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1.
夏秋季瓯江口海域鱼类数量的时空分布   总被引:6,自引:0,他引:6  
本文利用2007年6月和9月瓯江口海域渔业资源调查资料,研究瓯江口鱼类密度的时空分布,分析优势种、地形地貌、海流和水文等因素对鱼类分布的影响。结果表明,6月和9月鱼类重量密度分别为150.54kg/km^2和271.53kg/km^2,尾数密度为29.11×10^3ind./km^2和14.99×10^3ind./km^2。以此推算出:6月鱼类资源量为67923kg,9月为122193kg。鱼类资源量在3个月中增长近一倍。6月的白姑鱼(Argyrosomus argentatus)和9月的龙头鱼(Harpodon nehereus)分别是本海域最重要的优势种。鱼类重量密度与尾数密度分布趋势一致,呈调查水域东部高于西部的分布趋势。6月至9月是幼鱼索饵肥育季节,索饵群体往往停留在瓯江口洞头群岛外侧宽阔海域。水深和鱼类密度相关性显著。台湾暖流、浙江沿岸水和瓯江径流的交汇是形成鱼类高密度区域重要的水文因素,表层水温是影响鱼类数量变化的重要环境因子。瓯江口鱼类数量的变化动力来自主要优势种对鱼类数量变化的回归贡献[动物学报54(6):981—987,2008]。  相似文献   

2.
瓯江口夏、秋季浮游动物种类组成及其多样性   总被引:2,自引:0,他引:2  
依据2007年6和9月瓯江12水域两个航次的浮游动物调查资料,研究瓯江口浮游动物种类组成和多样性特征,并探索水团等因素对浮游动物优势种及物种多样性分布的影响.结果表明:调查水域共鉴定出浮游动物76种(不含18种浮游幼体和仔鱼),隶属于7门8纲20目41科,其中桡足类是最主要的优势类群;瓯江口水域浮游动物主要由亚热带种构成;就盐度适应而言,浮游动物种类数以外海种居多,而近海种在浮游动物总丰度中占有明显优势;秋季浮游动物种类数显著高于夏季;秋季的Shannon-Wiener多样性指数(2.89)明显高于夏季(2.23),这与秋季物种数较高有关;夏季水团交汇处的大门岛邻近水域多样性指数最高,秋季该水域多样性指数呈现从河口到外海逐渐增加的趋势.  相似文献   

3.
舟山渔场金塘岛海域春夏季的鱼类群落   总被引:2,自引:0,他引:2  
为了揭示金塘岛附近海域渔场鱼类资源特征,利用2009年5月和9月在舟山渔场金塘岛水域获得的渔业资源调查资料,研究金塘岛水域鱼类密度的时空分布,分析种类组成、优势种、种类数和多样性等群落结构等指标的变化特征,分析这些特征所反映这一水域的渔场属性。结果表明:5月和9月鱼类重量和尾数密度分别为47.51kg.km-2、3.44×103ind.km-2和92.50kg.km-2、20.51×103ind.km-2;鱼类重量密度与尾数密度分布趋势基本一致,呈现出近舟山群岛一侧的东部水域鱼类密度高于西部水域的趋势;5月和9月龙头鱼(Harpodon nehereus)是本海域最重要的优势种,几乎为幼体组成,而凤鲚(Coilia mystus)是次要优势种。总体上,两季平均鱼类幼体比例高达86%,显示出这一水域是鱼类的产卵场和育幼场;鱼类种类数夏季高于春季;种类数与多样性的分布格局相似,也是舟山群岛一侧的东部水域鱼类密度高于西部水域。可以认为,近金塘岛一侧海域是经济幼鱼的索饵场。  相似文献   

4.
兴化湾和闽江口海域春夏季鱼类区系特征   总被引:2,自引:0,他引:2  
为反映我国亚热带河口和海湾鱼类区系特点,作者于2008年春季(4月)和夏季(9月)在闽江口和兴化湾海域,采用单拖网进行鱼类学调查,并分析了两个海域鱼类种类组成和生态适应性等,进一步运用Ochilai相似性系数分析两个海域鱼类种类相似性.结果表明,在兴化湾共捕获鱼类108种,其中春季出现48种,夏季出现81种.春季竹筴鱼(Trachurus japonicus)是关键种,矛尾虾虎鱼(Chaeturichthys stigmatias)等是常见种;夏季六指马鲅(Polynemus sextarius)是关键种,赤魟(Dasyatis akajei)等是常见种.闽江口共捕获鱼类77种,其中春季出现36种,夏季出现57种.春季,凤鲚(Coilia mystus)和龙头鱼(Harpodon nehereus)是优势种,赤鼻棱鳀(Thryssa kammalensis)等是常见种;夏季凤鲚是优势种,横纹东方鲀(Takifugu oblongus)等是常见种.温度适应上,兴化湾和闽江口鱼类均以暖水种为主,分别占总种数的76.62%和75.00%,其余是暖温种;在盐度适应方面,则是沿岸种和近海种居多,分别占总种数的91.67%和87.01%.闽江口的河口种多于兴化湾.两个海域鱼类种类组成的相似度较高,而各自水体不同季节之间的相似度较低.由此推测,季节变化是导致兴化湾或闽江口鱼类种类组成变化的主要因素,盐度差异是次要因素.  相似文献   

5.
为了解凤鲚(Coilia mystus)早期群体在瓯江口的时空分布及其影响因素, 研究根据瓯江口渔业资源调查数据, 利用两阶段广义加性模型(Two-stage GAM)分析影响凤鲚鱼卵仔稚鱼分布的环境因子。采用交叉验证评价模型的预测性能, 对2020年5—7月的凤鲚鱼卵、仔稚鱼出现率及资源量进行预测。结果表明: 5—7月是瓯江口凤鲚的主要繁殖期, 鱼卵主要分布在瓯江上游七都岛附近低盐水域, 仔稚鱼在瓯江水域均有分布, 瓯江下游灵昆岛近岸水域仔稚鱼的相对资源丰度高于瓯江上游。GAM模型分析表温、表盐是影响凤鲚早期群体分布的主要环境因子, 表盐对鱼卵的分布具有极显著影响(P<0.01), 适宜表盐在1以下, 适宜表温在24—26℃; 仔稚鱼对水温、盐度的适宜度宽于鱼卵, 表温对仔稚鱼的分布具有显著影响(P<0.05), 适宜表温为22—27℃, 适宜表盐为5—13。交叉验证分析认为模型对鱼卵的预测性能(AUC均值0.83)优于仔稚鱼(AUC均值0.71)。2020年预测结果显示, 凤鲚鱼卵的适宜栖息环境较窄, 主要集中在江心屿上游及灵昆岛下游附近水域, 仔稚鱼主要栖息在江心屿至灵昆岛水域。瓯江口作为凤鲚的主要栖息场所之一, 掌握凤鲚早期群体在瓯江口的分布特征及与环境因子间的关系, 能够为其产卵场栖息地的保护和资源养护管理提供科学依据。  相似文献   

6.
本文阐述中国海及其邻近海域浮游介形类的物种和生态类群多样性及其分布特点。本文记录浮游介形类183种,但各海区种数差异极大,其中,南海种数最多,达122种,而黄海南部和北部湾东北部的种类极少,都只有7种。同时,将浮游介形类划归4个生态类群:1.高温高盐类群,其种数最多,约占介形类总种数的46.8%,主要分布于受暖流控制的海域;2.低盐暖水类群,其种数约占介形类总种数的31.2%,但个体数极少,主要分布于近岸暖水区;3.广温广盐类群,种数极少,仅占介形类总种数的1.7%,但个别种类的个体数很多,在许多海区形成优势种,并常以生态交错带为其密集区和运移通道;4.低温高盐类群,由深水或较深水种构成,主要分布于500m以深海域,且个体数极少。  相似文献   

7.
长江口邻近水域浮游动物群落特征及变动趋势   总被引:19,自引:2,他引:17  
徐兆礼 《生态学杂志》2005,24(7):780-784
根据2000~2003年长江口邻近海域5月和8月8个航次的调查资料,对长江口浮游动物群落特征的变动趋势进行了研究。结果表明,桡足类、毛颚类和异足类在8月种数明显多于5月。8月暖流势力增强的同时淡水水团势力也增强,不同水团交汇处,浮游动物种类数和多样性指数等值线密集排列,外海暖水带来丰富的种类使该季节的种类数和多样性均明显高于5月。盐度是影响长江口浮游动物群落特征最主要的环境因子。  相似文献   

8.
本文阐述中国海及其邻近海域浮游介形类的物生态类群多样性及其分布特点。本文记录浮游介形类183种,但经区种数差异极大,其中,南海种数最多,达122种,而黄海南部和北部湾东北部的种类极少,都只有7种。同时,将肖游介形类划归4个生态类群;1.高温高盐类群,其种数最多,约占介形类总种数的46.8%,主要分布于暖流控制的海域;2.低盐暖水类 ,其种数约占介形类总种数的31.2%,但个数极少,主要分布于近岸暖  相似文献   

9.
洞头岛养殖区浮游植物群落特征研究   总被引:1,自引:0,他引:1  
洞头位于温州瓯江口外约61km的洋面上,是全国12个海岛县之一,有103个岛屿和259座礁石组成,有"百岛县"之称.洞口属亚热带海洋性季风气候,常年平均气温17.4℃.洞头列岛海域时浙江省重要的海洋水产养殖基地,受浙江沿岸流和瓯江等径流的影响,营养物质输入丰富.近几年随着洞头列岛还与周边地区经济的快速发展,工业、农业(含水产养殖)和生活废水排放量不断增加,对洞头列岛海域的生态环境造成了一定的影像[1].  相似文献   

10.
洋山深水港工程对附近海域浮游动物多样性的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
根据2001、2003—2007年5月和8月在杭州湾附近水域(30°32′N—30°50′N、121°53′E—122°17′E)2个季节12个航次的海洋调查资料,研究了洋山岛附近水域浮游动物的种类组成变化、多样性以及工程对浮游动物群落结构的影响。结果表明:2003—2007年5月种类数变化不明显,8月种类数高峰期出现在2003年,随后逐年下降,糠虾类总体呈上升的趋势,毛颚动物变化不大,2003年受暖流影响,出现多种外海种和热带种;2003—2007年春季Shannon-Wiener物种多样性指数(H′)变化不明显,夏季逐年降低,丰富度(d)下降,均匀度(J′)下降;夏季不同年间的变化主要是个别年份出现了较多的外海种所致,可能与外海暖水势力变化有关;洋山工程对海域浮游动物的多样性变化影响不显著,洋山岛附近海域浮游动物种类组成的变化受外海暖流影响较明显,与洋山工程的开展及进程的关系不明显。  相似文献   

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Purulent wounds in 88 victims of the Armenian earthquake with the syndrome of long-term squeezing were examined microbiologically and the experience with using antimicrobial drugs for their treatment was analyzed. In all the cases microbial associations were detected, coliform and nonfermenting gram-negative bacilli, enterococci, anaerobes and yeast-like fungi being isolated from 80, 20, 15 and 25 per cent of the patients respectively. 130 bacterial strains were studied in detail. 80 to 100 per cent of the bacterial isolates were resistant to the antibiotics routinely used in surgical practice, i.e. benzylpenicillin, tetracycline, levomycetin, kanamycin, cephalothin and cefazolin and highly sensitive to new antimicrobial drugs belonging to ureidopenicillins (mezlocillin), quinolones (ciprofloxacin) and cephalosporins of the 3rd generation (cefoperazone and ceftazidime). Retrospective estimation of the antibiotic therapy revealed its inadequacy in 55.7 per cent of the patients for the most part because of the isolates resistance. The 19 variants of the antibiotic use prescribed by the physicians mainly included penicillins, aminoglycosides and their combinations (in 67.2 per cent of the cases). The use of the highly efficient drugs of the groups of ureidopenicillins and quinolones was extremely rare which was likely due to lacking of information on the drugs.  相似文献   

13.
The changes in the size of Purkinje cell (PC) nucleolus in the lateral and medial cerebellum zones were studied in dogs with different degree of neurologic status recovery after clinical death of various etiology and duration. PC always possess one nucleolus in the control and experimental groups. In the case of complete neurologic status recovery of animals the area of PC nucleolus increases in both zones studied, irrespective of the cause of clinical death. In the case of neurologic disorders the increase in PC nucleolus area is clearly expressed only in the medial zone of the cerebellum, being insignificant in the lateral zone. It is suggested that adaptive characteristics of PC are distinct in the two compared zones, which leads to greater PC vulnerability in the lateral zone during deep hypoxia.  相似文献   

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Diurnal rhythm in body temperature of pigeons subjected to different experimental conditions (pinealectomized, sham-operated, melatonin-implanted, cold-exposed) was studied under a 12 h light and 12 h dark regimen. The body temperature of pigeons during photophase was higher than that during scotophase in the normal as well as every treatment group studied. Pinealectomized pigeons showed higher body temperature in the photophase as well as scotophase, than that of the normal and sham-operated birds when examined 2 or 3 weeks following the post-surgical acclimatization to 25 or 3 degrees C. However, subcutaneous implantation of melatonin pellets into pinealectomized pigeons nullified or even reversed the hyperthermic effect of pinealectomy. Exposure of pigeons to--18 degrees C for 280 min during photophase as well as scotophase, produced a marked drop in body temperature in pinealectomized, sham-operated and normal pigeons. The pinealectomized pigeons exhibited a higher body temperature than that of the sham-operated and normal ones when exposed to--18 degrees C during the photophase, but not during the scotophase. It was concluded that while the pineal is not necessary for maintaining the daily thermal rhythm in the avian body, it has a thermoregulatory role, in that it prevents rise in body temperature in warm (25 degrees C) acclimatized and chronic cold (3 degrees C) exposed birds. In acute short-term cold (--18 degrees C) exposure however, the temperature regulatory role of the pineal was not effective during the scotophase.  相似文献   

17.
N A Dmitrieva 《Tsitologiia》1986,28(7):745-748
The developing taste buds of vallate papillae were studied with electron microscope in rats during the first 7 days after birth. Two types of cells--light and dark--are identified in the taste buds of a one day old animal. The apical parts of dark cells are characterized by numerous dark granules. A distinguishing feature of light cells is the presence of synaptic contacts with afferent intragemmal nerves. On the 4th day of development on the top of the apical parts of the cell, a microvillar apparatus is seen to form, which does not yet communicate with the oral cavity. On the 7th day, basal cells appear in the taste buds. Some of these cells are seen mitotically dividing. The differentiated microvillar apparatus now communicates with oral cavity. The structure of the taste buds is getting similar to that in the adults. The structural and functional peculiarities of the developing taste buds are discussed in association with the period of ontogenesis under consideration.  相似文献   

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This study determined the optimum number of tubules to be counted per testis cross section, and the number of animals per treatment group, when changes in stage frequencies in the cycle of the seminiferous epithelium are criteria for assessing effects of treatment on spermatogenesis. A data base of 9,672 observed and staged tubules was collected from testicular cross sections of 15 Sprague-Dawley rats. A significant variation between animals was found for the frequencies of Stages I, II, IV, VI, VIII, and XIII. Computer simulation was used to randomly select different combinations of animal and tubule numbers from the observed data. Stage frequency means from each simulation experiment were compared statistically to observed mean frequencies. A model that used data from all 14 stages was analyzed. The following conclusions were made: a) a minimum of 200 tubule cross sections/testis is recommended for estimating stage frequencies; b) for a fixed number of tubules scored, the number of animals sampled is more important than the number of tubules per animal in reducing variance; c) to detect a difference of 2 standard deviations from the mean with a 2% error rate and examining 200 tubules/testis, at least 12 animals must be used per group when assessing all 14 stages; d) when individual stages are examined using 10 animals per group, only Stage VII has 80% or greater power of test (alpha = 0.05) to detect a frequency difference; e) pooling stages into 3-4 groups is recommended to improve the power of detecting a treatment difference.  相似文献   

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