Late Mesozoic Exhumation of the Huangling Massif:Constraints on the Evolution of the Middle Yangtze River

Plate subduction leads to complex exhumation processes on continents.The Huangling Massif lies at the northern margin of the South China Block.Whether the Huangling Massif was exhumed as a watershed of the middle reaches of the Paleo-Yangtze River during the Mesozoic remains under debate.We examined the exhumation history of the Huangling Massif based on six granite bedrock samples,using apatite fission track(AFT)and apatite and zircon(U-Th)/He(AHe and ZHe)thermochronology.These samples yielded ages of 157–132 Ma(ZHe),119–106 Ma(AFT),and 114–72 Ma(AHe),respectively.Thermal modeling revealed that three phases of rapid cooling occurred during the Late Jurassic–Early Cretaceous,late Early Cretaceous,and Late Cretaceous.These exhumation processes led to the high topographic relief responsible for the emergence of the Huangling Massif.The integrated of our new data with published sedimentological records suggests that the Huangling Massif might have been the watershed of the middle reaches of the Paleo-Yangtze River since the Cretaceous.At that time,the rivers flowed westward into the Sichuan Basin and eastward into the Jianghan Basin.The subduction of the Pacific Plate beneath the Asian continent in the Mesozoic deeply influenced the geomorphic evolution of the South China Block.

Disentangling the influencing factors of spatiotemporal evolution of sloping farmland in the Yangtze River Economic Belt, China

Sloping farmland(SpF)is not only an important space for food production and supply in China’s hilly areas,but also a major source of soil erosion.Thus,it is important to achieve a healthy balance between regional food security and environmental protection.Yangtze River Economic Belt(YREB),an important grain production base where SpF concentrated in China,is also faced with serious soil erosion.However,research at the macro scale on the spatiotemporal change of SpF and its driving forces in YREB is still lacking.To bridge the gap,we first analyzed the long-term evolution characteristics of SpF in 1069 counties in the YREB and then explored the driving mechanism of SpF changes during 1980-2020.Results showed that the SpF in the YREB continuously decreased during the study period,with a total area decreasing by 26,300 km2.SpF was primarily concentrated in the upper reaches of the YREB while SpF use dynamic degree varied significantly with the most active change in the lower reaches,reaching to a maximum of 0.324%.The spatial gravity of SpF distribution relocated 20.15 km towards the southwest.As for the driving factors,the socioeconomic factors contributed greater to SpF changes in the whole YREB and its subregions.The intensity of human activities is the most crucial,with factor contribution rate constantly above 0.76.The interactive detection revealed that the prevailing interaction format was primarily bi-enhanced,supplemented with nonlinear-enhanced,which amplified the role of different factors after interacting with them.The pair-wise interaction involving socioeconomic factors had a more potential effect on SpF changes compared to those between physical geography and locational factors.The influence of the intensity of human activities on SpF changes is greatly enhanced after interacting with any factor.It dominated SpF changes in the YREB and its interaction with GDP played an important role at all times.These findings can enlighten differential management strategies of SpF use and ecological conservation in the YREB.

Evolution of Main Characteristics of the Registered Cotton Cultivars in National Cotton Regional Trials in Yangtze River Valley

[Objective] The aim of this study was to characterize the national regis- tered varieties selected from cotton regional trials in Yangtze River Valley （YaRV） in recent years. [Method] Cotton cultivar classification and comprehensive evaluation index were set up based on national cotton registration standard. GGE biplot method was adopted to analyze the correlation of major breeding target characters of 53 national registered cotton varieties in cotton regional trials in YaRV during 1981-2012. According to the shift of check cultivars in cotton regional trials in the past, the cotton regional trial practice since 1981 was divided into five periods. The dynamic of cultivar type＇s proportion and the evaluation index scores was analyzed across the five periods. [Result] There existed intricate interrelationship among cotton breeding target traits, which constrained it necessary to construct indices for com- prehensive evaluation of cotton varieties. The dynamic of cultivar types in the five periods indicated that type II varieties emerged since Simian 3 period and then its proportion decreased gradually; type Ⅲ varieties maintained a certain proportion in each period and kept on the rise overall; type Ⅳvarieties occupied the majority pro- portion of registered cultivars before 1993, but a minor proportion since Simian 3 period. On the other side, the change trend of the evaluation index demonstrated that the varieties registered before 2003 did not pass the qualified line at present. The peak scores appeared in the varieties registered during 2004-2008. The scores of the varieties registered after 2009 were only slightly over the qualified line. [Conclusion] More attention should be paid to the improvement and evaluation of micronaire, so as to guide the simultaneous development of high yielding and fiber quality in cotton breeding and registration procedure in YaRV.

Analysis of factors influencing carbon emissions in the Yangtze River Delta region and projections of carbon peak scenarios

Based on the supply-side perspective,the improved STIRPAT model is applied to reveal the mechanisms of supply-side factors such as human,capital,technology,industrial synergy,institutions and economic growth on carbon emissions in the Yangtze River Delta(YRD)through path analysis,and to forecast carbon emissions in the YRD from the baseline scenario,factor regulation scenario and integrated scenario to reach the peak.The results show that:(1)Jiangsu's high carbon emission pattern is the main reason for the YRD hindering the synergistic regulation of carbon emissions.(2)Human factors,institutional factors and economic growth factors can all contribute to carbon emissions in the YRD region,while technological and industrial factors can generally suppress carbon emissions in the YRD region.(3)Under the capital regulation scenario,the YRD region has the highest level of carbon emission synergy,with Jiangsu reaching its peak five years earlier.Under the balanced regulation scenario,the YRD region as a whole,Jiangsu,Zhejiang and Anhui reach the peak as scheduled.

The 2022 Extreme Heatwave in Shanghai,Lower Reaches of the Yangtze River Valley:Combined Influences of Multiscale Variabilities

In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.

Spatial-temporal Divergence Characteristics and Driving Factors of Green Economic Efficiency in the Yangtze River Economic Belt of China

The spatial and temporal variation of green economic efficiency and its driving factors are of great significance for the construction of high-efficiency and low-consumption green development model and sustainable socio-economic development.The research focused on the Yangtze River Economic Belt(YREB)and employed the miniumum distance to strong efficient frontier DEA(MinDs)model to measure the green economic efficiency of the municipalities in the region between 2008 and 2020.Then,the spatial autocorrelation model was used to analyze the evolution characteristics of its spatial pattern.Finally,Geodetector was applied to reveal the drivers and their interactions on green economic efficiency.It is found that:1)the overall green economic efficiency of the YREB from 2008 to 2020 shows a W-shaped fluctuating upward trend,green economic efficiency is greater in the downstream and smallest in the upstream;2)the spatial distribution of green economic efficiency shows clustering characteristics,with multi-core clustering based on‘city clusters-central cities'becoming more obvious over time;the High-High agglomeration type is mainly clustered in Jiangsu and Zheji-ang,while the Low-Low agglomeration type is clustered in the western Sichuan Plateau area and southwestern Yunnan;3)from input-output factors,whether it is the YREB as a whole or the upper,middle and lower reaches regions,the economic development level,labor input,and capital investment are the leading factors in the spatial-temporal evolution of green economic efficiency,with the com-prehensive influence of economic development level and pollution index being the most important interactive driving factor;4)from so-cio-economic factors,information technology drivers such as government intervention,transportation accessibility,information infra-structure,and Internet penetration are always high impact influencers and dominant interaction factors for green economic efficiency in the YREB and the three major regions in the upper,middle and lower reaches.Accordingly,the article puts forward relevant policy re-commendations in terms of formulating differentiated green transformation strategies,strengthening network leadership and informa-tion technology construction and coordinating multi-factor integrated development,which could provide useful reference for promoting synergistic green economic efficiency in the YREB.

City Network Evolution Characteristics of Smart Industry: Evidence from Yangtze River Delta, China

The dual-path model of industrial evolution and spatial progression has been widely acknowledged and incorporated into the strategic planning to promote the development of urban industries and regional collaborations.However,current research on inter-enter-prise city networks mainly focuses on the single sector of flows on all enterprise branches,such as product value chains and production factors,but neglects that of particular industry department.Built upon the new economic geography and city networks theory,this paper develops a methodological framework that focuses on the analysis of city network evolution characteristics of smart industry.Particu-larly,a conceptual model of smart industry enterprise-industry-city is proposed and then applied to a case study of smart industry in the Yangtze River Delta Region,China.Using enterprise supplier-customer data,a city network of smart industry is constructed and sub-sequently analyzed with the proposed model.Findings indicate that the smart industry network in Yangtze River Delta Region exhibits a hierarchical structure and the expansion of the network presents a small-world network characteristic.The study not only makes a meth-odological contribution for revealing the industrial and spatial evolution path of the current smart industry,but also provides empirical support for the formulation of new economic development policies focused on smart industries,demonstrating the role of city clusters as carriers of regional synergistic development.

Examining the evolution of tidal creeks in the Huanghe River delta using multi-temporal Landsat images

Coastal tidal creeks are important channels for exchanges of material and energy between sea and land,and play an important role in the ecological protection of tidal flats.Although tidal creeks have evolved differently in various regions,the evolutionary process of tidal creeks in the Huanghe(Yellow)River delta of China,one of the most active deltas worldwide,is not entirely clear.Therefore,the evolution of tidal creeks in the delta from 1981 to 2021 was investigated by quantitatively analysing the tidal creeks and developing a standard for dividing their evolution periods.Visual interpretation and supervised classification methods were applied to the Landsat images to extract the tidal creek network,and 17 groups of tidal creek systems were selected.Results indicate that Creek S 1 was the most developed creek for having 113 tidal creeks totaling 65.8 km in length,while Creek E 3 had the fastest growth rate for having average annual increase of 1.9 km.Meanwhile,the level of tidal creeks increased,the average and median lengths of tidal creeks increased,and the number of tidal creeks decreased since 1981.The evolution of the tidal creek system could be divided into four stages,namely,rising,developing,stabilizing,and degrading.Analyses of a representative tidal creek show that there was no degenerated tidal creek during the rising period,with an increase in the number of 50 and a length increase of 57.9 km between 1981 and 1989.The proportion of new tidal creeks in the developing period was more than 50%and the new tidal creeks in the stabilizing period were equal to the degraded tidal creeks.Extinct tidal creeks were greater than 50%during the degrading period.There was no fixed order of tidal creek evolution in each period,and there may be a skip in evolution.Our findings provided a reference for studying the evolution of tidal creeks.

Regional Brand and High-quality Development of Fruits in Ethnic Areas of the Yangtze River Economic Belt under the Greater Food Approach

Establishing the Greater Food Approach and promoting the Yangtze River Economic Belt s national major regional development strategy can better support and serve the agricultural power and Chinese-style modernization.This paper introduces the characteristics of fruit industry in 16 autonomous prefectures and 47 autonomous counties under the jurisdiction of the Yangtze River Economic Belt.It studies the intellectual property resources of brand marks from the aspects of geographical indications,collective trademarks,certification trademarks,well-known trademarks in China and national design patents,and analyzes the main problems of brand and high-quality development of fruit industry in these ethnic autonomous areas.Finally,it puts forward some strategies,such as improving the protection of intellectual property rights of geographical indications,using intellectual property rights of brand signs,building modern seed industry upgrading project,drawing lessons from the experience of thousand villages demonstration project,ensuring that large-scale poverty does not occur,and building a diversified food supply system.

Promoting High-quality Development of Grain and Oil in Ethnic Areas of the Yangtze River Economic Belt from the Perspective of Agricultural Power

Accelerating the construction of agricultural power,further promoting the high-quality development of the Yangtze River Economic Belt,and better supporting and serving Chinese-style modernization are the key issues at present.This paper first introduces the Yangtze River Economic Belt and its ethnic areas,and studies the characteristics of the grain and oil industry in the ethnic autonomous areas of the economic belt,as well as the current situation of various types of intellectual property resources,such as industrial cultural heritage,scientific and tech-nological innovation,and brand marking intellectual property.Besides,it analyzes the main problems in the high-quality development of grain and oil in the Yangtze River Economic Belt ethnic areas.Finally,it comes up with recommendations,including protecting the intellectual prop-erty rights of cultural heritage in the field of grain and oil,leading the inheritance and development of excellent traditional Chinese culture,use scientific and technological innovation intellectual property rights to promote the innovation-driven development strategy of the grain and oil in-dustry,and providing counterpart assistance to ethnic autonomous areas in the Yangtze River Economic Belt to further promote the high-quality development of the Yangtze River Economic Belt.

Evaluation of Ecological Sustainable Development in the Yangtze River Delta Region Based on Ecological Footprint Theory

The ecological footprint was employed as a quantitative indicator of resource inputs,enabling a detailed account of the structure of biological resources and energy occupancy,as well as the variation of resource productivity in the Yangtze River Delta(YRD)Region.From 2004 to 2018,there were notable variations in the ecological productivity of different types of land on basis of China’s equilibrium factor across the three provinces and one city in the YRD region.Jiangsu Province exhibited the highest ecological productivity of arable land,while Anhui Province exhibited the highest ecological productivity of forest land.Shanghai City exhibited the highest ecological productivity of pasture land,while Zhejiang Province exhibited the highest ecological productivity of water area.In 2018,the proportion of arable land within the total ecological carrying capacity of the YRD region reached 74.35%.Furthermore,the contribution of Jiangsu and Anhui provinces to the YRD’s total ecological carrying capacity was 41.36%and 41.26%,respectively.In the construction of a new development pattern in the YRD region,which is dominated by the domestic cycle as the main body and mutually reinforced by domestic and international double-cycle,the YRD region should combine the utilization of natural forces with innovation in science,technology and cooperation mechanisms.Furthermore,the government should guide the concentration of social capital towards green industries.It is also recommended that the moderate reduction of ecological footprints should be encouraged,and that the security of biological resources and energy,the leadership in the field of cutting-edge science and technology should be ensured in YRD region.This will facilitate the formation of a new development pattern of higher-quality integration at the national level firstly.

Spatiotemporal evolution and influencing factors of urban resilience in the Yellow River Basin,China

The Yellow River Basin of China is a key region that contains myriad interactions between human activities and natural environment.Industrialization and urbanization promote social-economic development,but they also have generated a series of environmental and ecological issues in this basin.Previous researches have evaluated urban resilience at the national,regional,urban agglomeration,city,and prefecture levels,but not at the watershed level.To address this research gap and elevate the Yellow River Basin’s urban resilience level,we constructed an urban resilience evaluation index system from five dimensions:industrial resilience,social resilience,environmental resilience,technological resilience,and organizational resilience.The entropy weight method was used to comprehensively evaluate urban resilience in the Yellow River Basin.The exploratory spatial data analysis method was employed to study the spatiotemporal differences in urban resilience in the Yellow River Basin in 2010,2015,and 2020.Furthermore,the grey correlation analysis method was utilized to explore the influencing factors of these differences.The results of this study are as follows:(1)the overall level of urban resilience in the Yellow River Basin was relatively low but showed an increasing trend during 2010–2015,and significant spatial distribution differences were observed,with a higher resilience level in the eastern region and a low-medium resilience level in the western region;(2)the differences in urban resilience were noticeable,with industrial resilience and social resilience being relatively highly developed,whereas organizational resilience and environmental resilience were relatively weak;and(3)the correlation ranking of resilience influencing factors was as follows:science and technology level>administrative power>openness>market forces.This research can provide a basis for improving the resilience level of cities in the Yellow River Basin and contribute to the high-quality development of the region.

Spatio-temporal evolution of the coordinated development of high-tech industry agglomeration and resource-environmental carrying capacity in the Yellow River Basin

Under the background of new infrastructure,the Yellow River Basin’s superior growth cannot be separated originating with the synergistic effect of scientific and technological inventiveness and ecological civilization construction.In light of the coupling coordination analysis of the coordination effect of provincial high-tech industry agglomeration and resource carrying capacity in the Yellow River Basin from 2009 to 2021,The evolution of the geographical and temporal pattern of development was investigated using the Moran index and kernel density estimation.The results show that the agglomeration of high-tech industries in the Yellow River Basin presents a development trend of seek improvement in stability,and there is a good coupling and coordination throughout the progression of scientific and technological innovation and the loading capacity of the resource,from the viewpoint of a time series.From the perspective of spatial pattern distribution,the whole basin aims at the lower reaches,accelerates the optimization of digital industry and promotes Yellow River Basin development of superior quality through innovation support and increase of input,and based on policy guidance.

Interdecadal change and projection of the relationship between spring Arctic Oscillation and summer precipitation in the Yangtze River valley in CMIP6 models

评估了20个CMIP6模式对春季北极涛动(AO)与长江流域夏季降水(YRP)关系的模拟能力.结果表明, 4个模式(ACCESS-ESM1-5, CMC-CM2-SR5, MRI-ESM2-0, NorESM2-LM))能合理模拟出1990年代后期AO-YRP关系的减弱. 1980-1998年,当春季AO位于正位相时,夏季东亚急流北移,长江流域为异常下沉运动,同时西太平洋副热带高压减弱,减少向长江流域的水汽输送,结果导致降水减少. 1999-2014年,上述大气环流与春季AO的联系不显著,从而减弱AO-YRP的关系.利用这四个模式进一步预估了RCP4.5情景下2015-2100年期间AO-YRP的关系.两者在2015-2040年为显著负相关关系,随后再次减弱.

Detrital Zircon Ages of Hanjiang River:Constraints on Evolution of Northern Yangtze Craton,South China

Clastic sedimentary rocks are natural samples of the exposed continental crust over large areas. The Hanjiang （汉江） River drains the northern Yangtze craton, including the South Qinling （秦岭） belt and the northern parts of the Yangtze craton. Detrital zircons from this river thus provide an ideal sample for studying the formation and evolution of the northern Yangtze craton. Here we report laser ablation inductively coupled plasma mass spectrometer U-Pb ages of 122 detrital zircons from one sand sample of the Hanjiang River. The 110 concordant zircons reveal four major age groups of 768, 444, 212, and 124 Ma, which well correlate with known magmatic events in the northern Yangtze craton. A minor group is present at 1 536 Ma, which is less known in the study area. Only seven zircons have ages of 〉1 750 Ma. Our results show that the Early Paleozoic, Late Triassic, and Early Cretaceous are important episodes of zircon growth and crustal growth/reworking in addition to the previously documented Neoproterozoic event. Our results suggest very limited exposures of Paleoproterozoic and Archean rocks in the northern parts of the Yangtze craton.

Basement Characteristics and Crustal Evolution of the Copper-Gold Metallogenic Belt in the Middle and Lower Reaches of the Yangtze River:Some Isotope Constraints

Studies of the Pb, Sr and Nd isotopic composition of Mesozoic intrusive rocks indicate that the basement of the copper-gold metallogenic belt of the middle and lower reaches of the Yangtze River has “two-layer structure” and partly has “multi-layered structure”, and is inhomogeneous and shows the distinct feature of E-W provincialism. The calculated model lead ages (t1) are mostly greater than 2600 Ma, and the model neodymium ages (TDM) vary from 953 to 2276 Ma and concentrate in two time intervals: 1800–2000 Ma and 1200–1600 Ma. It is concluded that the basement of the MBYR is composed of the Late Archaeozoic to Middle Proterozoic metamorphic series and that the crust was initiated in the Archaean and continued to grow in the Early and Middle Proterozoic, and the proportion of new crust formed by mantle differentiation during the Late Proterozoic is low.

Spatio-temporal evolution and factor explanatory power analysis of urban resilience in the Yangtze River Economic Belt

Urban resilience assesses a city’s ability to withstand unknown risks.Scholars are not comprehensive in assessing urban resilience,and they lack consideration of population resilience.This study investigated 110 prefecturelevel cities in the Yangtze River Economic Belt(YREB)as study areas.We calculated the YREB’s level of urban resilience based on the aspects of“economy-society-population-ecology-infrastructure”,which ensured that the comprehensive evaluation of urban resilience is complete and sufficient.The spatio-temporal evolution of urban resilience was analyzed using exploratory spatial data.Geodetectors were used to investigate the impact of several indicators,focusing on economic,social,population,ecological,and infrastructure factors,on urban resilience.The results showed that the urban resilience of the YREB has maintained a slow upward trend from 2005 to 2018,and the average urban resilience of the YREB has risen from 0.2442 to 0.2560.The resilience gap between cities in the study region increased initially and then decreased.The dominant factor in the spatial differentiation of urban resilience was the economic factors,followed by the population factors.Urban resilience has been clarified and an evaluation index system is constructed,which can provide an effective reference for the evaluation of urban resilience among countries around the world.Based on this,factors that optimize urban resilience are configured,and the regional and national sustainable development can be promoted.

Introduction to the China-Vietnam Cooperation Project: A Comparative Study of the Holocene Sedimentary Evolution of the Yangtze and Red River Deltas

Both China and Vietnam confront the challenges of natural geohazards and environmental changes in their deltas and coastal zones due to rapid urbanization, economic development, and the impacts of global climate change. China and Vietnam initiated a comparative study of the Holocene sedimentary evolution of the Yangtze River Delta(YRD) and Red River Delta(RRD) for the period 2015–2018 in order to improve the understanding of the two delta evolution histories in the Holocene. Previous investigative data of the two rivers, onshore delta plains, and offshore subaqueous deltas have been explored and reinterpreted. New data gleaned from boreholes, piston cores, shallow seismic and hydrodynamic sources have been collected from the offshore YRD and the East China Sea inner shelf, and surface sediments and short cores have been collected from the RRD near-shore areas. Six focal areas of the joint project have been defined for comparative studies of the two deltas, including morphological development, sequential stratigraphy, coastline shifting, sedimentary characteristics, sedimentary dynamics, and correlation with anthropogenic global climate change. The results of these study areas are presented herein. The joint project also includes cooperative capacity building; exchanges of young scientists have been organized during the project period, and hands-on training in laboratory geochemical analysis, numerical modeling, and seismic data processing and interpretation have been provided by China and its Vietnamese geoscientist partners. Joint field excursions were organized to the upstream of the Yangtze and Red Rivers in Yunan Province, China, all the way downstream along the Vietnamese portion of the Red River. These joint studies have, over the past three years, improved understanding of the evolutionary history of these two major rivers and their mechanisms of source to sink. Joint project results of these two major deltas are not limited to the geosciences; the cooperative mechanical and operational experiences have been helpful for future cooperation in the field of marine geoscience between China and Vietnam, as well for cooperative activities with other ASEAN member countries.

Behavioral migration diversity of the Yangtze River Japanese Eel,Anguilla japonica,based on otolith Sr/Ca ratios

The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from the Yangtze River estuary to the upper Jinsha River,which extend to nearly 3 000 km.However,their migration behaviors remain relatively unknown.We analyzed the biological characteristics of 153 specimens of silver eels collected from the Jingjiang section of Yangtze River（31o30＇N,120o42＇E） between September and November,2008,and tested the sagittal Sr/Ca ratios of 27 specimens.Among the 153 specimens examined,85 were female and 68 were male,which translated to a female-male ratio of 1：0.8.The ages of the female specimens ranged from 3 to 7 a（average 5.52） with an average total length（TL） of（669±80） mm,average body weight（BW） of（555±229）g,average condition factor of 1.77±0.22,and average gonad somatic index（GSI） of 1.32±0.31.The ages of the males ranged from 3 to 5 a（average：4.38） with an average TL of（518±51） mm,average BW of（234±76） g,average condition factor of 1.62±0.18,and average GSI of 0.21±0.11.All biological parameters of females were significantly larger than those of the male specimens（P0.05）.According to the average Sr/Ca ratio（7.99±1.05） ×10-3 of the elver mark of sagitta,17 individuals（62.96%） were river eels and 10 individuals（37.04%） were estuarine eels.Of 16 females,13 individuals（81.25%） were river eels and 3 were estuarine eels,while of 11 males,36.36% were river eels and 63.64% were estuarine eels.The analysis on Sr/Ca ratios for every growth layer group（GLG） indicated there were no significant differences between second-age males and females.However,significant differences were observed between the third-age,fourth-age,and migration-age male and female specimens.This was likely related to the fact that second-age eels of both sexes stay in the same inhabitation waters;however,as they grow older,they move to different areas.

An Overview of Coilia ectenes in Jiangsu Section of the Yangtze River

Anchovies are migratory fish and adult individuals migrate in group from the sea into the river every year because of reproductive needs. TheYangtze River is the largest river in China, with rich food and fish species, hence, the Yangtze River would be an ideal habitat for growth and reproduction of anchovy. In this pa- per, based on fishing log data of anchovy in Jiangsu section of the Yangtze River, realted analysis was conducted in digital map using statistical software and GIS. From 2008 to 2011, the number of anchovy fishing vessels and fishing days in Jiangsu section remained stable, but the fishing volume and economic profit of single-vessel fluctuated constantly. This study provides references and advices for plan and management of anchovy fishery resource to administrative department.