智利竹Jia鱼渔场与海洋环境因子的关系分析

本文通过对在执行863-AA63-0701课题时收集的东南太平洋竹Jia鱼渔场海洋环境调查资料。分析了竹Jia鱼生产渔场与环境因子的相互关系。结果认为：渔场CPUE的分布与海水表层水温有关，CPUE超过20t的表层水温分别为：5月份：12.4-41.1℃，6月份，11.5-12.8℃；7月份：11.5-12.5℃，在拖速不足的情况下，借助风力和海流可以提高CPUE的产量；竹Jia鱼叉长组成与捕获的时间和海区有关。     

智利外海渔场竹筴鱼资源分布特征

根据在智利 2 0 0海里专属经济区外海的渔场周年探捕调查 ,对智利竹鱼 (Trachurusmur phyi)单位努力量渔获量 (CPUE)的构成和季节变化及其资源分布特征进行了初步探讨。结果显示 ,竹鱼在智利外海分布广 ,30°～ 43°S ,78°～ 87°W海区均可形成拖网作业渔场。南半球冬季竹鱼密集分布区较偏南 (38°～43°S) ,8月密集分布区向北偏移至 35°～ 40°S,春季鱼群继续向北洄游至 30°～35°S ,并开始分散索饵 ,集群性较差 ,到翌年秋季再集群向南洄游 ,在 38°～ 43°S ,78°～ 85°W形成越冬场。CPUE以冬季最高 ,春、秋季次之 ,夏季最低。冬季以 6月份平均CPUE最高 ,达 1 5 .1 8t/h ,夏季以 3月份平均CPUE最低 ,仅 1 .1 2t/h。     

东南太平洋南部公海智利竹荚鱼生产初探

本文介绍了东南太平洋南部公海智利竹荚鱼的探捕、加工情况,并对不同时间、不同海区的探捕生产进行了分析,认为东南太平洋南部公海智利竹荚鱼6～7月份渔场主要集中于38°～41°S之间,其中以39°～40°S为最好,平均网产、日产、CPUE均为最高.6月份的平均CPUE和平均网产、日产呈下降趋势,一直持续到7月上旬,7月中旬开始回升,各项指标呈上升趋势.同时对我国渔船今后生产提出了设想和建议.     

东南太平洋智利竹筴鱼中心渔场的月间变动研究

根据2003年～2011年中国东南太平洋智利竹筴鱼（Trachurus murphyi）大型拖网渔捞数据和海表温度（SST）数据,利用ArcGIS 10.0绘制渔场产量重心时空分布图,用最短距离法对中心渔场进行聚类,对智利竹筴鱼渔场月间重心变动规律及其与SST之间的关系进行分析。结果表明,随着月份的变化,中心渔场从3月开始由南逐渐向西北方向移动,到10月之后逐渐向东南方向移动。3月～6月渔场主要分布在80°W～90°W、40°S～45°S,最适宜SST为12～14℃;7月～8月渔场主要分布在80°W～90°W、35°S～40°S,SST为13～14℃;9月～10月渔场分布为85°W～95°W、30°S～35°S,SST这15～16℃;11月～12月渔场分布在90°W～95°W、30°S～40°S,SST为16～17℃;而1月～2月渔场分布在85°W～95°W、35°S～45°S,最适宜SST为16～17℃。     

2011～2012年东南太平洋智利竹鱼CPUE的时空变化及其与捕捞因子关系

根据2011和2012年东南太平洋智利竹鱼(Trachurus murphyi)的渔业生产统计数据,利用广义可加模型(GAM)分析了智利竹鱼资源的时空变动及其与捕捞因子的关系。结果表明:GAM模型对单位捕捞努力量渔获量(CPUE)总偏差解释率为24.173%,其中贡献最大的是拖网时间,贡献率为13.758%。东南太平洋智利竹鱼作业渔场主要集中在35.5°~46°S、80°~91°W和25°~28.2°S、74°~76.5°W范围内;最佳捕捞时间为4月、8~11月;最佳拖网时间为8~10 h;最佳的网位为0~40 m;最佳的网口高度为72~95 m。逐步建模法结果显示,影响智利竹鱼CPUE的因子按重要性程度从高到低依次为拖网时间、网位、网口高度、月份、纬度、经度、曳纲长度、网口水平扩张。     

2009年秋冬季东南太平洋智利竹筴鱼的渔业生物学特征

根据2009年秋冬季(3~6月)东南太平洋智利竹筴鱼的渔业调查资料,对其群体组成、叉长与体重关系、性腺成熟度、摄食等级和渔获量作了初步研究。结果表明:叉长范围为100~650 mm,优势叉长组350~400 mm;体重范围为100~2 600 g,优势体重组400~800 g;3~5月性腺成熟度大部分为Ⅱ期,6月则有52%个体为Ⅲ期。3~5月总产量和CPUE(t/h)呈逐渐增加趋势,6月份均显著下降,仅为5月的38.7%和51.4%。冬季(6月)总产量的大幅下降,暗示该渔场的空间分布出现了一些新的变化。     

巴塔哥尼亚大陆架海域阿根廷滑柔鱼渔场分布及与表温的关系分析

根据 2 0 0 2年 1～ 6月中国大陆地区鱿钓渔船在西南大西洋的生产统计及其海表水温数据 ,按 1°× 1°的格式进行统计分析 ,并用MarineExplore 4 .0软件进行作图 ,对阿根廷滑柔鱼渔场、CPUE分布及其与表温的关系进行了分析。结果表明 ,1～ 3月份中心渔场集中在 4 5°S、6 0°W一带 ,4～ 6月份作业渔场集中在 4 2°S、5 7°W附近。各月产量和CPUE有很大变动 ,其中 1月份产量最高 ,3月份开始下降 ,6月份达到渔汛的末期。全年产量较高海区的表温为 12～ 15℃ ,各月份的最适渔获表温不同 ,1月为 14～ 15℃ ,2月为 13～ 15℃ ,3月为 12～ 14℃ ,4月为 9～ 13℃ ,5月为 8～ 10℃ ,6月为 7～ 9℃ ,并且每月的作业水温逐渐降低 ,平均每月下降约 1℃。经K S检验 ,结果表明 ,各月表温和CPUE的差异均不显著。     

南海及临近海域黄鳍金枪鱼渔场时空分布与海表温度的关系

为得到南海及临近海域黄鳍金枪鱼(Thunnus albacores)渔场最适宜栖息海表温度(SST)范围,基于美国国家海洋大气局(NOAA)气候预测中心月平均海表温度(SST)资料,结合中西太平洋渔业委员会(WCPFC)发布的南海及临近海域金枪鱼延绳钓渔业数据,绘制了月平均SST和月平均单位捕捞努力量渔获量(CPUE)的空间叠加图,用于分析南海及临近海域黄鳍金枪鱼渔场CPUE时空分布和SST的关系。结果表明,南海及临近海域黄鳍金枪鱼CPUE在16℃~31℃均有分布。在春季和夏季(3~8月),位于10°~20°N的大部分渔区CPUE较高,其南北侧CPUE较低;而到了秋季和冬季(9月到次年2月),高产渔场区域会向南拓宽。CPUE在各SST区间的散点图呈现出明显的负偏态分布,高CPUE主要集中在26℃~30℃,最高值出现在29℃附近;在22℃~26℃范围内CPUE散点分布较为零散,但在这个范围也会出现相当数量的高CPUE;在22℃以下的CPUE几乎属于低CPUE和零CPUE;零CPUE的平均SST为26.7℃(±3.2℃),低CPUE的平均SST为27.8℃(±2.1℃),高CPUE的平均SST为28.4℃(±1.5℃),高CPUE在各SST区间的分布要比零CPUE和低CPUE更为集中。采用频次分析和经验累积分布函数计算其最适SST范围,得到南海及临近海域黄鳍金枪鱼最适SST为26.9℃~29.4℃。本研究初步得到南海及临近海域黄鳍金枪鱼中心渔场时空分布特征及SST适宜分布区间,可为开展南海及临近海域金枪鱼渔情预报工作提供理论依据和参考。     

西北太平洋公海秋刀鱼渔场及CPUE值的时空分布

为了初步掌握西北太平洋公海秋刀鱼渔场的变动规律,利用"欧亚1号"渔船2014年5—11月的渔捞数据,对西北太平洋公海秋刀鱼渔场的空间分布进行了研究分析,结果表明,西北太平洋公海秋刀鱼各月作业渔场分布较广,作业区域范围在38°N~48°N、147°E~163°E之间;捕捞作业渔场西北太平洋秋刀鱼洄游路线基本一致;8月份的月平均单位捕捞努力量渔获量(CPUE)最低,仅为9.1 t/d,9—11月份CPUE平均值较高;39°N~40°N的CPUE平均值较高,为36.10 t/d,146°E~147°E的CPUE平均值较高,为52.29 t/d;捕捞作业区域的作业水温范围在9.8~16.5℃区间内,其中接近72%的作业时间处于12~14℃之间;西北太平洋公海秋刀鱼渔场时空分布具有明显的季节变化,CPUE值波动范围较大。     

秋冬季智利竹(竹夹)鱼栖息地指数模型比较

秋冬季是智利竹筴鱼的主要渔汛,准确建立其渔场预报模型具有现实的意义。为了找出适宜的秋冬季智利竹筴鱼栖息地指数模型,论文根据2003-2009年5-9月智利竹筴鱼的商业捕捞数据, 结合海表面温度(SST)和海表面高度(SSH)的海洋环境因子,以作业次数为基础,采用外包络法分别建立SST、SSH 的适应性指数(SI),采用算术平均法(AMM)、几何平均法(GMM)建立栖息地指数(HSI)模型计算其栖息地指数,并以2010-2011年度的捕捞数据进行验证。研究结果表明：以作业次数为基础,采用外包络法建立SST、SSH 的适应性指数为最适,5-9月SST权值分别为0.4、0.7、0.5、0.7、0.1的算术平均法适合秋冬季智利竹筴鱼栖息地指数模型。研究也以为,不同月份的SST和SSH对秋冬季智利竹筴鱼渔场分布有着不同的影响。     

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 hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

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).     

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.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.