Migration Of Sturgeon Research Articles

Spatial and temporal distribution of juvenile Gulf Sturgeon in the Pearl River, Louisiana, and adjacent estuaries of the Gulf of Mexico

AbstractObjectiveAcoustic telemetry was used to examine the spatial‐temporal distribution and anadromous migration pattern of juvenile Gulf Sturgeon Acipenser desotoi within the Pearl River and associated coastal estuaries of Louisiana and Mississippi.MethodsAcoustic transmitters were surgically implanted in 52 juvenile Gulf Sturgeon (<890 mm fork length) from the Pearl River between 2016 and 2019. Sturgeon were monitored on 247 acoustic receivers in the lower Pearl River and adjacent estuaries across numerous partnering arrays.ResultJuveniles were detected on receivers from Lake Pontchartrain, Louisiana, east to Bay St. Louis, and Biloxi Bay, Mississippi. The 3‐year study found that juvenile Gulf Sturgeon migration in the Pearl River occurred on cycles similar to those reported from other populations. Juveniles were rarely observed in the estuary and nearshore marine environments from May through mid‐October of each year, during which time most sturgeon inhabited the Pearl River. Conversely, most of the juveniles inhabited coastal estuaries from December through February of each year and were rarely observed in freshwater environments during this period. Migration from the river into the estuary occurred during late‐October through November, and migration from the estuary into the river occurred in March and April. Distribution patterns varied spatially within the river and estuary ecosystems during each phase of migration. Tagged juveniles occupied the lowest 40 km of the Pearl River while in freshwater, and they occupied the northeastern shoreline of Lake Pontchartrain and Bay St. Louis while in the estuary. Interestingly, juveniles seemed to target specific areas in the estuary during winter that were farther away from the mouth of natal rivers than has been previously reported.ConclusionThis study provides a new assessment of juvenile Gulf Sturgeon migration and seasonal distribution for the Pearl River and provides important information for designing and assessing the potential benefits and challenges of habitat restoration for Gulf Sturgeon.

Migration dynamics simulation of migratory fish in rivers

The decline of migratory fish stocks is a major problem facing the global aquatic ecosystem. Understanding the dynamics of fish migration and their entire life history is crucial for quantitatively assessing the impact of natural and anthropogenic barriers on migratory fish and to understand the mechanisms of their decline. However, this understanding is largely ambiguous due to limited field survey data in the absence of models. Although Huang and Wang (Curr. Biol. 28, 2018, 3640–3647) and Huang (iScience 19(9), 2019, 772–785) proposed a Migration Dynamics Model (MDM) to describe the upriver and downriver migration processes of the Chinese sturgeon, but a crucial intermediate link—the breeding aggregation process—is still missing, while the standard Crank-Nicolson scheme, a common computational method, of finite difference methods cannot adapt to the model parameters changing with time and space. Here we propose a six-point implicit scheme to address the complexity of model parameters. The parameters of migration speed and diffusion coefficient are decomposed into fish-related and current-related components for analyzing their effects on model parameters and estimating them. Additionally, we propose a parameterization method for the aggregation process of spawners during the breeding season by introducing a set of clustering functions. Next, we examine the complete migration processes of adult and juvenile Chinese sturgeons in the Yangtze River and elucidate the underlying mechanisms behind the fish migration dynamics, including their spatiotemporal distributions, aggregation behavior, and migration schedule. We discover that the Gezhouba Dam (GD) significantly impacted the breeding aggregation behavior of Chinese sturgeon during the breeding season. The GD altered the distribution of fish along their migration path and schedule. Prior to the construction of the dam, 99.9 % of the total Chinese sturgeon were able to reach the 240 km-long spawning ground. However, after the dam was built, only 36.7 % were able to reach the 30 km-long spawning ground below the GD on the day of mating. Finally, we discuss the aggregation phenomenon and its driving factors during Chinese sturgeon migration, and categorize it into three types, namely biotic-driven, abiotic-driven and dual-driven aggregation behaviors. We reveal the existence of aggregations for non-biological reasons, such as the slowdown of fish migration speed induced by natural and anthropogenic barriers and estuarine tidal effects.

Methodology for Identification of Areas with Possible Risk for Sturgeon Species Migration Disruption on The Lower Danube

In the context of the continuing decline of the species belonging to the order Acipenseriformes on a global level, the anadromous sturgeon species sturgeon species in the Lower Danube have been affected by a significant reduction in historical migration routes and fragmentation of breeding habitats. This paper presents the stages of the methodology for identifying areas that present a possible risk of interruption of sturgeon migration in correlation with satellite images and daily values for discharge/water level databases. In order to determine the two ranges of values that characterize the extreme phenomena (high/low flows), a hydrological statistical analysis was carried out for the most extensive period of time covered by recorded data (January 2011 – May 2023) in the hydrometric station located in Calarasi, Romania. Based on the 4524 values from the series of average daily discharge values, the discharge hydrograph, the empirical curve of insurance/exceedance probability and the frequency and duration curves using 200 m3/s discharge steps were determined and represented. Correlated with satellite imagery recorded during the determined time intervals with extreme phenomena, there were identified areas with possible risk for sturgeon species migration disruption.

The impact of anthropogenic pressures on sturgeon migration in the Lower Danube

The Black Sea sturgeons are anadromous fish species [1], which migrate upstream on the Danube River for breeding. The distance traveled in the migration process varies depending on each species, from tens to hundreds of kilometers [2]. After breeding, the anadromous sturgeons return to the Black Sea and go back to the Danube after a time that varies depending on the species between 3 and 5 years [3]. All sturgeon species that migrate in the Danube basin are on the IUCN Red List of Threatened Species [4]. Considering that sturgeon migration is a condition of the existence of species [5], INCDPM developed in 2011-2017 extensive research studies of their behavior. Using ultrasonic telemetry, unique information volumes have been obtained on the behavior during sturgeon migration in different hydrodynamic conditions and under the pressures caused by anthropogenic activities. The intensity of poaching was also analyzed, resulting in that this pressure represents a real threat to the existence of sturgeon species. Over 70% of the total specimens monitored in research studies, developed by INCDPM during the over 7 years of research, were poached. The research was conducted in Ml compliance with the provisions of the EU Biodiversity Strategy for 2030 [6], which aims to conserve endangered habitats and species, including by reducing and eliminating by-catches.

Dredging activity and associated sound have negligible effects on adult Atlantic sturgeon migration to spawning habitat in a large coastal river.

Dredging is considered a major threat/impedance to anadromous fish migrating to spawning habitat. Due to the perceived threat caused by dredging, environmental windows that restrict dredge operations are enforced within many rivers along the east coast. However, it is generally unknown how anadromous fish react to encountering an active dredge during spawning migrations. Atlantic sturgeon (ATS) are an endangered, anadromous species along the Atlantic slope of North America. To determine if and how an active dredge may affect ATS spawning migration, a Vemco Positioning System array was deployed around an active hydraulic-cutterhead dredge that adult ATS must traverse to reach spawning habitat in the James River, VA. Telemetry data showed that all ATS that entered the study area survived. ATS that migrated upstream during dredge operations (N = 103) traversed the dredge area and continued upstream to spawning habitat. Many ATS made multiple trips through the study area during dredge operations. There was no noticeable difference in swim behavior regardless of whether the dredge was absent or working within the study area. We suggest that dredging in the lower James River does not create a barrier for adult ATS migrating to spawning habitat or cause adults to significantly modify swim behavior. This is the first study to utilize fine-scale telemetry data to describe how an organism moves in relation to an active dredge. This methodology could be used to describe dredge-sturgeon interactions on different life stages and in other locations and could be expanded to other aquatic organisms of concern.

Detailed analysis of beluga sturgeon (Huso huso) and stellate sturgeon(Acipenser stellatus) migration in the Lower Danube River

The swimming ground speed and swimming depths of beluga sturgeon (Huso huso) and stellate sturgeon (Acipenser stellatus) were investigated using ultrasonic telemetry between 2011 and 2017 in the Lower Danube River (river kilometer (rkm) 0 Sulina-rkm 1075 Bazias). Acoustic telemetry receivers VR2W and V16TP tags (Vemco, Canada) were used to collect data about sturgeon migration behavior in the Lower Danube River between the Black Sea and the Iron Gate II dam. The tags, equipped with depth and temperature sensors, provided data about beluga and stellate sturgeon migration periods, swimming speeds, and depths. Twenty-three beluga sturgeon (184-245 cm TL) and twenty-one stellate sturgeon (92-135 cm TL) were ultrasonically tagged and passively tracked using hydrophone receivers installed in the river between rkm 71 and rkm 860. Three tagged beluga sturgeon returned after 2 and 5 years and two stellate sturgeon returned after 2 years since the time of their initial release in the river. This study provides, for the first time, further details concerning beluga sturgeon and stellate sturgeon migratory behavior patterns, traveled distances, swimming depths, and their swimming ground speeds during spawning migration.

Variation in the suitability of Chinese sturgeon spawning habitat after construction of dams on the Yangtze River

The Chinese sturgeon (Acipenser sinensis) is an anadromous fish inhabiting the Yangtze River. Migration of Chinese sturgeon from the estuary to upper Yangtze River was blocked by Gezhou Dam, completed in 1981, and a new, much smaller, spawning ground was established below the dam. However, Three Gorges Dam began operating in 2003, altering hydrological conditions in the new spawning grounds and the impact on Chinese sturgeon reproduction was severe. The annual survey of Chinese sturgeon shows that both spawning scale and breeding population decreased during this period. To illustrate the impact of Three Gorges Dam on the spawning grounds and reproduction of Chinese sturgeon, the habitat suitability of spawning grounds on spawning day was simulated using River2D. Results show that the area of suitable spawning grounds positively correlates with the scale of reproduction and both have decreased sharply since 2003.

Factors influencing the natural reproduction decline in the beluga ( Huso huso , Linnaeus, 1758), Russian sturgeon ( Acipenser gueldenstaedtii, Brandt & Ratzeburg, 1833), and stellate sturgeon ( A. stellatus , Pallas, 1771) of the Volga–Caspian basin: A review

The review describes the changes in natural reproduction of three important sturgeon species in the Volga–Caspian basin: (a) the beluga (Huso huso Linneaus, 1758), (b) the Russian sturgeon (Acipenser gueldenstaedtii Brandt &Ratzeburg, 1833), and (c) the stellate sturgeon (Acipenser stellatus Pallas, 1771). Since the past 60 years, these species responded to severe influences of natural and anthropogenic factors. On the basis of original and published data, an analysis has been made of (a) the numbers of larvae migrating from spawning sites (according to plankton net survey), (b) fecundity and histological anomalies in gonad development, (c) the numbers of adult sturgeons in the Caspian Sea and of spawners migrating to the Volga River (according to trawl and beach seine survey), and (d) foraging resources for the sturgeons. The results show that their natural reproduction in the Volga–Caspian basin has declined drastically during the past decades under the impact of (a) fluctuations of the Caspian Sea level and flow discharge from the Volga River, (b) blockage of sturgeon migration routes and loss of spawning sites because of dam construction, (c) water pollution in the lower reaches of the Volga River and in the Caspian Sea, and (d) intensive and selective illegal and unreported fishing. The relative significance of these factors has been changing during the study period.

An Overview of the Factors Affecting the Migration of Sturgeons in Yesilirmak

<div><!--block-->The Yeşilırmak is one of the rivers in Turkey where sturgeons migrate for spawning. It originates in the Kösedağ Mountains in Sivas and flows into the Black Sea at the plain of Çarşamba. The Yeşilırmak plays a major role in agricultural production and irrigation, and it also supplies energy due to the hydroelectric power plant (HPP). Serious structural changes and significant habitat loss for sturgeons and other fish species have occurred due to the dams and HPPs in the Yeşilırmak, especially since the 1970s. It is also a known fact that fish passages in these constructions are not suitable for the sturgeons to pass through. Unfortunately, coastal regulations along the river have had a negative effect on the habitats. Although the Yeşilırmak has lost quite a lot of its natural structure and its waterway gradually shortened due to the HPPs, sturgeons can still migrate upstream into it. Therefore, related sectors and stakeholders should consider the importance of the Yeşilırmak in their planned activities for the future of sturgeons in Turkish waters. In this study, the major factors affecting the sturgeon migration in the Yeşilırmak will be evaluated.</div>

СОВРЕМЕННОЕ СОСТОЯНИЕ ЕСТЕСТВЕННОГО ВОСПРОИЗВОДСТВА ОСЕТРОВЫХ РЫБ (ACIPENSERIDAE) В РЕКЕ УРАЛ

In the current conditions of a critical reduction of sturgeon stocks and the imposed moratorium on industrial sturgeon catching it is necessary to take urgent and cardinal measures to save the Caspian populations of these valuable fish species. To restore the number of sturgeons in the Ural-Caspian basin it is first of all necessary to increase the efficiency of natural reproduction. The Urals is the only river in the basin of the Caspian Sea with an undisturbed hydrological regime that allows to maintain the normal dynamics of migrations of sturgeon fishes and conditions for spawning and the subsequent ramp of the young. The current state of the natural reproduction of sturgeon in the Ural river was analyzed; data on the dynamics of sloping migration of young sturgeon, their number and mass are given. It has been established that the main factors affecting the reproduction of sturgeon are the hydrological conditions of the river of a particular year, as well as the number of producers that are allowed to enter spawning grounds. It has been stated that the beginning of sturgeon juveniles ramp into the Ural River shifted to later period and can be registered only since June; ramp duration has greatly decreased; average mass of ramping juveniles also decreased; since 2007 Acipenser nudiventris juveniles haven’t been observed, and since 2010 stellate sturgeon juveniles haven’t been come across. It is shown that at present, due to a number of reasons, the efficiency of natural reproduction of sturgeon in the Ural River is reduced to zero.

Long Distance Migration of Beluga (Huso huso) and Stellate Sturgeon (Acipenser stellatus) in Lower Danube River in Relation with Iron Gate II Dam

Construction of the dams in Lower Danube River (LDR- rkm 0 Sulina – rkm 1075 Baziasi) without fish passages, as well as illegal fishery and river bottom modification due to navigation had negative impact on sturgeon’s populations. Beluga Sturgeon, Stellate Sturgeon and Russian Sturgeon still migrate to spawn in LDR but there is lack of information relating to sturgeons long distance migration in this area. Tagging with Vemco V16 TP acoustic tags, equipped with temperature and depth sensors involved 36 adult Beluga and 44 Stellate Sturgeons provide new data about sturgeon migration. Their migrations are monitored by VR2W receivers, deployed on between rkm 71 and rkm 864. Analysis of data showed that 17% of Beluga and 30% of Stellate Sturgeon never recorded and 30% and 11% of Beluga and Stellate Sturgeon recorded in period more than 30 days after tagging. Only 5% of Beluga and 7% of Stellate Sturgeon have been recorded after a period of more than 1 year. During 2013-2016 4 adult Beluga and 1 adult Stellate Sturgeon were recorded in the IGII Dam area. Results of this investigation showed that sturgeons still approached the IG2 dam and construction of fish passage on this dam is needed.

Reach specific use of spawning habitat by adult green sturgeon ( Acipenser medirostris ) under different operation schedules at Red Bluff Diversion Dam

Mature green sturgeon, Acipenser medirostris, enter rivers along the western coast of North America in late winter to late spring and migrate upriver to spawning sites. After spawning, they may leave the river or spend the summer and autumn holding in deep pools before departing from the river with the onset of winter rains. Evidence exists that the seasonal Red Bluff Diversion Dam (RBDD) was an obstacle to the upriver migration of green sturgeon in the Sacramento River in Central California. We compared the migratory movements of green sturgeon under three different dam operation schedules, including post-decommissioning, to assess the impact of this management action. The proportion of green sturgeon carrying acoustic transmitters that moved above the RBDD was higher when the gates were closed on June 15, one month later than the historical closure date of May 15, and increased again after the dam was decommissioned. The application of statistical analyses (generalized linear and additive mixed models) to the detection records of green sturgeon highlighted an improvement in connectivity after dam decommissioning. The data also indicate that interannual variation in river condition is an important driver of sturgeon presence on the spawning grounds.

From continuous to occasional: Small-scale natural reproduction of Chinese sturgeon occured in the Gezhouba spawning ground, Yichang, China

PDF HTML阅读 XML下载 导出引用 引用提醒 从连续到偶发：中华鲟在葛洲坝下发生小规模自然繁殖 DOI: 作者: 作者单位: 中国水产科学研究院 长江水产研究所, 农业部淡水生物多样性保护重点实验室, 湖北 武汉 430223 作者简介: 吴金明(1984-),男,博士,研究方向为濒危鱼类保护.E-mail:jinming@yfi.ac.cn;王成友(1984-),共同第一作者,男,博士,研究方向为濒危鱼类保护.E-mail:wangcy@yfi.ac.cn 通讯作者: 中图分类号: S932 基金项目: 国家自然科学基金项目（31602160）；公益性行业（农业）科研专项（201203086）；国家自然科学基金应急管理项目（51641909） From continuous to occasional: Small-scale natural reproduction of Chinese sturgeon occured in the Gezhouba spawning ground, Yichang, China Author: Affiliation: Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture; Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:中华鲟（Gray）为国家一级重点保护野生动物，典型的溯河洄游产卵鱼类。历史上，中华鲟在长江上游及金沙江下游产卵，由于葛洲坝修建阻隔了其洄游通道，1981年以后在葛洲坝下形成了比较稳定的产卵场，1982-2013年，每年均有自然繁殖发生。由于其栖息生境退化，每年洄游进入长江的中华鲟繁殖亲本逐年减少，2013-2015年连续3年在已知葛洲坝下中华鲟产卵场未监测到中华鲟自然繁殖活动。2016年11-12月的野外监测发现，中华鲟在宜昌葛洲坝下已知产卵场发生了自然繁殖。其中底层网具采集到中华鲟鱼卵（卵膜）67粒、仔鱼22尾；解剖食卵鱼发现，10尾食卵鱼类共摄食中华鲟卵454粒；水下视频观测到5处中华鲟卵黏附底质位点。根据采集到的鱼卵发育期及采集位点推算，产卵时间为2016年11月24日凌晨，产卵场位于葛洲坝大江电厂以下约300 m的江段内，产卵日水温为19.7℃，流量为6610 m3/s，水位为39.7 m。 Abstract:The critically endangered Chinese sturgeon (Gray), a large anadromous fish, is strictly protected in Chinese waters, where it is deemed to be a national treasure. Mature individuals enter the Yangtze River estuary from July to August, before entering their spawning ground the following year from October to November. Historically, sturgeon spawned in the upper reaches of the Yangtze and lower reaches of the Jinsha Rivers, but construction of Gezhouba Dam (the first dam in the Yangtze mainstream) blocked this migratory route. A relatively stable spawning ground has since developed below this dam. From 1982, the Yangtze River Fisheries Research Institute has conducted annual monitoring of natural breeding of sturgeon within the newly formed spawning ground. Between 1982 and 2013, sturgeon spawned annually, though both fecundity and frequency of reproduction declined. Whereas the number of mature fish arriving at the spawning ground annually exceeded 2 000 individuals in the early 1980 s (near the closure of Gezhouba Dam), it also dropped to fewer than 100 individuals in recent years. Prior to impoundment of the Three Gorges Reservoir (1984-2003), sturgeon spawned on average 1.8 times per year, though this decreased to 1.1 times during impoundment (2004-2012). Although controlled propagation and augmentation of sturgeon stocks has been performed from as early as 1983, both mark-recapture and molecular genetic identification reveal more than 90% of juvenile within the Yangtze estuary originated from natural reproduction. Thus, it is critical that natural reproduction of the fish may be maintained in the only knowing spawning ground.Though there was an apparent interruption in sturgeon spawning between 2013 and 2015 at this only known spawning ground, we report a resumption of spawning in 2016, during which time 67 egg (or egg membrane) and 22 larval sturgeon were collected by bottom draft-net, and 454 eggs were found in the stomachs of 10 egg-preying fishes. Underwater camera observations also revealed five sites with fertilized sturgeon eggs adhering to the substratum. The spawning ground was 300 m downstream of the Dajiang power plant (Gezhouba Dam). Spawning likely occurred during the early morning of November 24; estimated fecundity was less than two million; water temperature at the time of spawning was 19.7℃; and the flow and water level were 6610 m3/s and 39.7 m, respectively.Recent monitoring indicates the Chinese sturgeon has changed from being a "continuous" to an "accidental" spawner, and that this is likely to continue. Increased water temperature was probably the main reason for the failed spawning between 2013 and 2015, as the Three Gorges Reservoir significantly altered water temperature within the middle reach of the Yangtze River, but other factors, such as navigation, waterway regulation, overfishing and environmental pollution, have also reduced environmental quality at the spawning ground and may have contributed to spawning failures. Without effective environmental management, the natural population of Chinese sturgeon is at high risk of extinction.In 2015 the Ministry of Agriculture issued the "Chinese Sturgeon Rescue Action Plan" to protect Chinese sturgeon, which introduced several conservation programs, such as artificial restocking, habitat management and restoration, and the prohibition of fishing. Artificial restocking of Chinese sturgeon would also be improved by increasing the number and size of released individuals, thereby increasing their survival. In the middle and lower reaches of the Yangtze River, port, waterway, shipping and other construction projects should be managed to avoid any negative impact on the habitat and migration of Chinese sturgeon. In particular, environmental protection of Hubei Yichang Chinese Sturgeon Natural Reserve needs strengthening to maintain the hydrological conditions of spawning grounds. Additionally, improvement and rebuilding of Chinese sturgeon spawning grounds would facilitate -protection of Chinese sturgeon. 参考文献 相似文献 引证文献

Dynamic seascapes predict the marine occurrence of an endangered species: Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus

Summary Categorical landscapes are powerful environmental partitions that index complex biogeochemical processes that drive terrestrial species distributions. However, translating landscapes into seascapes requires that the dynamic nature of the fluid environment be reflected in spatial and temporal boundaries such that seascapes can be used in marine species distribution models and conservation decisions. A seascape product derived from satellite ocean colour and sea surface temperature partitioned mid‐Atlantic coastal waters on scales commensurate with the Atlantic Sturgeon migration. The seascapes were then matched with acoustic telemetry records of Atlantic Sturgeon to determine seascape selectivity. To test for selectivity, we used real‐time satellite seascape maps to normalize the sampling of an autonomous underwater vehicle that resampled similar geographic regions with time varying seascape classifications. Our findings suggest that Atlantic Sturgeon prefer one seascape class over those available in the coastal ocean, indicating selection for covarying environmental properties rather than geographical location. The recent listing of Atlantic Sturgeon as Endangered throughout much of their United States range has highlighted the need for improved understanding of marine habitat requirements to reduce interactions with anthropogenic stressors. Narrow dynamic migration corridors may enable seascapes to be used as a daily decision tool by industry and managers to reduce interactions with this imperilled species during coastal migrations.

Spatial distribution and habitat choice of adult Chinese sturgeon (Acipenser sinensis Gray, 1835) downstream of Gezhouba Dam, Yangtze River, China

Summary Eight hydroacoustic surveys were conducted between 2007 and 2010 to determine the spatial distribution and habitat choice of adult Chinese sturgeon (Acipenser sinensis) within 85 km immediately downstream of Gezhouba Dam, which is the lower-most dam blocking upstream sturgeon migration in the Yangtze River. A potential 32 A. sinensis were identified; depth, velocity, etc., characteristics were determined at the sturgeon site with an Acoustic Doppler Current Profiler. Most targets (26 individuals, 81.3%) were in water >12 m deep, and most (29 individuals, 90.6%) targets were near the river bottom. All targets stayed in or were close to the river channel (distance to the thalweg about one tenth of the river width). Fish were primarily distributed among four separate and deep areas. Variations in the water level played no significant role in fish distribution. Large, deep areas attracted the most fish. A preliminary analysis of environmental factors including water depth, flow velocity, Froude number and Reynolds number indicated that the bedform morphology (deep areas) was probably the key factor determining the A. sinensis habitat preference. Future conservation of the sturgeon will be more effective when special attention is given to the four refuges.

Migration and distribution of released Acipenser sinensis in the sea based on Pop-up Archival Tag technique

Application of Pop-up Archival Tag (PAT) to research of migration and distribution of Chinese sturgeon (Acipenser sinensis) in the ocean was presented in this paper.In 2006 and 2008,14 individual fish tagged with PAT were released to Yangtze Estuary,including 6 3-year-old individuals and 8 9-year-old individuals,respectively.The data from 9 tagged fish were successfully transmitted and received by ARGOS satellite and the rate for data recovery amounted to 64%.Results revealed that Chinese sturgeon tagged with PAT would migrate to sea within one month after being released.The tagged fish can survive for more than 6 months,and they distributed in the continental shelf from western Korean coast in the north to Fujian coastal areas in the south.The migration range spanned 4°longitude and 9° latitude.The longest distance of the fish migration amounted to 697 km.The migration pattern of Chinese sturgeon was random and circuitous.The results showed that releasing of fish tagged with PAT was successful.

Effect of Release Temperature from Three Gorges Reservoir on the Procreation of Chinese Sturgeons

Chinese sturgeon is the national list endangered fish species. Since the construction of the Gezhouba dam in 1981, the migration of Chinese sturgeon for procreating to upstream of the Yangtze River has been blocked which cause the only spawning ground was left locating in a narrow zone downstream close to the dam site. The procreation of Chinese sturgeons need suitable ecological factors, including temperature, hydrology, sediment and so on, but after impoundment of Three Gorges Reservoir (TGR), the environment have changed a lot that brings a great threaten to the Chinese sturgeons. In this paper, based on previous hydrodynamics and thermal coupled model of TGR, three different scenarios including dry, normal and wet year is simulated to access the influences of release temperature from TGR on procreation of Chinese sturgeons. The result indicates that due to the weak stratification of the TGR, the release temperature changes compared to natural river water temperature, as a result, the time of the procreation is slightly delayed in different scenarios because the release temperature is higher than the upper bound temperature for spawning, of which the days been delayed is about 14 in dry years, 13 in normal years and 5 in wet years, respectively, so temperature becomes a limiting factor to the procreation of Chinese sturgeons.

Review of the current status of the Atlantic sturgeon Acipenser oxyrinchus oxyrinchus Mitchill 1815, in Poland: principles, previous experience, and results

Summary The article presents the principles of the program to restore the Atlantic sturgeon Acipenser oxyrinchus in Poland and the results obtained to date. Since 2004, various life cycle stages (fertilized eggs, hatchlings, fingerlings) obtained through the controlled reproduction of wild spawners caught in the St John River in Canada have been imported. Broodstocks are held in three facilities, two of which were built specifically for the Atlantic sturgeon restoration programme. From each group of the initial imports from Canada, 50–100 individuals are being held for further rearing. Additionally about fifty individuals from the 1997 and 2001 year classes were transferred from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (Berlin, Germany). These are also the offspring of earlier imports from Canada. Juvenile sturgeons are used for experimental stocking and studies aimed at increasing rearing effectiveness. Rearing early life cycle stages of Atlantic sturgeon was a difficult task, the final results of which remained unpredictable in early trials. The highest losses of larvae are incurred when the fish begin exogenous feeding. Feeding studies focus on the selection of appropriate diets and feeding strategies. The latest results indicate that during the initial feeding period, the fish can be fed once daily. Studies on sturgeon migration were conducted in the Drweca River, and the results indicated that migration rates vary significantly among juvenile sturgeon, with the mean migration rate in spring being lower than in autumn. Currently, the Polish efforts to restore the Atlantic sturgeon focusses on (i) building broodstocks at specialized facilities, (ii) improving hatching and early rearing techniques, (iii) performing experimental stocking with hatchery-reared juveniles, and (iv) acquiring knowledge on the basic elements of the Atlantic sturgeon life history under local conditions. Fertilized eggs of A. o. oxyrinchus will still have to be imported from Canada for several years before self-sufficient production from raised ex-situ brood stocks will become available. The formation of a Polish ex-situ founder population is imbedded in an overall restoration approach in close cooperation with the neighbouring country having shared sturgeon waters and this is in line with the respective international recommendations for sturgeon species conservations.

Diel activity of Gulf of Mexico sturgeon in a northwest Florida bay

In this paper, we assess patterns in activity of Gulf of Mexico sturgeon Acipenser oxyrinchus desotoi over a 24-h period in the Pensacola bay system, Florida. Although seasonal migration of sturgeon is well documented, little information is available pertaining to daily variation in activity. We surgically implanted 58 Gulf sturgeon with acoustic transmitters in the Escambia (n = 26), Yellow (n = 8), Blackwater (n = 12) and Choctawhatchee rivers (n = 12) in June, July, September and October 2005. Gulf sturgeon location was monitored using an array of 56 fixed-station acoustic receivers. The relationship between frequency of Gulf sturgeon observations recorded on all acoustic receivers and time of day for all seasons combined indicated a strong diel activity pattern. Gulf sturgeon were frequently detected at night in all seasons with the exception of summer. Consecutive hourly observations indicated lateral movement of Gulf sturgeon between independent acoustic receivers on 15% of all observations of individuals. The use of an acoustic receiver array not only provides continuous data within a defined area, but also provides insight into nocturnal behavior of Gulf sturgeon not previously identified.

Seasonal distribution of Gulf of Mexico sturgeon in the pensacola bay system, Florida

Summary Temporal and spatial distributions of Gulf of Mexico (Gulf) sturgeon Acipenser oxyrinchus desotoi were assessed in the Pensacola bay system, Florida, using stationary ultrasonic telemetry. Fifty-eight Gulf sturgeon were tagged within the Escambia (n = 26), Yellow (n = 8), Blackwater (n = 12) and Choctawhatchee Rivers (n = 12) in June, July, September and October, 2005. Fifty-four Gulf sturgeon were detected at least once during the study. Migration of sturgeon occurred throughout the bay system in fall, to various winter habitats in the Gulf of Mexico and Santa Rosa Sound. In spring, tagged sturgeon migrated back through the bay system to summer habitats in rivers. Based on the duration and number of detections, Gulf sturgeon primarily used the upper portions of East and Escambia Bays as migration routes in and out of all rivers during spring and summer and inhabited the lower portion of Pensacola Bay for longer durations in fall and winter. Specific areas within the Pensacola bay system were used in summer and winter that were not previously documented as essential sturgeon habitat. Areas in southeastern Pensacola Bay were heavily used during winter by a large portion of the population. Gulf sturgeon also exhibited long-term winter residency in Santa Rosa Sound for two consecutive years. An area in northeastern Escambia Bay supported Gulf sturgeon during the summer, which was unexpected and can not be explained by the data from this study. However, the discovery that Gulf sturgeon remain in the bay during the summer has important ecological and management implications that need further investigation.