The spatiotemporal variations of microbial community in relation to water quality in a tropical drinking water reservoir, Southmost China.

It is well-known that water quality has great significance on microbial community composition in aquatic environments. In this study, we detected water column indicates the microbial community composition of nine sampling sites over two seasons using Illumina TruSeq sequencing in Songtao Reservoir, Hainan Province, Southmost China. The study indicated that the dominant phylum was Actinobacteria, Proteobacteria, Bacteroidetes, and Cyanobacteria.

Spatio-temporal variation in water quality and phytoplankton community structure in Changwang, Meishe, and Wuyuan Rivers in Hainan Island, China.

For the first time, this study explored spatio-temporal variation in water quality and phytoplankton community structure in Changwang, Meishe, and Wuyuan Rivers in tropical Hainan Island, China. Phytoplankton samples and water were collected between March and December 2019 and analyzed using standard methods. Two-way ANOVA revealed significant spatial and seasonal variation in physico-chemical parameters (p < 0.

Long-term data show alarming decline of majority of fish species in a Lower Mekong basin fishery.

Overexploitation, habitat fragmentation, and flow alteration are major threats to freshwater biodiversity that can lead to fisheries collapse and species extinction. These threats are particularly alarming in poorly monitored ecosystems where resource use supports the livelihoods of numerous people. The Tonle Sap Lake in Cambodia is such an ecosystem, supporting one of the world's largest freshwater fisheries.

Fish biodiversity declines with dam development in the Lower Mekong Basin.

Hydropower dams are a source of renewable energy, but dam development and hydropower generation negatively affect freshwater ecosystems, biodiversity, and food security. We assess the effects of hydropower dam development on spatial-temporal changes in fish biodiversity from 2007 to 2014 in the Sekong, Sesan, and Srepok Basins-major tributaries to the Mekong River. By analyzing a 7-year fish monitoring dataset, and regressing fish abundance and biodiversity trends against cumulative number of upstream dams, we found that hydropower dams reduced fish biodiversity, including migratory, IUCN threatened and indicator species in the Sesan and Srepok Basins where most dams have been constructed.

Eutrophication induces functional homogenization and traits filtering in Chinese lacustrine fish communities.

Rapid anthropogenic nutrient enrichment has caused widespread ecological problems in aquatic ecosystems and the resulting eutrophication has dramatically changed fish communities throughout the world. However, few studies addressed how fish communities responded to eutrophication in terms of multidimensional functional and taxonomic structure, especially how eutrophication acted as an environment filter on functional traits. The aim of the present study was to investigate the effects of eutrophication on fish species composition, community metrics and species functional traits in 26 shallow lakes from the middle reaches of Yangtze River basin, China.

Speciation-specific Cr bioaccumulation, morphologic and transcriptomic response in liver of Plectropomus leopardus exposed to dietary Cr(III) and Cr(VI).

Trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) are the two mainly stable oxidation states of Cr in aquatic environments, while the difference of their bioavailability and toxicity by dietary exposure has been rarely known in aquatic organisms. Using juvenile coral trout (Plectropomus leopardus), Cr(III) and Cr(VI) as model system, this study tested the hypothesis that the dietary Cr bioaccumulation and toxicity in fish were highly dependent on Cr speciation. The fish were chronically exposed to 200 mg kg of dietary Cr(III) and Cr(VI) for 8 weeks, and then the Cr bioaccumulation, morphologic change, and RNA-Seq in fish liver were determined.

Species-specific bioaccumulation and health risk assessment of heavy metal in seaweeds in tropic coasts of South China Sea.

Seaweeds are widely known superfood in coasts where most anthropogenic heavy metal discharges are inputted and stored. The present study analyzed 11 seaweed species and 13 heavy metals to test the hypothesis that the species-specific capacity of heavy metal bioaccumulation had great significance to health risk of human. The seaweeds were collected from tropic coasts of Hainan Island.

Capturing response differences of species distribution to climate and human pressures by incorporating local adaptation: Implications for the conservation of a critically endangered species.

Considering local adaptation has been increasingly involved in forecasting species distributions under climate change and the management of species conservation. Herein, we take the critically endangered Chinese giant salamander (Andrias davidianus) that has both a low dispersal ability and distinct population divergence in different regions as an example. Basin-scale models that represent different populations in the Huanghe River Basin (HRB), the Yangtze River Basin (YRB), and the Pearl River Basin (PRB) were established using ensemble species distribution models.

Species range shifts in response to climate change and human pressure for the world's largest amphibian.

The Chinese giant salamander, Andrias davidianus, the world's largest amphibian, is critically endangered and has an extremely unique evolutionary history. Therefore, this species represents a global conservation priority and will be impacted by future climate and human pressures. Understanding the range and response to environmental change of this species is a priority for the identification of targeted conservation activities.

Spatial pattern and determinants of global invasion risk of an invasive species, sharpbelly Hemiculter leucisculus (Basilesky, 1855).

Invasive species have imposed huge negative impacts on worldwide aquatic ecosystems and are generally difficult or impossible to be eradicated once established. Consequently, it becomes particularly important to ascertain their invasion risk and its determinants since such information can help us formulate more effective preventive or management actions and direct these measures to those areas where they are truly needed so as to ease regulatory burdens. Here, we examined the global invasion risk and its determinants of sharpbelly (Hemiculter leucisculus), one freshwater fish which has a high invasive potential, by using species distribution models (SDMs) and a layer overlay method.

Age, growth, mortality and recruitment of thin sharpbelly Günther, 1873 in three shallow lakes along the middle and lower reaches of the Yangtze River basin, China.

Despite being the most dominant and widespread small fish species in the lakes along the middle and lower reaches of the Yangtze River basin, has been paid little attention by fisheries scientists and little is known about its population characteristics. For this reason, we estimated age, growth, mortality and recruitment of this species based on three shallow lakes, Biandantang Lake, Shengjin Lake and Kuilei Lake (BDT, SJH and KLH, respectively) in this region. A total of 13,585 (8,818 in BDT, 2,207 in SJH and 2,560 in KLH) individuals were collected during monthly sampling from July 2016 to September 2017.

Reproductive pattern and population dynamics of commercial red swamp crayfish () from China: implications for sustainable aquaculture management.

Background: The red swamp crayfish, (Girard, 1852), is one of the most promising freshwater species for aquaculture in China. Understanding its reproductive pattern and population dynamics is crucial for sustainable management, but there is currently a lack of fundamental knowledge of commercial populations. Therefore, the purpose of this study was to investigate the reproductive pattern and population dynamics of commercial throughout the yearly cycle.

Habitat effects on intra-species variation in functional morphology: Evidence from freshwater fish.

Biotic-environment interactions have long been considered an important factor in functional phenotype differentiation in organisms. The differentiation processes determining functional phenotypes can reveal important mechanisms yielding differences in specific functions of animal traits in the ecosystem. In the present study, we examined functional morphological variations in relation to increasing geographic altitude.

Seasonal variations in diet composition, diet breadth and dietary overlap between three commercially important fish species within a flood-pulse system: The Tonle Sap Lake (Cambodia).

Tropical lakes and their associated floodplain habitats are dynamic habitat mosaics strongly influenced by seasonal variations in hydrologic conditions. In flood-pulse systems, water level oscillations directly influence the connectivity to floodplain habitats for fish. Here, we aimed to investigate whether seasonal changes in the water level of a flood-pulse system (the Tonle Sap Lake, Cambodia) differentially affect diet breadth and dietary overlap of three common and commercially important fish species (Anabas testudineus, Boesemania microplepis and Notopterus notopterus) presenting important differences in their life-cycle (e.

Evidence of indiscriminate fishing effects in one of the world's largest inland fisheries.

While human impacts like fishing have altered marine food web composition and body size, the status of the world's important tropical inland fisheries remains largely unknown. Here, we look for signatures of human impacts on the indiscriminately fished Tonle Sap fish community that supports one of the world's largest freshwater fisheries. By analyzing a 15-year time-series (2000-2015) of fish catches for 116 species obtained from an industrial-scale 'Dai' fishery, we find: (i) 78% of the species exhibited decreasing catches through time; (ii) downward trends in catches occurred primarily in medium to large-bodied species that tend to occupy high trophic levels; (iii) a relatively stable or increasing trend in catches of small-sized species, and; (iv) a decrease in the individual fish weights and lengths for several common species.

Spatio-temporal variation of fish taxonomic composition in a South-East Asian flood-pulse system.

The Tonle Sap Lake (TSL) is a flood-pulse system. It is the largest natural lake in South-East Asia and constitutes one of the largest fisheries over the world, supporting the livelihood of million peoples. Nonetheless, the Mekong River Basin is changing rapidly due to accelerating water infrastructure development (hydropower, irrigation, flood control, and water supply) and climate change, bringing considerable modifications to the annual flood-pulse of the TSL.

Correction: Temporal Patterns of Larval Fish Occurrence in a Large Subtropical River.

[This corrects the article DOI: 10.1371/journal.pone.

Biodiversity and health: Lessons and recommendations from an interdisciplinary conference to advise Southeast Asian research, society and policy.

Southeast Asia is an economic, biodiverse, cultural and disease hotspot. Due to rapid socio-economic and environmental changes, the role of biodiversity and ecosystems for human health ought to be examined and communicated to decision-makers and the public. We therefore summarized the lessons and recommendations from an interdisciplinary conference convened in Cambodia in 2014 to advise Southeast Asian societies on current research efforts, future research needs, and to provide suggestions for improved education, training and science-policy interactions.

Temporal Patterns of Larval Fish Occurrence in a Large Subtropical River.

Knowledge of temporal patterns of larval fish occurrence is limited in south China, despite its ecological importance. This research examines the annual and seasonal patterns of fish larval presence in the large subtropical Pearl River. Data is based on samples collected every two days, from 2006 to 2013.

Evidence of Water Quality Degradation in Lower Mekong Basin Revealed by Self-Organizing Map.

To reach a better understanding of the spatial variability of water quality in the Lower Mekong Basin (LMB), the Self-Organizing Map (SOM) was used to classify 117 monitoring sites and hotspots of pollution within the basin identified according to water quality indicators and US-EPA guidelines. Four different clusters were identified based on their similar physicochemical characteristics. The majority of sites in upper (Laos and Thailand) and middle part (Cambodia) of the basin were grouped in two clusters, considered as good quality water with high DO and low nutrient levels.

Phenotypic variation as an indicator of pesticide stress in gudgeon: Accounting for confounding factors in the wild.

The response of organisms to environmental stress is currently used in the assessment of ecosystem health. Morphological changes integrate the multiple effects of one or several stress factors upon the development of the exposed organisms. In a natural environment, many factors determine the patterns of morphological differentiation between individuals.