Impacts of variability of habitat factors on species composition of ichthyoplankton and distribution of fish spawning ground in the Changjiang River estuary and its adjacent waters

During June, August and October 2006, there were three multi-disciplinary surveys carried out in the Changjiang River estuary and its adjacent waters (122°00′–125°00′E, 27°50′–34°00′N) by R/V Beidou to study the species composition and abundance of ichthyoplankton (including fish eggs, larvae and juveniles), the spatial distribution of fish spawning ground and their relationship with habitat factors. There were 29, 29 and 25 grid stations sampled in the three cruises, respectively. The ichthyoplankton samples were collected by horizontally towing with a macro-plankton net (mouth diameter 80 cm, length 270 cm, mesh size 0.50 mm) at the sea surface, and the towing speed was 3.0 n mile/h at each sampling station. The towing lasted for 10 min. After hauling for each station, habitat factors including temperature and salinity were measured by Sea Bird-25 CTD. Samples were preserved in 5% formaldehyde solution immediately after sampling for analysis in laboratory. Since the trawl speed could not be accurately evaluated due to the effects of ocean currents and wind-induced wave, the amount of ichthyoplankton was evaluated by actual number of the sampling haul in each station. Ichthyoplankton collected were divided into three categories: dominant species, important species and main species by the index of relative importance (IRI). There are 71 species (including 1200 fish eggs and 2575 fish larvae and juveniles) collected during 3 cruises and 59 species have been correctly identified to species level, which belongs to 50 genera, 37 families and 9 orders; while 5 species can only be identified to genera level, 1 species only identified to family level and 6 species identified to order level. These 59 species identified to species level and 5 species identified to genera level are divided into three ecological patterns, i.e., brackish water species, neritic water species and coastal water species. Warm water species have 34 species in those 59 species identified to species level, accounting for 57.63%, warm temperature species have 25 species, accounting for 42.37%. According to the analysis of IRI, the dominant species are Engraulis japonicus (in June and August, that is important species in October), Scomber japonicus (in August), and Johnius grypotus (in October) during the survey; important species are Cynoglossus joyneri (in June and August), Trichiurus lepturus (in June, August and October), Gonorhynchus abbreviatus (in August), Stolephorus commersonii (in October), Saurida undosquamis (in October) and Saurida elongate (in October), and main species have 12 species in June, 9 species in August and 10 species in October, respectively. The amount of fish eggs and larvae of the dominant species, important species and main species (28 species) are 97.50% and 97.13% of the total amount of fish eggs and larvae, respectively, which are the important composition of fish eggs and larvae in the Changjiang River estuary and its adjacent waters.
In June and August of 2006, if compared with that in corresponding months in 1986, there are great changes in the habitat factors especially for temperature and salinity in the investigating areas: high salinity water from off-shelf is much closer to the coastal areas which results in the dramatic increase of sea surface salinity during all three surveys. Sea surface temperature, on the other hand, decreases distinctively in June, but significantly increases in August. The run-off of the Changjiang River greatly reduced due to the long-term drought in summer 2006, which is responsible for the great changes of habitat factors in the Changjiang River estuary and its adjacent waters. The habitat of the Changjiang River estuary is greatly changed, which consequently has significant influences on the spawning, breeding and the spatial distribution of spawning ground of neritic water species, such as Sardinella zunasi, Thryssa kammalensis, Thryssa mystax, Setipinna taty and S. commersonii ect, and coastal water species, such as Ilisha elongate and Konosirus punctatus ect.     

Impacts of variability of habitat factors on species composition of ichthyoplankton and distribution of fish spawning ground in the Changjiang River estuary and its adjacent waters

During June, August and October 2006, there were three multi-disciplinary surveys carried out in the Changjiang River estuary and its adjacent waters (122°00′–125°00′E, 27°50′–34°00′N) by R/V Beidou to study the species composition and abundance of ichthyoplankton (including fish eggs, larvae and juveniles), the spatial distribution of fish spawning ground and their relationship with habitat factors. There were 29, 29 and 25 grid stations sampled in the three cruises, respectively. The ichthyoplankton samples were collected by horizontally towing with a macro-plankton net (mouth diameter 80 cm, length 270 cm, mesh size 0.50 mm) at the sea surface, and the towing speed was 3.0 n mile/h at each sampling station. The towing lasted for 10 min. After hauling for each station, habitat factors including temperature and salinity were measured by Sea Bird-25 CTD. Samples were preserved in 5% formaldehyde solution immediately after sampling for analysis in laboratory. Since the trawl speed could not be accurately evaluated due to the effects of ocean currents and wind-induced wave, the amount of ichthyoplankton was evaluated by actual number of the sampling haul in each station. Ichthyoplankton collected were divided into three categories: dominant species, important species and main species by the index of relative importance (IRI). There are 71 species (including 1200 fish eggs and 2575 fish larvae and juveniles) collected during 3 cruises and 59 species have been correctly identified to species level, which belongs to 50 genera, 37 families and 9 orders; while 5 species can only be identified to genera level, 1 species only identified to family level and 6 species identified to order level. These 59 species identified to species level and 5 species identified to genera level are divided into three ecological patterns, i.e., brackish water species, neritic water species and coastal water species. Warm water species have 34 species in those 59 species identified to species level, accounting for 57.63%, warm temperature species have 25 species, accounting for 42.37%. According to the analysis of IRI, the dominant species are Engraulis japonicus (in June and August, that is important species in October), Scomber japonicus (in August), and Johnius grypotus (in October) during the survey; important species are Cynoglossus joyneri (in June and August), Trichiurus lepturus (in June, August and October), Gonorhynchus abbreviatus (in August), Stolephorus commersonii (in October), Saurida undosquamis (in October) and Saurida elongate (in October), and main species have 12 species in June, 9 species in August and 10 species in October, respectively. The amount of fish eggs and larvae of the dominant species, important species and main species (28 species) are 97.50% and 97.13% of the total amount of fish eggs and larvae, respectively, which are the important composition of fish eggs and larvae in the Changjiang River estuary and its adjacent waters.
In June and August of 2006, if compared with that in corresponding months in 1986, there are great changes in the habitat factors especially for temperature and salinity in the investigating areas: high salinity water from off-shelf is much closer to the coastal areas which results in the dramatic increase of sea surface salinity during all three surveys. Sea surface temperature, on the other hand, decreases distinctively in June, but significantly increases in August. The run-off of the Changjiang River greatly reduced due to the long-term drought in summer 2006, which is responsible for the great changes of habitat factors in the Changjiang River estuary and its adjacent waters. The habitat of the Changjiang River estuary is greatly changed, which consequently has significant influences on the spawning, breeding and the spatial distribution of spawning ground of neritic water species, such as Sardinella zunasi, Thryssa kammalensis, Thryssa mystax, Setipinna taty and S. commersonii ect, and coastal water species, such as Ilisha elongate and Konosirus punctatus ect.     

A STUDY ON THE CLASSIFICATION OF THE BOTOID FISHES OF CHINA

The present paper deals with the fishes referring to the subfamily Botiinae found in the Chinese fresh-water. At present 3 genera, 22 species and 2 subspecies of this subfamily have so far been known in China. Among them, Botia (Hymenophysa) yunnanensis, Parabotia lijiangensis, Parabotia bimaculata, Parabotia parva, Leptobotia guilinensis are found to be new to science.     

Embryonic and genetic manipulation in fish

Fishes,the biggest and most diverse community in vertebrates are good experimental models for studies of cell and developmental biology by many favorable characteristics.Nuclear transplantation in fish has been thoroughly studied in China since 1960s.Fish nuclei of embryonic cells from different genera were transplanted into enucleated eggs generating nucleo-cytoplasmic hybrids of adults.Most importantly,nuclei of cultured goldfish kidney cells had been reprogrammed in enucleated eggs to support embryogenesis and ontogenesis of a fertile fish.This was the first case of cloned fish with somatic cells.Based on the technique of microinjection,recombinant MThGH gene has been transferred into fish eggs and the firsh batch of transgenic fish were produced in 1984.The behavior of foreign gene was characterized and the onsed of the foreign gene replication occurred between the blastula to gastrula stages and random integration mainly occurred at later stages of embryogenesis.This eventually led to the transgenic mosaicism.The MThGH-transferred common carp enhanced growth rate by 2-4 times in the founder juveniles and doubled the body weight in the adults.The transgenic common carp were more efficient in utilizing dietary protein than the controls.An “all-fish” gene construct CAgcGH has been made by splicing the common carp β-actin gene (CA) promoter onto the grass carp growth hormone gene (grGH) coding sequence.The CAgcGH-transferred Yellow River Carp have also shown significantly fast-growth trait.Combination of techniques of fish cell culture,gene transformation with cultured cells and nuclear transplantation should be able to generate homogeneous strain of valuable transgenic fish to fulfil human requirement in 21^st century.     

Water sources of Populus euphratica and Tamarix ramosissima in Ejina Delta,the lower reaches of the Heihe River China北大核心CSCD

Aims: We aim to evaluate the water sources of typical riparian arbor species (Populus euphratica) and shrub species (Tamarix ramosissima), and analyze the spatial and temporal dynamics of plant water source in Ejina Delta, the lower reaches of the Heihe River. China. Methods: Eight sampling sites were selected in the riparian zones along the East River and West River in Ejina. The plant xylem water, soil moisture, rainwater, stream water and groundwater were taken and pretreated during the growing season in 2015-2016, and the stable oxygen isotope ratio (δ18O) for each water sample was measured. The δ18O of plant xylem water and soil moisture were compared to estimate the dominant depth of root water uptake, and the linear-mixed model called "IsoSource" were applied to determine plant water sources and quantify their proportions. Important findings: This study indicated that the main recharge sources for P. euphratica and T. ramosissima were stream water and groundwater. The contributions of rain water to them was negligible due to the limited amount and the shallow infiltration depth of local rainfall. As affected by groundwater level fluctuation, soil physical properties, as well as lateral and vertical recharge of stream water on soil moisture, the dominant depth of root water uptake spatially varied. However, the relative contributions of stream water or groundwater to plant water sources did not change significantly across space. Populus euphratica used more stream water (68%), while T. ramosissima used more groundwater (65%). Plant water sources were sensitive to environmental flow controls. The contributions of stream water to the water sources of the two species went up to 84% and 48% for P. euphratica and T. ramosissima respectively during the discharge period, but dropped to 63% and 30% during the non-discharge period. On the other hand, the contributions of groundwater decreased to 16% and 52% during the discharge period, but increased to 37% and 70% during non-discharge period. It is noteworthy that the high similarity of δ18O between stream water and groundwater due to extensive water exchange in the riparian zone made increase the uncertain in quantifying plant water sources.     

Control the egg hatchling process of Pomacea canaliculata (Lamarck) by water spraying and submersion

Pomacea canaliculata (Lamarck) is an invasive snail species that has become a serious pest of rice and other hydrophytes. Usually it is aquatic but likes to lay its eggs higher than the waterline. In order to seek a feasible and efficient way to control the egg hatchling of this pest, here we systematically studied the effects of water spraying and submersion on its egg hatchling rates and durations. Our results demonstrated that water spraying and submersion could dramatically decrease the hatchling rates to maximal 5.8% and increase the hatchling duration up to 26.4 days on P. canaliculata. Not only the beginning time of water treatment, but also the frequencies of the water spraying is critical to control the hatchling rate and duration of P. canaliculata. Water submersion that began in 12 h after the eggs laid and lasted at least 48 h will significantly decrease the snails’ hatchling rates and extend the hatchling time. In addition, compared to spraying, the water submersion could achieve more remarkable effects. The capsule of the snail’s egg is able to withstand the water treatment. Based on our water spraying and submersion results, it can be inferred that 0–6 h after egg being laid, egg capsule precipitates are beginning to form, and this process will complete after 12–24 h. This special breeding characteristic of P. canaliculata makes the physical control by water treatment become feasible.     

鱼类雄核发育的研究进展

雄核发育是在雄核控制下发育的一种特殊的有性生殖方式,它是鱼类单性发育的重要组成部分。本文全面综述了国内外鱼类雄核发育研究的进展状况。主要包括雌核染色体灭活和雄核二倍化诱导技术。雌核染色体灭活主要通过γ、X和紫外线(UV)等辐射处理完成的,其辐射剂量和方法因研究者不同而不同。雄核的二倍化诱导则主要是采用静水压和温度休克阻止第一次有丝分裂来实现的,其二倍化诱导条件与研究的种类不同而有所差异。同时,本文对鱼类雄核发育在遗传育种中的应用前景作了评价。 Abstract：Fish andtogenesis is a kind of secial sexual development which is controlled by male nucleus and it is an important part of fish unisexual development. This paper summarizes the progress of fish androgenesis comprehensively in the world.It includes the techniques of inactive female nucleus of eggs and diploidization of male nucleus. The methods of inactive female nucleus are carride out by using γ,X and ultraviolet (UV)rays to irradiate the eggs,the irradiation dosages and methods are different based on the different researchers. The techniques of diploidization of male nucleus are carried out by using hydrostatic pressure, heat and cold shock to restrain the fish mitosis,the diploidization condition are different from species to species.Meanwhile,the paper evaluates the application perspectives of fish androgenesis on the genetics and breeding.     

Group-spawning and Simultanous Polyandry of a Stream-dwelling Frog Feirana kangxianensis

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.     

Trends of Superoxide Dismutase and Soluble Protein of Aquatic Plants in Lakes of Different Trophic Levels in the Middle and Lower Reaches of the Yangtze River,China

A limnological study was carried out to determine the responses of superoxide dismutase （SOD） activities and soluble protein （SP） contents of 11 common aquatic plants to eutrophication stress. Field investigation in 12 lakes in the middle and lower reaches of the Yangtze River was carried out from March to September 2004. Our results indicated that non- submersed （emergent and floating-leafed） plants and submersed plants showed different responses to eutrophication stress. Both SOD activities of the non-submersed and submersed plants were negatively correlated with their SP contents （P 〈 0.000 1）. SP contents of non-submersed plants were significantly correlated with all nitrogen variables in the water （P 〈 0.05）, whereas SP contents of submersed plants were only significantly correlated with carbon variables as well as ammonium and Secchi depth （SD） in water （P 〈 0.05）. Only SOD activities of submersed plants were decreased with decline of SD in water （P 〈 0.001）. Our results indicate that the decline of SOD activities of submersed plants were mainly caused by light limitation, this showed a coincidence with the decline of macrophytes in eutrophic lakes, which might imply that the antioxidant system of the submersed plants were impaired under eutrophication stress.     

Side effects of water liming on body size and eggs development of Daphnia species in Lake Orta (N. Italy)

Life-tables of the Daphnia species (D. longispina and D. obtusa), currently inhabiting the previously acidified Lake Orta, were followed to study the side effects of liming on the demographic parameters (e.g. longevity, body size increment, eggs and new-borns production), of both species. Different media were prepared to simulate the lake water pH's (5, 6 and 7), and copper concentrations (40 μg l^-1), before and after liming, using GF/C filtered lake water in such simulation and as a reference medium. The obtained results have shown that, the individuals of D. longispina were only able to survive after the liming and the consequent reduction in copper concentrations. However, due to shift occurred in the different media pH's after liming toward slightly alkaline conditions, no significant variations in body size increment or in eggs and newborns production were detected of this species in the different media (p = 0.38, p = 0.29, p = 0.09 respectively). On the other hand, the effect of the variations in pH on the body size increment of the B. obtusa individuals was marginally significant (p = 0.07). A highly significant (p = 0.002), increase in eggs production by D. obtusa individuals was detected in the different media after the CaCO₃ addition. Conversely, a corresponding highly significant (p = 0.0007), decrease in the production of new-borns, accompanied by the degeneration of about 78% of the produced eggs, was detected in the different media after liming. Our results suggest that in Lake Orta the actual irregular abundance of the studied Daphnia species and the eggs degeneration phenomenon, observed in our study, could be largely attributed to the interspecific competition resulting from species-specific sensitivity to the continuous variations in the lake water Chemistry after the liming operation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Seasonal changes on two different spatial scales： response of aquatic invertebrates to water body and microhabitat

Knowledge about the spatial and temporal scales of both habitat use and the functional significance of different adaptations is essential for an understanding of the population dynamics of invertebrate assemblages. This fundamental knowledge is not only interesting from an academic point of view, but is sorely lacking and needed in the field of restoration ecology. Many species are threatened due to degradation. Knowing what environmental conditions are needed dtLring the life cycle of these species is important in the design of restoration measures which aim to lift existing bottlenecks for threatened species. To assess the relative importance of water type and microhabitat in structuring the invertebrate assemblage during different seasons, invertebrates were sampled in three water bodies differing in trophic level and acidity. Different parts within a water body （microhabitats） were sampled separately and each water body was sampled in all four seasons. Results show that water body is an important factor structuring the invertebrate assemblage early in the season, whereas microhabitat became more important later in the season. Structural complexity of microhabitats was related to the type of locomotion employed by invertebrates. Seasonal differences could be related to population dynamics （reproduction, mortality）. Moreover, fluctuations in resource availability were expected to differ between the water bodies, with highest fluctuations in the eutrophic water body and with fluctuations becoming less predictable later in the season. This was confirmed by the data： species synchronization to pulses in food availability was strongest in the eutrophic water body. Moreover, synchronization was strongest in summer, while in autumn waters were invaded by dispersive species. Based on these results a synthesis is presented on the functioning of the different waters during the different seasons.     

Impacts of cascaded small hydropower plants on microzooplankton in Xiangxi River, China

The impacts of small hydropower plants (SHPs) on zooplankton assemblages were investigated in six cascaded SHPs along the Xiangxi River in October 2005. Five sites were sampled at each SHP. Fifty-six rotifer species which belong to 21 genera of 13 families and a nauplius species were identified in this study. Most rotifers were benthic species. The dominant rotifer species were Rotaria tardigrada, R. rotatoria, Philodina erythrophthalma, Colurella adriati, C. uncinata, Cephalodella catellina, Euchlanus dilatata, Lecane crenata and Keratella cochlearis. The Jaccard similarity index among these sections was very low, ranging from 24.33 to 58.54. The chlorophyll a (Chl a) of phytoplankton ranged from 0.37 to 1.22 ug/l, and the highest appeared in Xiaodangyang SHP. The richness, Simpson, Shannon–Wiener and Margalef diversity indices of zooplankton ranged in 4.8–21.4, 0.53–0.89, 1.12–2.58 and 0.42–1.64, respectively. In Xiangxi River, zooplankton density was low, no more than 9000 ind./m3, and the highest was observed at the down section of the river, while the lowest was at the up section of the river. Nevertheless, the richness and density in Xiaodangyang SHP were very high, only second to those in Zhaojun SHP. Apart from Xiaodangyang SHP, richness and diversity indices of zooplankton increased gradually from the upstream to the downstream. Xiangxi River was disturbed by human activities due to the cascaded development of SHPs. From Xiaodangyang SHP to Cangpinghe SHP, the richness and diversity indices of zooplankton were relatively higher at Site 3, whereas in Houzibao SHP and Zhaojun SHP, the lowest were at Site 3. The dam of SHP had significant effects on the zooplankton community. The outlet of SHP had no effect on the zooplankton community.     

CONTAMINATED LEVEL AND RISK ASSESSMENT OF PAES IN THE UPPER REACHES OF THE YANGTZE RIVER北大核心CSCD

PAEs have been proved to be one of the major organic pollutants. The present study determined the level of PAEs using surface water samples from the upper reaches of the Yangtze River. The results showed that DEHP contributed the most to PAEs pollution, followed by DBP. Risk Quotients of PAEs were used for preliminary screening, and DEHP and BBP were identified as potential risk factors with RQ of 310 and 70.7. The MOS10 of DEHP and BBP were 1.40 and 1.32×105, respectively, indicating that BBP may pose little risk to aquatic organisms. The potential risk of DEHP was further analyzed with joint probabilistic curves. Among different biological groups, fish and zoobenthos were two major groups sensitive to DEHP-induced damage under current concentrations with 99.4% and 98.3% for 5% species of each group. While among the toxicity endpoints, reproduction may be more sensitive than others. The 5% and 10% aquatic species were suffered from reproductive damages by 100% and 97.8%, respectively. Overall, our results indicated that DEHP in the surface water of the upper Yangtze River may pose potential risk to aquatic organisms, especially on their reproduction. Therefore, more concerns should be paid in species protection and environmental management. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.     

Distribution patterns of pelagic euphausiids in the East China Sea

Distribution patterns and abundance of the euphausiids were examined in the East China Sea (23°30′ –33°00′N, 118°30′ –128°00′ E) in relation to temperature and salinity. The data were collected in 4 surveys from 1997 to 2000. The density or yield density model was used to predict optimum temperature and salinity of water for euphausiid distribution, and thereafter distribution patterns of euphausiids were determined based on the predicted parameters. Of 23 species, Euphausia pacifica, E. nana, Pseudeuphausia sinica and P. latifrons were numerically dominant. The analyses indicate that Euphausia pacifica is an offshore temperate water species, E. nana is an offshore temperate warm water species, P. sinica is a coastal subtropical water species and P. latifrons is an oceanic tropical water species. The 4 species occupied 4 different water masses, respectively, namely, cold water mass, cold and warm water mixed masses in winter and spring, cold and warm water mixed masses in summer and autumn, and warm water mass, which could be the good designators of individual water masses, respectively. The predicated optimal temperatures for E. tenera, S. carinatum, E. diomedeae, Stylocheiron affine, Nematoscelis sp., N. gracilis, N. atlantica, Stylocheiron sp. and S. suhmii are all > 25°. These species are mainly distributed in southern Kuroshio in winter and spring, Kuroshio, the Taiwan Warm Current and Tsushima Current in summer and autumn, the equatorial waters of Pacific Ocean and the eastern waters of the Taiwan Strait. They are called as oceanic tropical water species. Nematoscelis tenella and T. tricuspidata are referred to as offshore subtropical water species according to their geographic distributions even if they are halobionts. Euphausia sanzoi is considered as a typical offshore subtropical water species, which inhabited waters below 25°. Stylocheiron microphthalma, occupying warm current waters where temperature and salinity are nearly 25° and 34 in summer and autumn, belongs to oceanic tropical water species. In the same way, E. similes, E. mutica, Euphausia sp., E. brevis and E. recurva are classified into offshore subtropical water species in accordance with the optimum temperature and salinity of waters as well as locations and seasons of their occurrence. Optimum temperature, rather than salinity, is a better parameter in determining the distribution patterns of euphausiids.     

Carbon Isotope Discrimination is not Correlated with Transpiration Efficiency in Three Cool-Season Grain Legumes （Pulses）

The carbon isotope discrimination （δ^13C） of leaves has been shown to be correlated with the transpiration efficiency of leaves in a wide range of species. This has led to δ^13C being used in breeding programs to select for improved transpiration efficiency. The correlation between δ^13C and transpiration efficiency was determined under well-watered conditions during the vegetative phase in six genotypes of lentil （Lens culinaris Medikus）, six genotypes of chickpea （Cicerarietinum L.） and 10 cultivars of narrow-leafed lupin （Lupinus angustifolius L.）. Biomass （dry matter） accumulation and water use （transpiration） varied among the genotypes in all three species and transpiration efficiency was 40% to 75% higher in the most efficient compared with the least efficient genotypes. However, δ^13C and transpiration efficiency were not significantly correlated in any of the species. This suggests that the δ^13C technique cannot be used in selection for transpiration efficiency in the three grain legumes （pulses） studied.     

Interspecies variation in DNA damage induced by pollution

The choice of a suitable species to translate pollution signals into a quantitative monitor is a fundamental step in biomonitoring plans. Here we present the results of three years of biomonitoring at a new coal power plant in central Italy using three different aquatic and terrestrial wildlife species in order to compare their reliability as sentinel organisms for genotoxicity. The comet assay was applied to the common land snail Helix spp., the lagoon fish Aphaniusfasciatus, and the green frog Rana esculenta sampled in the area potentially exposed to the impact of the power station. The tissue concentration of some expected pollutants （As, Cd, Ni, Pb, Cr） was analysed in parallel samples collected in the same sampling sites. The three species showed different values in the comet assay （Tail Intensity） and different accumulation profiles of heavy metals. Aphanius fasciatus showed an increasing genotoxic effect over time that paralleled the temporal increase of the heavy metals, especially arsenic, and the highest correlation between heavy metals and DNA damage. Helix spp. showed levels of damage inversely related to the distance from the source of pollution and in partial accordance with the total accumulation of trace elements. On the contrary, Rana esculenta showed a low capability to accumulate metals and had inconsistent results in the comet test. The fish appeared to be the most efficient and sensitive species in detecting chemical pollution. Overall, both the fish and the snail reflected a trend of increasing pollution in the area surrounding the power plant across time and space [Current Zoology 60 （2）： 308-321, 2014].     

Genetic basis and biotechnological manipulation of sexual dimorphism and sex determination in fish

Aquaculture has made an enormous contribution to the world food production,especially to the sustainable supply of animal proteins.The utility of diverse reproduction strategies in fish,such as the exploiting use of unisexual gynogenesis,has created a typical case of fish genetic breeding.A number of fish species show substantial sexual dimorphism that is closely linked to multiple economic traits including growth rate and body size,and the efficient development of sex-linked genetic markers and sex control biotechnologies has provided significant approaches to increase the production and value for commercial purposes.Along with the rapid development of genomics and molecular genetic techniques,the genetic basis of sexual dimorphism has been gradually deciphered,and great progress has been made in the mechanisms of fish sex determination and identification of sex-determining genes.This review summarizes the progress to provide some directive and objective thinking for further research in this field.     

The effect of ecological management in the upper reaches of Heihe River

Heihe River is the second largest inland river in northwest China which flows through Qinghai Province, Gansu Province and Inner Mongolia Autonomous Region. Because of the rapid development of social economy, the sharp increase of water utilization in the middle reaches and the aggravation of contradiction of supply and demand on water resources, the water to the lower reaches decreases and the ecological environment deteriorates constantly. According to the severe situation of ecology system depravation in Heihe River basin, Chinese government decided to invest 2.35 billion RMB to carry out 3 years ecological management in Heihe River basin from August in 2001. After 3 years ecological management, the depravation of ecological environment is controlled effectively. This paper researches the ecological management engineering in the upper reaches of Heihe River and evaluates the effect of the ecological management engineering. The methods of field sampling and measuring are used to obtain the index indicating the ecology change in the upper reaches of Heihe River in 2006. The effects of fencing grassland, fencing natural forest, and artificial afforestation to the ecology are evaluated. The result suggests that: Firstly, in fencing grassland area, the yield of grass had increased by 42–113%, average height of the grass had increased by 60–100%, and the degree of coverage had increased by 67–100%. Secondly, in fencing natural forests area, the degree of coverage had increased by 15–33%, the shade density had increased by 50–100%, average height had increased by 80–125%, and the crown size had increased by 63–186%. Thirdly, the growth increment of the trees in artificial afforestation area is bigger than that outside artificial afforestation area. In conclusion, ecological management leads to obvious ecological effect in the upper reaches of Heihe River.     

Sexual Dimorphism,Female Reproductive Characteristics and Egg Incubation in an Oviparous Forest Skink(Sphenomorphus incognitus) from South China

We studied sexual dimorphism and female reproduction in an oviparous forest skink(Sphenomorphus incognitus)from South China.We incubated eggs under five thermal regimes(22,25,28,25±3 and 27±5°C)to examine the effects of constant versus fluctuating temperatures on incubation length and hatchling morphology.In our sample the largest male and female were 110 mm and 108 mm snout-vent length(SVL),respectively.Adult males and females did not differ in mean SVL;adult males were larger in head size(both length and width),longer in foreand hind-limb lengths and shorter in abdomen length than females of the same SVL.Accordingly,we conclude that S.incognitus is a sexually monomorphic species in terms of SVL but shows sexual dimorphism in head size,abdomen length and appendage length.Females laid a single clutch of 3-10 eggs per breeding season from early May to midAugust,with larger females generally laying more(but not always larger)eggs per clutch than did smaller ones.Embryonic stages at laying ranged from Dufaure and Hubert's(1961)stage 31 to 32,with a mean stage of 31.3.The positive relationship between clutch mass and female SVL was not significant.The offspring size-number trade-off does not exist in S.incognitus,as revealed by the fact that egg mass was independent of relative fecundity.Incubation length decreased as temperature increased,and stable temperatures resulted in delayed hatching.Hatchlings incubated under the five thermal regimes did not differ from each other in any examined trait,suggesting that S.incognitus is among oviparous reptilian species where incubation temperature has no role in modifying hatchling morphology as long as eggs are not exposed to extreme temperatures for prolonged periods of time.