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1.
珠江口南沙海域秋季渔业资源群落结构特征   总被引:2,自引:0,他引:2  
根据2015年11月珠江口南沙海域的渔业资源调查资料,对该海域秋季渔业资源群落组成、优势种和生物多样性等群落结构特征进行了初步研究。结果表明,该海域共出现渔业生物40种,以鱼类和甲壳类为主。其中,底层鱼类21种,中上层鱼类3种,甲壳类16种。相对重要性指数(IRI)可用来度量物种的生态优势度,秋季优势种类有亨氏仿对虾(Parapenaeopsis hungerfordi)和锐齿(Charybdis acuta)2种(IRI≥1 000)。该区域内各站位质量渔获率为0.63~11.15 kg·h~(-1),平均为4.23 kg·h~(-1);尾数渔获率为84~885尾·h~(-1),平均为433尾·h~(-1)。Shannon-Wiener多样性指数(H')为2.07,Margalef丰富度指数(D)为1.64,Peilou均匀度指数(J')为0.59。分析表明,该海域渔获物以小型经济甲壳动物和经济幼鱼为主,渔获个体偏小,总体上多样性空间差异不大。与该区域2002年同月份的调查数据相比,目前渔获物多样性下降明显,群落结构相对简单。  相似文献   

2.
当前山东近海的渔业资源与生态环境面临较大压力,对海洋中的生物多样性水平有着较大影响。为探究山东近海生物多样性的空间分布特征及影响多样性水平的环境因子,实验基于2017年冬季在山东近海进行的渔业资源和环境调查数据,分析了整体与山东近海3个不同海域的物种数、辛普森多样性(Simpson’s index of diversity)、香农多样性指数(Shannon-Wiener index of diversity)、皮尔洛均匀度(Pielou evenness index)等物种多样性指数的空间分布,利用随机森林算法评估了多样性指数与环境因子所构建模型的拟合优度并且探究两者间的依存关系,研究将山东近海分成3个区域并将分区作为空间因子加入到算法模型中。结果显示,山东近海的多样性水平空间分布上呈现半岛南部海域高于北方的烟威渔场及其临近海域、莱州湾渔场的趋势。物种数和香农多样性指数模型拟合效果较好,方差解释率达到77.46%和45.66%,而对Pielou均匀度指数的拟合效果较差。研究表明,无论整体海域模型还是分区模型,海底温度、海底盐度及海水深度等3种环境因子都是对多样性指数最为显著的影响因子,...  相似文献   

3.
根据天津海域活牡蛎礁区人工鱼礁区2012年5月份的本底调查和2012年8月份、2013年5月份和8月份3个航次的渔业资源跟踪调查数据,采用生物多样性指数分析了投礁前后渔业资源种类组成和物种多样性的时空分布特征。海域游泳动物群落的健康状况指标(Exergy值)投礁后高于投礁前,但差异不明显(P0.05)。聚类分析表明,本底调查和跟踪调查样方分区明显,表明鱼礁投放后,鱼礁区群落结构明显改善。投礁后物种种类数和总生产效益的增加说明人工鱼礁建设取得了明显的生态效益和经济效益。  相似文献   

4.
为了解舟山群岛外海域鱼类资源状况,于2018年4月(春季)和10月(秋季)在舟山群岛外海域进行的渔业资源调查,用得到的数据分析了鱼类种类组成、优势种、群落结构及生物多样性。结果显示:(1)舟山群岛外海域鱼类有106种,隶属于12目47科80属;(2)本次调查鱼类种类数春季为63种,秋季为85种,总体与历史调查结果相比春季明显减少,而秋季却略有增加;(3)2个季节的鱼类优势种更替明显,春季优势种为黄鮟、日本红娘鱼和细条天竺鲷,秋季优势种为细条天竺鲷和日本发光鲷;(4)鱼类生物多样性指数值为秋季大于春季,春、秋季均匀度指数(J')对比多样性指数(H')和丰富度指数(D)都较小,且春、秋季生物多样性指数值基本都是随着水深的增加而增加,均以80 m以上水深区间较高;(5)通过聚类分析与非度量多维标度排序分析可得,春季在35%的相似水平上分为3个群落,秋季在45%相似水平上分为2个群落,秋季物种相似度比春季高,春季在生物量和丰度水平上均比秋季低。研究表明,舟山群岛外海域的春季鱼类群落结构可能处于未受干扰状态,秋季鱼类群落结构可能处于严重干扰状态。  相似文献   

5.
黄海无脊椎动物资源结构及多样性   总被引:10,自引:3,他引:7       下载免费PDF全文
根据1998~2000年在黄海进行的生物资源底拖网定点试捕调查,所取得的春、夏、秋、冬4季347个样方的无脊椎动物资料,分析了黄海无脊椎动物的资源结构及多样性。调查捕获无脊椎动物53种、2336.896kg、1385397尾。运用相对重要性指数(IRI)作为生态优势度的度量指标,依此来划定每个种在群落中的作用。IRI大于1000的种类定为优势种,全年只有1种,即冷温性的脊腹褐虾(Crangon affinis),该种的渔获量占总渔获量的61.4%;IRI值在1000~100的种类定为重要种,有3种(类),即枪乌贼(Loligo sp.)、太平洋褶柔鱼(Todarodes pacificus)和鹰爪虾(Trachypenaeus curuirostris),它们的渔获量占总渔获量的25.8%。使用物种丰富度指数(D)、Shannon-Wiener多样性指数(H’)和种类均匀性指数(J')剖析了该水域无脊椎动物群落的多样性特征。群落各样方指数D=0.000~2.347,H’=0.000~2.140,J=0.006~1.000。此外还采用Bray-Curis指数CN来比较黄海不同区域无脊椎动物群落之间物种组成的相似性。研究结果表明,黄海北部无脊椎动物群落与黄海南部无脊椎动物群落之间的种类组成相似性最高,CN=0.846,黄海中部无脊椎动物群落与黄海南部无脊椎动物群落之间的种类组成相似性最低,CN=0.478。经分析,黄海现有无脊椎动物群落的优势种及多样性具有比较好的稳定性。  相似文献   

6.
辽东湾北部海域鱼类群落结构及多样性   总被引:6,自引:2,他引:4  
根据2006年夏季(8月)、冬季(11月)和2007年春季(4月)、秋季(10月)在辽东湾北部海域进行的底拖网调查数据,应用相对重要性指数(IRI)、生物多样性指数和多元分析方法等研究了辽东湾北部海域鱼类群落结构特征及季节变化。结果表明:本次调查共出现鱼类39种,隶属于8目23科35属,种类组成以暖温性和暖水性鱼类为主。优势种有较明显的季节更替,季节性优势种包括矛尾虾虎鱼、斑尾复虾虎鱼、小黄鱼、梭鱼、印度鲬、大银鱼和黄,无四季共有优势种,季节性优势种组成较1998年发生较大变化。鱼类群落多样性指数季节变化范围分别为Margaler物种丰富度指数D(0.40~1.69)、Shannon-Wiener多样性指数H'(0.39~1.45)、Pielou物种均匀度指数J'(0.43~0.75),方差分析表明,3种多样性指数的季节变化差异显著。单因子相似性分析(AONSIM)表明鱼类群落结构存在明显的季节更替现象。相似性百分比分析(SIMPER)表明,小黄鱼、矛尾虾虎鱼、斑尾复虾虎鱼、斑、黄、梭鱼、印度鲬、蓝点马鲛、横带高鳍虾虎鱼、焦氏舌鳎是造成鱼类群落结构季节变化的主要分歧种。鱼类群落结构与环境因子的相关分析和BVSTEP分析表明,水温是影响辽东湾北部海域鱼类群落结构季节变化的主要环境因素。本研究可为渔业生物多样性保护和渔业资源可持续利用提供科学依据。  相似文献   

7.
为了解南昌市面积1 km2以上湖泊的鱼类群落结构及其物种多样性特征,探究影响湖泊鱼类群落结构空间分布的环境因子,于2019-2020年在南昌市13个湖泊进行了鱼类资源调查。结果显示,采集到的39种鱼类隶属5目、9科、33属;优势种以鲫(Carassius auratus)、?(Hemiculter leucisclus)为主;不同湖泊的鱼类群落结构被划分为3个类群,与湖泊功能定位密切相关。鱼类Shannon-Wiener多样性指数值平均值为2.15,丰富度指数平均值为2.97,均匀度指数平均值为0.92,Shannon-Wiener多样性指数、丰富度指数与湖泊面积、水深、pH和透明度存在显著的相关性。冗余分析(RDA)表明,水深、pH、总氮和氨氮是引起鱼类群落结构在南昌市不同湖泊间差异的主要影响因子,人为活动干扰可能对调查区域内湖泊的鱼类群落结构和生物多样性特征施加影响。  相似文献   

8.
根据2017年4月于嵊泗列岛邻近海域开展渔业资源底拖网调查的渔获数据,运用相对重要性指数、Shannon-Weaver指数、均匀度指数、丰富度指数、等级聚类和非度量多维度分析、生物量曲线等方法分析该海域鱼类种类组成、优势种、物种数量空间分布、生物多样性。该海域共鉴定出鱼类33种,其中优势种有棘头梅童鱼(Collichthys lucidus)、银鲳(Pampus argenteus)、龙头鱼(Harpodon nehereus)、凤鲚(Coilia mystus)等4种;与历史数据相比,该海域春季鱼类种类数锐减,优势种更替显著。根据适温性可分为暖温性和暖水性2类,分别为17和16种。各站位鱼类物种数在9~20种之间,整体呈嵊泗列岛北部海域高于南部海域的趋势。生物多样性分析表明,均匀度指数(J′)值较低,可能是舟山水域的污染导致多样性指数偏低。聚类分析结果表明,该海域鱼类群落结构空间差异较大。ABC曲线结果表明,舟山嵊泗列岛邻近海域鱼类群落结构处于严重干扰状态。综上所述,嵊泗列岛邻近海域鱼类资源受人类活动影响强烈,鱼类多样性指数偏低,群落结构空间差异较大。  相似文献   

9.
采用大连湾海域四季底拖网调查数据(2006年夏、冬季和2007年春、秋季),对其鱼类群落结构进行研究,并利用多样性指数法和丰度/生物量比较法(ABC曲线)评价鱼类群落受外界扰动的程度。研究结果表明,该海域四季共采集鱼类31种,隶属于10目24科31属,鱼类区系组成在适温性上以暖温性鱼类为主,在栖息水层上以底层鱼类为主。夏季鱼类生物量(43.16kg/h)和生物数量(950个/h)均明显高于其他3个季节。四季共有优势种为大泷六线鱼和许氏平鲉。鱼类群落多样性指数季节变化范围分别为物种丰富度指数0.76~2.16、多样性指数0.63~1.96、物种均匀度指数0.36~0.91。各季节间生物量和丰度组成的Bray-Curtis相似性均较高。多样性指数法和丰度/生物量曲线法对鱼类群落受外界扰动评价结果一致,均表明鱼类群落受到中度扰动,且秋冬季高于春夏季。本研究可为大连湾海湾生态系统健康评价和生态修复提供科学依据。  相似文献   

10.
威海寻山人工鱼礁海域底栖生物群落组成与结构   总被引:2,自引:0,他引:2  
2009年4月30日对威海寻山人工鱼礁投放海域5个礁区及1个对照区底栖生物群落进行对比调查。共鉴定出底栖生物31种(礁区31种,非礁区1种),隶属于4门24科,软体、环节、节肢动物门为优势类群,其中软体动物门14科20种,占总种数的64.51%。多种生态学指数计算底栖生物群落的特征值,发现礁区与非礁区在底栖生物群落组成和结构差异显著,礁区物种多样性更为丰富,群落结构更趋复杂,建礁效果明显:建礁后礁区底栖生物量呈明显上升趋势,礁区平均生物量(95.4 g/m~2)明显高于非礁区(1.78 g/m~2),是后者的53.60倍;非礁区多毛类数量较多,礁区生物平均丰度与非礁区基本持平。礁区Margalef物种丰富度指数、Shannon-Wiener物种多样度指数分别为4.34和5.34。McNaughton物种优势度指数显示礁区杂色蛤、凸壳肌蛤、双带核螺等贝类为丰度优势种。Jaceard种类相似性指数仅0.032(0.5),底栖生物区域性分布较为明显,两区域物种相似度较小。  相似文献   

11.
12.
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   

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.
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   

15.
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   

16.
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   

17.
18.
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   

19.
  1. Humanity is facing a biodiversity crisis, with freshwater-associated biodiversity in a particularly dire state. Novel ecosystems created through human use of mineral resources, such as gravel pit lakes, can provide substitute habitats for the conservation of freshwater and riparian biodiversity. Many of these artificial ecosystems are subject to a high intensity of recreational use, however, which may limit their biodiversity potential.
  2. The species richness of several taxa (plants, amphibians, dragonflies, damselflies, waterfowl, and songbirds) was assessed and a range of taxonomic biodiversity metrics were compared between gravel pit lakes managed for recreational fisheries (n = 16) and unmanaged reference lakes (n = 10), controlling for non-fishing-related environmental variation.
  3. The average species richness of all the taxa examined was similar among lakes in both lake types and no substantial differences in species composition were found when examining the pooled species inventory. Similarly, there were no differences between lake types in the presence of rare species and in the Simpson diversity index across all of the taxa assessed.
  4. Variation in species richness among lakes was correlated with woody habitat, lake morphology (surface area and steepness), and land use, but was not correlated with the presence of recreational fisheries. Thus, non-fishing-related environmental variables had stronger effects on local species presence than recreational fisheries management or the presence of recreational anglers.
  5. Collectively, no evidence was found that anglers and recreational fisheries management constrain the development of aquatic and riparian biodiversity in gravel pit lakes in the study region; however, the conservation of species diversity in gravel pit lakes could benefit from an increasing reliance on habitat enhancement activities.
  相似文献   

20.
The aim of this study was to describe two epizootics of high mortalities from infection with Streptococcus agalactiae, occurring in captive rays held in a marine display aquarium in south‐east Queensland, Australia, in 2009 and 2010. Five different species of rays were affected, including mangrove whiprays (Himantura granulata), estuary rays (Dasyatis fluviorum), eastern shovelnose rays (Aptychotrema rostrata), white‐spotted eagle rays (Aetobatus narinari) and blue‐spotted mask rays (Neotrygon kuhlii). This report describes the history of both epizootics including collection, quarantine and husbandry of rays, the disease epizootics, clinico‐pathological features of the disease, antimicrobial therapy, autogenous vaccine production, and laboratory studies including clinical and histopathology, bacteriology, PCR, molecular serotyping and sequencing of the bacterium S. agalactiae.  相似文献   

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