salinity, surface temperature, and Yellow River runoff significantly affected the fishing yield in the Bohai Sea. A comparison of the initial (1982) and end states (2008) of the model showed that the maturity of the ecosystem decreased. Overfishing resulted in the degeneration of the ecosystem and a decline in the total biomass. Thus, fishing and environmental changes were the main factors affecting the changes in the fishery resources in the Bohai Sea ecosystem.

Abstract:The age composition, growth, and fecundity of was studied based on 209 samples collected in Jiaozhou Bay, Qingdao, in 2013 and 2014. Age was determined from the otoliths, which showed that the age of years, with a dominant age group of 2⁺-4⁺ years (77.5%). The relationship between the body length and bodyweight of =0.861). The von Bertalanffy growth equations for the body length and bodyweight of +2.697]) and 2.797, respectively. The growth of was initially rapid and then gradually stabilized. Its growth history could be divided into three stages: (1) rapid growth at 1⁺-3⁺ years old; (2) mature and stable growth at 3⁺-6⁺ years old; and (3) aged period at > 6⁺ years old. The sex ratio of < 0.05), and at every growth stage, the number of females was higher than that of males. The gonadal index and hepatosomatic index displayed opposite trends, suggesting that the liver of provides material and energy for gonadal maturation. The absolute fecundity of individuals ranged from 482 to 6166 grains (mean 3266 grains) and the individual relative fecundity was lower than that of oviparous fish, suggesting that this kind of reproductive strategy allows to maintain its population continuity with lower fecundity. Based on the age at inflection point and the body length at 50% sexual maturity, we suggest that a body length of 80 mm and a bodyweight of 20 g be set as the minimum landing standards for , to protect the fishery resource in Jiaozhou Bay, Qingdao.

Abstract:is one of the commercially important fish stocks that is depleted in Xiangshan Bay, a semi-enclosed tidal inlet located on the east coast of Zhejiang Province, East China. To rebuild the depleted stock and increase the fishermen's incomes, hundreds of thousands of hatchery juvenile are released into the bay annually. However, the effectiveness of the stock enhancement program has not yet been evaluated. In this study, we evaluated the recaptured yield and abundance of spawners originating from the hatchery-released juveniles of in Xiangshan Bay with a mark-recapture experiment and classical fishery models. We propose a method to prioritize the fishing strategy for the released stock. In September 2011, 11 055 5-month-old hatchery-reared juvenile were tagged with a scutcheon tag and released into Xiangshan Bay. The tagged fish were collected by local commercial fisheries during the two months following their release. The natural and fishing mortality of the hatchery-released individuals was 0.51/a and 1.31/a, respectively. In the fishery scenario, the stock enhancement program would generate 737 kg of recapture yield, and the direct input-output cost ratio would be 1: 3.99. The number of hatchery-released juveniles surviving to sexual maturity would be approximately 554, which would contribute to the spawning stock and help restore the depleted stock enhancement is strongly dependent on the level of fishing effort, and the appropriate reduction in the fishing effort would benefit both the recapture yield and the abundance of spawners originating from hatchery-released juvenile . If the fishing mortality declined to 0.46/a, or 36% of the estimated value, the total recapture yield would reach 1045 kg and the abundance of spawners originating from the hatchery-released juveniles would be 4413. These two values are 41.49% and 326.90% higher, respectively, than those in the current fishery scenario. In conclusion, the enhancement program in Xiangshan Bay shows good ecological performance and economic efficiency. An appropriate reduction in the fishing effort is essential to improve its effectiveness.

Abstract:The Nanji Islands marine conservation area is one of the first five national marine nature reserves established in China with the approval of the State Council. Because it has a reputation for marine life, and especially for its abundance and variety of shellfish and algae, it is called the "kingdom of shellfish and algae". It is an excellent place for the spawning, feeding, and growth of fish and shrimp, but few scholars or experts have studied the species composition and quantitative distribution of shrimp in the Nanji Islands marine conservation area. We collected shrimp data based on comprehensive fishery resource surveys in November, 2013, and in February, May, and September, 2014, in the Nanji Islands marine conservation area. We studied the species compositions, quantitative distributions, trends in dominant species, and their relationships to environmental factors affecting shrimp in the Nanji Islands marine conservation area, according to survey data for the four seasons, and used catch rates as a quantitative index of the shrimp resource distribution. (1) A total of 25 species were identified, from 74 genera in 49 families, and the seasonal shrimp biomass was (in decreasing order) summer (32358.0 g) > autumn (13033.0 g) > winter (3938.6 g) > spring (3635.6 g). (2) The seasonal change in the distribution of the shrimp population is clear, and the shrimp biomass in reef areas outside the open ocean was considerably higher. (3) The seasonal variation in the dominant species, or the seasonal succession phenomenon, was very obvious, and the dominant species were Parapenaeopsis hardwickii in spring; H. ensirostris, Exopalaemon carincauda, in winter. (4) The depth of the water clearly affected the vertical distribution of the shrimp biomass and the correlation relationship has greatly changes between the shrimp biomass and environmental factors in different seasons. According to our research,the shrimp species mainly belonged to seasonal, eurythermic, and euryhaline groups. The biomass of the dominant shrimp species was clearly higher in the summer and autumn than in the spring and winter, perhaps because many shrimp leave the area for other waters to breed in spring and winter, but return to the sea to spawn, fatten, and grow in summer and autumn. The shrimp biomass in the coastal area exceeded that in the reef and gravel areas in summer, autumn, and winter, perhaps because the shrimp live their general lives in the bottom silt of coastal areas, which benefit to bait and grow up. The replacement of dominant species was significant, and was related to the growth cycles and different size characteristics of the main dominant species. The shrimp biomass has complex relation with environmental factors because the characteristics of the Nanji Islands marine conservation area are complex, with changeable salinity and temperature and diverse fauna. The distribution of the shrimp biomass clearly changed with depth, which was mainly attributable to the range of activities of the dominant species, which are related to the depth of the water in the survey area.

Abstract:In this study, Landsat data for 1989, 1994, 2004, and 2014 were used to evaluate the process of land reclamation in the Nansha wetland area, using methods including remote sensing imagery interpretation, geographic information system (GIS) digital methods, and spatial overlay analysis. The data obtained from two in situ surveys during the periods 2002-2003 and 2013-2014 were also used to compare the changes in the biological resources of organisms. The results were as follows: (1) The lengths of the coastline during the four periods of 1989, 1994, 2004, and 2014 were 213.6 km, 230.0 km, 232.5 km, and 248.6 km, respectively, with increase rates of 3.28 km/a, 0.25 km/a, and 1.61 km/a during 1989-1994, 1994-2004, and 2004-2014, respectively; the maximum distance of the seaward extension from the coastline during these three periods were about 4900 m, 1700 m, and 7700 m, respectively. (2) The total increase in land area was 46.3 km² in 1989-2014; the proportional increases in area relative to the total increase were 40.6% in 1989-1994, 24.41% in 1994-2004, and 34.99% in 2004-2014; reclamation activities were more frequent on Wanqingsha Island and Longxue Island than those at other sites in the Nansha wetland. (3) The numbers of zooplankton, macrozoobenthos, intertidal organisms, fish, and cephalopods decreased by 60.34%, 73.21%, 26.67%, 79.78%, and 50.00%, respectively. Their densities decreased by 58.49%, 12.38%, 79.96%, 78.78%, and 66.79%, respectively. Their biomasses decreased by 82.16%, 73.23%, 15.83%, 70.49%, and 62.43%, respectively. The numbers and densities of shellfish decreased by 13.33% and 69.85%, respectively, whereas their biomass increased by 114.20%. (4) The Shannon-Wiener diversity index for zooplankton increased by 10.24%, whereas the indices for the macrozoobenthos, intertidal organisms, fish, shellfish, and cephalopods decreased by 71.10%, 91.82%, 18.18%, 66.90%, and 73.68%, respectively. The dominant species changed markedly between 2002-2003 and 2013-2014. Land reclamation of Nansha wetland not only changes the type and length of costline, occupuies valuable wetland resource, but also leads passive effect on the around marine animals.

Abstract:Ras-related nuclear proteins (Rans), a family of small monomeric G proteins, are important in many cell activities, participating in the regulation of eukaryotic nucleocytoplasmic transport, DNA replication, mitotic spindle assembly, nuclear envelope dynamics, etc. In this study, a Cryptocaryon irritans trophonts and characterized. The full-length cDNA was 771 bp, and contained an open reading frame (ORF) of 654 bp, encoding a putative polypeptide of 217 amino acids. The ORF contained 6 TAAs and 2 TAGs, which encode glutamine in the ciliate rather than stop codons, as in the universal genetic code. The calculated molecular weight of the CiRan protein was 25.3 kD, with a pI of 8.9. The sequence information has been deposited in GenBank under accession number KP662712. A bioinformatic analysis predicted that the deduced CiRan protein contains a typical Ran domain, extending from residue 11 to residue 174. A GTP/Mg²⁺-binding site occurs at residues 17-153, a Switch I area at residues 30-50, a Switch II area at residues 67-87, a G1 ring at residues 17-26, a G2 ring at residues 40-42, a G3 ring at residues 65-70, a G4 ring at residues 120-125, and a G5 ring at residues 148-152. The predicted structural characteristics confirm that CiRan is a member of the Ran protein family. A phylogenetic tree of CiRan and 10 Ran proteins from other species revealed that CiRan is closely related to the Ran proteins of Tetrahymena thermophila. Reverse transcription-PCR showed that the C. irritans life cycle. After the non-universal codons, TAA and TAG, in the ORF of the cDNA were modified to CAA and CAG, respectively, and the ORF DNA was amplified and inserted into the I restriction sites of the bacterial expression vector pGEX-4T-1, generating the recombinant plasmid pGEX-4T-1/. The transformed was induced with isopropyl-β-D-1-thiogalactopyranoside to express the recombinant protein rCiRan, as a fusion protein with gluthathione S-transferase (GST). After purification with glutathione Sepharose 4B, rCiRan was used to intraperitoneally immunize specific-pathogen-free Kunming mice to prepare a polyclonal antibody against rCiRan. Another group of mice was immunized with GST to prepare a polyclonal antibody against GST for the negative control. The results of a western blotting analysis showed that the polyclonal antibody against rCiRan recognized the native CiRan protein in lysates of different developmental stages of . The molecular mass of native CiRan was 25.3 kD, which is consistent with the value calculated from the coding sequence. The native CiRan protein in theronts was localized with an indirect immunofluorescent antibody assay with the antibody directed against rCiRan, showing that native CiRan was not only distributed in the cytoplasm of theronts, but also in the nuclei. It was especially abundant around the nuclear membrane, implying that the protein has nuclear-membrane-related functions. This study extends our theoretical understanding of the biology of the pathogen , and lays the foundation for future studies of the functions of CiRan, which may be important in the prevention of infection and the control of cryptocaryonosis.

Abstract:The relationships between skin ulcer symdrome occurrence in the sea cucumber, , and environmental factors were analyzed by comparing the environmental indices in ponds containing diseased and non-diseased sea cucumber in two communities of Shaogezhuang (SGZ) and Suliu (SL) in Hongdao, Qingdao, Shandong Province. Between July 23, before any disease occurred, and August 11, we detected 4 cultivable bacterial groups (heterotrophic bacteria, vibrios, nitrifying bacteria, and sulfurring bacteria) and measured 7 physical-chemical indices (temperature, pH, salinity, dissolved oxygen, inorganic nitrogen, and chemical oxygen demand) in the pond water and detected 6 bacterial groups (heterotrophic bacteria, vibrios, nitrifying bacteria, sulphuring bacteria, sulphurate-reducing bacteria, nitrate-reducing bacteria) and measured four physical-chemical indices (pH, redox potential, content of sulfide, and organic carbon) in the pond sediments. The number of bacterial groups in the diseased pond SGZ-1^# did not differ significantly from those in the non-diseased pond SGZ-2^# on the day that disease occurred, whereas the temperature was higher (25.94℃) and the salinity was lower (24.47). Furthermore, concentration of the nitrite (79.56 μg/L) in pond water and the sulfide (221.1 mg/g) in the sediment were higher in the diseased pond SGZ-1^#, exceeding the tolerance thresholds of the sea cucumber. The number of vibrio species in the diseased pond SL-S2^# of the Suliu community was significantly higher (1.85×10⁴ CFU/mL) than that in the non-diseased pond SL-N2^# on the day that disease occurred, and was also higher than the number in the diseased pond SGZ-1^# in the Shaogezhuang community. The physical-chemical indices in pond SL-S2^# was much better than those in pond SL-N2^#. Therefore, we infer that the disease that occurred in the sea cucumbers in Shaogezhuang was closely related to the large sudden changes in the physical-chemical indices of the water and poor sediment conditions, whereas the disease in the sea cucumbers in Suliu was closely related to the proliferation of pathogenic bacteria in the environment. Therefore, the factors associated with disease must be analyzed in individual outbreaks, be they pathogenic organisms or physical-chemical factors, and the appropriate strategies used for disease control.

Abstract:White spot syndrome virus (WSSV) is highly pathogenic to penaeid shrimp and has caused significant economic losses in the aquaculture industry worldwide. With the constant expansion of the areas and scale of prawn farming, variations between different strains of WSSV have emerged. The differences between isolates may cause variations in the virulence of WSS. Deletions in the ORF14/15 and ORF23/24 variable regions have been used as molecular markers to study the epidemiology of the virus. The repeat units of ORF75, ORF94, and ORF125 vary in different isolates and the numbers of repeat units in these three genomic regions are a useful marker for epidemiological studies and for genotyping strains of WSSV. However, each repeat unit may contain single-nucleotide polymorphisms (SNPs) that are important for differentiating haplotypes with the same numbers of repeat units. The results of epidemiological studies may differ if the variability provided by these SNPs is not considered and only the number of repeat units is taken into account.To understand the variations in WSSV ORF14/15 and ORF23/24 and the variable number of tandem repeats (VNTR) and SNPs located in ORF75, ORF94, and ORF125 in different regions of China, we investigated 64 samples that were WSSV-positive on PCR, collected in a disease outbreak area between March and December 2013. The tested samples were from Hainan, Guangdong, Guangxi, Zhejiang, Shandong, Hebei, and Tianjin. Using specific primers, WSSV-positive samples were genotyped with PCR and the amplified fragments were ligated to a T-vector and used to transform Top10 cells. The positive clones were selected and sequenced. After sequencing, the fragments deleted from ORF14/15 and ORF23/24 in different samples were compared with the sequences of Th-96-II and TW respectively, and the three WSSV VNTR regions and SNPs in ORF75, ORF94, and ORF125 from different samples were analyzed with the DNAMAN software. The results showed that there were five samples which had the products of ORF14/15 amplification, and one sample had the products of ORF23/24 amplification. The lengths of the amplified fragments of ORF14/15 were 1267 bp, 1270 bp, and 1892 bp, corresponding to deletions of 6533 bp, 6530 bp, and 5908 bp, respectively, compared with Th-96-II. One type of ORF23/24 was confirmed in this experiment, and the amplified fragment was 1140 bp, corresponding to a deletion of 12070 bp compared with the TW isolate. No fragment was amplified from ORF75. Four different ORF94 VNTRs, including 0, 3, 4, or 12 repeat units, were identified. The ORF125 VNTR, which included 0 or 7 repeat units, was identified. The SNP analysis showed that the bases on the special site in this study were different from the reported types. The bases at site 48 in ORF94 were T, T, T(Type I: 3 RUs), or the bases at site 48 were T, T, T, T(Type II: 4 RUs), and the base were T and 11 A(Type III: 12RUs), respectively. The bases at site 8, 18, 25, 66, and 69 in ORF125(contained 7 RUs), were G, G, G, G, and A, respectively. It is noteworthy that there were also some variations at sites 9, 50, 53, and 61 in ORF125. These results suggest that there are certain degrees of prevalence and variation in WSSV, which causes white spot disease in most parts of China, with clear variations between the different strains in ORF14/15, ORF23/24, ORF75, ORF94, and ORF125.