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1.
同安湾浮游动物数量的平面分布和季节变动   总被引:4,自引:0,他引:4  
本文主要研究2000年同安湾浮游动物的种类组成和数量分布,并就其与环境因子的关系进行了初步探讨。结果表明,在同安湾共记录到浮游动物69种及12种浮游幼虫,以近岸低盐种类为主。浮游动物数量季节分布呈现春季高,冬、夏季居中,秋季最低的特点。种类数的季节分布与水温的季节变化一致。浮游动物数量与养殖贝类、浮游植物细胞数密切相关,并与浮游植物数量呈显著的正相关关系。同安湾浮游动物的数量与邻近养殖水域西海域的相当,比马銮湾的低。与历史资料比较,同安湾浮游动物的次级生产力水平比1995年的有所上升,但恢复得较慢。  相似文献
2.
The horizontal and vertical distribution of myctophid fish larvae is described based on discrete depth sampling from the surface down to 200 m at seven stations on a transect crossing the Kuroshio Current on 6–9 July 1977. A total of 7819 larvae was collected. Myctophid larvae accounted for 72% of the total fish larvae and included 18 species or types belonging to 12 genera. Based on horizontal distribution patterns these species (or types) were categorized into three groups, i.e. Kuroshio-axis group ( Myctophum asperum , M. orientale , Lampadena luminosa and Symbolophorus evermanni ), Kuroshio east group ( Hygophum reinhardtii , Lampanyctus alatus , Diogenichthys atlanticus , Lobianchia gemellarii , M. nitidulum , Benthosema suborbitale , Lampadena sp. and Ceratoscopelus warmingii ) and Pan- Kuroshio group [ Diaphus stubby type (mostly D. garmani ) and D. kuroshio ]. Larvae of the subfamily Lampanyctinae were distributed in shallower (0–30 m) waters than those of the subfamily Myctophinae (50–150 m), while this relationship was opposite of the night-time depth distribution of adults of the two subfamilies.  相似文献
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大亚湾桡足类的生态学研究   总被引:1,自引:0,他引:1  
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。  相似文献
5.
本文根据1998年5月、9月两航次调查材料,对深沪湾网采浮游植物样品进行鉴定,结果表明,深沪湾浮游植物种类丰富,两个航次共鉴定到种的为161种,浮游植物生物量较高,其中9月份较5月份高。有足够的饵料生物供应,适合于水产养殖,浮游植物丰度和多样性指数较高。优势度低,渔业环境质量良好。  相似文献
6.
1985年8、10、11月,1986年3、5月及1993年8月对芝罘岛至地留星近海水体叶绿素含量进行了调查,分析了叶绿素含量的水平分布及季节变化规律,建议调整养殖品种、养殖密度和深度。  相似文献
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Coupled three-dimensional (3-D) physical oceanographic modelling and field sampling programmes were carried out in May 1988 and August 1991 to investigate the potential drift of larval cod ( Gadus morhua L.) in the Bornholm Basin of the Baltic Sea. The goals were to predict the transport of cod larvae, thus aiding the identification of physical processes influencing larval retention/dispersal. Numerical simulations were performed using a 3-D eddy-resolving baroclinic model based on the Bryan–Cox–Semtner code adapted for the Baltic Sea. Within the Bornholm Basin, the model was initialized with ground truth data of physical parameters obtained on the research cruises, and all simulations were forced with actual wind data. Outside the basin, generalized hydrographic features of the Baltic Sea were utilized by incorporation of simulated hydrographic fields from previous model runs typical for the time periods considered. Larval drift was simulated either by incorporation of passive drifters, or as the initial horizontal distribution of larvae implemented into the model. Drift model simulations of larval transport agreed relatively well with field observations. The influence of variations in the vertical distribution on a smaller scale, i.e. vertical deviations of ± 6 m from the observed mean centre of mass, on the drift was examined, revealing no significant differences in the drift of larvae depending on their vertical distribution. The different wind forcing during the investigated time periods was linked to a retention situation in May 1988 and to a dispersal situation in August 1991. Finally, observed spatial distribution patterns of 1-group cod based on Baltic Young Fish Surveys (BYFS) were compared with their predicted transport in the larval phase and examined with respect to recruitment.  相似文献
9.
We examined seasonal, annual variation and horizontal distribution of zooplankton in the Sea of Japan from 1966 to 1990. Zooplankton was most abundant in the spring. The spring maximum appeared in February–March and in April–May in the southern and eastern parts of the study areas, respectively. In the summer and autumn, a secondary peak was most conspicuous in the eastern part. The difference between the estimated biomass at night and day was large in the spring and small in summer and autumn. The biomass in the offshore southern area peaked about every 3 years between 1966 and 1983, and increased abruptly in 1990. The density in the area north of 39°N or 40°N was high. Total biomass estimated in the upper 150 m layer in the Sea of Japan (106 km2) was 9.5 × 106 t in the daytime and 16.6 × 106 t at night.  相似文献
10.
Abstract –  Spatial distribution of the fish community in the deep canyon-shaped Římov Reservoir, Czech Republic, was studied using overnight gillnetting fishing in 1999–2007. Effects of depth, distance from the dam to the tributary and habitat type (benthic and pelagic) on fish community structure, catch per unit of effort (CPUE), biomass per unit of effort (BPUE) and average weight were tested. Fish were recorded in all sampled depths and parts of the reservoir. Redundancy analysis revealed that effects of three environmental variables were significant and most variability was explained by depth, then by distance from the dam and habitat type. CPUE and BPUE of all species decreased with depth and responses of individual species to depth were similar for juvenile and adult fish. Number of species, CPUE and BPUE of all species except perch increased heading towards the tributary and peaked close to or at the tributary part of the reservoir. Responses of juvenile fish to distance from the dam differed from that of adult fish. Structure of fish community differed in benthic and pelagic habitats with species preferably occupying epipelagic (bleak, asp, rudd and juvenile bleak, roach and bream) or littoral waters (perch, pikeperch, ruffe, roach, bream and juvenile percids). This study showed that fish distribution in the reservoir followed distinct patterns, which were probably shaped by a combination of physiological constraints plus trade-off between food resources and competition.  相似文献
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