秋季长江口鱼类浮游生物群落时空结构

根据1998—2009年11月长江口及其邻近海域7个航次的调查资料,探讨了秋季长江口鱼类浮游生物群落种类组成、群落结构及多样性时空变化特征。研究结果显示,7个秋季航次共捕获鱼类浮游生物969个(尾),隶属于10目19科33种,以鲈形目种类最多(7科9种)。秋季长江口鱼类浮游生物以沿岸型种类最多(12种),其次是半咸水(10种)和近海种类(9种),淡水种类最少(4种)。秋季长江口鱼类浮游生物优势种年度间演替显著,对鱼类浮游生物群落丰度贡献最大的种类包括:半咸水型的矛尾鰕虎鱼(Chaeturichthys stigmatias)和前颌间银鱼(Salanx prognathus)、沿岸型的康氏小公鱼(Stolephorus commersonnii)、近海型的鳀(Engraulis japonicus)和带鱼(Trichiurus lepturus)。2004年以后,长江口鱼类浮游生物种类数量、丰度和多样性均显著高于2004之前的调查航次。ANOSIM分析显示,长江口鱼类浮游生物群落结构年度间差异显著,且2007和2009年与其他年度不相似性最高。可以看出,秋季长江口鱼类浮游生物种类组成呈年度变异状态,2004年后长江口鱼类浮游生物群落结构变异最大,多样性呈增加趋势。     

长江口邻近海域夏季底栖纤毛虫的多样性与群落结构特点

采用Ludox-QPS方法,研究了2011年8月采自长江口邻近海域9个站位沉积物中纤毛虫的群落结构及分布特点,并结合沉积环境进行综合分析。结果表明,表层8cm沉积物中底栖纤毛虫的平均丰度为(2782±1493)cells/10cm2,生物量为(10.06±6.41)μgC/10cm2。长江口海域北部站位的丰度和生物量呈从近岸向外海增加,南部的站位呈现相反的分布趋势。在垂直分布上, 62%的底栖纤毛虫分布在表层2cm, 12%分布在5—8 cm。本研究共检获纤毛虫106种,隶属于15纲/亚纲, 24目, 69属,前口纲在丰度及生物量上均为最优势类群(丰度占45.5%,生物量占56.4%),核残迹纲在生物量上居第二位。就食性来看,肉食性纤毛虫物种数最多(44种),其丰度和生物量所占比例也最高(40.3%,66.8%),但在长江口外站位(M1站),菌食性纤毛虫为最优势摄食类群。分析表明,研究海域底栖纤毛虫群落结构与底层水盐度最相关。聚类分析结果显示,由于较多量的伪钟虫属(Pseudovorticella)和原领毛虫属(Prototrachelocerca)种类出现导致长江口北部L1站的纤毛虫群落结构不同于其他站位。本研究所获底栖纤毛虫的丰度和生物量较东海离岸海域已有研究结果均高,表层8cm沉积物中纤毛虫的丰度约是上层30m水柱中浮游纤毛虫的116倍,生物量约是后者的150倍。基于目前黄东海有关底栖纤毛虫物种多样性的已有报道,其多样性在长江口离岸海域高于近岸潮间带,且在离岸海域东海低于黄海。     

兴化湾大型底栖生物生态研究

兴化湾大型底栖生物已鉴定有314种,平均生物量为36.60g/m2,平均栖息密度为162个/m2.按Bray-Curtis相似性指数和多维排序尺度可划分为4个群落.应用丰度生物量比较法(ABC)和种类个体几何级数显示群落结构相对稳定.     

捕捞和气候变化在南海北部湾口鱼类长期种类演替和种群动态的作用

捕捞压力在改变南海鱼类种类演替和生物量波动方面所起的作用大于气候和环境因素是一个普遍的、有争议的假设。根据1959~2010年南海北部北部湾口底拖网的调查数据，报告了该海域鱼类种类组成、优势类群的丰度比例、生物量的季节和年际变化。建立了鱼类生物量与捕捞压力和气候变化外部因素之间的广义加性模型。结果表明，捕捞压力驱动底层渔业资源急剧下降的主要因素，并随着时间的推移，高值鱼类被低值鱼类所取代。1993年和1998年期间鱼类生物量的突然减少与同期厄尔尼诺事件相对应，气候变化可能是渔业拖网捕捞中中上层鱼类比例变化的主要驱动因素。为了更好地了解鱼类群落动态，需要区分捕捞压力和环境驱动因素对不同生活史策略鱼类物种的影响。     

山东荣成天鹅湖大叶藻形态和生长的季节性变化研究

2012年8月至2013年7月,作者逐月对天鹅湖大叶藻(Zostera marina L.)的形态特征、植株密度、生物量和生产力进行了监测。结果表明,大叶藻周年株高最高值和最低值分别出现在7月和1月;叶鞘高度、叶鞘宽度和叶宽的最高值均出现在7月,叶鞘高度最低值出现在1月,叶鞘宽度和叶宽最低值均出现在2月;大叶藻顶枝、侧枝和花枝的周年密度最大值分别出现在6月、4月和5月,最小值分别出现在1月、8月和7月;单株生物量和地上部分生物量最大值均出现在7月,地下部分出现在10月,而单株生物量和地上部分生物量最小值均出现在1月,地下部分生物量最小值出现在3月;单株地上和地下生产力最大值均出现在6月,最小值则分别出现在1月和2月。分析显示,大叶藻在冬季由于水温较低导致生长缓慢,且植株较小,在春季随水温上升,生长开始加快。水温在夏初达到大叶藻的最适生长水温,大叶藻的生物量和初级生产力达到最高值,而夏末和初秋由于水温过高导致大叶藻个体生物量、密度和初级生产力开始降低。这种季节性变化与水温的季节性变化密切相关。     

2014—2015年硇洲岛大型海藻场浮游动物的群落结构和季节变化

2014年4月、7月、10月和2015年1月分别对硇洲岛大型海藻场附近海域的浮游动物进行了季节调查，分析了浮游动物的种类组成、优势种、群落结构、丰度和生物量的季节变化及影响因素。结果共检出浮游动物91种和浮游幼虫36种，隶属于17大类群。其4个季节的平均丰度和生物量分别为186.5 ind/m3和431.0 mg/m3，高峰期均位于夏季，低谷位于冬季。优势种共有19种（类）。生物多样性分析表明，研究海域浮游动物具有较高的均匀度（0.74），生物多样性指数较高（3.14）。根据聚类分析结果，可将调查海区的浮游动物在38％相似性水平上划分为4组，浮游动物的群落组成呈较明显的季节变化。组群的组内相似性和组间非相似性均大于50%，对组内相似性及组间非相似性起主要贡献的种类有37种。通过生物-环境匹配（BIOENV）分析，水温、盐度、浮游植物丰度和叶绿素a浓度是影响浮游动物群落结构的环境因子。     

长江口邻近海域大型底栖生物群落结构分析

2004年5月的调查共获大型底栖生物50种,种数和丰度的优势生物为多毛类动物,而底栖鱼类和螠虫的生物量占明显优势。长江口大型底栖生物平均生物量为17.57g/m2,平均丰度为150ind./m2。生物量和丰度密集区集中在盐度25度线附近海域。根据Bray-Curtis相似性系数聚类分析和多维排序尺度分析,长江口大型底栖生物可划分为四个群落:Ⅰ圆筒原盒螺-滩栖阳遂足-棘刺锚参-背蚓虫群落;Ⅱ圆筒原盒螺-钩虾群落;Ⅲ背蚓虫-奇异稚齿虫-不倒翁-尖叶长手沙蚕-近辐蛇尾群落;Ⅳ短叶索沙蚕-长吻沙蚕-纽虫群落。通过引入环境变量的二维MDS图分析,长江口大型底栖生物群落分布与底层盐度、有机物具有较大的相关性。生存环境短时间内的剧烈变化是导致群落Ⅱ和Ⅳ种群贫乏的重要原因之一。河口区悬浮粉砂颗粒的短期快速沉降现象可能也是导致群落Ⅱ和Ⅳ种群贫乏的另一重要原因。     

长江口邻近海域夏季大型底栖生物群落特征

本文根据2014年6月长江口邻近海域大型底栖生物的调查资料, 采用优势度指数, 物种多样性指数、丰富度指数、均匀度指数, Bray-Curtis相似性聚类和非参数多维标度排序(nMDS)标序方法, 分析了长江口邻近海域夏季大型底栖生物的群落特征。本次调查共采集大型底栖生物135种, 其中多毛类66种, 甲壳动物33种, 棘皮动物14种, 软体动物13种, 其他类群9种。调查海域的大型底栖生物平均丰度为122.2ind/m₂,平均生物量为7.8g/ m₂。丰度、生物量和多样性指数在不同海区间的空间差异均不显著。大型底栖生物在20%的相似性水平上可以划分为8个群组,各站位间相似性水平较低。ABC曲线表明,伴随海岸带开发及人类活动的持续影响, 长江口邻近海域底栖生境的稳定性受到轻微扰动, 建议继续开展长期连续的监测, 为研究长江口海域环境变化和大型底栖生物群落演替提供基础资料。     

2009年春季舟山海域大型底栖生物群落结构的生态特征

2009年4月对舟山海域13个站位的大型底栖生物群落结构的生态特征进行了调查,并结合2001—2008年浙江近岸海域生态环境监测数据资料,分析了该海域大型底栖生物的变化趋势及其生存环境现状。结果表明,调查海域共鉴定出大型底栖生物84种,其中多毛类31种,甲壳类25种,软体动物12种,鱼类8种,腔肠动物4种,棘皮动物和其它类各2种。2009年春季该海域大型底栖生物的生物量平均值为11.62g/m2,丰度平均值为208.5个/m2,生物多样性指数(H′)为1.64,丰度呈由近岸向外海递增的趋势。根据Bray-Curtis相似性系数聚类分析和多维尺度排序分析,该海域大型底栖生物可划分为3个群落,分别为群落Ⅰ:双鳃内卷齿蚕-织纹螺-孔鰕虎鱼群;群落Ⅱ:色斑角吻沙蚕-脊尾白虾群落;群落Ⅲ:葛氏长臂虾-织纹螺群。通过丰度/生物量累积k-优势度曲线分析可知,该海域大型底栖生物群落已受到中度程度的污染或扰动,群落结构不稳定。比较分析2001—2009年舟山海域大型底栖生物生物量和丰度变化趋势可知,个体较小、生长周期较短的种类逐步成为舟山海域的优势类群。     

夏冬季黄海浮游动物群落结构及其影响因素

根据2016年7月和2017年1月在黄海进行的57个站位的调查数据,研究了大型网采集的浮游动物的种类组成、丰度、生物量、群落聚类、优势种、多样性、均匀度、丰富度以及与环境因子的关系。本次调查共鉴定出浮游动物97种,其中夏季67种,冬季76种。该海区夏季浮游动物的丰度和生物量的高值区分布在黄海冷水团和长江口附近海域,冬季分布在黄海暖流主轴部分。根据各站位的地理位置和浮游动物相似程度,对黄海浮游动物Cluster聚类和MDS多维定标分析,将夏季划分为4个群落,将冬季划分为3个群落。共计有8个优势种类,夏季的优势种多为桡足类,冬季除中华哲水蚤(Calanus sinicus)优势度占绝对优势外,其余优势种的优势度较为相近。将浮游动物的丰度、生物量和生物多样性指数和环境因子做相关性分析得出:温度、盐度是影响黄海浮游动物群落结构的主要影响因子。     

The Larval Fish Assemblage in Nearshore Coastal Waters off the St Lucia Estuary, South Africa

This paper reports on the composition, abundance and distribution of the larval fish assemblage in the nearshore coastal waters off the St Lucia Estuary mouth, South Africa. Ichthyoplankton samples were collected over a 12 month period from five stations located along a transect up to 2·5 km offshore, and from two stations north and south of the estuary mouth, respectively. In all, 6126 fish larvae, representing 89 families and 186 species, were collected. Larvae in the families Myctophidae and Tripterygiidae comprised 21% and 16% of the total catch, respectively. The most abundant species were an unidentified triplefin, Tripterygiid 1 and the lanternfish Benthosema fibulatum, together which contributed nearly 18% of the total catch. Larvae of marine spawners independent of estuaries dominated the catch both in terms of density (90%) and in terms of number of taxa (89%). Some larvae of estuarine-associated species were present, in addition to a few specimens of estuarine resident species. Overall the dominant environmental variable affecting larval densities was temperature, particularly for Trypterygiid 1 where temperature contributed to 9% of the variance model. Densities of fish larvae peaked in November and December 1990 (late spring and early summer) and were lowest from January to June 1991 (summer, autumn an early winter). Different taxa dominated the catch each month with reef- and shelf-associated species accounting for the peak in August and September 1990, oceanic species in November 1990 and a mixture of the two groups in December. Overall larval densities were significantly higher in bottom samples with a trend of increasing densities offshore for reef and shelf taxa. The larvae of reef and shore taxa were predominantly preflexion larvae, whilst the few estuarine spawner species that were collected were mainly postflexion. Ontogenetic patterns related to depth and distance offshore were evident for the dominant species in each estuarine-association category.The present study has shown that temporal and spatial variations in the larval fish assemblage off St Lucia are related to environmental conditions and ontogenetic behavioural patterns of certain species. The origin of many of the larvae in the assemblages off the coast of St Lucia is probably from both local spawning populations in the shelf waters off KwaZulu-Natal and spawning populations farther north in shelf waters off Mozambique. Additional studies with more detailed oceanographic measurements will further our understanding of the physical processes that supply larvae to the St Lucia region.     

莱州湾游泳动物群落结构研究

本文根据2010和2011年春季（5月）、夏季（8月）、秋季（10月）和冬季（12月）进行的8航次调查数据，研究了莱州湾游泳动物群落格局及其与环境因子关系。结果显示，调查共捕获游泳动物85种，2011年生物量略高于2010年；生物量季节间差别较大，各季节生物量排序为夏季、秋季、冬季和春季；不同年间相同季节生物量差异多不显著（秋季除外）；除2010年春季外，其余季节均为鱼类生物量最高，甲壳类次之，头足类最低；从全年调查平均值来看，莱州湾西侧游泳动物生物量（60.2 kg/h）明显高于东侧（33.4 kg/h）。根据8航次31个主要种类生物量聚类分析，莱州湾20调查站位可划分为4组：组I由位于调查海域东南的3个站位组成，组II由位于调查海域东部及中部的8个站位组成，组III由调查海域西北部（黄河口南侧）的3个站位组成，组IV由西部6个站位组成。组I浮游植物丰度、浮游动物生物量、游泳动物生物量和游泳动物多样性指数在各组中均最低，而底栖动物生物量最高；组III和组IV的浮游植物丰度、浮游动物生物量以及游泳动物生物量高于组I和组II。ANOSIM分析表明，各聚类组间群落结构虽有不同，但差异并不显著。DCCA分析表明，温度、盐度、底栖动物生物量以及浮游植物丰度是影响游泳动物群落的重要因子。研究表明，目前莱州湾游泳动物群落总生物量处于较低水平，特别是春季生物量下降尤为严重；生物量的季节分布发生了较大的改变，春季生物量极低，夏季生物量相对较高；底层鱼类比例下降的趋势有所逆转，头足类比例明显增加。莱州湾游泳动物群落格局异质性较低，可能与莱州湾生境异质性低以及人类剧烈干扰密切相关。     

黄河口邻近海域浮游幼虫群落结构季节变化

基于2019-2020年4个季节的6个航次海上生态调查,研究黄河口邻近海域的浮游幼虫群落结构及其与环境因子的关系,旨在为海域生物多样性保护与重要生物资源养护提供科学基础.结果显示:在黄河口邻近海域,共鉴定出浮游幼虫16类,阶段性浮游幼虫是主要组成类群.浮游幼虫月均丰度以11月最高、1月最低.浮游幼虫香农-威纳多样性指数...     

2011年南黄海辐射沙脊群海域浮游植物种类组成和密度的时空变化

于2011年2～12月,在南黄海辐射沙脊群海域设置6个采样站位,每逢双月份调查1次,研究该海域浮游植物密度及优势种的时空变化.调查共获得浮游植物87种,以硅藻种类最多.浮游植物密度呈周年双峰变化,分别在4月和8月成峰,4月峰值最大,水样浮游植物平均密度为1.59×104cells/dm3,网样浮游植物平均密度为2.71×106cells/m3,8月峰次之,水样浮游植物的平均密度为1.28×104cells/dm3,网样浮游植物平均密度为7.38×105cells/m3;浮游植物密度在2月和4月,北高南低,6月和8月中部高,外围较低,10月和12月南部高北部低.2月和4月,中肋骨条藻（Skeletonema costatum）为第一优势种,6月和12月虹彩圆筛藻（Coscinodiscus oculus-iridis）为第一优势种,8～10月琼氏圆筛藻（Coscinodiscus jonesianus）为第一优势种,枯水期（2月）铁氏束毛藻（Trichodesmium thiebautii）在局部海域形成优势.     

Fish Assemblages of Posidonia oceanica Beds at Port-Cros (France, NW Mediterranean): Assessment of Composition and Long-Term Fluctuations by Visual Census

Abstract. Observations of the fish fauna of Posidonia oceanica (L.) DELILE seagrass beds were undertaken in two shallow stations and one deeper station in Port-Cros National Park, between November 1984 and September 1987. Demographic structure, density and biomass of the 19 most abundant species or taxa were assessed by several non-destructive sampling methods. The fish assemblages studied were dominated in number and biomass by a small number of species (Labridae: Symphodus ocellatus and S. tinca ; Sparidae: Diplodus annularis and Sarpa salpa ). Large individuals were infrequent and small size class fish were dominant especially in sheltered shallow areas. Recruitment and migrations (shortor long-term) have been identified as the most important causes of abundance variations over the year. The four trophic categories were sampled only in the sheltered shallow zone, where the herbivore Sarpa salpa represents a strong proportion of the fish fauna (40–70%) during summer. The fish assemblages differ between the three seagrass beds, and the depth appears as the most important factor affecting the fish assemblages in P. oceanica . The functional difference between shallow and deeper seagrass beds is therefore discussed.     

Abundance,biomass and species composition of nearshore fish assemblages in Ghana,West Africa

Many of the world's fish populations are overexploited, including Ghana's fish resources. This study examines spatio-temporal trends in fish species composition in relation to biotic, abiotic and anthropogenic factors, towards achieving better-informed management of the beach-seine fisheries. Fishery-dependent data were collected between November 1999 and October 2001 from 94 beach-seine hauls fished at two stations along the Ghanaian coast. The catch consisted of fish, crustaceans, other invertebrates, and macroalgae. Generally, juveniles of species that are exploited by offshore fisheries were found in the catches. Species abundance and their occurrence generally peaked between November and January. Duration of solar radiation and tide level appeared to be important predictors of fish biomass. It is important to exploit the nearshore fish assemblage sustainably because of its nursery role. A co-managed (fishers and government) three-month ban on beach-seining (between May and July) is recommended as the most appropriate control measure towards the sustainability of Ghanaian fish stocks.     

Tidal exchange of zooplankton between Lough Hyne and the adjacent coast

Plankton samples collected in November 2002, February, May and August 2003 were used to examine seasonal variation in tidal exchange of zooplankton biomass, abundance and species composition between Lough Hyne Marine Nature Reserve and the adjacent Atlantic coast. Micro- to mesozooplankton were collected by pump over 24-h sampling periods during spring and neap tides from the narrow channel connecting the semi-enclosed water body to the Atlantic. Sample biomass (dry weight) and total zooplankton abundance peaked in the summer and were lowest in winter, showing a positive relationship with temperature. Zooplankton biomass, total abundance and numbers of holo- and meroplankton revealed import during some diel cycles and export in others. However, the tidal import of these planktonic components was generally dominant, especially during May. The greatest import of numbers of holoplankters and meroplanktonic larvae occurred during May and August, respectively. There was no significant variation in sample biomass between periods of light and dark, but some variation in zooplankton abundance could be explained by this diel periodicity. Significant differences in sample assemblage composition between flood and ebb tide samples were always observed, except during winter neap tides. There was a net import of the copepods Temora longicornis and Oithona helgolandica and the larval stages of Mytilus edulis during spring and summer. Proceraea cornuta and Capitellid trochophores were imported during winter, and a hydrozoan of the genus Obelia during the spring spring tides. Seasonal export from the lough was shown by Pseudopolydora pulchra larvae (autumn and spring), Serpulid trochophores (autumn) and veligers of the bivalve Anomia ephippium (summer). It is suggested that the direction of tidal exchange of meroplanktonic taxa is related to the distribution of the adult populations. Copepod naupliar stages dominated the assemblages except during May spring tides when the copepod Pseudocalanus elongatus made up over 22% of the abundance. The general import of micro- to mesozooplankton may, in part, explain the higher densities of this size-class of zooplankton within the semi-enclosed system of Lough Hyne.     

莱州湾大型底栖动物群落结构及其动态变化特征

本文以莱州湾2009年夏季(8月)、秋季(10月)及2010年春季(5月)、夏季(8月)4个季节大型底栖动物资料为基础，对莱州湾大型底栖动物的种类组成、丰度、生物量、优势种进行了研究，同时与历史资料进行对比，探讨了莱州湾大型底栖动物的群落结构特征及动态变化。4个航次中共鉴定出大型底栖动物272种，其中包括环节动物多毛类122种，软体动物46种，甲壳动物64种，棘皮动物18种，鱼类9种，其他类13种。调查海域平均丰度为(1102.56 ± 216.32) ind./m2, 多毛类在丰度上占绝对优势；平均生物量为(28.16 ± 8.45) g/m2，软体动物占据优势。丰度和生物量空间分布规律具有很强的相似性，低值区位于莱州湾西部黄河口邻近海域，高值区位于渤海中部海域。丰度和生物量季节变化明显，夏季最高，秋季其次，春季最低。多毛类不倒翁虫(Sternaspis sculata)、寡鳃齿吻沙蚕(Nephthys oligobranchia)、紫壳阿文蛤(Alvenius ojianus)等是莱州湾调查海域的优势种。通过与历史资料的对比发现，莱州湾大型底栖动物种类组成及优势种类出现小型化的趋势。     

Copepod community structure during upwelling and non-upwelling seasons in coastal waters off Cochin, southwest coast of India

Vypeen, an island of Cochin estuarine system, acts as the spawning site of several marine and estuarine fishes. We assumed that, physical process(upwelling) make changes in hydrography and the production of chlorophyll a in coastal waters off Vypeen. These alterations can influence the zooplankton abundance and copepod community structure in that area. For justifying this hypothesis, samples were collected from Vypeen at 10 m and 30 m locations during January(pre-southwest monsoon), August(late-southwest monsoon) and November(postsouthwest monsoon) 2014. During August, subsurface water column was cool, nutrient rich and less oxygenated(signatures of upwelling) than in November and January. Maximum concentrations of nitrate and chlorophyll a were recorded during August. In the present study, 15 zooplankton groups were recorded; of which copepods were the most predominant group(73%–90%). Copepod density in the present study ranged between 527.2 ind./m~3 and 5 139.2 ind./m~3. Totally, 37 copepods species were reported in present study and copepod species richness was higher during January. The abundance of zooplankton and copepods was high in August during late-southwest monsoon. These variations were closely associated with the coastal upwelling in August and weakening of moderate upwelling in November. In SIMPER analysis, it was found that the copepods species distribution was similar within season and dissimilar between the three seasons. Moreover, the higher abundance of upwelling indicator species Temora turbinata was recorded in August, which confirms the signs of seasonal upwelling in Vypeen. The present study emphasized on the influence of hydrographical parameters associated with physical process, in governing the copepod community organization of the Vypeen Island.     

胶州湾桡足类幼虫和浮游生纤毛虫的丰度与生物量

1997年9月，12月，1998年2月，4月，8月，11月以及1999年2月和5大以胶州湾采集桡足类幼虫和浮游生纤毛虫的样品，样品用Lugol‘s试剂固定（最后浓度1％），用显微镜计数桡足类幼虫和浮游生纤毛虫的丰度，并计算总生物量（表层生物量和水体生物量）。桡足类幼虫，无壳纤毛虫和砂壳纤毛虫的最大丰度分别为850ind/L(1998年8月），21300ind/L(1998年8月）和172ind／L(1999年5），表层的总丰度为10－22630ind/L，平均分布湾内比湾外多，表层纤毛虫和桡足类幼虫的总生物量为0．10－380.27ugC/L，水体的生物量为0．20－1426.02mgC/m^2.