溯河洄游长江刀鲚(Coilia nasus)摄食虾类的调查   总被引：4，自引：0，他引：4  

姜涛  刘洪波  李孟孟  杨健 《湖泊科学》2018,30(2):458-463

刀鲚(Coilia nasus)是长江的名贵经济鱼类.虽然传统上认为其溯河生殖洄游全过程不会摄食,但该问题一直尚未完全弄清.作为有效解明这一问题的第一步,本研究在前期长江流域干流和湖泊刀鲚资源调查的基础上,先利用耳石微化学技术筛选出长江河口区、江苏江段、安徽江段和鄱阳湖水域溯河洄游型的刀鲚个体,再对其胃、肠容物的大型游泳动物(鱼、虾类)进行调查分析.结果发现,在河口区、江苏和安徽江段所有刀鲚个体胃充塞度为0级,均未发现摄食有游泳动物;而鄱阳湖水域刀鲚个体的胃充塞度达4~5级,均发现有摄食淡水虾类的日本沼虾(Macrobrachium nipponense)和秀丽白虾(Exopalaemon modestus)的情况.其中29%和71%的刀鲚胃中分别含有1只和2只虾.所有刀鲚个体肠内均未发现有内容物.鉴于鄱阳湖已被确定为溯河洄游型刀鲚的产卵场之一,结果表明长江刀鲚在经河口,通过长江江苏和安徽江段干流到达鄱阳湖产卵场的过程中应该不会摄食大型游泳动物;而进入鄱阳湖产卵场后会开始摄食日本沼虾和秀丽白虾.这种两阶段的现象可能反映出了刀鲚的一种在洄游通道上节约能量,以利长距离溯河;而在产卵场补充能量,以利于性腺最终成熟的生存策略.  相似文献   

不同饲养方式对乌鳢(Ophiocephalus argus)肠道微生物群落结构差异及种类多样性的影响     

盛鹏程  周冬仁  韩新荣  胡晓波  叶雪平  徐磊  周聃  吴琦芳  郝贵杰 《海洋与湖沼》2020,51(1):148-155

以乌鳢(Ophiocephalus argus)为研究对象,采用不同日粮饲喂,试验W1组饲喂冰鲜鱼,试验W2组饲喂畜禽内脏。12周后,取肠道内容物,利用16S rDNA技术研究投喂不同饲粮的乌鳢肠道生物群落结构差异和微生物多样性,分别获得W1组和W2组乌鳢肠道细菌有效序列51124和39298条。结果分析表明;W1组和W2组物种注释(operational taxonomic unit,OTU)数目分别为2631和4114条,分类地位明确的细菌种类分别隶属5个属和49个属,W1组和W2组乌鳢肠道细菌种类差异很大。W1组乌鳢肠道细菌的优势类群是邻单胞菌属(Plesiomonas)、狭义梭菌属(Clostridium sensu stricto)、鲸蜡菌属(Cetobacterium);W2组乌鳢肠道细菌的优势类群是狭义梭菌属(Clostridium sensu stricto)、邻单胞菌属(Plesiomonas)、Spartobacteria、甲基副球菌属(Methyloparacoccus)、杆菌属(Alsobacter)、Saccharibacteria、分支杆菌属(Mycobacterium)。W2组乌鳢肠道细菌香农指数高于W1组乌鳢肠道细菌,表明前者肠道细菌多样性大于后者。本实验揭示了畜禽内脏饲喂乌鳢肠道细菌的群落种类多样性、OTU丰富度和物种总数均高于冰鲜鱼饲喂乌鳢;W1组肠道有益菌OTU丰富度大于W2组,且W2组还存在一些潜在致病菌。本研究为乌鳢的健康养殖和后续肠道微生物资源的挖掘提供了理论依据。  相似文献   

Feeding intensity and molecular prey identification of the mantis shrimp,Oratosquilla oratoria (De Haan, 1844), in the Tianjin coastal zone of Bohai Bay     

Qi-Kang Bo  Yun-Zhao Lu  Hui-Jing Mi  Yan-Guang Yu  De-Xian Gu  Hong-Zheng You  Shuang Hao 《Marine Ecology》2020,41(4):e12594

Bohai Bay, a representative semi-enclosed bay of China, has been severely impacted in recent decades by rapid human development. Although the mantis shrimp Oratosquilla oratoria plays an important role in the Bohai Bay ecosystem and fishery, its feeding ecology and the impact of habitat changes on its feeding habits are poorly known. In this study, we sought to identify its feeding strategy through the separation of stomach contents, and to describe its trophic ecology during maturation in the Tianjin coastal zone of Bohai Bay by the DNA barcoding method using a fragment (about 690 bp) of the mitochondrial cytochrome oxidase I (CO I) gene. A total of 594 specimens were collected from March to July 2018, and 347 (58.42%) stomachs were found to have food remains. More than half of the O. oratoria individuals had poor feeding activity, and the degree of feeding of females was higher than that of males, but there was no significant difference in the visual fullness index and the fullness weight index (FWI) between sexes for each month. In addition, the feeding activity of O. oratoria was consistent across the months, suggesting in artificial breeding programs it is not worried too much about the accessional diet supplied to the female bloodstocks except maintaining their normal food. A total of 167 retrieved prey items yielded 187 readable sequences; 86.63% of these sequences could be assigned to the species level. Consequently, 25 different prey taxa covering all readable sequences were identified, showing O. oratoria is a generalist predator. In terms of percent composition by frequency of occurrences (%N), crustaceans and fishes accounted for the same and highest percentage (35.83%) in the mantis shrimp diet, followed by mollusks (24.59%) and the remaining marine organisms (3.73%) including Polychaeta (2.67%), Sagittoidea (0.53%), and Chromadorea (0.53%). The result shows the benthic fish Oxudercidae (family) appears to be an especially important food supply for O. oratoria during maturation. The degree of cannibalism decreased with an increase in diet species and the frequencies of cannibalism in this study was noticeably higher than that in previous studies, suggesting that cannibalism may be a significant feeding strategy in the mantis shrimp O. oratoria in the Tianjin coastal zone of Bohai Bay, and because of the frequently cannibalistic behavior, the high stocking density of broodstocks should be avoided.  相似文献   

微塑料对海洋桡足类摄食、排泄及生殖的影响     

于娟  许瑞  魏逾杰  田继远  王雪丹  来敬广  陈容  杨桂朋  张正雨  邵云粹 《中国海洋大学学报(自然科学版)》2020,50(3):73-80

微塑料污染目前成为海洋污染普遍关注的一个研究热点。本文在实验室内将青岛近海常见的海洋桡足类猛水蚤暴露于不同浓度的微塑料尼龙6中,研究了猛水蚤的摄食、排泄以及生殖的变化。研究结果表明,微塑料尼龙6对猛水蚤的摄食、排泄、生殖均产生不利的影响,并且存在剂量-效应关系。微塑料尼龙6对猛水蚤摄食率、滤水率、排粪率的24 h·EC 50分别为67.7、62.2、84.1 mg·L^-1,对猛水蚤抱卵率的144 h·EC 50为30.3 mg·L^-1。“饱食感”造成猛水蚤摄食率降低,从而能量和营养摄入不足可能是导致猛水蚤抱卵率降低的原因。猛水蚤对微塑料的摄食,导致猛水蚤排泄的粪便颗粒小型化,由长椭球体变为短小椭球体,可能与其粘度或物理结构的改变有关。暴露于尼龙6的猛水蚤的粪便体积和沉降速率显著低于未暴露微塑料的对照组。本实验结果对于研究微塑料对海洋桡足类以及滤食性浮游动物的生态毒理影响具有一定的帮助。  相似文献   

Improving sustainability of urban drainage systems for climate change adaptation using best management practices: a case study of Tehran,Iran     

Negin Binesh  Amin Sarang  Wolfgang Rauch 《水文科学杂志》2019,64(4):381-404

Although the effectiveness of best management practices (BMPs) in reducing urban flooding is widely recognized, the improved sustainability achieved by implementing BMPs in upstream suburban areas, reducing downstream urban floods, is still debated. This study introduces a new definition of urban drainage system (UDS) sustainability, focusing on BMP usage to enhance system performance after adaptation to climate change. Three types of hydraulic reliability index (HRI) plus robustness and improvability indices were used to quantify the potential enhanced sustainability of the system in a changing climate, together with a climate change adaptability index (CCAI). The sustainability of UDS for the safe conveyance of storm-water runoff was investigated under different land-use scenarios: No BMP, BMP in urban areas, and BMP inside and upstream of urban areas, considering climate change impacts. Rainfall–runoff simulation alongside drainage network modelling was conducted using a storm-water management model (US EPA SWMM) to determine the inundation areas for both base-line and future climatic conditions. A new method for disaggregating daily rainfall to hourly, proposed to provide a finer resolution of input rainfall to SWMM, was applied to a semi-urbanized catchment whose upstream runoff from mountainous areas may contribute to the storm-water runoff in downstream urban parts. Our findings confirm an increase in the number of inundation points and reduction in sustainability indices of UDS due to climate change. The results present an increase in UDS reliability from 4% to 16% and improvements in other sustainability indicators using BMPs in upstream suburban areas compared to implementing them in urban areas.  相似文献   

海洋环境因子对澳洲鲐亲体补充量关系的影响——基于贝叶斯模型平均法的研究   总被引：1，自引：1，他引：0  

张畅  陈新军 《海洋学报》2019,41(2):99-106

澳洲鲐（Scomber australasicus）是西北太平洋重要的中上层经济鱼类，生命周期相对较短，资源量受补充量影响明显，了解澳洲鲐太平洋群系补充量状况对掌握其资源量及确保其可持续利用具有重要的意义。本文利用产卵场1（30°~32°N，130°~132°E）海表面温度（sea surface temperature，SST1）、产卵场2（34°~35°N，138°~141°E）海表面温度（SST2）、索饵场（35°~45°N，140°~160°E）海表面温度（SST3）、潮位差（tidal range，TR）、太平洋年代际涛动（Pacific decadal oscillation，PDO）和亲体量（spawning stock biomass，SSB）6个影响因子任意组合与补充量构建多个模型，运用贝叶斯模型平均法（Bayesian model averaging，BMA）分析各个环境因子对资源补充量的解释能力，并预测其补充量的变化。结果表明，SSB对补充量具有最长期且稳定的解释能力，其次是SST3，PDO、TR、SST2、SST1也对补充量模型具有一定的解释能力。SST3是环境因子中影响最大的因子，可能是由于补充群体在索饵场内生活时间较长，索饵场温度对仔鱼或鱼卵的生长存活有较大的影响。研究认为，基于BMA的组合预报综合考虑了各个模型的优势，优于单一模型，可用于澳洲鲐资源补充量的预测。  相似文献   

Mid-Century Strategies: pathways to a low-carbon future?     

Narayan Gopinathan  Narayan S. Subramanian 《Climate Policy》2019,19(9):1088-1101

Since the Paris Agreement was adopted in 2015, both national and subnational governments have been encouraged to submit Mid-Century Strategies, outlining how they would reach their deep decarbonization goals. However, research on the design and potential of these strategies has been very limited. To address this shortcoming, here we assess 13 such strategies – six national, seven subnational – in a comparative fashion. We find that the energy-economy-climate models underpinning these strategies are generally of high quality, though national jurisdictions generally performed better. However, most strategies are not plausible without significant changes to policy, and the industrial sector in particular presents a major limitation. The strategies are helpful in revealing this gap, but much works remains to be done for plausible mid-century decarbonization trajectories to become a reality. We also find that public input and societal participation in strategy building were a double-edged sword depending on the constellation of domestic preferences.

• Governmental Mid-Century Strategies for deep decarbonization are underpinned by high-quality energy-economy-climate models

• Governments’ proposed strategies require significant new policies, as even among jurisdictions that have an MCS, extant policies are insufficient to achieve deep decarbonization

• No jurisdiction studied has yet put forward a plausible decarbonization policy for the industrial sector.

• Public input and societal participation can be a double-edged sword: they can increase durability of the strategy but also enable opposing forces to mobilize against ambitious changes.

  相似文献   

Working towards conceptual consistency in discussing “diaspora” and “diaspora strategies”: Ethnicity and affinity in the case of Japan     

《Geoforum》2015

The terms “diaspora” and “diaspora strategies” are both used in inconsistent, and often, conflicting ways. Who encompasses “the diaspora” and what are “diaspora strategies”? What roles do ethnicity and affinity play in conceptualizing relationships between diasporas and homeland governments? This paper extrapolates from programs and organizations that link overseas coethnic and former resident non-coethnic populations to Japan to offer clarity and consistency in usage by bringing together concepts not typically put in conversation with each other and introducing new terms that conceptualize more specific aspects of who we are referring to as “diaspora” and what we are referring to as “diaspora strategies”. Conceptualizations of diaspora often gloss over internal differences, including whether or not people deemed members of a diaspora actually demonstrate a homeland orientation. Focusing on the difference between ethnicity-based and affinity-based definitions of diaspora, I distinguish between three types of diaspora strategies: “diaspora-connecting”, “diaspora-cultivating”, and “diaspora-creating strategies”. Finally, as a way to discuss the potential contributions of both overseas coethnic and non-coethnic populations to a given nation, I conclude by considering Joseph Nye’s notion of “soft power” in relation to diaspora strategies. By engaging these concepts together, the paper highlights the tensions between considering ethnicity and affinity as factors for deciding who to target for diaspora strategies, and demonstrates how diaspora strategies can also target non-coethnics.  相似文献   

经济空间场与ESDA结合的公共卫生事件应急策略制定     

俞艳  蒙文清  樊建  马薇霖  夏杨玲 《武汉大学学报(信息科学版)》2021,(2)

新型冠状病毒肺炎疫情引起了人们对国家公共卫生事件应对能力的广泛关注。基于波及效应梯度场提出了生产诱发梯度,进一步完善了经济空间场理论,并将其与探索性空间数据分析(exploratory spatial data analysis,ESDA)相结合,对医药制造业波及效应及空间布局进行了研究,制定了有效的公共卫生事件应急策略。经济空间场理论分析结果揭示了产业经济空间中医药制造业与各产业部门之间的波及效应,并由此得到了医药密切相关产业。同时,经济空间场理论与ESDA方法的结合能在区分中国大陆各省空间聚集类型的基础上,评估各省公共卫生事件的应对能力,从而为各省提出相应的应急策略和医药制造业发展建议。该方法综合考虑了产业波及效应和产业空间布局现状,不仅能够促进各省医药制造业的健康合理发展,也有助于增强各省突发公共卫生事件的应对能力。  相似文献   

砂粒粒径与砂层厚度对单体筐养养殖系统中三疣梭子蟹幼蟹摄食行为与生长特性的影响研究*     

徐永健  申屠基康  丁张妮 《海洋与湖沼》2015,46(1)

提要 在梭子蟹的单体筐养养殖系统中,试验了生态掩体(砂盒)中不同的砂粒粒径大小以及砂层厚度对梭子蟹幼蟹摄食行为与生长特性的影响。砂粒粒径设三个水平,分别为：>2 mm、<0.2 mm以及混合砂;砂层厚度有0cm、2cm、5cm、8cm四个水平。试验共进行6天,结果表明：砂粒粒径及砂层厚度对梭子蟹幼蟹的摄食与生长都有明显的影响。从砂粒粒径看,幼蟹在细砂(SPS)中挖洞休息,蟹体与砂面呈30-45°角,仅露眼睛及触角在外。一天内有3-6次进食,总进食时间为142.7±22.52 min,在摄食次数、总进食时间、平均摄食量(0.2427±0.0137 g/gBW)、以及脱皮及成活率都远高于其他粒径组,该组中幼蟹的体重增长最快,增加了0.814±0.113 g,增长率为91.5±3.43%;而该组的饵料系数(FCR)最低为1.17±0.11。因此,筐养养殖系统砂掩体的砂粒粒径最好为0.2 mm以下。砂层厚度也有类似结果,5 cm以上厚度养殖效果最佳。平均摄食量为0.2087±0.0046 g/gBW,该厚度下,幼蟹无死亡、100%脱皮,体重也增加最快,增加了0.791±0.121 g,增长率为88.9±3.74%,饵料系数(FCR)达到1.37±0.23,表明筐养系统掩体中砂层厚度要在5 cm以上。三种保护性酶类(SOD, POD, CAT)活性随着砂粒粒径变小和砂层厚度增加而降低,而消化酶类(淀粉酶、蛋白酶、脂酶)活性则表现与保护性酶类相反特性。从两类酶的活性变化也能证实,在优选条件下(细砂、厚度>5 cm),幼蟹所受的胁迫在降低。  相似文献