小石岛刺参国家级水产种质资源保护区综合评价

为全面掌握小石岛刺参国家级水产种质资源保护区状况,于2012―2018年对该保护区的水环境、沉积物环境、海洋生物生态、保护生物资源概况和主要保护对象刺参(Apostichopus japonicus)的遗传多样性进行调查,并分别采用单因子污染指数(Pi)、有机污染指数(A)、生物多样性指数(H´)、线粒体DNA D-loop序列单倍型多样度指数和核苷酸多样度指数进行分析评价。11个航次的监测中,海水除2016年5月无机氮超标(Pi =1.08)、2017年8月无机氮超标(Pi =1.31)且水质开始受到有机污染(A=1.001)外,其他所有参数均符合海水评价标准。沉积物均符合国家Ⅰ类质量标准。海洋生物多样性通常处于较高水平(H?≥2),但2016年5月和2017年8月浮游植物多样性偏低(H?=0.45、H?=0.28),2018年5月小型浮游动物多样性偏低(H?=0.77)。保护区生物资源丰富,近年来,刺参密度从约2 ind./m2逐渐增加至3~5 ind./m2。2012年和2018年刺参群体的遗传多样性均较高(单倍型多样度指数分别为0.995和0.993,核苷酸多样度指数分别为0.039和0.037)且无显著遗传差异。综合评价认为,该保护区的海洋生态环境和水产种质资源保护良好,但需要防控海水无机氮污染风险。     

莱州湾蛏类生态国家级海洋特别保护区环境质量分析与评价

2017年3、5、8、10月分别对莱州湾蛏类生态国家级海洋特别保护区海水质量、沉积物质量、生物生态开展调查监测,并通过多种评价方法进行了评价。结果表明,保护区海水质量整体符合二类标准,主要污染因子为无机氮;沉积物质量总体良好,符合一类标准;保护区浮游植物生物多样性指数较低,个别站位优势种明显,存在发生赤潮可能。     

海洋自然保护区社区共管机制探讨

雷州珍稀海洋生物国家级自然保护区位于北部湾东侧、广东雷州半岛西侧,总面积46864．67公顷,主要保护对象为珍稀濒危海洋生物及其栖息地,是环北部湾建区历史最长、面积最大的海洋自然保护区。保护区海域拥有丰富的生物多样性和珍稀海洋生物资源,是维持北部湾海洋生态系统良性循环的重要组成部分,具有极高的科研价值和重要的生态作用。     

海州湾大竹蛏种质资源保护区生态环境质量分析与评价

本研究根据2018年5、8月对海州湾大竹蛏(Solen grandis)国家级水产种质资源保护区表层海水营养盐、重金属、石油类及相关环境因子的调查数据,运用综合质量指数法对该保护区海水生态环境质量进行综合评价,并采用富营养化指数和有机污染指数从不同角度分析该保护区的海水环境质量。结果显示,除部分站位无机氮(DIN)含量略超标外,海州湾保护区其他监测因子均符合国家Ⅰ类海水水质标准。2018年海州湾保护区海水综合质量指数范围为0.31~0.39,属于尚清洁等级。N/P值均大于Redfield系数,且磷酸盐(PO4-P)含量较低,表明该海域营养盐结构为磷限制。富营养化指数范围为0.05~0.27,海水为贫营养状况。有机污染指数范围为-0.24~0.81,该水域有机污染程度较轻。与2008~2013年历史调查数据相比,近年来,海州湾保护区海水生态环境质量保持较好。     

止锚湾海水增养殖区重金属现状评价分析

2018年采用单因子评价标准对葫芦岛市绥中止锚湾增养殖区海水水质、海洋沉积物和养殖生物体中重金属污染现状做出评价与分析。结果表明:止锚湾贝类养殖区海水重金属各项指标符合国家一类海水水质标准。沉积物重金属各项监测指标符合国家海洋沉积物质量一类标准,养殖贝类铅污染指数介于0.5~1.0,其它监测指标均满足国家海洋生物质量一类标准要求。绥中止锚湾海水增养殖区中重金属含量满足功能区的环境质量要求。     

2015年乐清湾北部渔业水域及种质资源保护区监测与评价

根据2015年4个季度对乐清湾北部海水养殖区及乐清湾种质资源保护区环境质量监测结果,分析和评价了两个区域的渔业水质及沉积物质量状况,并与2014年监测结果做了比较.结果表明:2015年乐清市主要渔业水域水质整体能满足渔业水质功能需求,两个监测区总体水质与上年保持一致.2015年度影响水质综合评价的主要超标指标有无机氮、活性磷酸盐、石油类和挥发酚;沉积物主要超标指标为重金属铜和粪大肠菌群.在综合水质(WQI)方面,乐清湾北部海水养殖区全年水质状况为中,乐清湾种质资源保护区全年综合水质为良.     

文登海洋生态国家级海洋特别保护区水质现状分析

2015年3月、5月、8月、10月分别对文登海洋生态国家级海洋特别保护区海域进行了4个航次的水质环境调查,并采用三种方法对该特别保护区海域的水质进行了分析。调查结果显示,该海域水质良好,4个航次各水质要素污染指数均小于1;海水营养指数平均值为1.08,处于轻度富营养状态,保护区内高于保护区外;有机污染指数平均值为-0.13,水质良好。结果表明,调查海域水质良好,但保护区内水质差于保护区外,且富营养化呈增加趋势。目前保护区已经建立,为进一步开展保护区的治理,还需对该保护区进行长期的监测与科学研究。     

锦江河国家级水产种质资源保护区浮游植物群落时空动态及其多样性指数

2015年1月到12月,通过对锦江河国家级水产种质资源保护区浮游植物群落结构进行调查,分析了浮游植物群落的时空动态,运用细胞密度及群落多样性指数等进行了水质综合评价。研究表明,浮游植物6门17目1亚目32科45属101种,其中硅藻门最多,共42种,占总数的41.58%;绿藻门次之,共32种,占总数的31.68%,该保护区为硅藻-绿藻型河流;在夏季浮游植物密度达到2.59×106cells/L,为全年最大值,冬季密度最低,仅为1.82×105cells/L;Margalef指数(Dm)、Shannon-Wiener指数(H'')、Pielou指数(J'')季节变化趋势一致,夏季、秋季、春季到冬季依次减小。利用浮游植物细胞密度评价,锦江河国家级水产种质资源保护区水体为贫营养水体;从多样性指数分析来看,水体介于β-中污染带到寡污染带之间。通过综合分析,锦江河国家级水产种质资源保护区整体上说为β-中污染或贫营养水平。     

惠州东山海人工鱼礁区生态养护效果初步探究

正实践证明,人工鱼礁的建设对保护和恢复海洋生物资源具有积极意义。此外,人工鱼礁建设能改善水域生态环境,提高水体初级生产力,为海洋生物栖息、繁殖、索饵、避敌提供良好环境,是海洋生态环境修复最有效的途径之一。2018年底,在惠州市稔平半岛南端东侧的东山海2.55km~2海域,投放人工鱼礁3252个、总空方16.2199万m~3,建成惠州东山海人工鱼礁区。为评价人工鱼礁区的生态养护效果,作者通过现场采样对其进行了沉积物和环境生物的现状调查。结果显示,人工鱼礁区海域的初级生产力和浮游动植物多样性比对照海域更高,且礁体投放后未出现明显沉降和掩埋,其表面已开始附着生物,对当地海域环境带来一定的生态效益。     

天津大神堂牡蛎礁国家级海洋特别保护区水质分析

为了对天津大神堂牡蛎礁国家级海洋特别保护区进行水质环境分析,2012年4月、9月和2013年5月、9月分别对该特别保护区海域进行了4个航次的水质环境调查,并通过单项水质评价法、海水营养指数评价法、有机污染综合指数法等对该特别保护区海域的水质进行质量分析。调查数据表明,该保护区海水受无机氮污染严重,4个航次无机氮污染指数均大于1;海水营养指数分布范围为1．60～93．76,平均值为14．58,处于重度富营养状态;有机污染指数分布范围为0．96～6．58,平均值为2．76,处于3级轻度污染状态。结果表明,无机氮为该海域主要污染因子,富营养化及有机污染情况严重并呈增加趋势。目前保护区已经建立,但对于保护区的治理有待进一步开展,还需对该保护区进行长期的监测与科学研究。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

The optimal dietary protein level of juvenile silver sillago Sillago sihama at three dietary lipid levels

A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.