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This paper evaluates the outcome of the first release programme for Acipenser dabryanus rehabilitation in its natural habitat and focuses specifically on the growth rate of released juveniles, and on the dispersal of the fish after release. To conserve and restore natural recruitment, the conservation propagation programme has released hatchery-reared juveniles annually in the upper Yangtze River. This paper summarized the release activities and analysed post-release monitoring data. From 2010 to 2012, 7030 juveniles aged 1-3 years were released in the Shuifu and Yibin reaches of the upper Yangtze River. Incidental catches of 112 samples were recorded during the three-year observation period. Recapture sites were located between Yibin and Chongqing reaches (approximate range of 385 km), with 72.3% of the individuals recaptured within 20 km from the release site. Incidental catches were mainly in shallow water within 20 m of the riverbank. Body weight of the released sturgeon initially declined but this lost weight was soon regained. The low recaptured rate indicates that only a few of the released juveniles were able to survive and settle in the upper Yangtze River. The observed movement patterns suggest a potential additional downstream release site for future consideration to improve the performance of the released fish. [ABSTRACT FROM AUTHOR]

A better understanding of the runoff variations contributes to a better utilization of water resources and water conservancy planning. In this paper, we analyzed the runoff changes in the Yangtze River Basin (YRB) including the spatiotemporal characteristics of intra-annual variation, the trend, the mutation point, and the period of annual runoff using various statistical methods. We also investigated how changes in the precipitation and temperature could impact on runoff. We found that the intra-annual runoff shows a decreasing trend from 1954 to 2008 and from upper stream to lower stream. On the annual runoff sequence, the upstream runoff has a high consistency and shows an increasing diversity from upper stream to lower stream. The mutation points of the annual runoff in the YRB are years 1961 and 2004. Annual runoff presents multitime scales for dry and abundance changes. Hurst values show that the runoffs at the main control stations all have Hurst phenomenon (the persistence of annual runoff). The sensitivity analyses of runoff variation to precipitation and temperature were also conducted. Our results show that the response of runoff to precipitation is more sensitive than that to temperature. The response of runoff to temperature is only one-third of the response to precipitation. A decrease in temperature may offset the impact of decreasing rainfall on runoff, while an increase in both rainfall and temperature leads to strongest runoff variations in the YRB. [ABSTRACT FROM AUTHOR]

Summary: This paper provides the length‐weight and length–length relationships for five fish species in the Zigui section of the lower Three Gorges Reservoir of the Yangtze River. Specimens were collected from December 2014 to January 2017, using various types of fishing gear and electroshock fishing techniques. Length‐weight relationships (LWRs) for one fish species and Length–length relationships (LLRs) for five fish species are unknown to FishBase. New maximum total lengths for four species were also recorded for FishBase. Moreover, standard‐length to total‐length equations for converting size measurements for these five species are presented. [ABSTRACT FROM AUTHOR]

The structure and temporal variations of the fish community in the intertidal estuarine zone of shallow mud areas have been poorly studied in China. This paper analyses the diel, semi-lunar and seasonal patterns of fish assemblages in the Yangtze estuary in 2006. Fish were collected by consecutive day and night samplings using tide-stow-nets deployed parallel to each other in three stations. A total of 56 fish species belonging to 21 families was caught during the study period. The family Cyprinidae dominated with 25 species. Freshwater fish species were the important dominant commercial fishery species and well represented with five species (sharpbelly Hemiculter bleekeri, goldfish Carassius auratus, bream Parabramis pekinensis, likely-bream Pseudobrama simony, and glossy yellow catfish Pelteobagrus nitidus) in the three stations. Juvenile fishes dominated the fish community, comprising 93.9% in station 1 and 96.6% in station 2 of the total abundance. The number of fish species in day tides was slightly lower than those in night tides in spring and summer, but the opposite in other seasons. In neap tides, the numbers and abundance of fish species were both lower than those in the spring tides. Fish abundance was lowest in winter, increasing during spring and summer (March-September) in both stations 1 and 2, with obviously large fluctuations in each season. The pattern of habitat selection of fishes could effectively decrease the food competition of intraspecies or interspecies and favour the growth and nursing of young fishes. These findings indicate that the intertidal zones in the estuary may serve as important nursery areas for fish communities. [ABSTRACT FROM AUTHOR]

This paper provides length-weight relationships for nine fish species from the Laohegou River, a tributary of the upper Yangtze River. Length-weight relationships for six of these species are recorded for the first time. New maximum lengths for two species are also reported. [ABSTRACT FROM AUTHOR]

Satellite-based precipitation products are expected to offer an alternative to ground-based rainfall estimates in the present and the foreseeable future. In this paper, we evaluate the performance of TRMM 3B42 precipitation products in the Yangtze River basin for the period of 2003~2010. The results are as follows: (1) the performance of RTV7 (V7) products is generally better than that of RTV6 (V6) in the Yangtze River basin, and the percentage of best performance (bias ranging within −10%~10%) for the annual mean precipitation increases from 21.72% (54.79%) to 36.70% (59.85%) as the RTV6 (V6) improved to the RTV7 (V7); (2) the TMPA products have better performance in the wet period than that in the dry period in the Yangtze River basin; (3) the performance of TMPA precipitation has been affected by the elevation and a downward trend can be found with the increasing elevation in the Yangtze River basin. The average CC between the V7 and observed precipitation in July decreases from 0.71 to 0.40 with the elevation of gauge stations increasing from 500 m below to 4000 m above in the Yangtze River basin. More attention should be paid to the influence of complex climate and topography. [ABSTRACT FROM AUTHOR]

This paper examined the sediment gain and loss in the river mouth reach of the Yangtze River by considering sediment load from the local tributaries, erosion/accretion of the river course, impacts of sand mining, and water extraction. A quantitative estimation of the contribution of the river mouth reach to the sediment load of the Yangtze River was conducted before and after impoundment of the Three Gorges Dam (TGD) in 2003. The results showed that a net sediment load loss of 1.78 million ton/yr (Mt/yr) occurred from 1965 to 2002 in the study area. The contribution of this reach to the sediment discharge into the sea is not as high as what was expected before the TGD. With impoundment of the TGD, channel deposition (29.90 Mt/yr) and a net sediment loss of 30.89 Mt/yr occurred in the river mouth reach from 2003 to 2012. The river mouth reach has acted as a sink but not a source of sediment since impoundment of the TGD, which has exacerbated the decrease in sediment load. Technologies should be advanced to measure changes in river channel morphology, as well as in water and sediment discharges at the river mouth reach. [ABSTRACT FROM AUTHOR]

Structural health monitoring can provide a practical platform for detecting the evolution of structural damage or performance deterioration of engineering structures. he final objective is to provide reasonable suggestions for structural maintenance and management and therefore ensure the structural safety according to the real-time recorded data. In this paper, the establishment of the wind and structural health monitoring system(WSHMS) implemented on the Runyang Yangtze River Bridge (RYRB) in China is introduced. The composition and functions of the WSHMS are presented. hereinto, the sensory subsystem utilized to measure the input actions and structural output responses is introduced. And the core functions of the data management and analysis subsystem (DMAS) including model updating, structural condition identification, and structural condition assessment are illustrated in detail. A three-stage strategy is applied into the FE model updating of RYRB, and a two-phase strategy is proposed to adapt to structural health diagnosis and damage identification. Considering the structural integral security and the fatigue characteristic of steel material, the condition assessment of RYRB is divided into structural reliability assessment and structural fatigue assessment, which are equipped with specific and elaborate module for effective operation. This research can provide references for the establishment of the similar structural health monitoring systems on other cable-supported bridges. [ABSTRACT FROM AUTHOR]

The Fuzishan Cu-Mo deposit is located in the Edong district of the Middle-Lower Yangtze River Metallogenic Belt, China. The orebodies mainly occurred as lenticular and bedded shapes in the skarn zone between the Lower Permian Qixia Formation carbonate rocks and the quartz diorite. Four paragenetic stages have been recognized based on petrographic observations: (1) prograde skarn stage, (2) retrograde skarn stage, (3) quartz-sulfide stage, and (4) carbonate stage. Six fluid inclusion types were recognized: S1 (vapor + liquid + halite ± other daughter minerals), S2 (vapor + liquid + daughter minerals except halite), LV (rich liquid + vapor), VL (rich vapor + liquid), V (vapor), and L (liquid) types. Fluid inclusion studies show distinct variations in composition, final homogenization temperature, and salinity in four stages. Daughter minerals of the primary fluid inclusions include chalcopyrite, molybdenite, hematite, anhydrite, calcite, and halite in the prograde skarn stage and hematite, calcite, and sulfide (?) in the retrograde skarn stage. No daughter minerals occurred in the quartz-sulfide and carbonate stages. Final homogenization temperatures recorded in these stages are from 405 to >550°C, from 212 to 498°C, from 150 to 485°C, and from 89 to 223°C, respectively, while salinities are from 3.7 to 42.5, from 2.6 to 18.5, from 2.2 to 17.9, and from 0.2 to 11.5 wt.% NaCl equivalent, respectively. The coexisting VL and S1 type fluid inclusions show similar homogenization temperature of 550 to about 650°C in the prograde skarn stage, indicating that immiscibility occurred at lithostatic pressure of 700 bars to perhaps 1000 bars, corresponding to a depth of 2.6 km to about 3.7 km. The coeval VL and LV types fluid inclusions with homogenization temperature of 350 to 400°C in the late retrograde skarn and quartz-sulfide stages suggest that boiling occurred under hydrostatic pressure of 150 to 280 bars, equivalent to a depth of 1.5 to 2.8 km. Mo mineralization in the retrograde stage predated Cu mineralization which mainly occurred in the quartz-sulfide stage. Fluid compositions indicate that ore-forming fluid has high fO2 and rich Cu and Mo concentration in the early stage, while relatively lower fO2 and poor Cu and Mo concentration in the middle to late stages. Microthermometric data show a decreasing trend in temperature and salinity in the fluid evolution process. Decreasing temperature and boiling event may be the main factors that control the ore precipitation. [ABSTRACT FROM AUTHOR]

Operational Doppler radar observations have potential advantages over other above-surface observations when it comes to assimilation for mesoscale model simulations with high spatial and temporal resolution. To improve the forecast of a heavy frontal rainfall event that occurred in the Yangtze-Huaihe River Basin from 4 July to 5 July 2014 in China, operational radar observations are assimilated by the Local Analysis and Prediction System (LAPS). Radar reflectivity data are used primarily in the LAPS cloud analysis procedure, which retrieves the number of hydrometeors and adjusts the moisture and cloud fields. Radial velocity data are analyzed through the LAPS wind analysis-based successive correction method. A new correction method is developed to correct three-dimensional radar reflectivity data based on hourly surface rain gauge observations. The performance of the correction method is demonstrated by assimilating radar reflectivity observations into LAPS. Experiments with different radar data assimilation are examined. Results show that the assimilation of radar data can effectively correct the background errors and improve the heavy rainfall forecast. The simulated intensity, pattern, and temporal evolution of the heavy rainfall event are better improved with radar reflectivity assimilation, especially when the correction method is implemented to correct radar observations. [ABSTRACT FROM AUTHOR]

Summary: The feeding habits of the Chinese minnow, Rhynchocypris oxycephalus (Sauvage & Dabry de Thiersant, 1874), were investigated in the Laohegou River, a tributary of the upper Yangtze River, China. A total of 412 specimens were collected by electrofishing in four seasons of 2012, 7 days per season. Diet composition was analyzed according to season, size classes and sex. The Chinese minnow is a generalist omnivorous species, whose diet consists of aquatic insects and plants. Besides algae, Hemiptera, Ephemerida, Trichoptera, Odonata, Diptera were the most dominat food items. The Shannon‐Wiener index on diet items showed no significant differences between major food items (p > .05) or between seasons, size classes and sexes. In contrast, fullness index and dietary breadth analysis both indicated significant diet changes between seasons. Consequently, this study provides information on feeding habits of R. oxycephalus, which may be useful in cultivation trials. [ABSTRACT FROM AUTHOR]

State-space (SS) model is proposed to identify the time lag between the asynchronous accelerations at different locations of the Jiangyin Bridge measured during a ship-bridge collision. One of the accelerations is chosen as the reference signal, and the time axis of the rest of them are shifted relative to that of the reference signal with a series of shifting times. For each pair of reference and time shifted signals, SS models in correspondence to the shifting time series are formulated. Their system matrices are identified with data-driven stochastic subspace identification algorithm, and their model order is determined by Akaike's information theoretic criterion and final prediction error. If the 2 accelerations for model fitting are asynchronous, errors may be introduced into the SS model and its prediction error is expected to be greater than the counterpart obtained with synchronous accelerations. Therefore, the actual time lag between them is identified from the shifting time that corresponds to the minimum of loss function, which is used to map the prediction error vector sequence to a real number. In addition, asynchronous acceleration data measured 2 hr ahead of the ship-bridge collision and synchronous acceleration data measured long after the ship-bridge collision are also analyzed. The former dataset is exploited to evaluate the reproducibility of the SS model for time synchronization, and the latter dataset is utilized to examine its anti-false-identification capability. The results show that the SS model achieves a satisfactory performance in the identification of time lag for both asynchronous and synchronous measurement data. [ABSTRACT FROM AUTHOR]

Swimming performance is one of the most important capacities for fish to cope with the harsh conditions in natural ecosystems and thus determines fitness of hatchery-reared fishes for stocking in the wild. Poor swimming capabilities of hatchery-reared fishes, including sturgeons, may be linked to the fact that the flow regimes in conventional culturing tanks are very often static and with very low currents, obviously differing from the natural environment. The objectives of the present studies were to: (i) learn about the swimming performance of the Dabry's sturgeon Acipenser dabryanus, one of the critically endangered species restricted to the Yangtze River, China; (ii) ascertain if it is possible to improve the swimming capacity of Dabry's sturgeon ( DS) by changing the current flow regime in conventional culturing tanks; (iii) determine the potential effects of such an environmental enrichment practice on the growth and survival of DS. Long-term culturing protocols with two culturing stages were conducted in a conventional tank with static water (Control, CT) as well as in a current-enriched tank with a step-controlled water velocity ( CET). Results showed after the first culturing stage, which began with 500 15-day-old post-hatch (dph) DS and ended with 40 dph DS, that the survival rates in CT (91.6%) were higher than that in the CET (84.4%). Total length, fork length and weight of DS in CET (n = 30) were higher than in CT (n = 30), but with no significant differences (P > 0.05). The Ucrit (13.2 ± 2.9 cm s−1, or 2.19 ± 0.48 FL s−1, n = 30) of the 40 dph DS in CET were significantly higher (10.2 ± 3.5 cm s−1, or 1.70 ± 0.59 FL s−1, n = 30) than in CT (P < 0.05) and the swimming endurance (101.6 ± 38.2 min, n = 15) of the 40 dph DS in CET at a velocity of 20 cm s−1 (representing 1.5-2.0 times Ucrit of 40 dph DS) is obviously longer (72.4 ± 38.2 min, n = 15) than in CT. The second culturing stage followed with 200 individuals of 40 dph DS coming from the first stage and ended with 80 dph DS. The survival rates during the second stage and the final growth parameters of 80 dph DS in CT and CET were not obviously different from each other (P > 0.05), whereas the Ucrit (48.5 ± 6.9 cm s−1, or 3.25 ± 0.46 FL s−1, n = 20) of the 80 dph DS in CET were also obviously higher (35.9 ± 8.5 cm s−1, or 2.41 ± 0.58 FL s−1, n = 20) in CT (P < 0.05). The results suggest a possible conservation culturing practice to improve the swimming capabilities of DS and will be foreseeably beneficial for hatchery-reared DS fitness when stocked in the wild, and will contribute to the effectiveness of future DS rehabilitation programmes. [ABSTRACT FROM AUTHOR]

This study examined the growth and mortality of two widespread small fish species, Toxabramis swinhonis (Cyprinidae) and Hyporhamphus intermedius (Hemiramphidae), from a shallow lake (Niushan Lake, China) along the Yangtze River, by analyzing monthly length frequency data (July 2005 to June 2006) with the FAO- ICLARM stock assessment tool (Fi SAT). Estimated von Bertalanffy growth equation parameters were: L∞ (asymptotic length) = 145 mm TL, and K (growth coefficient) = 0.66 year−1 for T. swinhonis; L∞ = 189 mm TL, and K = 0.68 year−1 for H. intermedius. The instantaneous rates of natural mortality ( M) calculated for T. swinhonis and H. intermedius were 1.35 and 1.28 year−1, respectively. The length-converted catch curve method gave the total annual instantaneous mortality rate ( Z) of 2.92 year−1 for T. swinhonis and 1.53 year−1 for H. intermedius. Recruitment patterns of both species were continuous, displaying a single major peak event per year. Despite not being of direct fishing interest, T. swinhonis, with high abundance and productivity as indicated by a high Z-value, can be an important species in fisheries management as an excellent food source for aquatic organisms, especially for larger fishes of economic value. These results represent the first information on population characteristics of T. swinhonis and H. intermedius, and constitute a comparison base for future growth studies in other lake environments. [ABSTRACT FROM AUTHOR]

The aim of this 2008-2012 study was to prove the hypothesis that the Three Gorges Reservoir ( TGR) and the upper free-flowing section can offer a habitat for restocking the Chinese sturgeon, Acipenser sinensis. Thus, 498 cultured A. sinensis (including 28 sub-adults tagged with ultrasonic transmitters) were released into the TGR and the adjacent free-flowing section of the Yangtze River. The distribution, movement and growth of the released fish were collected by acoustic telemetry and bycatch information. Results indicated that only three sub-adults migrated upstream to the free-flowing section where they remained for the three-year observation (limited by the longevity of the transmitter battery). However, most sub-adults migrated downstream after release, with a migration distance of 15-877 km as well as a tracking duration from 19 to 6063 h. The downstream traveling speed in the free-flowing section (mean = 3.70 km h−1, range = 1.51 -8.25 km h−1) was significantly faster than that in the reservoir section (mean = 1.05 km h−1, range = 0.12 -1.82 km h−1; p < 0.05). Only three sub-adults migrated to within 3 km of Three Gorges Dam ( TGD) and stayed in the reservoir. Sub-adults stayed obviously deeper within the reservoir (mean = 11.47 m) than in the free-flowing section (mean = 3.63 m; p < 0.05). Juveniles were recaptured from 45 -810 km downstream their release sites with a mean traveling speed of 1.05 km h−1 (range = 0.13 -1.82 km h−1), lower than that of the sub-adults released in the free-flowing section. Twelve percent of juveniles released in one of the tributaries of the Yangtze River found the entrance and migrated downstream to the reservoir within the first 30 days. Average body weight of the recaptured juveniles increased by 10.3% (range = 2.3% -15.3%) and some crustaceans (e.g. river shrimp) were found in the stomach and gut of two juveniles. The results demonstrate that the TGR and its adjacent upstream free-flowing Yangtze River section can serve as reintroduction sites to support a certain quantity of Chinese sturgeon to remain and mature there. [ABSTRACT FROM AUTHOR]

The article presents a study on various cross-section vorticity on the spawning grounds of the four major Chinese carps in the middle reach of the Yangtze River in China. It identifies several characteristics of spawning grounds through hydroacoustics. The study offers a theoretical basis for ecological regulation and spawning grounds restoration.

The article presents a study which aims to reveal the impacts of the Three Gorges Project (TGP) operation on the adult population of the sturgeon downstream of the dam in the Yangtze River, China. It cites another study showing that the springtime high water level could prolong the juvenile residence period in the middle and lower Yangtze River reaches. It reveals that fishery acoustics have been used in studies of the spawning stock as of 1998.

The article presents a study on temporal and spatial distribution of fishes in the middle reaches from Chenglingji to Yichang of the Yangtze River in China. The study aims to analyse the fish distribution on a spatial and temporal scale. It also discusses possible factors that might cause or could explain the regional distribution patterns, in an attempt to provide some reference data for further use in assessment research.

Hydroacoustic surveys were performed in an oxbow lake (Lake Laojianghe, China) along the Yangtze River. The study took place during the day and night in October 2012 using the Simrad EY60 split beam echo sounder. A clear day-night difference in fish densities was observed in selected transect areas. The mean density estimate at night was three times higher than during the day, while at night densities were similar in the two adjacent areas. Significantly positive relationships were found between fish density and average depth for the night and daytime transects, however, the regression slope for the daytime density estimates was much smaller than for the surveys at night. Small fish dominated the acoustic size structure during both day and night, but were more accessible at night. The average biomass estimate from the daytime transects was nearly 60% lower than those from the corresponding night transects. These results indicate that an entire lake estimate of a fish population may be severely biased if fish tend to aggregate temporarily in the bottom or littoral zone or display diurnal behaviour. The conclusion is that acoustic sampling in Lake Laojianghe is best done at night. Diel differences in the lake should be further investigated by carrying out additional day-night comparison experiments and also by using control catches. [ABSTRACT FROM AUTHOR]

The article presents a study which aims to examine the role of ship locks in fish transfer through Three Gorges Dam (TGD) and Genchouba Dam (GD) in China. The study shows that some of the fish have the capacity of entering the locks and might even migrate by the ship locks to Yangtze River upstream part. It reveals that 40 fishes transited the gates of the locks from 04.35 to 22.47, indicating that the peak of fish migration happened during the night in the Yangtze River.

This study presents a method of combining hydroacoustics and hydraulic data to estimate fish preference in a large and rapidly flowing river system. A typical middle reach of the Yangtze River with three islands and two wandering sections was taken as the research object to interpret schools of fish with different sizes and densities for their preference of physical habitat features such as water depth and velocity by using Geographic Information Systems ( GIS). Fish density and size were determined based on the hydroacoustic data, and hydraulic variables were simultaneously collected using an Acoustic Doppler Current Profiler ( ADCP) system. Results show that fish sizes are correlated with water depth and velocity and that fish density correlated only with water depth. Small fish prefer high water depth average velocity ( WDAV), lower vertical average velocity ( VAV), deep water, as well as a wide depth and velocity range; large fish prefer low WDAV, high VAV, deep water, and a narrow depth and velocity range. High fish densities appear around islands and areas with deep water. The results show that large fish may be sufficiently strong enough to select their preference for water depth and velocity. Areas of deep water can provide broad velocity diversity and more space to accommodate fish. The island littoral zone could provide a variety of habitats with a diverse pattern of depth and velocity for fish. This study provides a contributive method for the field habitat suitability assessment for fish. [ABSTRACT FROM AUTHOR]

Over the past few decades, fish resources have declined severely owing to the river-lake disconnection within the Yangtze River floodplain. Studies on fish migrations between rivers and floodplain waters are imperative for fish resources restoration and lake management. However, few studies have as yet documented the migration rhythms of river-lake migratory fishes. Monthly investigations of the fish assemblage structure were conducted in three regions of the Dongting Lake, which is connected to the Yangtze River. Main results were: (i) Fish catches varied greatly, depending on the water level and area of the lake; (ii) Ten river-lake migratoty species were caught during the study, 80% of these during July-October when the water level was high. Species richness and relative abundance both decreased with increasing distance from the river, and the timing of peak abundance occurred later in the year; (iii) Abundance of grass carp ( Ctenopharyngodon idella) and silver carp ( Hypophthalmichthys molitrix) peaked in July and August and were mainly composed of 0 + fishes. The results revealed that the key time for migration into the lake is July-August. Combining the results from previous studies, a comprehensive view is given of migration patterns of four domestic Chinese carps; (iv) Brass gudgeon ( Coreius heterodon), appeared to migrate into the Dongting Lake as two separate shoals, differentiated by body size. They also appeared to remain close to the lake mouth area. Based on the above results, two recommendations can be made for river-lake migratory fish conservation in the Yangtze floodplain: prolonging the current fishing ban period of April-June to April-September; and opening sluice gates for as long as possible during April-September in order to maximize the opportunities for fish migration. [ABSTRACT FROM AUTHOR]

This study was performed to determine the spatial structure and bottom characteristics of the only remaining spawning area of Chinese sturgeon ( Acipenser sinensis) located just downstream of the Gezhouba Dam. During the period 1996-2003, three methods were employed, including (i) the examination of the stomachs of opportunistic predatory fishes that feed on sturgeon eggs, (ii) tracking the mature sturgeons by ultrasonic tags and (iii) capturing eggs and yolk-sac larvae (ELS) at and near the river bottom by D-shaped bottom drift nets to monitor the spawning activities of A. sinensis. It was found that A. sinensis selected permanent locations to mate. There were two mating locations: an upstream mating area (UMA), in the tailrace of the Dajiang Hydroelectric Station and about 870 m far from the Gezhouba Dam (area, 0.1 km), and a downstream mating area (DMA), about 2500 m from Gezhouba Dam (area, 0.3 km). The DMA was the chief mating area and was used every year. The incubation area (for dispersal of fertilized eggs to incubate) was range from 870 m to 7 km from the dam. Generally, the total length of the spawning area was 5-7 km length (area 2.0-2.7 km) with the range slightly varied in different spawning activities. A relief map of the riverbed and a bottom hydroacoustic survey of the DMA found a deep depression and rocky substrate. These may be important characteristics of geomorphology for the spawning area of A. sinensis. [ABSTRACT FROM AUTHOR]

Chinese Sturgeon Natural Reserve (CSNR) is a typical river ecosystem in the middle of the Yangtze River. An evaluation system of the river ecosystem services of CSNR was established using the so-called 'Market Price Approach', 'Expense Payment Method', 'Contingent Valuation Method', 'Substituted Value Method', 'Cost Analysis Method' and 'Opportunity Cost Method'. The results showed that the total values of the ecosystem goods and services of the natural reserve amount to an estimated 73.57 million USD. The use-values and non use-values were 72.5 and 27.5%, respectively. The direct use values, including fisheries, water supplies and others, reach a total of about 24.23 million USD; On the other hand, the indirect use values, which include endangered species, purification costs and degradation losses, have been estimated at cost levels of approximately 29.12 million USD, indicating with 39.6% its important role of the total value. Meanwhile the non-use values of CSNR in the Yichang Reaches of the Yangtze River were assessed by a contingent valuation method (CVM) and the willingness to pay (WTP), The study shows that the annual non-use values of CSNR is up to 20.22 million USD, of which its existence values is in the range of 8.59 million USD, its bequest values 8.03 million USD, and the option values around 3.6 million USD. This preliminary analysis indicates that this natural reserve represents a special hydro-ecosystem in China with the sturgeon as target species, which is highly valued. The value of endangered aquatic species is up to 25.2% of the total, which places much emphasis on aquatic species. Investment in scientific research and management is presently quite low, amounting to only 0.7% of the total; this fact incidates that research work should be given more concern and support. Limited by the data availability, data processing capacity and time given, result of this initial investigation only represents part of CSNR's assessable value, however, considering the reality that lots of water resource and hydropower projects are now on the way, this valuation will still be helpful to inform the public with the importance of protecting endangered aquatic wildlife and such special hydro-ecosystem. [ABSTRACT FROM AUTHOR]

Herein, we describe the embryonic and larval development stages of Coilia nasus, an anadromous fish that is indigenous to the Yangtze River and the northwest region of the Pacific Ocean. The success of artificial breeding programmes and modern methods of reproduction allowed us to accurately describe the development stages of C. nasus. These stages were recorded using a binocular microscope and a digital camera-equipped microscope, and histological and scanning electron microscopy observations were also conducted. Development can be divided into four periods: embryonic, prelarval, larval and juvenile. The fertilized eggs were spherical, transparent, non-adhesives and buoyant, with an average diameter of 0.80±0.10 mm. Complete early embryonic development took place within 40-43 h post hatching, and the new hatchlings were 2.85±0.20 mm long. The mouth openings (0.25-0.35 mm) appeared at day 6 post hatching. Complete metamorphosis took place by day 60, at which time the larvae transformed into juveniles (65±5.8 mm) and attained skin coloration. [ABSTRACT FROM AUTHOR]

A sampling system for capturing sturgeon eggs using a D-shaped bottom anchored drift net was used to capture early life stages (ELS) of Chinese sturgeon, Acipenser sinensis, and monitor annual spawning success at Yichang on the Yangtze River, 1996–2004, before and just after the Three Gorges Dam began operation. Captured were 96 875 ELS (early life stages: eggs, yolk-sac larvae = eleuthero embryos, and larvae); most were eggs and only 2477 were yolk-sac larvae. Most ELS were captured in the main river channel and inside the bend at the Yichang spawning reach. Yolk-sac larvae were captured for a maximum of 3 days after hatching began, indicating quick dispersal downstream. The back-calculated day of egg fertilization over the eight years indicated a maximum spawning window of 23 days (20 October–10 November). Spawning in all years was restricted temporally, occurred mostly at night and during one or two spawning periods, each lasting several days. The brief temporal spawning window may reduce egg predation by opportunistic predators by flooding the river bottom with millions of eggs. During 1996–2002, the percentage of fertilized eggs in an annual 20-egg sample was between 63.5 to 94.1%; however, in 2003 the percentage fertilized was only 23.8%. This sudden decline may be related to the altered environmental conditions at Yichang caused by operation of the Three Gorges Dam. Further studies are needed to monitor spawning and changes in egg fertilization in this threatened population. [ABSTRACT FROM AUTHOR]

Reproductive strategies were compared between obscure puffer Takifugu obscurus and ocellated puffer Takifugu ocellatus captured in waters near Yangzhong Island in the lower reaches of the Yangtze River during the spawning migration season from February to June in two consecutive years (1995 and 1996). Results showed that obscure puffer and ocellated puffer have adopted different reproductive strategies, including different spawning times, different size at maturity, and different number and size of oocytes, resulting in two different larval sizes. In detail, the timing of the spawning migration and status of gonad development of obscure puffer was about 1 month earlier than that of ocellated puffer; the obscure puffer was obviously longer and heavier than ocellated puffer in both mature male and female fish; mean GSI of obscure puffer females (15.8%) was significantly higher than that of ocellated puffer females (14.6%); the average diameter of ocellated puffer eggs (1.49 ± 0.12 mm) was significantly larger than that of the obscure puffer (1.22 ± 0.08 mm); and obscure puffer females (320.8 oocytes mg−1 somatic wet weight) had significantly higher relative fecundity than ocellated puffer females (125.2 oocytes mg−1 somatic wet weight). These differences in reproductive strategies between two closely related species of the Takifugu genus indicate that both obscure puffer and ocellated puffer fit the r/K dichotomy. Obscure puffer shows K-selected characters with maturity at relatively large size and r-selected characters with relatively many and small offspring, whereas ocellated puffer shows r-selected characters with maturity at a relatively small size and K-selected characters with relatively few and large offspring. [ABSTRACT FROM AUTHOR]

An extensive risk analysis should always precede a stocking program. In order to determine the genetic effects of the program, information on genetic composition of the population both prior and after the stocking program is required. Genetic variations within and among three annual spawning runs of Chinese sturgeon were measured by six microsatellites. We found substantial genetic variation remaining within all spawning runs, probably related to the recent nature of the population impact, the longevity of the species, and their apparent self-incompatibility. A subtle genetic structure was detected in the annual spawning runs by an unsupervised self-organizing model. Meanwhile these genetically differentiated spawning stocks may occur sympatrically on a small geographic scale. These results further suggest that the current supportive breeding of A. sinensis may require a careful identification of broodstocks in artificial propagation in order to avoid admixture and hybridization among these genetically different spawning stocks. [ABSTRACT FROM AUTHOR]

In this study, the facilities and techniques of fingerling production for the Chinese Sturgeon (Acipencer sinesis) cultivation as practiced in the hatchery of the Yangtze River Fisheries Research Institute are described. Initiation of feeding in larvae, adaptation of young fish to formulated feeds, water temperature control, and maintaining other water quality parameters within limits as well as disease control techniques were the key factors affecting the survival rate and growth performance of young Chinese Sturgeons. The suitable range of water temperatures for fingerling rearing is considered to be between 18 and 22. The feed conversion rate when using formulated turtle-feed at 70 days post-hatch was 0.45 while that of specific sturgeon-feed was 0.67. Under our experimental conditions, SGR (Specific Growth Rate) of the young Chinese sturgeon was 8.15% day-1, 7.71% day-1 and 6.96% day-1 in the years 2000, 2001 and 2003, respectively. Fingerlings of 10-15 cm total length were produced in our facilities and were at that time ready for release into the natural Chinese Sturgeon habitats. Disease control still is a major problem requiring more intensive research. [ABSTRACT FROM AUTHOR]

Length-weight relationships were estimated for the first time for five loaches of the Jinshajiang River, China. Four of the species are endemic to China. The scientific names are: Clea dabryi ( Sauvage, 1874); Homatula variegata ( Dabry de Thiersant, 1874); Sinibotia superciliaris ( Gunther, 1892); Triplpphysa anterodorsalis ( Zhu & Cao, 1989); and Triplophysa leptosoma ( Herzenstein, 1888). [ABSTRACT FROM AUTHOR]

Length-weight relationships ( LWRs) of diploid and tetraploid loach Misgurnus anguillicaudatus from the Yangtze River basin, China were estimated and compared. [ABSTRACT FROM AUTHOR]