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1.
2006年夏秋季东海群系澳洲鲐数量分布特征   总被引：5，自引：0，他引：5  
利用2006年7~11月大型机轮灯光围网在东海外海的生产资料,并结合生物学测定数据以及水温遥感数据,对夏秋季东海群系澳洲鲐数量分布时空变化特征进行了研究,并探讨了它们与海洋环境条件的关系。结果表明:夏秋季东海外海海域的澳洲鲐主要为索饵群体,它们的高度集群期主要在7~9月份,其中以8月份较为明显;10月份以后,由于鱼群开始进行越冬洄游,移动速度明显加快,虽然有偶尔的高度集群现象,但是持续时间较短。在地理分布上,7~8月份,澳洲鲐索饵群体的主要分布在125°00′E以西、28°00′N以南海域;9月份,鱼群重心向东北方向转移,范围为125°00′~126°00′E、28°00′~28°30′N海域;10月份相对于9月份鱼群重心向东转移50 n mile,群体向北移动达150 n mile左右;11月份以后,澳洲鲐群体向东北方向的对马海峡转移且可能至日本海越冬。群体结构分析表明,夏秋季澳洲鲐的个体逐月迅速增大,且增长量以7~8月份较大,以后逐渐下降。根据澳洲鲐的群体移动规律以及海洋环境条件的变化,认为东海群系澳洲鲐属于黑潮边缘种,其中心渔场的变动和黑潮的强弱具有密切的关系。  相似文献   

2.
Climate‐induced nonlinearity in biological variability and non‐stationary relationships with physical drivers are crucial to understand responses of marine organisms to climate variability. These phenomena have raised concerns in the northeastern North Pacific, but are out of the spotlight in the northwestern North Pacific in spite of potential implications for this productive system under increased climate variability. Pelagic communities in the Kuroshio ecosystem have both ecological and economic importance. However, patterns of climate‐induced nonlinearity in pelagic communities are not well understood, and existence of non‐stationarity in their relationships with physical drivers remains obscure. Here, we compile large numbers of climatic, oceanic and biological long‐term time‐series data and employ diverse statistical techniques to reveal such climate‐induced nonlinearity and non‐stationarity. Results show that pelagic communities in the Tsushima and Pacific areas (major areas in the Kuroshio ecosystem) had regime shifts in the late 1990s and late 1980s, respectively. Winter sea surface temperatures in the Kuroshio Current path and in the eastern part of East China Sea, which are respectively affected by the Kuroshio Current and Siberian High, correlate with dominant variability patterns in their pelagic communities. Furthermore, non‐stationarity was identified with threshold years in the 1990s in the Tsushima area and in the 1980s in the Pacific area as a possible result of the declined variances in the Siberian High and Aleutian Low, respectively. Our findings provide insights on spatial differentiation of climate‐induced nonlinearity and non‐stationarity, which are valuable for the management of pelagic communities in the northwestern North Pacific under changing climatic conditions.  相似文献   

3.
春季东海区近海浮游动物群落结构及其影响因子   总被引：7，自引：1，他引：7  
研究了 2 0 0 3年春季东海区 (2 7°0 0′～ 34°0 0′N)禁渔线附近近海浮游动物群落结构及其影响因子。根据各站位浮游动物种类组成和丰度 ,用聚类分析法可将该海域的浮游动物分为 5个群落。群落Ⅰ的优势种为 :中华哲水蚤、强额拟哲水蚤、尖额唇角水蚤和强壮箭虫 ;群落Ⅱ的优势种为 :中华哲水蚤、小哲水蚤和小拟哲水蚤 ;群落Ⅲ的优势种为 :中华哲水蚤、亚强真哲水蚤、普通波水蚤 ;群落Ⅳ的优势种为 :中华哲水蚤和五角水母 ;群落Ⅴ的优势种为 :孔雀唇角水蚤、丹氏纺缍水蚤、中华哲水蚤和刺尾纺缍水蚤。另外 ,在春季影响该海域浮游动物分布的主要非生物因子的可集中体现在纬度因子方面。  相似文献   

4.
Horizontal distribution patterns of jack mackerel (Trachurus japonicus) larvae and juveniles were investigated in the East China Sea between 4 February and 30 April 2001. A total of 1549 larvae and juveniles were collected by bongo and neuston nets at 357 stations. The larvae were concentrated in the frontal area between the Kuroshio Current and shelf waters in the upstream region of the Kuroshio. The abundance of small larvae (<3 mm notochord length) was highest in the southern East China Sea (SECS) south of 28°N, suggesting that the principal spawning ground is formed in the SECS from late winter to spring. Jack mackerel also spawned in the northern and central East China Sea (NECS and CECS, respectively), as some small larvae were also collected in these areas. In the SECS, the abundance of small larvae was highest in February and gradually decreased from March to April. The habitat temperature of small larvae in the SECS and CECS (20–26°C) was higher than that in the NECS (15–21°C), suggesting higher growth rates in the SECS and CECS than in the NECS. The juveniles (10‐ to 30‐mm standard length) became abundant in the NECS off the west coast of Kyushu Island and CECS in April and were collected in association with scyphozoans typical of the Kuroshio waters. However, juveniles were rarely collected in the SECS, where the small larvae were concentrated. Considering the current systems in the study area, a large number of the eggs and larvae spawned and hatched in the SECS would be transported northeastward by the Kuroshio and its branches into the jack mackerels’ nursery grounds, such as the shallow waters off the west coast of Kyushu and the Pacific coast of southern Japan.  相似文献   

5.
东海发光鲷生物量分布及其与环境的关系   总被引：1，自引：0，他引：1  
江胜锋  程家骅 《海洋渔业》2007,29(3):221-225
根据2005年12月~2006年11月东海(27°00′~34°00′N、122°00′~127°00′E)底拖网资源调查资料,分析了东海发光鲷的生物量的分布特征以及与环境条件的关系。结果表明:春、秋季发光鲷主要分布在东海南部外海,生物量较高;夏季分布较广,以东海北部外海为主,生物量较低;冬季分布较为集中,以东海南部外海为主。夏季发光鲷的生物量与温度、盐度以及水深的关系的曲线拟合显示,夏、秋季发光鲷主要分布于24℃左右的水温,最适盐度在33左右,最适水深在75 m左右。  相似文献   

6.
东海有尾类数量分布   总被引：1，自引：1，他引：1  
根据1997~2000年东海23°30′~33°N、118°30′~128°E海域4个季节海洋调查资料,探讨了东海有尾类数量分布和季节变化。结果表明:秋季有尾类丰度最高,均值为149 ind/100m3,夏季38 ind/100m3,冬季20 ind/100m3,春季9 ind/100m3;有尾类数量在冬春夏季与水温和盐度相关关系不显著,秋季与表温有显著的正相关关系。有尾类数量季节变化机制具有暖水种的特征,这些特征形成与其优势种适温适盐特性有密切的关系。东海有尾类的数量波动,与东海暖流势力消长有密切的联系,也同暖流势力从夏到秋季维持一段时间有密切的关系。在东海,暖流势力较强的海域往往可以成为有尾类高丰度分布区域。秋季有尾类高分布区出现,对东海北部外海绿鳍马面鲀(Navodon septentrionalis)渔场和东海南部的带鱼(Trichiurus lepturus)和日本鲭(Scom ber japonicus)等多种经济鱼类渔场的形成有重要意义。  相似文献   

7.
东海区七星底灯鱼数量分布以及与温盐度的关系   总被引：1，自引：2，他引：1  
本文利用从2000年12月到2001年9月一个周年的渔业资源调查数据,对东海区七星底灯鱼的数量分布及其与温盐度的关系进行了研究。结果表明:东海区的七星底灯鱼可分为东海北部和浙江中南部近海2个群体。以东海北部群体较大,主要分布在30°N以北的海域;浙江中南部近海群体较小,且只有零星分布。七星底灯鱼在东海北部海域从沿岸到外海都有分布,但沿岸数量较少,主要分布在30°30′~32°30′N、124°00′~126°30′E之间的海域;以冬春季节分布面较广,夏秋季节的分布面较窄。东海北部群七星底灯鱼栖息海域的表层温度值变化较大,以春季最低,秋季最高;密集分布区的等温线变化范围在1~2℃左右。浙江中南部近海群的栖息水温变化较小,全年都在20℃以上。各季节浙江中南部近海群的适宜水温均高于东海北部群。各季节东海北部群密集分布区的表层盐度在32.0~34.5之间,以冬春季的盐度值较高,夏秋季的盐度值较低;浙江中南部近海群的栖息海域表层盐度除冬季较高外,其余季节相对较低。  相似文献   

8.
Do disparate mechanisms determine growth rates of fish larvae in the different regions? The relationship between growth rates and environmental factors (sea temperature and food availability) was examined for larval Japanese anchovy Engraulis japonicus in geographically and environmentally different waters, through sagittal otolith microstructure analysis. Recent 3‐day mean growth rates directly before capture were positively related with sea‐surface temperature (SST) but not with food availability (plankton density) for the larvae in the Kuroshio Extension and Kuroshio–Oyashio transition regions of the western North Pacific. On the contrary, variations in recent growth rates were attributed to food availability (plankton density) as well as SST for the larvae in the East China Sea. In the shirasu fishing ground in Sagami Bay, larval growth rates were variable under the influences of both SST and food availability (feeding incidence). On the surface, the growth–environment relationships seemed to differ among regions. However, a definite general pattern of the dome‐shaped relationship between recent growth rates and SST was observed when all the regions were combined. Growth rates were similar even among clearly different regions if at the same SST. Overall, growth rates roughly increased with SST until they reached the maximum at SST of 21–22°C (i.e. optimal growth temperature), and declined when SST went over 21–22°C. On the contrary, no clear relationship was observed between growth rate and plankton density or between SST and plankton density. Therefore, the apparent among‐region differences would be firstly caused by the differences in regional SST range. The systematic mechanism of growth determination for widespread pelagic fish species larvae would be run by primarily sea temperature and secondarily food availability, at the species level.  相似文献   

9.
We studied the otolith microstructure and growth of sardine, Sardina pilchardus, in the North Aegean Sea (eastern Mediterranean Sea), using samples of larvae and juveniles that had hatched in winter (November–January) and winter–spring (February–May), respectively. The juveniles had developed during an extended period coinciding with marked pelagic ecosystem changes (from winter, mixed conditions to summer, stratified waters). To examine the relationship between environmental changes and the observed variability in their otolith increment–width trajectories (width‐at‐age), we summarized the shape of trajectories with a four‐parameter set estimated from a growth model fit to each width trajectory. The individual parameter sets were then related to the potential oceanographic conditions that fish experienced during their development, derived from a hydrodynamic–biogeochemical model (POM‐ERSEM), implemented in the sampling area. Substantial seasonal effects were demonstrated on the otolith microstructure (platykurtic versus leptokurtic trajectories in winter‐mixed versus summer‐stratified conditions), which were related to the progressive sea surface warming. In a subsequent step, in order to study the effect of oceanographic conditions on larval and juvenile daily growth rates, a GAM (Generalized Additive Model) analysis of otolith increment widths was carried out, using model‐derived oceanographic parameters and taking into account the ‘inherent otolith growth’, expressed by the explanatory variables ‘previous increment width’ and ‘Age’. Results showed a strong and positive, linear effect of temperature on the growth rate of winter‐caught larvae, whereas in juveniles, which had developed within a wide range of temperatures, an optimum temperature for growth was observed at around 24°C.  相似文献   

10.
东海区短鳄齿鱼数量分布及其与环境因子的关系   总被引：1，自引：3，他引：1  
根据2005年东海区(26°30′～35°00′N、121°00′～127°00′E)渔业资源监测底拖网调查资料,结合广义相加模型(GAM)方法分析了东海区短鳄齿鱼资源的时空分布特征以及水深、水温、盐度与数量分布的关系。结果表明:东海区短鳄齿鱼主要分布区域为:28°00′～30°00′N、123°00′～126°30′E;生物量季节变化明显,以秋季(9月)最高,春季(4月)最低;短鳄齿鱼适宜水深、温度、盐度范围分别为70～110 m、17～23℃、34.3～35.2。结合东海海流分布特点,初步推断短鳄齿鱼为暖水性海洋小型鱼类,其生物量分布和季节变化受台湾暖流影响。  相似文献   

11.
Concern about impacts of climate change in the Bering Sea prompted several research programs to elucidate mechanistic links between climate and ecosystem responses. Following a detailed literature review, Hunt et al. (2011) (Deep‐Sea Res. II, 49, 2002, 5821) developed a conceptual framework, the Oscillating Control Hypothesis (OCH), linking climate‐related changes in physical oceanographic conditions to stock recruitment using walleye pollock (Theragra chalcogramma) as a model. The OCH conceptual model treats zooplankton as a single box, with reduced zooplankton production during cold conditions, producing bottom‐up control of apex predators and elevated zooplankton production during warm periods leading to top‐down control by apex predators. A recent warming trend followed by rapid cooling on the Bering Sea shelf permitted testing of the OCH. During warm years (2003–06), euphausiid and Calanus marshallae populations declined, post‐larval pollock diets shifted from a mixture of large zooplankton and small copepods to almost exclusively small copepods, and juvenile pollock dominated the diets of large predators. With cooling from 2006–09, populations of large zooplankton increased, post‐larval pollock consumed greater proportions of C. marshallae and other large zooplankton, and juvenile pollock virtually disappeared from the diets of large pollock and salmon. These shifts in energy flow were accompanied by large declines in pollock stocks attributed to poor recruitment between 2001 and 2005. Observations presented here indicate the need for revision of the OCH to account for shifts in energy flow through differing food‐web pathways due to warming and cooling on the southeastern Bering Sea shelf.  相似文献   

12.
Despite the low productivity that has been thought to characterize plankton communities in the western boundary current of the North Pacific Subtropical Gyre, many migratory fishes risk encountering low food availability during crucial life history stages by reproducing and recruiting in the Kuroshio region (i.e., the Kuroshio Paradox). Here, we report on geographic variability in taxonomic composition, biomass, and productivity of the mesozooplankton community in the Kuroshio Current and neighboring waters in the East China Sea. Calanoid copepods were the most abundant mesozooplankton taxon throughout our sampling stations. Small copepods, which include nauplii and poecilostomatoids, and gelatinous metazoans were the next most abundant. Seasonal variability in mesozooplankton standing stock (i.e., abundance and biomass) and productivity (i.e., production rate and protein synthetase activity) exceeded spatial variability across the stations and regions. The mesozooplankton community was characterized by high biomass and production rates in the summer, as well as high abundance and protein synthetase activity in the fall. No significant differences were found for mesozooplankton standing stock and productivity in the Kuroshio Path relative to those on the continental shelf or on the outside of the Kuroshio Path. Our results indicate that the standing stock and productivity of the mesozooplankton community in the Kuroshio Path are equivalent to those on the continental shelf, and that these communities are supported by small copepods and gelatinous zooplankton. We suggest that the mesozooplankton standing stocks and productivity provide adequate food availability for migratory fishes in the Kuroshio and neighboring waters in the East China Sea.  相似文献   

13.
Temperature is an important factor in defining the habitats of marine resource species. While satellite sensors operationally measure ocean surface temperatures, we depend on in situ measurements to characterize benthic habitats. Ship‐based measurements were interpolated to develop a time series of gridded spring and fall, surface and bottom temperature fields for the US Northeast Shelf. Surface and bottom temperatures have increased over the study period (1968–2018) at rates between 0.18–0.31°C per decade and over a shorter time period (2004–2018) at rates between 0.26–1.49°C per decade. A change point analysis suggests that a warming regime began in the surface waters in 2011 centered on Georges Bank and the Nantucket Shoals; in following years, most of the Northeast Shelf had experienced a shift in surface temperature. A similar analysis of bottom temperature suggests a warming regime began in 2008 in the eastern Gulf of Maine; in following years, change points in temperature occurred further to the west in the Gulf of Maine, finally reaching the Middle Atlantic Bight by 2010. The spatial pattern in bottom water warming is consistent with well‐known oceanographic patterns that advect warming North Atlantic waters into the Gulf of Maine. The varying spatial and temporal progression of warming in the two layers suggests they were actuated by different sets of forcing factors. We then compared these trends and change points to responses of lower and higher trophic level organisms and identified a number of coincident shifts in distribution and biomass of key forage and fisheries species.  相似文献   

14.
根据2000～2004年7～12月东、黄海鲐碜鱼生产统计以及表层温度和盐度数据,利用地理信息系统软件和数理统计方法,对鲐碜鱼产量分布及作业渔场与表层温度、盐度的关系进行分析。结果表明,鲐碜鱼高产（20000区域主要在122～125°E、26～28°N和123～125°E、32～38°N之间的海域。整个渔场的产量分布呈南部和北部高而中部低的态势。南北渔场汛期差异明显,南部渔场高产期集中在8～9月份,北部渔场高产期集中在10～11月份,且北部渔场高产期的产量比南部渔场高出22．7％。鲐碜鱼适温范围为9．5～29．5℃,最适范围为28．5～29．5℃;适盐范围为30．9～34．4,最适范围为32．8～34．2。经非参数统计K—S检验结果是可信的。  相似文献   

15.
Forage fish occupy a central position in marine food‐webs worldwide by mediating the transfer of energy and organic matter from lower to higher trophic levels. The lesser sandeel (Ammodytes marinus) is one of the ecologically and economically most important forage fish species in the North‐east Atlantic, acting as a key prey for predatory fish and sea birds, as well as supporting a large commercial fishery. In this case study, we investigate the underlying factors affecting recruitment and how these in turn affect productivity of the North Sea sandeel using long‐term data and modelling. Our results demonstrate how sandeel productivity in the central North Sea (Dogger Bank) depends on a combination of external and internal regulatory factors, including fishing and climate effects, as well as density dependence and food availability of the preferred zooplankton prey (Calanus finmarchicus and Temora longicornis). Furthermore, our model scenarios suggest that while fishing largely contributed to the abrupt stock decline during the late 1990s and the following period of low biomass, a complete recovery of the stock to the highly productive levels of the early 1980s would only be possible through changes in the surrounding ecosystem, involving lower temperatures and improved feeding conditions. To that end, we stress the need for ecosystem‐based management accounting for multiple internal and external factors occurring within the broader context of the ecosystem in which forage fish species, such as sandeel, play an important and integral part.  相似文献   

16.
Transport processes of jack mackerel (Trachurus japonicus) larvae in the waters off the west coast of Kyushu in the eastern East China Sea, have been investigated using satellite‐tracked surface drifters and consecutive satellite thermal images. Trajectories of drifters describe northward flows over the continental shelf, eastward flows of the Kuroshio south‐west of Kyushu, and a weak clockwise gyre off the west coast of Kyushu. In particular, the clockwise gyre causes the entrainment of jack mackerel larvae into the waters off the west coast of Kyushu. Consecutive satellite thermal images help to elucidate the northward warm water intrusion from the Kuroshio front south‐west of Kyushu. Particle trajectories using sea surface current fields computed with the Maximum Cross Correlation (MCC) technique also reveal that the transport of jack mackerel larvae into the nursery ground off the west coast of Kyushu caused by the anti‐cyclonic gyre and the warm streamers are an important process for successful recruitment.  相似文献   

17.
夏季东海水团变动特征及对鲐鲹渔场的影响   总被引：13，自引：1，他引：13       下载免费PDF全文
杨红 《水产学报》2001,25(3):209-214
应用模糊聚类方法，采集东海30个站表层及底层1996-1998年夏季的水温（T）、盐度（S）、溶解氧（DO）、磷（P）、三态氮（N）、硅（Si)、pH值等九个指标的测样数据，对东海水团进行划分，其表层水团配置为大陆沿岸冲淡水（I），黄东海混合水团（Ⅱ）台湾暖流水（Ⅲ），黑潮表层水（Ⅳ）等水团，底层水团配置为黑潮次表层水团（Ⅴ），黄海冷水团（Ⅵ），台湾暖流水（Ⅲ）等水团，并分析了1996-1998年夏季由大陆径流和外海水团热力强弱影响所致的东海水团变动特征及沿岸冲淡水转向问题，同时讨论了东海水团分布与鲐Sheng渔场关系。  相似文献   

18.
A drastic population change in Japanese sardine (Sardinops melanostictus) has been noted as being related to winter sea surface temperature (SST) in the Kuroshio Extension region. The former studies suggest two possible explanations. One is that temperature itself affects sardine. The other is that SST represents the environmental change of the Kuroshio Extension region and other causes directly affecting sardine. In this study, we found that sardine mortality from post‐larva to age 1 negatively correlated with the winter mixed layer depth (MLD) in the Kuroshio Extension region from 1979 to 1993. During the period of a deep winter mixed layer (during the early 1980s), sardine mortality was low, whereas mortality was high when the winter mixed layer was shallow (during the late 1980s to early 1990s). By using a lower trophic‐level ecosystem model forced by the observed time series of MLD, SST, light intensity and nutrient data, we found that the estimated spring zooplankton density drastically varies from year to year and has a significant negative correlation with sardine mortality. The inter‐annual variation of spring zooplankton density is caused by the winter MLD variation. During the deep winter mixed layer years, a phytoplankton bloom occurs in spring, whereas during the shallow winter mixed layer years, the bloom occurs in winter. The results of our study suggest that the decline in the Japanese sardine population during the late 1980s to early 1990s was due to an insufficient spring food supply in the Kuroshio Extension region where sardine larvae and juvenile are transported.  相似文献   

19.
The impacts of ocean warming resulting from recent climate change on the abundance patterns of marine species have been well documented in temperate seas of the northern hemisphere, but the impacts of a widening tropical belt are largely unexplored. Using measurements of sea surface temperature and spear‐fishing records for 84 species spanning a 19‐yr period, we examined the effects of ocean warming on a sub‐tropical reef‐fish community on the southeastern coast of Africa. Corresponding with a 0.46°C increase in average sea surface temperature between the time periods 1989–97 and 2002–2007, the ratio of species showing an overall decrease/ no change/increase in abundance was 1 : 3 : 2 among six species at the northern limits of their distribution in the region (temperate species), 1 : 15 : 6 among 22 broadly distributed species, and 1 : 5 : 9 among 15 species at the southern limits of their distribution (tropical species). Also, the relative abundance of temperate species as a whole decreased by 10–13% whereas that of tropical species increased by 9%, and broadly distributed species showed little change. Average species richness and diversity increased 33 and 15% respectively between the two time periods. These results are broadly consistent with a predicted poleward shift in species ranges and a predicted increase in species richness and diversity with increasing sea temperature. Our findings confirm that large‐scale climate change causing a widening of the tropical belt and subsequent ocean warming is having a profound impact on marine species abundance patterns and community composition at a local scale in the sub‐tropics.  相似文献   

20.
An Empirical Biomass Model for the Japanese sardine, Sardinops melanostictus, was developed on the basis of the relationship between February sea surface temperature (SST) in the Kuroshio Extension (30–35°N, 145–180°E) and the mortality coefficient during the period from egg to age 1, observed in 1979–94, to examine the long‐term variation of biomass. The periods of the good and bad catch, the year of the biomass peak, and the speed of the biomass decline in the period from 1957 to 1994 were successfully reproduced, except for the biomass increase in the early 1970s. When the model also included with a density‐dependent effect, the whole history of the observed catch during 1957–94 was almost perfectly reproduced. These results suggest that the environment in the Kuroshio Extension region, represented by winter–spring SST, is regarded as a leading factor for determining fluctuations of the sardine biomass in the long term, and that the density effect has a secondary contribution.  相似文献   

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