渤海金州湾石线岛海域斑海豹种群动态初步调查

2011、2012年的3—5月,采用目视观察和拍照观察相结合的方法,对金州湾石线岛及周边海域斑海豹栖息地的斑海豹种群进行了数量统计和行为观察。观察发现,2011年,3月中下旬斑海豹数量较多,最多为3月22日观察到的247头,4月中旬至5月初斑海豹数量逐渐减少。2012年,3月29日观察斑海豹数量最多,为221头,随后逐渐减少。斑海豹日间不同时段观察数量变化较大,上午观察到斑海豹数量较多,尤其是5:00—7:00,为日间观察到斑海豹数量最多时段。斑海豹在金州湾石线岛有交配、抚育幼崽的行为,说明石线岛是斑海豹良好的栖息地。本研究为未来金州湾石线岛斑海豹的种群动态研究提供基础数据。     

渤海虎平岛周围海域的斑海豹种群动态初步调查

在2005年4月和2006年3—5月,分别对大连虎平岛周围海域的斑海豹栖息地及斑海豹资源进行了调查,斑海豹的数量调查采用领地计数法;调查发现2005年春季在此处的斑海豹日最多为54头,2006年春季日最多为67头。在风浪较小,晴好天气,斑海豹在该海域出现的几率多;通过斑海豹数量的脉冲式变化推测每一批斑海豹在本调查海域不做长时间的停留。     

栉孔扇贝

栉孔扇贝Chlamys farreri(Jones et Preston)属软体动物门，瓣鳃纲，扇贝科，是珍贵海产品之一。在我国多分布于山东半岛的东褚岛、俚岛、庙岛群岛的北三岛、烟台、威海近海和辽宁省大连市近海。由于自然资源数量少，年产量不多，远远不能满足国家和人民的需要，     

栉孔扇贝

栉孔扇贝Chlamys farreri (Jones et Preston)属软体动物门,瓣鳃纲,扇贝科,是珍贵海产品之一。在我国多分布于山东半岛的东褚岛、俚岛、庙岛群岛的北三岛、烟台、威海近海和辽宁省大连市近海。由于自然资源数量少,年产量不多,远远不能满足国家和人民的需要,有待进一步加强繁殖保护和人工养殖生产。     

渤海斑海豹的分布调查

本文是1986—1988年乘破冰船和飞机对渤海冰区斑海豹的分布调查结果。斑海豹在辽东湾的繁殖场位于40°00′N,120°50′—121°40′E至40°40′N,121°10′—121°50′E之间的流冰区内。为了调查渤海斑海豹Phoca largha的种群数量和资源分布,作者在国家海洋局的大力支持下,于1986年、1987年和1988年的1月至3月参加了海冰调查队,乘海军的破冰船在渤海共出海3个航次,乘海冰航空调查的飞机在辽东湾飞行1个航次,对斑海豹在渤海冰区的分布进行了观察,现将调查资料整理报道。     

庙岛群岛毗邻海域底层渔业生物群落多样性特征

庙岛群岛毗邻海域位于黄渤海交汇处,是渔业生物的重要栖息地与洄游通道,也是生物多样性的热点区域。为系统掌握庙岛群岛毗邻海域渔业生物多样性特征及其影响因素,分别于2020年9、11、12月和2021年3―12月对该海域底层渔业生物开展了调查,共鉴定出渔业生物115种,其中,鱼类49种,软体动物29种,甲壳动物28种,棘皮动物8种,腕足动物1种。鱼类主要为白姑鱼(Pennahia argentata)、虾虎鱼类和其他鱼类;甲壳动物主要为口虾蛄(Oratosquilla oratoria)、日本鼓虾(Alpheus japonicus)和其他甲壳类。3―6月庙岛群岛毗邻海域底层渔业生物高密度区主要集中在调查海域东南部,7、8月集中分布于调查海域西南部,其余调查月份没有明显的高密度集中分布区。7―10月整个调查区域呈现出较高的生物多样性,而11、12月则具有较高的渔业生物丰度和生物量。白姑鱼和日本鼓虾在生物量(r= –0.75, P<0.01)和丰度(r= –0.73, P<0.01)方面均具有极显著的负相关。主要生物类群和环境因子的冗余分析(redundancy analysis, RDA)表明,水深和温度可能是影响庙岛群岛毗邻海域底层渔业生物的主要因子(P<0.05),其中,棘皮动物和酸浆贝(Terebratella coreanica)与水深表现出正相关性,其他大部分种类与温度表现出正相关性。丰度生物量比较曲线(abundance-biomass comparison curves, ABC曲线)分析发现,庙岛群岛毗邻海域ABC曲线虽然各有不同,但大部分W统计值为负,仅有3个月的W统计值为正(接近于0),说明该海域底层渔业生物群落整体受到较高程度干扰,仅部分季节呈现中等程度干扰,群落处于不稳定状态。本研究可为庙岛群岛毗邻海域生物多样性保护提供科学基础,同时,为探究典型岛屿生物多样性形成的内在、环境与人为因素提供基础资料和数据支持,但典型岛屿生态系统生物多样性的形成与演化机制尚需进行长时间序列深入研究。     

大连旅顺渤海侧沿海虾夷扇贝幼虫来源调查

旅顺渤海侧沿海没有虾夷扇贝资源,但是每年的5月中旬-6月中旬出现虾夷扇贝幼虫,使该海域形成采苗场.2006-2007年笔者通过在虾夷扇贝主要增养殖海区投放漂流瓶跟踪移动方向,监测浮游幼虫数量及个体大小分布等方法,调查了旅顺渤海侧沿海虾夷扇贝幼虫来源.结果表明,2006年4月30日、2007年4月8日和4月28日,在獐子岛海域投放的漂流瓶,回收率分别为7.5%、14.0%和17.2%,其中在獐子岛至旅顺渤海侧沿海回收的比例分别为6.0%、10.4%和4.0%.2006年4月6日,大钦岛海域投放的漂流瓶,回收率为13.0%,在旅顺渤海侧回收率为0%.獐子岛至旅顺渤海侧沿海设置10～12个站位,调查浮游幼虫数量及个体大小分布,结果表明,进入5月中旬以后随着时间的推移,幼虫向旅顺渤海侧沿海集中,而且大个体幼虫的比例增加.调查结果证明,旅顺渤海侧沿海虾夷扇贝幼虫主要来自黄海北部增养殖海区.     

国外信息

<正> 日本在新西兰南方海域发现萤乌贼渔场日本海洋水产资源开发中心的远洋底拖网调查船第51富丸(349.47总吨),于1979年11月下旬～12月下旬在新西兰南方海域的斯内斯群岛南侧和奥克兰岛北侧之间调查试捕时,发现了一个萤乌贼的好渔场,渔获以长     

2005～2013年辽东湾北部近海白色霞水母的数量分布

2004年中国北方渤海辽东湾白色霞水母(Cyanea nozakii)暴发,给辽东湾带来巨大的生态灾难。为了分析辽东湾白色霞水母的暴发原因,对2005~2013年每年5月下旬至7月下旬在渤海辽东湾北部近海进行的大型水母监测调查数据进行了分析。结果显示:辽东湾北部近海白色霞水母主要分布在辽东湾东北部和西北部近海的非河口水域,该水域属于辽东湾北部近海盐度较高的水域,体现出白色霞水母高盐的生态属性。2004~2013年夏季辽东湾北部近海海水盐度呈逐渐下降的趋势,2004~2013年辽东湾白色霞水母的数量也呈现逐渐减少的趋势,2010~2013年辽东湾北部近海未发现白色霞水母。研究结果表明:近几年辽东湾夏季海水盐度的持续偏低,是白色霞水母在辽东湾北部近海近几年数量偏少甚至未出现的主要原因之一。     

南极半岛邻近水域南极大磷虾商业捕捞群体的年龄结构时空变化

2009/2010和2010/2011两渔季,我国渔轮在南极公约区内、位于CCAMLR48.1亚区邻近南设得兰群岛和48.2亚区邻近南奥克尼群岛的南大西洋水域开展了南极磷虾捕捞作业。根据两渔季采集的捕捞群体中南极大磷虾体长及性比资料,利用体长频数的混合分布法,比较和分析了两渔季我国商业捕捞所获南极大磷虾Euphausia superba Dana的种群年龄结构特点。结果表明,2009/2010和2010/2011渔季夏至秋初(12月～翌年4月),近南极半岛的南设得兰群岛和南奥克尼群岛附近水域,南极大磷虾捕捞群体中至少有5个年龄组,雌雄性比、种群年龄组成存在较为明显的年间和季节、区域差异。48.1亚区近南设得兰群岛水域,2009/2010和2010/2011渔季的1月和12月,南极大磷虾以5+龄虾数量最多,雌性临产个体占相当比例(>40%),雌性临产个体的年龄分布为3+～5+龄,以5+龄为主。而48.2亚区邻南奥克尼群岛的水域,2009/2010渔季的2月,以5+龄虾数量最多,出现一定比例的5+龄雌性临产个体;2010/2011渔季2～4月连续3月,随时间后移,该水域的大磷虾年龄构成由复杂转为单一;以3+龄虾数量最多,雌雄比值增加;雌性临产个体由很少至基本不出现(<1%);各年龄组生长率随月减少,3～4月均为负值。由上述结果推测,2010/2011渔季南极大磷虾产卵高峰期应早于2011年2月,较2009/2010渔季有所提前。     

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.