首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
东海有尾类数量分布   总被引:2,自引:1,他引:1  
根据1997~2000年东海23°30′~33°N、118°30′~128°E海域4个季节海洋调查资料,探讨了东海有尾类数量分布和季节变化。结果表明:秋季有尾类丰度最高,均值为149 ind/100m3,夏季38 ind/100m3,冬季20 ind/100m3,春季9 ind/100m3;有尾类数量在冬春夏季与水温和盐度相关关系不显著,秋季与表温有显著的正相关关系。有尾类数量季节变化机制具有暖水种的特征,这些特征形成与其优势种适温适盐特性有密切的关系。东海有尾类的数量波动,与东海暖流势力消长有密切的联系,也同暖流势力从夏到秋季维持一段时间有密切的关系。在东海,暖流势力较强的海域往往可以成为有尾类高丰度分布区域。秋季有尾类高分布区出现,对东海北部外海绿鳍马面鲀(Navodon septentrionalis)渔场和东海南部的带鱼(Trichiurus lepturus)和日本鲭(Scom ber japonicus)等多种经济鱼类渔场的形成有重要意义。  相似文献   

2.
摘要:根据2002~2003年长江口29°00´~32°00´N、122°00´~123°30´E海域4个季节的海洋调查资料,运用定量、定性方法,探讨了长江口邻近海域浮游十足类丰度的季节变化、水团对丰度分布的影响、优势种对总丰度的贡献以及其生态适应特征。结果表明,长江口邻近海域浮游十足类丰度季节变化主要受温度影响,平面分布变化主要受盐度影响。夏季平均丰度最高(10.42 ind/m3),主要集中在长江口羽状锋(122°40′~123°30′ E)处,冬季丰度最低(0.004 ind/m3)。中型莹虾(Lucifer intermedius)和细螯虾(Leptochela gracilis)是最主要的优势种。夏季,中型莹虾的贡献率(0.97)远大于细螯虾(0.12)。中型莹虾平均丰度夏季最高(8.93 ind/m3),春季为0.28 ind/m3,秋季为0.14 ind/m3,冬季最低 (0.005 ind/m3)。细螯虾在春季平均丰度0.11 ind/m3, 夏季0.67 ind/m3,秋季0.13 ind/m3,冬季0.004 ind/m3。  相似文献   

3.
仿刺参的微卫星标记   总被引:6,自引:1,他引:5  
战爱斌 《水产学报》2006,30(3):341-346
根据1997-2000年东海23°30′~33°00′N、118°30′~128°00′E海域4个季节海洋调查资料,探讨了东海糠虾类的数量波动、相应的动力学过程及与渔场的关系。结果表明:东海糠虾类秋季丰度最高,均值为10ind.10-2m-3,春季次之(5ind.10-2m-3),夏季最低(1ind.10-2m-3);春季的漂浮囊糠虾(Gastrosaccus pelagicus)、夏季的极小假近糠虾(Pseudanchialina pusilla)、秋季的四刺端糠虾(Doxomysis quadrispinosa)和冬季的中华节糠虾(Siriellasinensis)对糠虾类总丰度变化的贡献较大。冬夏季不同优势种间对总丰度的贡献值较为接近,春秋季则有明显的差异。糠虾类春季和4季总丰度与底层水温线性相关;冬夏季与底层盐度相关;秋季与表层水温和10m层水温相关。东海糠虾类的数量波动,与东海沿岸河流的径流量,特别是长江径流势力消长有密切的联系,也与东海暖流势力从夏季到秋季维持一段时间有密切的关系。秋季糠虾类高分布区出现,对东海北部外海鲐鱼渔场和闽南-台湾浅滩渔场的形成有重要的意义。  相似文献   

4.
东海浮游磷虾类的数量分布   总被引:14,自引:3,他引:11  
徐兆礼 《水产学报》2005,29(3):373-378
根据1997-2000年东海23°30′~33°N、118°30′~128°E海域4个季节海洋调查资料,运用定量、定性分析方法,探讨了东海浮游磷虾类总丰度的平面分布、季节变化,相应的动力学及与渔场的关系。结果表明,东海磷虾类总丰度秋季最高,春季次之,冬季最低;冬,春,夏季的小型磷虾(Euphausianana)和秋季的中华假磷虾(Pseudeuphausiasinica)对总丰度的贡献较大,是影响磷虾类总丰度变化的主要优势种;冬、春和秋季总丰度与水文环境因子的线性相关性不显著,夏季总丰度与底层温度和10m层盐度的二元线性相关关系非常显著。秋季磷虾高丰度区位于台湾暖流与各水团的交汇处。磷虾类总丰度的变化动力来自水团的影响和主要优势种对总丰度变化的回归贡献,后者与优势种的生态习性有关。磷虾类秋季高丰度区的分布与带鱼、小黄鱼和日本鲭索饵场的位置基本一致。  相似文献   

5.
长江口海域浮游软体动物生态特征的季节变化   总被引:1,自引:0,他引:1       下载免费PDF全文
根据2002-2003年长江口28°00′-2°00′N、122°00′-123°30′E海域4个季节的海洋调查资料,运用定量、定性方法,探讨了长江口邻近海域浮游软体动物总丰度的平面分布、季节变化、种类组成及优势种的环境适应类型。结果表明,长江口海域浮游软体动物总丰度分别为:春季64.61ind/m3,夏季191.84ind/m3,秋季59.11ind/m3,冬季1.4ind/m3。四季共出现软体动物24种,其中春季8种,夏季21种,秋季10种,冬季2种。马蹄螔螺(Limacina trochiformis)适温较低,是春季主要优势种;明螺(Atlanta peroni)作为暖水种,是夏季主要的优势种;秋季主要优势种为尖笔帽螺(Creseis acicula),适应于较高的水温;强卷螺(Agadina stimpsoniji)适温较低,是冬季的主要优势种。春季浮游软体动物大多聚集在苏北沿岸流和长江径流交汇处或偏沿岸流一侧,夏季在河口咸淡水水团内,秋季的高丰度则主要出现在台湾暖流和长江径流交汇偏暖水的一侧,冬季出现种类较少,低温是其最主要的因素。浮游软体动物作为一种偏大洋性的种类,在外海的数量和种类分布要远高于近海。  相似文献   

6.
东海毛颚类优势种及与环境的关系   总被引:23,自引:2,他引:21       下载免费PDF全文
根据1997~2000年东海23°30′~33°N、118°30′~128°E海域4个季节海洋调查资料,对东海毛颚类(Chaetognatha)优势种与环境的关系进行研究。结果表明,毛颚类优势种季节交替不明显,优势度最高的种分别是:夏季肥胖箭虫(Sagittaenflata)、冬、春季海龙箭虫(Sagittanagae)和秋季百陶箭虫(Sagittabedoti)。主要优势种中,百陶箭虫聚集强度指标值最高,其次是海龙箭虫,肥胖箭虫最低。肥胖箭虫与表层温度线性关系极其显著,肥胖箭虫和海龙箭虫与表层盐度的关系以及百陶箭虫与表层温度和表层盐度的关系符合YieldDensity模型。肥胖箭虫高丰度区往往位于台湾暖流与浙江沿岸流交汇处偏暖水的一侧,海龙箭虫高丰度区位于暖流与沿岸流交汇处偏冷水团的一侧。在水温较高的环境下,百陶箭虫高丰度区位于暖流与沿岸流交汇处偏淡水水团的一侧。  相似文献   

7.
东海浮游桡足类的数量分布   总被引:27,自引:4,他引:23  
徐兆礼 《水产学报》2003,27(3):258-264
根据1997-2000年在东海23°30′~33°N、118°30′~128°E水域进行的4个季节海洋调查资料,对东海浮游桡足类生态特征,分数量、群落特征、种类组成及优势种三部分从不同侧面作了探讨,本文为该研究的第一部分。结果表明,东海浮游桡足类丰度占浮游动物总丰度的55.5%,占饵料浮游动物总丰度的64.8%;秋季丰度最高、夏季次之、春季最低;平面分布不均匀,呈斑块状分布,一般东海近海高于外海和台湾海峡海域;高值区一般出现在不同水系的交汇区,其中,大陆沿岸水和东海外海水交汇区丰度值较其它混合区高。本次调查东海北部(29°~32°N、125°E以西)水域桡足类丰度约为20年前同期的1/3;东海浮游桡足类丰度的平面分布往往取决于中华哲水蚤(Calanussinicus)、精致真刺水蚤(Euchateconcina)和亚强真哲水蚤(Eucalanussubcrassus)的分布。  相似文献   

8.
东海区短鳄齿鱼数量分布及其与环境因子的关系   总被引:4,自引:3,他引:1  
根据2005年东海区(26°30′~35°00′N、121°00′~127°00′E)渔业资源监测底拖网调查资料,结合广义相加模型(GAM)方法分析了东海区短鳄齿鱼资源的时空分布特征以及水深、水温、盐度与数量分布的关系。结果表明:东海区短鳄齿鱼主要分布区域为:28°00′~30°00′N、123°00′~126°30′E;生物量季节变化明显,以秋季(9月)最高,春季(4月)最低;短鳄齿鱼适宜水深、温度、盐度范围分别为70~110 m、17~23℃、34.3~35.2。结合东海海流分布特点,初步推断短鳄齿鱼为暖水性海洋小型鱼类,其生物量分布和季节变化受台湾暖流影响。  相似文献   

9.
东海海樽类种类组成和多样性   总被引:3,自引:0,他引:3  
根据1997~2000年在东海海域23°30′~33°N、118°30′~128°E 4个季节海洋调查资料,运用定量、定性方法,探讨东海海樽类(Thaliacea)种类组成、物种数平面分布和多样性变化及与环境的关系.结果显示,东海调查水域共发现浮游海樽类20种,夏季16种,春季12种,秋季11种,冬季9种;季节更替率显示,海樽类物种季节更替,从春季到冬季,是温度的季节变化和暖流势力消长共同作用的结果;从冬季到春季,主要受暖流势力增长的影响.春季海樽类物种数与表温和底盐相关,夏季与10 m水层温度和盐度相关;秋季相关性不明显,冬季与表温相关.东海海樽种类季节特征和地区特征的形成,主要与暖流势力消长有关.双尾纽鳃樽东方亚种(Thalia democratica orientalis)等7个种是东海的常见种,羽环纽鳃樽(Cyclosalpa pinnata)等6个种是次常见种,其余则是稀有种.东海各分海区海樽类多样性指数大多较低,主要是由于优势种具有很强的聚集性,这种种间和各站位之间分配的不均匀性,是多样性指数较低的最主要的原因.  相似文献   

10.
利用1981年2、5、8和11月4个航次的海洋调查资料,对黄海南部及东海(28°00′~34°00′N、121°00′~127°00′E)水域中、小型浮游桡足类隆剑水蚤科(Oncaeidea)的种类组成和分布特征进行了初步分析。研究结果表明,调查水域共出现隆剑水蚤9种,其中等刺隆剑水蚤(Oncaeamediterranea)、背突隆剑水蚤(Oncaeaclevei)和角突隆剑水蚤(On caeaconifera)为主要优势种。夏季丰度最高(60.38ind·m-3),秋季次之(15.16ind·m-3),冬季最低(2.34ind·m-3)。通过对同步温度和盐度资料分析后发现,隆剑水蚤主要分布在受台湾暖流和黑潮暖流影响的高温、高盐区域,其中等次隆剑水蚤可作为暖流的指示种。  相似文献   

11.
12.
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.  相似文献   

13.
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.  相似文献   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
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.  相似文献   

15.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

16.
17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号