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Elevated ammonia levels in aquaculture systems could reduce fish growth and survival rates and produce a range of physiological problems. Ammonia toxicity in aquatic environments was regulated by various factors. Feeding was usually reported to help in the detoxification of fish, thereby increasing their capacity to tolerate ammonia nitrogen. However, the impact of different feeding amounts on fish in relation to ammonia exposure stress remains to be determined. To determine how feeding levels affected fish's responses to different ammonia nitrogen concentrations, two acute toxicity experiments were conducted with Carassius auratus gibelio, the major strain of gibel carp in aquaculture systems in China. In Test I, fed Carassius auratus gibelio (3 % body weight) showed a higher survival rate under a specific ammonia exposure stress. 96-h LC 50 of NH 3 -N to 3 %F gibel carp was 1.1 times greater than that for NF (no feeding). In Test II, all fed groups (2 %F and 4 %F) under low and high ammonia stress exhibited improved ammonia detoxification, evidenced by higher liver GSase, GDH, and glutamine concentrations compared with the NF treatment. Muscle glycogen levels in feeding treatments were higher than those in NF, indicating that fed fish have more energy for ammonia detoxification. While compared with low ammonia treatment (2.70 mg L -1 TAN; NH 3 0.06 mg L -1 ), fish exposed to high ammonia levels (26.03 mg L -1 TAN; NH 3 0.57 mg L -1 ) demonstrated a decrease in food consumption, severe histopathological alterations in their liver, gill, and kidney, and decreased GSase, GDH, and glutamine production in the liver and brain. The results partly supported our hypothesis and suggested that increasing feeding enhances gibel carp's tolerance to ammonia nitrogen. The highest detoxification metabolism was observed under low ammonia stress. While excessive ammonia exposure could inhibit feeding and damage the detoxification organs of fish, and thus reduce the detoxification metabolism of gibel carp., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Yellow catfish (Pelteobagrus fulvidraco) has been an economically important freshwater species in China because of its good meat quality. In present, the high-density breeding industry has suffered great damage from bacterial infections, in especial, the rapid illness and death of fish caused by bacterial septicemia leads to huge economic losses. Therefore, it is urgent and important to identify pathogenic bacteria and study its pathogenicity. In this study, we isolated a bacterial strain from the yellow catfish with typical septicemia and named it E. 719, then, by morphological observations, regression infection, biochemical identification, 16S rDNA sequence analysis and triple PCR identification, E. 719 was determined to be Edwardsiella ictaluri. Further, we infected yellow catfish with E. ictaluri to study its effects on mortality rate, hematological, histopathological disturbances and expression of immune genes. The mortality results showed that E. ictaluri was highly pathogenic, all infected fish died after 14 days post injection, and the distribution of bacteria in body kidney, spleen, liver, head kidney and brain of fish was continuously detected by measuring the amount of bacteria in the tissues. In addition, the number of red blood cells decreased significantly with the time of infection, while the number of white blood cells and thrombocytes increased. In particular, the number of monocytes and neutrophils increased significantly in the differential leucocyte count (DLC). Histopathologic changes observed by HE staining showed similar results, gill, intestine, spleen and head kidney showed obvious inflammation, bleeding and necrosis. Besides, checking by real time quantitative RT-PCR assays, in both spleen and head kidney tissues which were the major immune organs, mRNA expressions of immune gene IL-1β, TNF-α, and MR significantly increased in the early and middle stages of infection, which suggested that the infection of E. ictaluri caused a strong immune response in yellow catfish. This study provides a preliminary basis for the diagnosis and treatment of pathophysiology septicemia in yellow catfish induced by E. ictaluri. • Edwardsiella ictaluri is the pathogenic bacterium of septicemia in yellow catfish. • Infection caused by E. ictaluri leads to tissue necrosis and fish death. • The invasion of E. ictaluri causes rapid changes in blood cell counts. • The early inflammatory immune response was activated after E. ictaluri infection. [ABSTRACT FROM AUTHOR]

Fish introduction and nutrient enrichment are two major environmental stressors for many freshwater lakes. Thus far, their ecological impacts have largely been evaluated independently, despite that fish invasion and predation may interact with lake trophic status. We examined paleoecological records from four large lakes of Southwest China to quantify the strength and interaction of icefish invasion and eutrophication in affecting zooplankton over time. There was a significant and positive relationship (P< 0.01) between sediment Chl a concentration and bosminid flux in each lake with bosminid size structure being greater in more productive lakes, indicating a strong bottom-up control. Furthermore, a consistent decrease in bosminid body sizes after fish introduction was found in Fuxian where icefish grew most successfully among our lakes. The variance partitioning results showed a decrease in the relative importance of planktivorous predation in driving zooplankton production with increased trophic status across lakes, with their joint effect showing a unimodal model in strength. In all, there was regional heterogeneity in the population status and ecological impact of invasive icefish that varied with lake trophic status over time. Therefore, nutrient status needs to be considered in assessing long-term ecological status and consequences of fish invasion in stressed freshwaters. [ABSTRACT FROM AUTHOR]

Summary: Length–weight relationships (LWRs) for five fish species which were captured by trap‐nets and gillnets (major mesh size: 1–10 cm) from the middle Yangtze River, China (29°47′ – 29°26′N; 112°51′ – 113°08′E) were determined in September 2017. These were Acheilognathus hypselonotus (Bleeker, 1871), Culter oxycephaloides Kreyenberg & Pappenheim, 1908, Distoechodon tumirostris Peters, 1881, Sarcocheilichthys nigripinnis (Günther, 1873) and Micropercops swinhonis (Günther, 1873). The LWRs were estimated using the logarithmic form of the formula W  =  a  ×  Lb. The b value ranged from 2.879 for A. hypselonotus to 3.285 for M. swinhonis. LWRs for four fish species and new maximum lengths for three species are presented to FishBase for the first time. [ABSTRACT FROM AUTHOR]

The length-weight relations (LWR) were estimated for 20 fish species from the Pearl River, South China. A total of 3610 specimens representing 10 families were used to estimate the relation parameters. The b values in the LWR (W = aLb) ranged from 2.068 for Odontamblyopus lacepedii (Temminck et Schlegel, 1845) to 3.423 for Pseudogobius javanicus (Bleeker, 1856). The LWR with high coefficient of determination (r²) is significant for all the species. The r² value ranged from 0.919 to 0.993. This study presents the first reference on length-weight relations for 7 species and new records of maximum total length for 6 species. The results may be helpful in future fisheries studies in this areas. [ABSTRACT FROM AUTHOR]

Recent discoveries of early bony fishes from the Silurian and earliest Devonian of South China (e.g. Psarolepis, Achoania, Meemannia, Styloichthys and Guiyu) have been crucial in understanding the origin and early diversification of the osteichthyans (bony fishes and tetrapods). All these early fishes, except Guiyu, have their dermal skeletal surface punctured by relatively large pore openings. However, among these early fishes little is known about scale morphology and dermal skeletal histology. Here we report new data about the scales and dermal skeletal histology of Psarolepis romeri, a taxon with important implications for studying the phylogeny of early gnathostomes and early osteichthyans. Seven subtypes of rhombic scales with similar histological composition and surface sculpture are referred to Psarolepis romeri. They are generally thick and show a faint antero-dorsal process and a broad peg-and-socket structure. In contrast to previously reported rhombic scales of osteichthyans, these scales bear a neck between crown and base as in acanthodian scales. Histologically, the crown is composed of several generations of odontodes and an irregular canal system connecting cylindrical pore cavities. Younger odontodes are deposited on older ones both superpositionally and areally. The bony tissues forming the keel of the scale are shown to be lamellar bone with plywood-like structure, whereas the other parts of the base are composed of pseudo-lamellar bone with parallel collagen fibers. The unique tissue combination in the keel (i.e., extrinsic Sharpey's fibers orthogonal to the intrinsic orthogonal sets of collagen fibers) has rarely been reported in the keel of other rhombic scales. The new data provide insights into the early evolution of rhombic (ganoid and cosmoid) scales in osteichthyans, and add to our knowledge of hard tissues of early vertebrates. [ABSTRACT FROM AUTHOR]

Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardants (BFRs). It has been detected in various environment media and has been approved to be high toxic to aquatic organisms. However, the exposure levels of TBBPA in the main watersheds in China have not been investigated sufficiently. In this study TBBPA concentrations in water, sediment and tissues of four fish species from Lake Chaohu were determined. Spatial and temporal distribution patterns of TBBPA in water and sediment, and the relationship among TBBPA concentrations in fish tissues and fish size were analyzed. The results showed that the maximum TBBPA concentration in sediment was 518 ng/g in March 2008. It is almost the highest value than those ever reported anywhere in the world. In lake water, TBBPA level reached the maximum value of 4.87 μg/L in July. Tissue distributions of TBBPA in four fish species were similar, and the mean concentrations in the fish were in the range of 28.5-39.4 ng/g, much higher than those reported in Japan, Europe, and the United States. The maximum concentrations of TBBPA were found in kidneys where TBBPA concentration was positively correlated with fish size of Cyprinus carpio. Results demonstrated a widespread distribution of TBBPA in Lake Chaohu. The source was mainly inflow rivers near the cities. The distribution coefficient among water, fish, and sediment was 1:28:117. This indicated that sediment was the main repository for TBBPA within Lake Chaohu. Furthermore, TBBPA may pose a potential ecological risk in the lake during summer. [ABSTRACT FROM AUTHOR]

Abstract: Physiological and biochemical responses in kidneys of fishes with different trophic levels to toxic cyanobacterial blooms were studied. We sampled four fishes: the phytoplanktivorous Hypophthalmichthys molitrix and Aristichthys nobilis, the omnivorous Carassius auratus, and the carnivorous Culter ilishaeformis. Alterations of the antioxidant (GSH) and the major antioxidant enzymes (CAT, SOD, GPx, GST) were monitored monthly. Catalase and glutathione S-transferase were significantly higher during blooms than before and after blooms. All fishes showed ultrastructural alterations during blooms, which mainly are inosculation of foot processes in epithelial cell of glomeruli and mitochondria swelling in the proximal tubules. The results suggested that kidney impairment from chronic exposure of toxic cyanobacterial blooms might be the first step, and then followed by hepatic failure. Compared with livers in terms of physiological status, the weaker antioxidant ability of kidney made it more susceptible to chronic MCs exposure, besides its effective accumulation of MC metabolites. [Copyright &y& Elsevier]

Wild fish from Qiandao Hu, a reservoir in the Zhejiang Province in eastern China, have increased mercury (Hg) concentrations exceeding the World Health Organization's (WHO) recommended guidelines. Due to the importance of freshwater biota in the local cuisine, dietary exposure to increased neurotoxic Hg is a concern in this region. An environmental hair-marker study was undertaken coincident with a cross-sectional epidemiologic study with 50 women age 17-46 years living in a Qiandao Hu fishing village. Diet, occupation, and other possible sources of Hg were recorded by way of questionnaires. Total mercury (THg) and selenium (Se) concentrations were measured in human hair samples and in important market fish species. Fish THg and Se concentrations were increased, with some fish concentrations >200 ng/g THg and 500 ng/g Se (wet weight [ww]). However, the average hair THg was low at 0.76 ± 0.51 μg/g dry weight, lower than the WHO's no observable-adverse effect level (50 μg/g), whereas the average hair Se was 1.0 μg/g. Hair THg concentration was positively associated with the average mass of fish consumed weekly, indicating that fish consumption is the main contributor to hair THg in this geographic area. The age-related hair THg trend was not linear but instead demonstrated a rapid increase in THg before age 25 years, followed by consistent concentrations in all ages after age 25 years. There was a positive correlation ( p < 0.001) between molar Se and Hg in the hair samples, suggesting a possible antagonistic relation. This is the first study examining the relation between dietary Hg exposure and hair THg in an eastern China community where freshwater fish, as opposed to marine fish, dominates the cuisine. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the concentrations of cadmium, chromium, copper, iron, nickel, lead and zinc among feather tissues in sexes of Black-browed Albatross Thalassarche melanophrys killed in longliners off Argentina in 2005. We found no different metal concentration with sex for cadmium, copper, iron, lead and zinc in feathers of adult birds, though there were significant body-size differences between sexes. However, the concentrations of trace metals differed significantly among the type of feather within individual bird. The mean concentrations of copper, iron, and zinc in breast feathers of T. melanophrys were lower than those reported for the species from Georgias del Sur/South Georgia, the southern Indian Ocean and for other seabirds’ worldwide. While cadmium fall within the known range of concentrations for bird feathers lead were not. Our results may be indicating that level of pollution in Patagonia may not be as negligible as previously thought at least for some trace metals. [Copyright &y& Elsevier]

The article presents a study on Telestei and Cobitidae species of cobitis fish found in the Nanliu and Beiliu rivers in Guangxi Province, China. An overview of the physiological description of the species including their color pattern, body size, and cardioid is provided. It explores the genus cobitis in the river along with its polyploidy unisexual gynogenetic nature.

The article presents a study which investigates the frequency distribution and seasonal changes of intestinal helminths in yellowhead catfish Pelteobagrus fulvidraco from Liangzi Lake, China. It notes on the convex curves observed on the analysis of the changes in the variance and abundance of Gangesia pseudobagri, Orientocreadium siluri, Coitocoecum plagiorchis, and Echinoparyphium limgulatum. It reveals that G. pseudobagri and O. siluri have harmful effects to the Pelteobagrus fulvidraco.

Phoxinus lagowskii is a popular fish in Chinese cuisine. Though it is found mainly in China's high-latitude regions, where diel-cycling hypoxia (DCH) is known to have unique impacts on aquatic organisms, there is little known about its response to hypoxia. Currently, nothing is known about the changes in blood parameters, gill and liver morphology, glucose and lipid metabolism, or expression of genes involved in clock and glucose metabolism in response to sustained hypoxia (SH) and diel-cycling hypoxia (DCH). To elucidate the influence of sustained and diel-cycling hypoxia on fish hypoxia tolerance, resting oxygen consumption (MO 2) analysis was performed after ten days of hypoxia. This analysis revealed that hypoxia tolerance profoundly improved after ten days of either sustained or diel-cycling hypoxia acclimation, with DCH groups showing greater improvements than SH groups. Additionally, an increase in RBCs was found in P. lagowskii , suggesting an increase in the O 2 -carrying capacity of the blood to tolerate hypoxia. Hemoglobin (Hb) concentrations in P. lagowskii were increased at four days of diel-cycling hypoxia, confirming that physiological and metabolic adaptation to hypoxia is based on the duration of O 2 exposure. Increased Hb and hematocrit (Hct) were found in DCH-exposed fish, both of which have been directly linked to high-latitude hypoxia tolerance. In the gills, lamella surface area increased in SH-exposed fish more than DCH-exposed fish, and these increases were accompanied by a decrease in the volume of interlamellar cell mass (ILCM). Histology changes in the liver showed a higher frequency of cytoplasmic vacuolization in DCH-exposed fish. PK increases in SH-exposed fish suggest that fish can use more energy sources in persistent hypoxia. Meanwhile, DCH-exposed fish use TG as an energy source. In SH-exposed fish, self-regulation of Cry1a was observed, whereas Cry1b gene was up-regulated significantly. In DCH-exposed fish, three of eight clock genes studied had increased expression, including Per1a , Clocka, and Cry1b , suggesting that SH and DCH result in different hypoxic responses. This study presents a novel approach to the study of fish responses to hypoxia in high latitude and shows that sustained hypoxia and diel-cycling hypoxia induce large differences in fish physiology. [Display omitted] • Hypoxia tolerance profoundly improved in DCH fis h more than in SH fish. • RBC and HGB increased during hypoxia. • Gill lamella surface area increased in SH fish. • Triglyceride was the main energy sources in DCH fish. • The SH and DCH fish showed different expression levels in clock genes. [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]

Length-weight relationships ( LWR) were estimated for 37 fish species belonging to ten families from the middle and lower stream of the Hongshui River, one of the main tributaries to the Pearl River, Southwest China. Length-weight relationships for 26 species are unknown to FishBase and new maximum lengths are recorded for 20 species. These results are useful for fishery research, conservation and management in the Hongshui River. [ABSTRACT FROM AUTHOR]

The increasing prevalence and spread of antibiotic resistance genes (ARGs) in intensive aquaculture environments are of great concern to food safety and public health. However, the level of ARGs and their potential propagation factors in an industrial recirculating aquaculture system (RAS) have not previously been comprehensive explored. In this study, the levels of 14 different ARG markers and 2 kinds of mobile genetic elements (MGEs) were investigated in a RAS (including water, fish, feces, pellet feed meal, and biofilm samples) located northern China. qnrA , qnrB , qnrS , qepA , aac(6′)-Ib , and floR were dominant ARGs, which average concentration levels were presented at 4.51–7.74 copies/L and 5.36–13.07 copies/g, respectively, suggesting that ARGs were prevalent in RAS with no recorded history of antibiotic use. Elevated level of ARGs was found in water of RAS even after the final UV treatment compared with its influent. In RAS, Proteobacteria , Verrucomicrobia , Bacteroidetes, and Planctomycetes were the predominant phyla. Notably, elevated levels of potential opportunistic pathogens were observed along with abundant ARGs suggesting an increasing risk of capturing ARGs and MGEs for human pathogens. This study has revealed for the first time that reared fish, their feces, pellet feed meal as the introduction sources and the selection roles of treatment units co-driven the ARG profile, and the co-selection of water environmental factors and their consequently induced bacterial community shifts formed by their influence are the determining drivers for the ARG propagation in RAS. Image 1 • Elevated level of ARGs was found in the water of RAS even after the final UV treatment. • The introduction sources of reared fish, their feces, pellet feed and the selection roles of treatment units co-driven the ARG profile. • The water environmental factors are the determining drivers for the ARG propagation in RAS. Propagation of antibiotic resistance genes (ARGs) was found in RAS. Reared fish, their feces, pellet feed meal as the introduction sources and co-selection roles of treatment units co-driven the ARG propagation by the co-selection of water environmental factors and their consequently induced bacterial community shifts. [ABSTRACT FROM AUTHOR]

Background: Spinibarbus hollandi is an economically important fish species in southern China. This fish is known to have nutritional and medicinal properties; however, its farming is limited by its slow growth rate. In the present study, we observed that a compensatory growth phenomenon could be induced by adequate refeeding following 7 days of fasting in S. hollandi. To understand the starvation response and compensatory growth mechanisms in this fish, the muscle transcriptomes of S. hollandi under control, fasting, and refeeding conditions were profiled using next-generation sequencing (NGS) techniques. Results: More than 4.45 × 108 quality-filtered 150-base-pair Illumina reads were obtained from all nine muscle samples. De novo assemblies yielded a total of 156,735 unigenes, among which 142,918 (91.18%) could be annotated in at least one available database. After 7 days of fasting, 2422 differentially expressed genes were detected, including 1510 up-regulated genes and 912 down-regulated genes. Genes involved in fat, protein, and carbohydrate metabolism were significantly up-regulated, and genes associated with the cell cycle, DNA replication, and immune and cellular structures were inhibited during fasting. After refeeding, 84 up-regulated genes and 16 down-regulated genes were identified. Many genes encoding the components of myofibers were significantly up-regulated. Histological analysis of muscle verified the important role of muscle hypertrophy in compensatory growth. Conclusion: In the present work, we reported the transcriptome profiles of S. hollandi muscle under different conditions. During fasting, the genes involved in the mobilization of stored energy were up-regulated, while the genes associated with growth were down-regulated. After refeeding, muscle hypertrophy contributed to the recovery of growth. The results of this study may help to elucidate the mechanisms underlying the starvation response and compensatory growth. [ABSTRACT FROM AUTHOR]

Summary: Length‐weight relationships (LWR) were calculated for seven fish species from the Wutong River, northeast China(47°58'‐47°10'N; 130°07'‐130°48'E), including Ladislavia taczanowskii Dybowski, 1869; Gobio cynocephalus Dybowski, 1869; Rhynchocypris lagowskii (Dybowski, 1869); Lefua costate (Kessler, 1876); Cobitis lutheri Rendahl, 1935; Cobitis sibirica Gladkov, 1935; Perccottus glenii Dybowski, 1877. All fish specimens were collected by electric fishing gear (voltage, 12 V) and gillnets (mesh size: 1.1 cm × 1.1 cm, 1.4 cm × 1.4 cm, 1.8 cm × 1.8 cm, 2.5 cm × 2.5 cm) from May to July 2017. The a values ranged from 0.0038 (Cobitis lutheri) to 0.0084 (Lefua costata), and b values from 2.716 (Lefua costata) to 3.450 (Perccottus glenii) and r2 values from 0.973 (Cobitis lutheri) to 0.995 (ladislavia taczanowskii). This study provides the first published the LWRs for the five species, and new maximum total lengths were recorded for two species, including Gobio cynocephalus and Lefua costata. [ABSTRACT FROM AUTHOR]

This study provides the length-weight relationships ( LWRs) for four fish species [Leptobotia rubrilabris (Dabry de Thiersant, 1872); Opsariichthys bidens Günther, 1873; Xenocypris yunnanensis Nichols, 1925; and Sinogastromyzon sichangensis Chang, 1944] collected from the Niulan River, China. Samples were obtained between April 2008 and June 2011 using various types of fishing gear [drift gill nets (mesh: 5 × 5 cm), hook and electro fishing]. A total of 136 specimens belonging to four fish species were analyzed. For each species the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Prior to this study, the LWRs for S. sichangensis and X. yunnanensis were unknown. New maximum sizes for S. sichangensis and X. yunnanensis are also provided. [ABSTRACT FROM AUTHOR]

Focusing on adaptation of aquatic organisms, especially fish, can help elucidate complex dynamics in freshwater ecology. The differences in genetic and epigenetic regulation between diploid and triploid Carassius auratus affect survival under eutrophication. To identify the underlying mechanisms that lead to better adaption of triploids than diploids, we compared mRNA and microRNA (miRNA) expressions in liver tissue of diploid and triploid individuals obtained from the Dongting lake water system in central China. Differential expression analysis revealed that 566 transcripts were significantly up-regulated, whereas 758 were down-regulated in triploids; of these differentially expressed transcripts, 33 transcripts including cacna1d, nfkb2, hspa1 and fgfr4 were involved in the MAPK signaling pathway, and eight transcripts were determined to be regulated by seven miRNAs. Additionally, four of 25 differential expressed (DE) transcripts (mhc1, irf7, nfkb2 and pik3c) involving the viral carcinogenesis pathway were regulated by four miRNAs. Furthermore, genetic polymorphisms analysis showed that more heterozygous mutations were detected in triploids than diploids. The dN/dS results revealed that 21 genes were under positive selection (dN/dS>1) in C. auratus complex. We hypothesize that these changes related to genetic and epigenetic regulation may be caused by abiotic stresses, and facilitate adaptation to environmental changes.

Di-(2-ethylhexyl) phthalate (DEHP) associated in vitro/vivo toxicity at current environmentally relevant concentration (ERC) with attendant ecological risks in the Three Gorges Reservoir Area (TGRA) is still elusive. Responding to this challenge, a novel integrated study based on analytical and biological assays was designed to elucidate the underlying mechanisms for toxicity of DEHP and its ecological risks at ERC. In this study, GC-MS analysis showed that the highest environmental concentration of DEHP in the TGRA surface water was nearly double that of WHO and USEPA standards. Both distribution and ecological risk decreased from the upper to middle and lower reaches of the TGRA. In vitro toxicity was assessed by cell viability and DNA damage assays: DEHP exposure at ERCs (100-800 μg/L) caused significant reduction in cell viability and elevated DNA damage. Further, DEHP exposure above 400 μg/L resulted in enhanced migration behavior of cancer cells. For in vivo toxicity assessment, short term acute exposure (7 d, 400 μg/L) apparently activated the PI3K-AKT-mTOR pathway, and chronic low-level exposure (3 months, 10-33 μg/L) suppressed the hypothalamus pituitary thyroid (HPT) axis pathway in zebrafish. In addition, acute low-level exposure (5 d, 33-400 μg/L) to DEHP increased aryl hydrocarbon receptor (AhR) activity in Tg(cyp1a:gfp) zebrafish in a concentration-dependent manner. In short, DEHP at ERC has extended potential to induce diverse in vitro and in vivo toxicity at concentrations that also cause impairment of biochemical function in aquatic species of the TGRA., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Length-weight relationships ( LWRs) were estimated for 15 fish species representating 15 genera and six families from the Hunan Hupingshan National Nature Reserve, China. Six species are endemic to China, one of which is also endemic to the Yangtze River. The b values of all species were within the expected ranges, varying between 2.68 and 3.26. Data of 11 species represent the first description of LWRs and nine species have new records of maximum length. [ABSTRACT FROM AUTHOR]

Length-weight relationships ( LWR) are described for eleven indigenous fishes from the upper Jinsha River, which is the upper stretch of the Yangtze River, China. This is the first record of length-weight relationships for ten of these species in FishBase and new maximum lengths are recorded for seven species. [ABSTRACT FROM AUTHOR]

With the rapid growth of the Chinese zebrafish community, there is an increasing demand for various types of zebrafish-related resources and technologies. The China Zebrafish Resource Center (CZRC, web: http://zfish.cn) was established at the Institute of Hydrobiology (IHB), Chinese Academy of Sciences (CAS) in 2012. Till now, CZRC has built the largest zebrafish aquaculture unit in China, organized a resource bank containing more than 1200 zebrafish lines and more than 10 000 frozen sperm samples, among which over 200 mutant and transgenic lines were generated by CZRC. CZRC has established several technical supporting platforms, such as the zebrafish husbandry and health control program of international standard, a high-efficient gene manipulation technology platform, and a stable and efficient sperm cryopreservation technology platform. The main task of CZRC is to provide different types of services to zebrafish investigators in China and worldwide, such as resource services (e.g. zebrafish lines), technical services (e.g. gene knockout) and transgenic services, consultancy services (e.g. zebrafish husbandry and health consultation), and conference services [e.g. holding regular technical training courses and biennale Chinese Zebrafish Principal Investigator Meeting (CZPM)]. After five years' development, CZRC is now recognized as one of the three major resource centers in the global zebrafish community.

The Carassius auratus complex in natural populations includes diploid triploid and polyploidy individuals. Diploid individuals belong to the species Carassius auratus whereas triploid and polyploidy individuals are from the subspecies Carassius auratus gibelio. Triploid individuals are all female and reproduce clonally by gynogenesis. Therefore the Carassius auratus complex is an ideal system for studying evolution of unisexual reproduction. Identification of triploid individuals and clonal lines is the first step towards understanding of the evolution of unisexual clonal lines. We examined the ability of 10 microsatellites in identifying triploid individuals in 94 individuals from Japan and China. In 40 confirmed triploid individuals and eight confirmed diploid individuals, all triploid and diploid individuals can be identified by genotyping 10 microsatellite, and four triploid clonal lines were identified. Using the 10 microsatellites we genotyped 46 adult individuals (40 females and six males) from a natural population in China and found that all six males were diploid whereas the majority of females (36 of 40) were triploid and three triploid clonal lines were detected. In 18 diploid individuals from China, all individuals showed different genotypes, suggesting there is no diploid clonal line in diploid crucian carp. A phylogenetic analysis of 94 individuals from China and Japan showed that triploid individuals and clonal lines have originated recurrently., (© Ivyspring International Publisher.)

Objective: To investigate the effect of suspension concentrate of niclosamide (SCN) on killing cercariae of Schistosoma japonicum on water surface, optimization and impact on fish, so as to establish an emergency-treatment intervention for rapidly killing cercariae and eliminating water infectivity., Methods: SCN was formulated into different concentrations of solutions, and then the solutions were sprayed on the surface of water containing S. japonicum cercariae. The water infectivity was determined by using mice at 0, 10, 30 min after spraying SCN. SCN was formulated into a solution of 100 mg/L and then sprayed on the surface of the water by using the spraying values of 0.01, 0.02, 0.03 g/m2 and 0.04 g/m2. At 30 min and 60 min after spraying, the water infectivity was determined by using mice. Zebra fish were transferred into the static water, then 100 mg/L SCN (s), using spraying values of 0.01, 0.02, 0.03 g/m2 and 0.04 g/m2, were sprayed on water surface. At 0, 10, 30, 60 min after spraying, the samples were collected at water depths of 0, 10, 20, 30, 40 cm, and niclosamide was determined by using high-performance liquid chromatography. The death of zebra fish was continually observed within 96 h after spraying SCN., Results: At 0, 10, 30 min after spraying 1 000, 100, 10, 1, 0.1 mg/L SCN on water surface, the infectivity of water significantly decreased. At 30 min after spraying 1 000 mg/L and 100 mg/L SCN, no schistosome infectivity was detected in the water. At 30 min after spraying 100 mg/L SCN, with spraying values of 0.01, 0.02, 0.03, 0.04 g/m2, the water infectivity significantly reduced, and no infectivity was found 60 min after spraying SCN. After the surface of static water was sprayed with 100 mg/L SCN, the peak concentration was found at 0 min, and the solution diffused to site with a water depth of 10 cm after 10 min, and 30 min later, SCN diffused to the whole water body, and distributed evenly. After spraying 100 mg/L SCN on the surface of water with a volume of (3.14 x 20(2) x 50) cm3, by using the spraying value of 0.02 g/m2, 96 h later, no death of zebra fish was found., Conclusions: From 30 to 60 min after spraying 100 mg/L SCN, with the value of 0.02 g/m2, on the surface of S. japonicum-infested water, the water infectivity can be eliminated, and there is no evident toxicity to fish. This cercaria-killing method, as an emergency-treatment intervention for infested water, can be applied in those surveillance and forecast sites.