长江口羽状锋海区浮游值物的生态研究↑（*）

丰、枯水期的数量均值分别为２５０５．４×１０￣３个／米￣３（１９８８年８月）、３０３．５×１０￣３个／米￣３（１９８８年１２月）和１８９２２２．０×１０￣３个／米￣３（１９８９年８月），平面分布的斑块现象明显，丰、枯水期的数量密集区主要形成于表层盐度２５为中心的河口羽状锋锋面一带及其东侧海区。在影响研究海区浮游植物数量时间和空间分布的诸多因素中，长江径流量的变动是一个至关重要的因素。种类组成隶属于河口型的生态组成模式，河口沿岸低盐种是浮游植物群落的主要成份，决定着长江口浮游植物群落的性质。河口羽状锋海区存在着一个生物地球化学作用带，其位置的变动主要取决于锋面位置的变动。根据浮游植物数量密集区，ｐＨ和溶解氧的异常区的位置，可大致推断出长江口羽状锋的位置及其走向。     

长江口外水域叶绿素a分布的基本特征

本文根据１９８８年８月、１２月、８９年８月和１９９１年９月对长江口外附近水域进行的多学科的综合调查结果，着重探讨长江河口羽状锋区附近叶绿素ａ含量的分布特征及其与海洋环境因子的关系。调查海区叶绿素ａ含量从长江口外向东构成低、高、最低的分布趋势，夏季形成向东或东北扩展的、清晰可辨的叶绿素ａ的羽状锋。     

长江口河口锋区浮游动物生态研究Ⅱ种类组成、群落结构、水系指示种↑（*）

１９８８年８月、１９８９年８月水期及１９８８年１２月枯水期间，对长江口羽状锋水域内浮游动物进行了垂直分布调查研究。初步鉴定了浮游动物９４种，其中甲壳类为６９种，浮游动物种类出现随季节变化而异。河口锋区内浮游物群落结构由五个生态群组成，即低盐近岸生态群落、温带外海高盐群落、热带高温高盐群落、半咸水性河口群落和淡水生态群落。     

长江口水质及沉积物中污染物含量与分布↑（*）

1994年与1996年的调查结果显示,长江口表层沉积物已受到铜、锌、铅的污染,其中以吴淞口、上海市西区和南区排污口最严重,而122↑（。）E以西长江河口锋区为铜、锌、铅高含量区,系由河口屏障所致。污染程度为铅＞铜＞锌。长江口沉积物中污染物含量与分布与长江口水相污染物     

长江河口锋区桡足类优势种聚集特征的研究↑（*）

对长江河口锋区桡足类优势种的聚集强度测度进行了分析。本文选择优势度Ｙ≥０．１的桡足类为本水域优势种,丰水期优势种有：中华哲水蚤（Ｃａｌａｎｕｓ ｓｉｎｉｃｕｓ）、真刺唇角水蚤（Ｌａｂｉｄｏｃｅｒａ ｅｕｃｈａｅｔａ）、背针胸刺水蚤（Ｃｅｎｔｒｏｐａｇｅｓ ｄｏｒｓｉｓｐｉｎａｔｕｓ）、太平洋纺锤水蚤（Ａｃａｒｔｉａ ｐａｃｉｆｉｃａ）、火腿许水蚤（Ｓｃｈｍａｃｋｅｒｉａ ｐｏｐｌｅｓｉａ）;枯水期有：中华哲水蚤、真刺唇角水蚤、虫肢歪水蚤（Ｔｏｒｔａｎｕｓ ｖｅｒｍｉｃｕｌｕｓ）、汤匙华哲水蚤（Ｓｉｎｏｃａｌａｎｕｓｔｅｎｅｌｌｕｓ）、亚强真哲水蚤（Ｅｕｃａｌａｎｕｓ ｓｕｂｃｒａｓｓｕｓ）。运用聚集强度指标,通过对这些优势种在长江口锋区空间分布特征的研究,发现长江河口锋区桡足类聚集强度丰水期高于枯水期;河口半咸     

九段沙湿地渔业资源管理初探

<正>九段沙湿地位于(东经121°46′12″-122°15′03″,北纬31°03′02″-31°17′24″)长江河口和东海的交汇处,是陆地、海洋和淡水3种生态系统的交错区,是长江口一块重要的河口湿地生态区。河口是海淡水的交汇区,环境因子复杂多变,河流每年把大量的淡水、颗粒物质和     

长江口最大浑浊带区浮游动物的生态研究↑（*）

本文阐明了长江口浑浊带水域内浮游动物的生物量、种类组成、群落结构等生物学特征及生物学过程。研究结果表明：在丰水期平均生物量为９８．９毫克／米＾３，明显低于长江口外河口锋区内同期生物量。种类组成也少于河口锋区内组成。     

环境因子对长江口咸淡水混合水体中硅酸盐浓度的影响

通过室内培养实验,模拟了不同条件下(水体盐度、温度、pH值、富氧缺氧等)长江径流淡水和东海外海水的混合过程,初步了解了上述主要环境因子对长江口硅酸盐(SiO3-Si)混合模式的影响。结果表明,在实验条件下:1)长江淡水(包括已滤和未滤)与外海水在混合过程中,SiO3-Si浓度在大约40 h后可基本达到平衡。2)混合水体中SiO3-Si浓度与其盐度表现出良好的负相关关系,长江口SiO3-Si浓度主要受物理混合稀释影响,已滤长江淡水与未滤长江淡水同外海水混合,二者混合水体中SiO3-Si浓度随盐度的变化无显著差异。实验条件下,水体泥沙等颗粒物的存在对SiO3-Si在稀释过程中的浓度没有显著影响。3)随着混合水体温度升高,其SiO3-Si浓度略有升高,表明长江冲淡水对外海海域SiO3-Si的补充存在季节性差异。4)pH为4-8时,混合水体中SiO3-Si浓度相差不大,pH=10时,SiO3-Si浓度发生改变,可能是悬浮颗粒物对SiO3-Si的解吸增加、pH影响了SiO3-Si的存在形式。5)在富氧和缺氧状态下长江淡水同外海水混合,混合水体中SiO3-Si浓度无显著差异。     

长江口及邻近海域凤鲚生境履历重建

利用 X-射线电子探针微区技术(EPMA)对长江口崇明和邻近吕四凤鲚(Coilia mystus)耳石 Sr 和 Ca 的微化学进行了分析。定量线分析和 Sr 含量面分布图谱显示,凤鲚耳石核区的 Sr/Ca 比值存在 Sr/Ca<3、37 这 3 种类型,分别对应的耳石核心面分布同心环区域颜色为蓝色、绿色和黄-红色,据此推断长江口及邻近海域凤鲚孵化场存在 3 种,即淡水孵化场、河口半咸水孵化场及海水孵化场。凤鲚个体耳石从核心到边缘的 Sr/Ca比值变化波动极为显著,有对应淡水生活的低值阶段(Sr/Ca<3,最小为 2.04±0.87),也有对应海水生活的高值阶段(Sr/Ca >7,最大为 7.81±0.91),可将凤鲚的生境履历类型分为 4 种类型:淡水河口半咸水型、河口半咸水定居型、河口半咸水海水型和淡水河口半咸水海水型。长江口邻近海域吕四凤鲚有淡水和河口半咸水孵化个体,其生境履历类型包括淡水河口半咸水型、河口半咸水海水型和淡水河口半咸水海水型,而长江口崇明岛海域有海水及河口半咸水孵化个体,其生境履历类型包括淡水河口半咸水型、河口定居型及淡水河口半咸水海水型,这反映了长江口崇明岛及邻近海域吕四 2 个海域凤鲚个体间的共性以及差异性。通过本次研究,首次证明了长江口及邻近海域凤鲚存在 3 种孵化场及 4 种生境履历类型,准确反映了凤鲚个体组成及其生活史的多样性和复杂性。     

南昌地区中小型水库大银鱼移殖试验

大银鱼Protsalanx hyalocraniua(Abbott)主要分布于我国长江下游湖泊，长江口，黄海、渤海沿岸河口及朝鲜西海岸，系河口洄游性鱼类，进入淡水产卵，亦可在淡水中定居生活，是银鱼科中个体最大的种类，产卵期为12月到翌年3月，是目前主要移殖，增殖的品种之一，我们从1994年开始在南昌地区的四个中小型水库采取投放大银鱼受精卵的方式进行大银鱼移殖试验，以探明大银鱼在长江以南天然水域中的生长繁殖情况。     

Spatial correspondence between areas of concentration of Patagonian scallop (Zygochlamys patagonica) and frontal systems in the southwestern Atlantic

It has been hypothesized that the geographical location of scallop beds in extensive shelf regions mirrors hydrographic structures (e.g. frontal systems) that favor the retention/concentration of pelagic larvae. Large, discontinuous concentrations of the Patagonian scallop (Zygochlamys patagonica) are known to have occurred recurrently (for more than 30 yr) at certain geographical locations over the extensive Patagonian shelf. These stocks, exploited since 1996, currently support one of the most important scallop fisheries in the world. Here, we investigate whether those aggregations are spatially coincidental with major frontal systems. Several pieces of information were used: historical survey data documenting the geographic distribution of the Patagonian scallop beds, catch and effort data from the commercial fleet, oceanographic data on frontal systems, and remote sensing imagery. We found that large-scale aggregations do match the location of three major and very different frontal systems in the southwestern Atlantic: the Shelf-Break Frontal System, the Northern Patagonia Frontal System, and the Southern Patagonia Frontal System. We describe the three frontal systems and their associated scallops fishing grounds and discuss which processes can contribute to sustaining the productivity of the scallop grounds in each case.     

On the relationship between the Oyashio front and saury fishing grounds in the north-western Pacific: a forecasting method for fishing ground locations

The relationships between fishing ground locations of Pacific saury (Cololabis saira) and the two Oyashio fronts, the offshore front between 146^oE and 155^oE and the coastal Oyashio intrusion, before the saury fishing season, were examined using data from 1971 to 1991. Interannual geographical shifts of both the offshore Oyashio front and saury fishing grounds had a dominant interdecadal fluctuation. In years when the offshore front shifted north (south), the fishing grounds were formed relatively nearshore (offshore). When the offshore front shifted north, the fishing grounds were formed further nearshore in years the coastal Oyashio intrusion extended south. When the offshore front shifted south, on the other hand, the southward extension of the coastal intrusion did not necessarily cause formation of coastal fishing grounds. These results showed that locations of the fishing grounds depend not only on local and instantaneous oceanographic environments around the fishing grounds, but also on oceanographic conditions over an extensive range of the Oyashio area. This might indicate that the ecology of the saury's northward migration, through mixed water regions between the Kuroshio and Oyashio fronts in spring and summer, has a close relation to the shift of the offshore Oyashio front over a time range of months. A practical forecasting method for locations of saury fishing grounds is proposed based on the oceanography before the fishing season.     

Acoustic observations of fish schools and scattering layers in a Kuroshio warm-core ring and its environs

Biological sound scattering characteristics in a frontal region between warm and cold waters were examined at the southern edge of a Kuroshio warm-core ring off Sanriku, the northeast coast of Japan. The scattering strength was low in the surrounding cold water and high in the warm-core ring. The depth and thickness of sound-scattering layers changed in accordance with the vertical structure of the water mass during the day or at night. Intense, thick scattering layers were observed on the warm-water side of the front and farther inside the warm-core ring. Fish schools were distributed in the mixed layer warmer than 17°C at depths of 10-30m above the scattering layers on the warm-water side of the front.     

前置导管对螺旋桨性能改善的研究

分析了前置导管的水动力性能及其对其他性能的影响，结果表明：前置导管使尾流均匀化和稳定化，有效地改善了螺旋桨和导管的空泡剥蚀现象。     

Are tidal fronts good recruitment areas for herbivorous copepods?

Horizontal distributions of phytoplankton biomass and numerical abundance of copepod nauplii were investigated across a tidal front in the northern part of Bungo Channel, the Inland Sea of Japan, in May and June 1988. The frontal area was characterized by abrupt changes in subsurface (3 m deep) temperature and salinity, and by an increased standing stock of phytoplankton. The density of copepod nauplii was lower in the frontal area than in adjacent stratified and mixed areas. The population egg production rate of a predominant copepod species (Paracakmus sp.) was higher due to elevated fecundity on an individual basis in response to increased chlorophyll concentrations, in the frontal zone. However, the frontal population was subjected to higher mortality, probably due to predation by carnivores that were mainly accumulated passively within the area. From these facts, we conclude that tidal fronts are not always good areas for recruitment of herbivorous copepods, although fronts give rise to high standing stocks of phytoplankton.     

The effects of temperature on growth,development and settlement of northern rock sole larvae (Lepidopsetta polyxystra)

Northern rock sole (Lepidopsetta polyxystra) is a commercially important fish in the North Pacific and a focal species in understanding larval transport to nursery grounds in the Bering Sea. However, the temperature‐dependent vital rates and settlement dynamics for this species have not been described in detail. We reared northern rock sole larvae in the laboratory to measure growth, condition, development and settlement parameters across four temperatures (2, 4, 7 and 10°C). Both length and mass‐measured growth rates increased with temperature and were best described by non‐linear regression. Residuals of the length–mass relationships were positively related to temperature, indicating larval condition also increased with temperature. Larval development and settlement were largely size dependent, resulting in reduced larval stage duration and earlier settlement at higher temperatures owing to more rapid growth at elevated temperatures. However, larvae at colder temperatures were less developed at a given size, but more likely to settle at smaller sizes than larvae reared in warmer conditions. These temperature–response parameters can be used to refine current and future transport models for northern rock sole larvae under changing environmental conditions in the North Pacific.     

New production in the equatorial Pacific: a coupled dynamical–biogeochemical model

A simple 3-D biogeochemical model is coupled to a dynamical model forced by weekly winds deduced from ERS1 scatterometer data, to simulate new production in the equation Pacific from April 1992 to June 1995. The biogeochemistry is modelled as a nitrate sink modulated by chlorophyll, using nitrate/chlorophyll regressions derived from field data. The first simulation was carried out assuming that remineralization below the euphotic layer is totally controlled by sinking particles. In the second simulation, it is shown that the simulation of nitrate and new production by the biogeochemical model is improved, in comparison with field data, by adding an explicit dissolved organic nitrogen compartment. In the equatorial band, the model simulates a nitrate-poor region (low new production) in the fresh warm pool separated from richer waters of the upwelling region by a salinity front. The zonal displacement of this salinity/nitrate front is associated with the El Niño–Southern Oscillation (ENSO). The modelled new production and physics, both in good agreement with the field data, represent useful tools for the study of skipjack tuna ( Katsuwonus pelamis ) forage distribution in the Pacific.