黄河口及其邻近水域浮游动物群落结构特征及其季节变化

根据2013年8月、10月和2014年2月、5月在黄河口及其邻近水域4个航次的调查数据,分析了该海域浮游动物的种类组成、数量变动、优势种、种类多样性及其季节变化。本次黄河口及其邻近水域调查共鉴定浮游动物43种,其中原生动物、毛颚动物、尾索动物和栉水母各1种,刺胞动物8种,浮游甲壳类18种,浮游幼体及鱼卵、仔稚鱼共13种(类)。浮游动物的平均丰度为2115.64 ind/m~3,不计夜光虫的平均丰度为95.93 ind/m~3,其中浮游甲壳类占71.43%。浮游动物丰度存在显著的季节变化,数量高峰出现在春季(5月),其次为冬季(2月)、秋季(10月)和夏季(8月)。毛颚动物强壮箭虫(Sagitta crassa)和双刺纺锤水蚤(Acartia bipinnata)、小拟哲水蚤(Paracalanus parvus)等桡足类为夏、秋、冬三个季节的主要优势种,夜光虫(Noctiluca scintillans)为春季的绝对优势种。浮游动物群落物种丰富度指数(D)、Shannon-Wiener指数(H')和均匀度指数(J')的变化趋势一致,表现为夏秋季高,冬春季低。黄河口及其邻近水域浮游动物的群落结构特征具有明显的季节变化;桡足类和浮游幼体是主要类群,对该水域浮游动物的数量变动及种类多样性的变化具有较大影响。     

东海浮游桡足类的种类组成及优势种

根据1997-2000年东海23°30′～33°N、118°30′～128°E水域4个季节海洋调查资料,对浮游桡足类种类组成及优势种作了探讨。东海浮游桡足类经鉴定共有226种,呈外海高近海低的分布趋势,夏季(163种)>秋季(152种)>春季(140种)>冬季(123种),4个季节皆出现的有78种。优势种(优势度Y≥0.02的17种,主要有中华哲水蚤(Calanus sinicus)、普通波水蚤(Undinula vulgaris)、精致真刺水蚤(Euchate conicina)和亚强真哲水蚤(Eucalanus subcrassus)等,季节更替明显,在秋、冬季优势种中还新出现了多种中、小型桡足类。北部近海(29°～32°N、125°E以西)春季中华哲水蚤、夏秋季精致真刺水蚤与水温、盐度多元一次逐步回归相关性显著(P<0.05),秋季普通波水蚤与水温、盐度相关性非常显著(P<0.01),春季鳀(Engraulis japonicus)中心渔场(>100kg·h~(-1))分布与中华哲水蚤高密集区(50～100ind·m~(-3))平面分布具有良好的对应关系;春、夏季鳀鱼仔、稚鱼高密度区(≥100ind·net~(-1))与中华哲水蚤高丰度区(50～100ind·m~(-3))相重叠。     

武汉南湖的浮游甲壳动物

通过周年4次采样,在南湖5个采样站一共鉴定出浮游甲壳动物14种,年平均密度为119.7ind./L,平均生物量为1.67mg/L。其中枝角类8种,优势种为短尾秀体Diaphanosomabrachyurum和微型裸腹Moinamicrura;桡足类6种,优势种为近邻剑水蚤Cyclopsvicinusvicinus。浮游甲壳动物现存量的季节变化明显,密度由高到低依次为冬季>春季>秋季>夏季;生物量由高到低则依次为秋季>冬季>夏季>春季。浮游甲壳动物密度的水平分布差异明显,密度由高到低为Ⅳ>Ⅲ>Ⅴ>Ⅰ>Ⅱ站;生物量由高到低为Ⅴ>Ⅳ>Ⅲ>Ⅱ>Ⅰ站。     

黄海北部春季和夏季浮游动物生态特性与时空分布

根据2015年3月(春季)和6月(夏季)对黄海北部辽宁近岸海域的浮游动物调查结果,分析了两个季节的浮游动物种类、生物量、丰度等群落结构特征。此次调查共鉴定出浮游动物47种,其中春季42种,夏季34种。浮游动物以浮游幼虫和小型桡足类为主。桡足类幼虫、棘皮动物幼体、桡足类幼体、洪氏纺锤水蚤、短角长腹剑水蚤、小拟哲水蚤、拟长腹剑水蚤和腹针胸刺水蚤为春季优势种;夏季浮游动物优势种依次为桡足类幼体、洪氏纺锤水蚤,拟长腹剑水蚤、短角长腹剑水蚤、桡足类幼虫、小拟哲水蚤和腹针胸刺水蚤。春季浮游动物平均生物量为512.09mg/m~3,平均丰度为15 522.18个/m~3;夏季浮游动物平均生物量为218.84mg/m~3,平均丰度为7582.39个/m~3;浮游动物生物量和丰度均为春季较高。黄海北部辽宁沿岸海域的浮游动物生物量、丰度较高。水温是影响浮游动物群落结构的重要环境因子。     

东海浮游桡足类的数量分布

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。     

2018—2019年余姚市主要内河浮游甲壳动物群落变化特征

为探明2018—2019年余姚市主要内河(余姚江、临周江、长泠江和湖塘江)浮游甲壳动物群落变化特征,于2018年和2019年2月(冬季)、5月(春季)、8月(夏季)和11月(秋季)调查8次,比较分析浮游甲壳动物种类组成、优势种、密度和生物量等参数,并采用优势度曲线和相似性分析方法,分析浮游甲壳动物种类数与累计丰度百分比,以及浮游甲壳动物群落年际、季节及空间上的差异性。调查结果显示：2018年共鉴定浮游甲壳动物39属67种,其中桡足类35种、枝角类32种;2019年共鉴定浮游甲壳动物26属46种,其中桡足类25种、枝角类21种。2018年浮游甲壳动物、桡足类和枝角类种类数高于2019年。密度和生物量年际变化不大,各年度季节排序均为春季>秋季>夏季>冬季。优势种年际更替率为78.26%。浮游甲壳动物群落结构年际差异极显著,季节上夏季两年之间群落结构差异不显著,空间上各江段两年之间均差异不显著。2019年较2018年,浮游甲壳动物群落具有一定的单一性表现,水体亦有趋于富营养化的态势。     

辽宁省黄海北部沿岸夏季和秋季浮游动物群落结构

2014年8月(夏季)和10月(秋季)对辽宁省黄海北部沿岸海域进行了2个航次的浮游生物调查,共检测出浮游动物35种,其中夏季30种,秋季34种。浮游动物以小型桡足类和浮游幼虫为主。洪氏纺锤水蚤、短角长腹剑水蚤、小拟哲水蚤、近缘大眼剑水蚤、强壮箭虫、异体柱囊虫和双壳类幼体为夏季优势种;洪氏纺锤水蚤、短角长腹剑水蚤、近缘大眼剑水蚤、强壮箭虫、异体柱囊虫、桡足类幼虫、沃氏纺锤水蚤为秋季优势种。夏季浮游动物生物量高于秋季,生物量则低于秋季。季节变化会影响浮游动物的丰度和生物量。辽宁省黄海北部沿岸浮游动物丰度、生物量较高,小型桡足类在黄海北部沿岸浮游动物群落结构中具有重要的作用。     

长江口海域浮游软体动物生态特征的季节变化

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。     

长兴岛沿岸春季和夏季的浮游动物群落结构

2005年8月(夏季)的大、小潮期间和2006年3月(春季)的大、小潮期间对长兴岛沿岸进行了4个航次的浮游生物调查,共检出浮游动物47种,其中春季32种,夏季44种。浮游动物的优势类群为桡足类和浮游幼虫。小拟哲水蚤、双毛纺锤水蚤、拟长腹剑水蚤、无节幼虫为春季优势种。小拟哲水蚤、双毛纺锤水蚤、近缘大眼剑水蚤、桡足类幼体、太平洋纺锤水蚤为夏季优势种。春季浮游动物的丰度、生物量及种类数均低于夏季。小潮期间浮游动物的丰度、生物量高于大潮期间。浮游动物的丰度、生物量及优势种受潮周期的影响。北部沿岸和南部沿岸浮游动物丰度、生物量较高。小型桡足类在长兴岛沿岸浮游动物群落结构中扮演重要角色,长兴岛沿岸浮游动物群落结构较为成熟稳定。     

大亚湾桡足类的生态学研究

根据2003年12月～2004年9月对纬度22.617°以北的大亚湾海域进行4个航次海域生态环境监测的资料,对大亚湾浮游桡足类的种类组成、生态类群、数量的季节变化和平面分布进行了分析。结果表明,所记录的54种浮游桡足类中,以红纺锤水蚤、亚强真哲水蚤、微刺哲水蚤和锥形宽水蚤的数量最丰富。桡足类种类数和丰度均以夏季最高,春季最低。通过这次调查,得出以下结论:大亚湾桡足类种类较多,是浮游动物第一大类群,但数量上次于毛颚类和枝角类;夏、秋2季是桡足类数量的高峰期,都以红纺锤水蚤占绝对优势;该次调查中大亚湾出现的浮游桡足类分属热带大洋类群、近岸低盐类群和广布类群,种类组成属印度西太平洋热带边缘区系。     

珠江三角洲河网桡足类群落结构及其与水环境因子的关系

为了解珠江三角洲典型河网水域浮游桡足类的生态特征,于2012年3月、5月、8月和12月对该水域进行4个季度的采样调查,通过数据分析,对桡足类的种类组成、现存量及生物多样性等指标进行了分析。共鉴定桡足类9科24属31种,以及桡足幼体和无节幼体。结果显示,该水域桡足类优势种的季节演替及空间变化明显,广布中剑水蚤(Mesocyclops leuckarti)、跨立小剑水蚤(Microcyclops varicans)和透明温剑水蚤(Thermocyclops hyalinus)等种类为常见种。桡足类及无节幼体的现存量分布具有明显的季节变化,丰水期现存量大于枯水期;桡足类现存量的平面分布较为均匀,无节幼体的现存量基本呈现自西南向东北方向降低的趋势。总体看来,丰水期桡足类的平均生物多样性指数及均匀度指数高于枯水期,空间分布格局基本呈现自西南向东北方向降低的趋势。PCA分析结果表明,珠江三角洲河网水域桡足类群落结构与水温、总磷、总氮、氨氮、高锰酸盐指数以及叶绿素a含量呈显著正相关,与透明度和p H呈显著负相关。     

Food habits of small fishes in seagrass habitats in Trang,southern Thailand

To clarify the feeding habits of seagrass fishes, we examined the gut contents from 42 fish species collected in seagrass habitats in Trang. Thirteen species showed ontogenetic and/or seasonal changes in food-use patterns. Smaller individuals generally preyed on small planktonic items (e.g., copepod larvae) or small benthic/epiphytic crustaceans (e.g., harpacticoid copepods), with subsequent changes to other prey items (e.g., shrimps, crabs, detritus and filamentous algae) with growth. The most important dietary items for the seagrass fish assemblages comprised benthic/epiphytic crustaceans, detritus, and planktonic copepods. Cluster analysis based on dietary overlaps showed that the seagrass fishes comprised eight feeding guilds (large benthic/epiphytic crustacean, detritus, planktonic animal, small benthic/epiphytic crustacean, mollusc, invertebrate egg, polychaete, and fish feeders). Of these, the first three guilds were the most abundantly represented, whereas the last three were each represented by only a single species.     

珠江口大型底栖动物数量与生物多样性的分布特征

为了更好地了解河口生物多样性的演变规律及退化机制,根据2015年1—12月珠江口大型底栖动物调查资料对珠江口大型底栖动物现存量和生物多样性的分布特征进行了研究。结果表明,11次采样(受台风影响7月珠江口未采集到大型底栖动物)共获取大型底栖动物67种,其中环节动物多毛纲27种,节肢动物24种,软体动物12种,其它类群4种,主要是底栖鱼类、刺胞动物和纽形动物。2015年珠江口各站位大型底栖动物丰度的变化范围在8~1192个·m^-2之间,珠江口大型底栖动物丰度的高值出现在6月和9月的崖门(分别为1192个·m^-2和1048个·m^-2)以及9月的虎跳门(1048个·m^-2),日本大螯蜚(Grandidierella japonica)、中华拟亮钩虾(Paraphotis sinensis)、凸壳肌蛤(Musculus senhousei)和彩虹明樱蛤(Moerella iribescens)丰度较高。大型底栖动物生物量变化范围在0.02~42.50g·m^-2之间,生物量的高值出现在9月的崖门、5月的鸡啼门、2—3月的磨刀门及4月的蕉门,上述站位的生物量均大于30.00g·m^-2,缢蛏(Sinonovacula constricta)、光滑河篮蛤(Potamocorbula laevis)、黑龙江河篮蛤(P.amurensis)、凸壳肌蛤和日本大螯蜚生物量较高。珠江口大型底栖动物香浓威纳指数高值出现在3月鸡啼门,为2.46;低值出现在10月磨刀门,为0.21。香浓威纳指数均值在1.11~1.81之间。鸡啼门和虎跳门大型底栖动物香浓威纳指数值月际变化较稳定。运用ABC曲线对珠江口大型底栖动物扰动状况进行评价,结果表明,1月珠江口大型底栖动物受到中等程度扰动,2—4月大型底栖动物群落有受到中等程度干扰的趋势。     

2006年夏季珠江口浮游动物群落结构特征分析

2006年8月对珠江8大入海口浮游动物群落的种类组成和数量平面分布进行了调查。经鉴定有浮游动物57种,其中桡足类占优势,有20种;其次为轮虫和枝角类,分别为18和8种;此外,被囊动物2种,原生动物、多毛类、异足类、水母类、糠虾类各1种;还有阶段性各种幼虫以及未知种类2种。调查期间各站位均出现的种类有萼花臂尾轮虫（Brachionus calyciflorus）、镰状臂尾轮虫（B.falcatus）和长额象鼻溞（Bosmina lon-girostris）。浮游动物的种数变化范围为19～29种,密度的变化范围为2288～300000ind·m^-3,生物量的变化范围为10.03～111.94mg·m^-3。     

Preliminary experiments on the development of extensive culture methods for juvenile sole, Solea solea (L.)

Abstract. The effect of different levels of organic enrichment on benthic productivity was studied over a 16-week period in trays of sediment placed in a fertilized seawater pond. Primary and secondary planktonic production were also monitored. The exploitation of these sources of food by juvenile sole and their growth and survival over an 8-week period were assessed.
The colonization of the sediments showed a marked succession. Nematodes were numerically the most abundant group and reached a peak after about 8 weeks. This was followed by a peak in the abundance of epibenthic copepods after 11 weeks. The maximum numbers of poiychaetes and larger Crustacea (mainly amphipods) occurred at the end of the trial (15 weeks). The high-organic sediment supported fewer polychaetes and copepods than either the low- or medium-organic sediments. The species composition of the benthos varied both with the level of organic enrichment and with time. Peaks of zooplankton concentrations of 23 to 25 organisms/l occurred during the spring and late summer. There was some evidence of an inverse relationship between zooplankton abundance and standing crop of algae, as indicated by chlorophyll a concentrations.
Harpacticoid copepods were the dominant food item consumed by small (21-50mm total length) sole. Polychaetes, amphipods and Crangon spp. were exploited by large (61-90mm total length) sole to a much greater extent, though harpacticoid copepods were also commonly taken.
The percentage increase in length of the juvenile sole at low-, medium- and high-organic levels was 108, 146 and 152 respectively. Survival, however, was highest (100%) on the untreated sediment and lowest (57%) at the medium-organic level.     

Aspects of the feeding biology of the copepod Pseudodiaptomus hessei (Copepoda: Calanoida) under culture conditions

This study aimed to investigate the feeding behaviour (particularly gut fullness and evacuation, preying on rotifers and feeding preference in the water column) of the calanoid copepod, Pseudodiaptomus hessei, as a potential live feed species for aquaculture. Fed and starved, male and female P. hessei were fed rotifers (Brachionus plicatilis) in the presence and absence of microalgae for 24 hr. Starved copepods consumed more rotifers (11.31 ± 1.01, individual rotifers) than fed (8.06 ± 1.01, individual rotifers) while the number of rotifers consumed in the presence of microalgae was similar when fed or starved. Gut fullness and evacuation was determined by feeding copepods two different cell size microalgae species (Tetraselmis suecica and Isochrysis galbana). Gut fullness and evacuation percentage were observed under the dissecting microscope (as 0, 25, 50, 75 and 100%). Copepods fed on T. suecica (large cell) filled their guts more rapidly, while those fed on I. galbana (small cell) evacuated their guts faster. Feeding preference was determined using a multifactorial experiment where copepods were fed two microalgae species, T. suecica and I. galbana, each presented as benthic and planktonic food sources. P. hessei preferred to feed on planktonic microalgae first regardless of microalgae choice species for ±80 min, before shifting to benthic food source. This information can be used as baseline information for aquaculturists to rear the species as live feed for marine fish larvae.     

Annual cycle of epiplanktonic copepods in Canary Island waters

The species composition of epiplanktonic (0–20 m depth) copepods was studied over an annual cycle at a sampling interval of approximately 10 days at an oceanic station off Tenerife Island (Canary Islands). A taxonomic list of 110 species was obtained but only species represented by more than 300 individuals in the collection of 35 samples were studied. These comprised 23 species from which only 7 species were represented by more than 1000 individuals from all samples combined. Oithona plumifera was the most abundant species; Oithona setigera, Temora stylifera and Clausocalanus arcuicornis were also well represented. Acartia negligens was only observed after the temperature minimum in late winter. By contrast, Lucicutia flavicornis was observed before this temperature minimum. Nannocalanus minor , although numerically important, was represented only by copepodite stages during the period of study. There was great variability in the abundance of the above-named species, with some indications of higher abundance at about a 28–30 day period, possibly coinciding with the full moon phase. These fluctuations are discussed in relation to the vertical distribution of copepods, lunar phase, the impact of deep scattering layers on epizooplankton and the importance of these fluctuations in the energy flux through planktonic communities in subtropical waters.     

基于生计渔业调查的黄河口西南侧潮间带渔业生物多样性及其季节变化

基于2020年黄河口须子网生计渔业和生物组成周年监测数据,开展黄河口潮间带渔业生物多样性及其季节变化研究,评价须子网生产对黄河口渔业资源补充的影响。结果显示,黄河口潮间带的渔业生物种类丰富,共鉴定记录61种生物,以鱼类和甲壳类居多。生物多样性和优势种组成均具有明显的月变化。多样性水平以夏季7―8月较高,秋季10―11月较低;5―9月、10―11月组群分别具有较高的种类组成相似度。各类群的数量组成中,4―7月螺类数量居多,8月螺类和鱼类数量居多,9月鱼类数量居多,10―11月蟹类数量居多。鱼类是各调查月渔获的优势类群,其中,花鲈(Lateolabrax maculatus)和 (Liza haematocheila)为各调查月都出现的优势种。个体大小–频数百分比分布显示,黄河口潮间带是小型渔业生物以及多种幼鱼分布的重要区域。4―9月,渔获物的主体均由个体重量< 2 g的生物组成(44%~82%),鱼类以个体质量< 20 g为主,优势种类组成月更替明显。研究表明,开展须子网生计渔业调查和监测是采集黄河口沿岸咸、淡水交汇区潮间带包括鱼类补充群体在内的诸多渔业生物分布资料的有效途径。研究还表明,须子网渔业生产虽为黄河口沿岸当地传统的生计渔业,但其低选择性及在迁移通道的布设方式等易对渔业资源自然补充和增殖养护群体造成破坏,建议主管部门根据幼鱼种类组成和出现季节特征,重点在夏季和初秋季对该渔业的网目和布设区域进行相应管控。     

珠江口虾拖网的副渔获组成

拖虾是南海捕捞渔业的一种主要作业方式,南海北部的珠江口是广东省虾拖网的优良渔场之一。文章以珠江口铜鼓水道虾拖网渔业生物调查资料为基础,对该渔业的副渔获组成进行了分析研究。结果表明,珠江口虾拖网渔获种类多,以底栖鱼类和甲壳类为优势类群;副渔获的组成在不同月份有所变化;副渔获比例较高,虾与副渔获之比为1:10-1:19;副渔获中大部分鱼种未达到可捕规格,对幼鱼资源造成损害。建议渔业管理部门重视对副渔获问题的调查研究。     

Predation by seals on salmonids in two Scottish estuaries

Detailed observations of the behaviour of harbour seals, Phoca vitulina L., at sites within the estuaries of the Rivers Dee and Don, in north-eastern Scotland, were made over two full years between 1993 and 1996. Small numbers of grey seals, Halichoerus grypus Fab., were also present. The presence of seals within the estuaries was strongly related to season, with maximum numbers observed in winter and early spring; seals were virtually absent in June and July. The River Don was used largely as a haul-out site, while the River Dee was used predominantly as a foraging site, although it was not possible to determine whether the same seals were using the two estuaries. More seals were hauled-out on the River Don during twilight and dark than in daylight. The seals were observed to eat mostly salmonids, Salmo salar L. and S. trutta L., unidentified roundfish and flounder, Pleuronectes flesus L. The otoliths identified in scats collected at the mouth of the River Don belonged to marine species indicating that the seals were also feeding outside the estuaries. A minimum estimate is given of the numbers of large salmonids eaten in each river during the course of the year. Although no information was available on the numbers of salmonids using the rivers or the reproductive status of the fish eaten by the seals, as a cause of mortality, seal predation on large salmonids in estuaries is apparently an order of magnitude less important than mortality caused by angling within the river.