The estuarine tapertail anchovy(Coilia nasus)is a high-value commercial fish.Estimating the spawning site or hatchery origin and habitat is essential for its conservation.This study aimed to determine the habitat use ...The estuarine tapertail anchovy(Coilia nasus)is a high-value commercial fish.Estimating the spawning site or hatchery origin and habitat is essential for its conservation.This study aimed to determine the habitat use and life history characteristics of C.nasus from the Changjiang River Estuary.We investigated the environmental signatures of strontium(Sr)and calcium(Ca)in the otoliths of the collected specimens using electron probe microanalysis;additionally,we examined their gonadal maturity stage.Our results indicate that the 31 adult C.nasus specimens used in this study could be classified into two types based on their otolith Sr:Ca concentration ratios and their gonadal maturity stage.The long freshwater early life history type(Type LF)had wider central region in the otolith with low Sr:Ca concentration ratios ranging from 1.24±0.62 to 1.92±0.78 and a bluish pattern of low Sr content level.These fish are of riverine origin and had a relatively long early life history in freshwater and low gonadal maturation when captured.The short freshwater early life history type(Type SF)had a shorter central region in the otolith with low Sr:Ca concentration ratios ranging from 1.35±0.5 to 2.82±0.97 and a correspondingly bluish pattern.These fish also had a relatively short-term early life history in freshwater and high gonadal maturation when captured.The results of the otolith microchemical analysis indicated that Type LF and Type SF originated in spawning/hatching sites far from and close to the estuary,respectively.The mature gonads of Type SF fish indicated that they may breed in areas close to the estuary,whereas the immature gonads of Type LF fish indicated that they may breed in areas far from the estuary.This study is the first to reveal that the Changjiang River Estuary contains stocks of anadromous C.nasus originating in different spawning sites during the same season.The estuarine habitat plays a critical role in the connectivity between freshwater recruitment and the marine resources available to adult spaw展开更多
Here we provide an example of simultaneous polyandry based on genetic evidence in Feirana kangxianensis. This stream-dwelling species occurs only in Kangxian County, southern Gansu Province, where it is sympatric with...Here we provide an example of simultaneous polyandry based on genetic evidence in Feirana kangxianensis. This stream-dwelling species occurs only in Kangxian County, southern Gansu Province, where it is sympatric with its sibling species E quadranus. During the breeding season the sex ratio of E kangxianensis was marginally female- biased （44~：59~） and the encounter rate in a relatively pristine habitat was significantly higher than that in heavily quarried habitats （9.6 ± 4.8 indiv./km vs. 3.2 ± 2.5 indiv./km）. Three egg masses containing an average of 698 eggs were deposited on the underside of one or two adjacent flat rocks, 6.0-10.0 cm under the water surface and 1.0-3.5 cm above the streambed. Using Bayesian sibship clustering of nine polymorphic microsatellite genotypes, two females were detected as group-spawning in one oviposition site, with three males fertilizing each female＇s eggs simultaneously. We also discuss the conservation requirements of this range-restricted species and the evolutionary implication of its unusual reproductive strategy.展开更多
Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site.The mean egg s...Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site.The mean egg survival rates per day were highest in the mid intertidal zone(45.1%±25.4%)and the lowest in the low intertidal zone(13.3%±27.6%).Differences in the elevation,air exposure time,and water content of the spawning ground were significant factors determining the egg survival rates.Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones and could reduce egg survival.On the other hand,moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone.This dynamic is considered as one of the crucial factors for the survival of eggs and is considered optimal for spawning.Therefore,the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development.By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches,a positive contribution can be made to future management and conservation.The study also suggests that translocating eggs from marginal to optimal spawning sites might be a recovery strategy for this globally endangered species.展开更多
Chilo suppressalis （Walker） is one of the important pests in rice produc-tion. ln this paper, the spawning condition of Chilo suppressalis on rice seedlings in Wuxue, Qichun, Chongyang and Xiaogan of Hubei Province ...Chilo suppressalis （Walker） is one of the important pests in rice produc-tion. ln this paper, the spawning condition of Chilo suppressalis on rice seedlings in Wuxue, Qichun, Chongyang and Xiaogan of Hubei Province was investigated, and the spawning habit of overwintering-generation Chilo suppressalis on rice seedlings was analyzed. The results showed the overwintering-generation Chilo suppressalis prefers to spawn on verdant rice leaf blades （face, upper part）. The investigation on spawning habit of Chilo suppressalis would provide a theoretical basis for the fore-casting and control of Chilo suppressalis.展开更多
针对中华鲟面临的不良生态环境和正面临濒危的状况,运用水动力学的N-S方程和k-ε紊流数值模型,结合计算水气两相流的方法VOF(volume of finite),采用控制体积法离散计算区域,通过建立葛洲坝下游中华鲟产卵场的生态水动力学模型,来模拟...针对中华鲟面临的不良生态环境和正面临濒危的状况,运用水动力学的N-S方程和k-ε紊流数值模型,结合计算水气两相流的方法VOF(volume of finite),采用控制体积法离散计算区域,通过建立葛洲坝下游中华鲟产卵场的生态水动力学模型,来模拟葛洲坝下游不足5 km江段的三维水流特征.并结合中华鲟的生态水力学特性(对流场改变的敏感性和选择性),分析中华鲟产卵繁殖的流场特性,以期为三峡水库优化调度提供理论依据和技术参数.展开更多
基金The National Natural Science Foundation of China under contract No.31602159the Agricultural Finance Special Project under contract No.CJDC-2017-22the Scientific Research Foundation of Wuxi City for Returned Oversea Chinese Scholars under contract No.CZ2019231400.
文摘The estuarine tapertail anchovy(Coilia nasus)is a high-value commercial fish.Estimating the spawning site or hatchery origin and habitat is essential for its conservation.This study aimed to determine the habitat use and life history characteristics of C.nasus from the Changjiang River Estuary.We investigated the environmental signatures of strontium(Sr)and calcium(Ca)in the otoliths of the collected specimens using electron probe microanalysis;additionally,we examined their gonadal maturity stage.Our results indicate that the 31 adult C.nasus specimens used in this study could be classified into two types based on their otolith Sr:Ca concentration ratios and their gonadal maturity stage.The long freshwater early life history type(Type LF)had wider central region in the otolith with low Sr:Ca concentration ratios ranging from 1.24±0.62 to 1.92±0.78 and a bluish pattern of low Sr content level.These fish are of riverine origin and had a relatively long early life history in freshwater and low gonadal maturation when captured.The short freshwater early life history type(Type SF)had a shorter central region in the otolith with low Sr:Ca concentration ratios ranging from 1.35±0.5 to 2.82±0.97 and a correspondingly bluish pattern.These fish also had a relatively short-term early life history in freshwater and high gonadal maturation when captured.The results of the otolith microchemical analysis indicated that Type LF and Type SF originated in spawning/hatching sites far from and close to the estuary,respectively.The mature gonads of Type SF fish indicated that they may breed in areas close to the estuary,whereas the immature gonads of Type LF fish indicated that they may breed in areas far from the estuary.This study is the first to reveal that the Changjiang River Estuary contains stocks of anadromous C.nasus originating in different spawning sites during the same season.The estuarine habitat plays a critical role in the connectivity between freshwater recruitment and the marine resources available to adult spaw
基金supported by the National Natural Science Foundation of China (31471964, 31200411)the Chinese Academy of Sciences (Y3C3011100)
文摘Here we provide an example of simultaneous polyandry based on genetic evidence in Feirana kangxianensis. This stream-dwelling species occurs only in Kangxian County, southern Gansu Province, where it is sympatric with its sibling species E quadranus. During the breeding season the sex ratio of E kangxianensis was marginally female- biased （44~：59~） and the encounter rate in a relatively pristine habitat was significantly higher than that in heavily quarried habitats （9.6 ± 4.8 indiv./km vs. 3.2 ± 2.5 indiv./km）. Three egg masses containing an average of 698 eggs were deposited on the underside of one or two adjacent flat rocks, 6.0-10.0 cm under the water surface and 1.0-3.5 cm above the streambed. Using Bayesian sibship clustering of nine polymorphic microsatellite genotypes, two females were detected as group-spawning in one oviposition site, with three males fertilizing each female＇s eggs simultaneously. We also discuss the conservation requirements of this range-restricted species and the evolutionary implication of its unusual reproductive strategy.
文摘Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site.The mean egg survival rates per day were highest in the mid intertidal zone(45.1%±25.4%)and the lowest in the low intertidal zone(13.3%±27.6%).Differences in the elevation,air exposure time,and water content of the spawning ground were significant factors determining the egg survival rates.Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones and could reduce egg survival.On the other hand,moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone.This dynamic is considered as one of the crucial factors for the survival of eggs and is considered optimal for spawning.Therefore,the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development.By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches,a positive contribution can be made to future management and conservation.The study also suggests that translocating eggs from marginal to optimal spawning sites might be a recovery strategy for this globally endangered species.
基金Supported by National Five-year Science&Technology Support Program(2012BAD19B03)Special Scientific Research Fund of Agricultural Public Welfare Profession of China(201303017)~~
文摘Chilo suppressalis （Walker） is one of the important pests in rice produc-tion. ln this paper, the spawning condition of Chilo suppressalis on rice seedlings in Wuxue, Qichun, Chongyang and Xiaogan of Hubei Province was investigated, and the spawning habit of overwintering-generation Chilo suppressalis on rice seedlings was analyzed. The results showed the overwintering-generation Chilo suppressalis prefers to spawn on verdant rice leaf blades （face, upper part）. The investigation on spawning habit of Chilo suppressalis would provide a theoretical basis for the fore-casting and control of Chilo suppressalis.
文摘由于葛洲坝工程的修建,中华鲟的洄游路线被阻断了,使中华鲟产卵场由过去的屏山至木洞800 km江段压缩至现在的葛洲坝下游不足5 km江段。中华鲟也由水产资源演变成一级保护动物。运用水动力学的N-S方程和k-ε紊流数值模型,结合计算水气两相流的方法VOF(volume of fluid),采用控制体积法离散计算区域,对葛洲坝下游中华鲟产卵河段的流场进行了计算。并结合中华鲟的生态特性,分析其产卵繁殖对流场特性的要求,以期在三峡水库下游河道整治中注意保护其产卵场地。
文摘针对中华鲟面临的不良生态环境和正面临濒危的状况,运用水动力学的N-S方程和k-ε紊流数值模型,结合计算水气两相流的方法VOF(volume of finite),采用控制体积法离散计算区域,通过建立葛洲坝下游中华鲟产卵场的生态水动力学模型,来模拟葛洲坝下游不足5 km江段的三维水流特征.并结合中华鲟的生态水力学特性(对流场改变的敏感性和选择性),分析中华鲟产卵繁殖的流场特性,以期为三峡水库优化调度提供理论依据和技术参数.
