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Steven Weiss - One of the best experts on this subject based on the ideXlab platform.
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Genetic evaluation of the self-sustaining status of a population of the endangered Danube salmon, Hucho Hucho
Hydrobiologia, 2016Co-Authors: Steven Weiss, T. SchenekarAbstract:A new multiplex microsatellite protocol was developed for population screening of the endangered Danube salmon (or huchen) Hucho Hucho. Allelic variation was screened at five newly cloned and four previously published loci in 246 samples to help evaluate the self-sustaining status of an urban population of huchen in the framework of a controversial environmental assessment in the Mur River, Austria. The loci revealed 78 alleles (mean = 8.6), and in the Mur River an average expected heterozygosity of 0.668. We inferred that the huchen population in and around the city of Graz is self-sustaining based on the following evidence, which includes both genetic and non-genetic sources of information: (1) there is little to no current stocking; (2) presence of juvenile huchen in multiple year classes; (3) sighting of spawning events; (4) documentation of 14 spawning redds; (5) no deviation from Hardy–Weinberg equilibrium; and (6) limited number of recaptures or parental matches with presumed parent fish of stocking operations. We discuss the potential application of such an analysis in evaluating threatened huchen populations throughout their native distribution.
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the huchen Hucho Hucho in the balkan region distribution and future impacts by hydropower development
12. HRVATSKI BIOLOŠKI KONGRES s međunarodnim sudjelovanjem, 2015Co-Authors: Jorge Freyhof, Steven Weiss, Avdul Adrovic, Marko Caleta, Aljosa Duplic, Boris Hrasovec, Belma Kalamujic, Zoran Marcic, Dragana Milosevic, Milorad MrakovcicAbstract:The Huchen is one of the most enigmatic species of Europe's freshwater fauna. Historically, the species was wide‐spread across the entire Danube basin. Since the late 19th century, however, Huchen populations declined by two thirds and the remaining populations are now highly endangered by hydropower development. In this study, we review the actual occurrence of Huchen in the Balkan region. A total of 1842 river km supporting self‐sustaining populations of Huchen in the region have been identified, making it the global hot spot for the species. These populations are found in 43 rivers or distinct river reaches in Slovenia, Croatia, BIH, Serbia and Montenegro. About 65% of all Huchen rivers globally are located in these countries, highlighting the importance of Balkan Rivers for the survival of the species. The major threat to these populations is a massive hydropower development plan. A total of 93 dam projects were identified directly in river reaches supporting Huchen and a large number of additional projects are located in tributaries or headwater reaches upstream of Huchen habitat that will invariably degrade environmental conditions downstream. If these plans are carried out, we predict that at least 60‐70% of the Balkan population and about 35‐ 40% of the global population of Huchen would be lost with the remaining populations being small and severely fragmented and eventually no longer able to survive in the long term.
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Danube salmon (Hucho Hucho) in Central and South Eastern Europe: a review for the development of an international program for the rehabilitation and conservation of Danube salmon populations.
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Animal Science and Biotechnologies, 2014Co-Authors: Andrada Maria Ihut, Steven Weiss, Andreas Zitek, Clemens Ratschan, Georg Holzer, Thomas Kaufmann, Daniel Cocan, Radu Constantinescu, Vioara MireșanAbstract:Danube salmon Hucho Hucho (L.), known as one of the world’s largest salmonids, is among the most endangered fish species inhabiting the Danube basin of Central Europe. It is classified as endangered (EN) by the IUCN due to its very low abundance and continual decline. Historically, the natural distribution range of the Danube salmon included drainages in Austria, Bosnia-Herzegovina, Montenegro, north-western Croatia, Czech Republic, Germany, Poland, Romania, Serbia, Slovakia, Slovenia and western Ukraine. Currently, Danube salmon populations are fragmented within the Danube drainage, with many being supported by artificial reproduction and stocking programs. It is not yet possible to report that this species is safe from extinction in the wild. As a starting point to develop a sustainable conservation program, this manuscript provides a review of the current biological knowledge on Danube salmon existing in the different countries within the species distribution range in Central and South Eastern Europe.
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First mtDNA sequencing of Volga and Ob basin taimen Hucho taimen: European populations stem from a late Pleistocene expansion of H. taimen out of western Siberia and are not intermediate to Hucho Hucho.
Journal of fish biology, 2014Co-Authors: Saša Marić, S. S. Alekseyev, Aleš Snoj, Oleg Askeyev, Igor Askeyev, Steven WeissAbstract:New concatenated mtDNA sequences (three genes; n = 22) of Siberian taimen Hucho taimen primarily from west Siberian and European regions of the species' range were added to 12 previously published sequences to provide a phylogeographic overview of the species. European samples show only very minor divergence from west Siberian populations, supporting a late Pleistocene expansion from Siberia into the Urals, with no particular relation to the Danube River basin huchen Hucho Hucho as once hypothesized. The disjunct distribution of the genus is most likely based on an early Pleistocene vicariant event.
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Regional structure despite limited mtDNA sequence diversity found in the endangered Huchen, Hucho Hucho (Linnaeus, 1758)
Hydrobiologia, 2010Co-Authors: Steven Weiss, Saša Marić, Aleš SnojAbstract:We evaluate the hypothesis of no geographic structure in the Huchen (Hucho Hucho), a large, predatory salmonid endemic to the Danube basin. Forty-seven individuals sampled from throughout the Huchen’s native range were genetically characterized. Extremely limited sequence diversity across 1,800 bases of mtDNA (the complete control region and partial NADH-1 subunit) evidenced by four closely related mtDNA haplotypes was found. Nonetheless, the geographic distribution of mtDNA repeats (5–10, 82-bp long copies per individual) as well as allelic diversity across two microsatellite loci indicated large-scale geographic structure between the north-western (Austria and Slovenia) distribution area and eastern (Slovakia and Ukraine) or southern (Bosnia-Herzegovina and Montenegro) sample sites. An extremely slow rate of substitution for the H. Hucho mtDNA is considered along with the alternative hypotheses to explain the limited mtDNA diversity. Considering the regional genetic structure implied by our data, we advocate restrictions on the transport of brood fish or yearlings across the range of the species distribution and sale of Huchen across international boundaries. Future genetic analysis to support local conservation and monitoring efforts must focus on developing a high-resolution screen that may be applied to identify hatchery versus naturally reproduced individuals in the wild.
Robert Patzner - One of the best experts on this subject based on the ideXlab platform.
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Cryopreservation of semen of the grayling (Thymallus thymallus) and the Danube salmon (Hucho Hucho)
Aquaculture, 1996Co-Authors: Franz Lahnsteiner, T. Weismann, Robert PatznerAbstract:Abstract Cryopreservation of semen of Thymallus thymallus and of Hucho Hucho was investigated with a method that was originally developed for Oncorhynchus mykiss . Assessments of fertilization rate were used to establish the type and concentration of cryoprotectant, freezing rates and thawing conditions for the two species. In both H. Hucho and T. thymallus , 10% methanol was the most effective cryoprotectant, followed by a 5% DMSO-1% glycerol mixture, 10% DMSO, 10% n , n -dimethylacetamide and 5% glycerol. Using an open system and 0.5ml straws, freezing of semen was optimal 1.5 cm above the level of liquid nitrogen (at − 110 ± 2 °C) and thawing was best in a 25 °C water bath for 30s. Post-thaw fertilization rates were 90–100% of control with fresh semen at sperm/egg ratios of (1.2–1.6) × 10 6 spermatozoa per egg in T. thymallus and at sperm/egg ratios of (4.3–5.5) × 10 6 spermatozoa per egg in H. Hucho .
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Composition of the ovarian fluid in 4 salmonid species: Oncorhynchus mykiss, Salmo trutta f lacustris, Salvelinus alpinus and Hucho Hucho
Reproduction nutrition development, 1995Co-Authors: Franz Lahnsteiner, T. Weismann, Robert PatznerAbstract:The ovarian fluid of rainbow trout (Oncorhynchus mykiss), charr (Salvelinus alpinus), lake trout (Salmo trutta f lacustris) and Danube salmon (Hucho Hucho) was analyzed for its inorganic and organic composition. The qualitative composition of the ovarian fluid of the investigated species was similar, but significant quantitative differences were found. The following components were determined: sodium 106.6-142.2 mmol/l, potassium 1.7-2.7 mmol/l, calcium 0.45-0.61 mmol/l, osmolality 256.4-291.6 mosmol/kg, pH 8.4-8.8, glucose 1,698-4,195 mumol/l, fructose 17-399 mumol/l, lactate 34-227 mumol/l, cholesterol 650-1,230 mumol/l, phosphatidylcholine 0.25-3.0 mumol/l, lysophosphatidylcholine 10-100 mumol/l, choline 0-1.1 mumol/l, protein 95.0-278.4 mg/100 ml. Arginine, cystine, glycine, histidine, lysine, proline, serine, tyrosine and valine were the free amino acids occurring in concentrations of more than 10 mumol/l. Activities of alkaline phosphatase (200-6,000 mumol substrate/l/h), lactate dehydrogenase (9-690 mumol substrate/l/h), beta-D-glucuronidase (70-410 mumol substrate/l/h), proteases (140-215 mumol/l/h with collagen substrate, 25-90 mumol/h/l with gelatine substrate) and acid phosphatase (100-130 mumol substrate/l/h) were measured, but not the glucose-6-phosphate dehydrogenase and alpha-glucosidases activities.
Franz Lahnsteiner - One of the best experts on this subject based on the ideXlab platform.
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Semen cryopreservation in the Salmonidae and in the northern pike.
Aquaculture Research, 2000Co-Authors: Franz LahnsteinerAbstract:The present paper summarizes the data on a semen cryopreservation method for the Salmonidae (Oncorhynchus mykiss, Salmo trutta f. lacustris, Salvelinus fontinalis, Salvelinus alpinus, Salmo trutta f. fario, Hucho Hucho, Coregonus lavaretus, Thymallus thymallus) and for the Northern pike (Esox lucius) published during recent years. It describes (1) methods used for the determination of sperm viability; (2) the protective efficiency of substances specifically for protection of internal and external parts of cells and the process of extender development; (3) the freezing, thawing and fertilization conditions; and (4) the tolerable deviations from the freezing protocol for more easy application. Finally, biomarkers are reported that predict the suitability of semen for cryopreservation and the quality of frozen–thawed semen.
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Cryopreservation of semen of the grayling (Thymallus thymallus) and the Danube salmon (Hucho Hucho)
Aquaculture, 1996Co-Authors: Franz Lahnsteiner, T. Weismann, Robert PatznerAbstract:Abstract Cryopreservation of semen of Thymallus thymallus and of Hucho Hucho was investigated with a method that was originally developed for Oncorhynchus mykiss . Assessments of fertilization rate were used to establish the type and concentration of cryoprotectant, freezing rates and thawing conditions for the two species. In both H. Hucho and T. thymallus , 10% methanol was the most effective cryoprotectant, followed by a 5% DMSO-1% glycerol mixture, 10% DMSO, 10% n , n -dimethylacetamide and 5% glycerol. Using an open system and 0.5ml straws, freezing of semen was optimal 1.5 cm above the level of liquid nitrogen (at − 110 ± 2 °C) and thawing was best in a 25 °C water bath for 30s. Post-thaw fertilization rates were 90–100% of control with fresh semen at sperm/egg ratios of (1.2–1.6) × 10 6 spermatozoa per egg in T. thymallus and at sperm/egg ratios of (4.3–5.5) × 10 6 spermatozoa per egg in H. Hucho .
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Composition of the ovarian fluid in 4 salmonid species: Oncorhynchus mykiss, Salmo trutta f lacustris, Salvelinus alpinus and Hucho Hucho
Reproduction nutrition development, 1995Co-Authors: Franz Lahnsteiner, T. Weismann, Robert PatznerAbstract:The ovarian fluid of rainbow trout (Oncorhynchus mykiss), charr (Salvelinus alpinus), lake trout (Salmo trutta f lacustris) and Danube salmon (Hucho Hucho) was analyzed for its inorganic and organic composition. The qualitative composition of the ovarian fluid of the investigated species was similar, but significant quantitative differences were found. The following components were determined: sodium 106.6-142.2 mmol/l, potassium 1.7-2.7 mmol/l, calcium 0.45-0.61 mmol/l, osmolality 256.4-291.6 mosmol/kg, pH 8.4-8.8, glucose 1,698-4,195 mumol/l, fructose 17-399 mumol/l, lactate 34-227 mumol/l, cholesterol 650-1,230 mumol/l, phosphatidylcholine 0.25-3.0 mumol/l, lysophosphatidylcholine 10-100 mumol/l, choline 0-1.1 mumol/l, protein 95.0-278.4 mg/100 ml. Arginine, cystine, glycine, histidine, lysine, proline, serine, tyrosine and valine were the free amino acids occurring in concentrations of more than 10 mumol/l. Activities of alkaline phosphatase (200-6,000 mumol substrate/l/h), lactate dehydrogenase (9-690 mumol substrate/l/h), beta-D-glucuronidase (70-410 mumol substrate/l/h), proteases (140-215 mumol/l/h with collagen substrate, 25-90 mumol/h/l with gelatine substrate) and acid phosphatase (100-130 mumol substrate/l/h) were measured, but not the glucose-6-phosphate dehydrogenase and alpha-glucosidases activities.
Youyi Kuang - One of the best experts on this subject based on the ideXlab platform.
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first high resolution genetic linkage map of taimen Hucho taimen and its application in qtl analysis of growth related traits
Aquaculture, 2020Co-Authors: Guangxiang Tong, Longwu Geng, Yi Zhou, Huan Xu, Yongquan Zhang, Youyi KuangAbstract:Abstract Taimen (Hucho taimen) is an excellent aquaculture species. Currently, no selective breeding program has been conducted. To promote molecular breeding for taimen, we used genotype-by-sequencing technology to construct a high-resolution linkage map and performed QTL studies of growth-related traits. We sequenced 177 individuals of two full-sib families and obtained 58,016 SNPs. Among them, 30,535 SNPs were assigned to 42 linkage groups. The linkage map contained 6734 unique loci and spanned 4253.484 cM in total, with an average interval distance of 0.657 cM. The length for each linkage group ranged from 66.257 cM to 135.533 cM, with an average interval distance of 0.468 cM to 1.110 cM. This SNP linkage map integrated 65.1% scaffolds of the Hucho Hucho genome to form 42 pseudo-chromosomes, with a mean correlation coefficiency of 0.893 between the linkage map and the genome. Based on this high-resolution linkage map, we performed QTL analyses of four growth-related traits of taimen aged 6–7 months. The analyses discovered 27 QTLs, including 18 QTLs for body weight, 5 QTLs for standard length, 3 QTLs for body thickness, and 1 QTL for body height. Based on Hucho Hucho genome annotation, 487 genes within QTL regions were enriched in metabolism-related pathways; these genes could serve as candidate genes associated with the growth of taimen. The linkage map and QTLs obtained in this study provide useful tools for genetic studies and molecular breeding of taimen.
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de novo assembly and characterization of the Hucho taimen transcriptome
Ecology and Evolution, 2018Co-Authors: Guangxiang Tong, Yongquan Zhang, Qingyu Zhang, Jiasheng Yin, Youyi KuangAbstract:Taimen (Hucho taimen) is an important ecological and economic species that is classified as vulnerable by the IUCN Red List of Threatened Species; however, limited genomic information is available on this species. RNA-Seq is a useful tool for obtaining genetic information and developing genetic markers for nonmodel species in addition to its application in gene expression profiling. In this study, we performed a comprehensive RNA-Seq analysis of taimen. We obtained 157 M clean reads (14.7 Gb) and used them to de novo assemble a high-quality transcriptome with a N50 size of 1,060 bp. In the assembly, 82% of the transcripts were annotated using several databases, and 14,666 of the transcripts contained a full open reading frame. The assembly covered 75% of the transcripts of Atlantic salmon and 57.3% of the protein-coding genes of rainbow trout. To learn about the genome evolution, we performed a systematic comparative analysis across 11 teleosts including eight salmonids and found 313 unique gene families in taimen. Using Atlantic salmon and rainbow trout transcriptomes as the background, we identified 250 positive selection transcripts. The pathway enrichment analysis revealed a unique characteristic of taimen: It possesses more immune-related genes than Atlantic salmon and rainbow trout; moreover, some genes have undergone strong positive selection. We also developed a pipeline for identifying microsatellite marker genotypes in samples and successfully identified 24 polymorphic microsatellite markers for taimen. These data and tools are useful for studying conservation genetics, phylogenetics, evolution among salmonids, and selective breeding for threatened taimen.
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analysis of genetic diversity in the endangered Hucho taimen from china
Acta Ecologica Sinica, 2009Co-Authors: Youyi Kuang, Guangxiang Tong, Jiasheng Yin, Xiaowen SunAbstract:Abstract Hucho taimen are listed as endangered in China. The population size has declined recently, prompting an increase in the level of listing from grade three in 2002 to grade five in 2006. We analyzed the genetic diversity of wild populations using 17 microsatellite markers to establish a scientific basis for conservation of this species. We collected tissue samples from four populations in the Heilongjiang River basin: Huma River (HM), Hutou (HT), Haiqing (HQ), and Zhuaji (ZJ). A total of 21 loci were amplified, 18 of which were polymorphic. The number of alleles per locus ranged from 2 to 9 (mean: 4.1905). There were 13 highly polymorphic loci and 5 moderately polymorphic loci. Analysis of five genetic diversity parameters ( Na, Ne, Ho, He, and PIC) suggested moderate levels of diversity within the populations. The populations were ranked HT > HQ > ZJ > HM, but the differences in diversity were not statistically significant ( P > 0.05). A comparison of variation among all four populations suggested Hardy–Weinberg disequilibrium at 20% of the loci. Genetic differentiation ( Fst ) was 0.0644 and the gene flow among populations was estimated at 3.36 individuals per generation. The majority of diversity (93.88%) occurred among individuals within a population. In contrast, relatively little (6.12%) of the genetic diversity was distributed between the populations. An analysis of genetic differentiation and genetic distance between pairs of populations revealed that both parameters were higher in comparisons of the HM population to the HT, HQ, and ZJ populations than among the three latter populations. This suggests that the HM population has a distinct genetic structure. We hypothesize that habitat degradation and excessive fishing, not low genetic diversity, has caused the decline in H. taimen populations. However, this species should be protected from further declines in genetic diversity.
Guangxiang Tong - One of the best experts on this subject based on the ideXlab platform.
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first high resolution genetic linkage map of taimen Hucho taimen and its application in qtl analysis of growth related traits
Aquaculture, 2020Co-Authors: Guangxiang Tong, Longwu Geng, Yi Zhou, Huan Xu, Yongquan Zhang, Youyi KuangAbstract:Abstract Taimen (Hucho taimen) is an excellent aquaculture species. Currently, no selective breeding program has been conducted. To promote molecular breeding for taimen, we used genotype-by-sequencing technology to construct a high-resolution linkage map and performed QTL studies of growth-related traits. We sequenced 177 individuals of two full-sib families and obtained 58,016 SNPs. Among them, 30,535 SNPs were assigned to 42 linkage groups. The linkage map contained 6734 unique loci and spanned 4253.484 cM in total, with an average interval distance of 0.657 cM. The length for each linkage group ranged from 66.257 cM to 135.533 cM, with an average interval distance of 0.468 cM to 1.110 cM. This SNP linkage map integrated 65.1% scaffolds of the Hucho Hucho genome to form 42 pseudo-chromosomes, with a mean correlation coefficiency of 0.893 between the linkage map and the genome. Based on this high-resolution linkage map, we performed QTL analyses of four growth-related traits of taimen aged 6–7 months. The analyses discovered 27 QTLs, including 18 QTLs for body weight, 5 QTLs for standard length, 3 QTLs for body thickness, and 1 QTL for body height. Based on Hucho Hucho genome annotation, 487 genes within QTL regions were enriched in metabolism-related pathways; these genes could serve as candidate genes associated with the growth of taimen. The linkage map and QTLs obtained in this study provide useful tools for genetic studies and molecular breeding of taimen.
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de novo assembly and characterization of the Hucho taimen transcriptome
Ecology and Evolution, 2018Co-Authors: Guangxiang Tong, Yongquan Zhang, Qingyu Zhang, Jiasheng Yin, Youyi KuangAbstract:Taimen (Hucho taimen) is an important ecological and economic species that is classified as vulnerable by the IUCN Red List of Threatened Species; however, limited genomic information is available on this species. RNA-Seq is a useful tool for obtaining genetic information and developing genetic markers for nonmodel species in addition to its application in gene expression profiling. In this study, we performed a comprehensive RNA-Seq analysis of taimen. We obtained 157 M clean reads (14.7 Gb) and used them to de novo assemble a high-quality transcriptome with a N50 size of 1,060 bp. In the assembly, 82% of the transcripts were annotated using several databases, and 14,666 of the transcripts contained a full open reading frame. The assembly covered 75% of the transcripts of Atlantic salmon and 57.3% of the protein-coding genes of rainbow trout. To learn about the genome evolution, we performed a systematic comparative analysis across 11 teleosts including eight salmonids and found 313 unique gene families in taimen. Using Atlantic salmon and rainbow trout transcriptomes as the background, we identified 250 positive selection transcripts. The pathway enrichment analysis revealed a unique characteristic of taimen: It possesses more immune-related genes than Atlantic salmon and rainbow trout; moreover, some genes have undergone strong positive selection. We also developed a pipeline for identifying microsatellite marker genotypes in samples and successfully identified 24 polymorphic microsatellite markers for taimen. These data and tools are useful for studying conservation genetics, phylogenetics, evolution among salmonids, and selective breeding for threatened taimen.
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analysis of genetic diversity in the endangered Hucho taimen from china
Acta Ecologica Sinica, 2009Co-Authors: Youyi Kuang, Guangxiang Tong, Jiasheng Yin, Xiaowen SunAbstract:Abstract Hucho taimen are listed as endangered in China. The population size has declined recently, prompting an increase in the level of listing from grade three in 2002 to grade five in 2006. We analyzed the genetic diversity of wild populations using 17 microsatellite markers to establish a scientific basis for conservation of this species. We collected tissue samples from four populations in the Heilongjiang River basin: Huma River (HM), Hutou (HT), Haiqing (HQ), and Zhuaji (ZJ). A total of 21 loci were amplified, 18 of which were polymorphic. The number of alleles per locus ranged from 2 to 9 (mean: 4.1905). There were 13 highly polymorphic loci and 5 moderately polymorphic loci. Analysis of five genetic diversity parameters ( Na, Ne, Ho, He, and PIC) suggested moderate levels of diversity within the populations. The populations were ranked HT > HQ > ZJ > HM, but the differences in diversity were not statistically significant ( P > 0.05). A comparison of variation among all four populations suggested Hardy–Weinberg disequilibrium at 20% of the loci. Genetic differentiation ( Fst ) was 0.0644 and the gene flow among populations was estimated at 3.36 individuals per generation. The majority of diversity (93.88%) occurred among individuals within a population. In contrast, relatively little (6.12%) of the genetic diversity was distributed between the populations. An analysis of genetic differentiation and genetic distance between pairs of populations revealed that both parameters were higher in comparisons of the HM population to the HT, HQ, and ZJ populations than among the three latter populations. This suggests that the HM population has a distinct genetic structure. We hypothesize that habitat degradation and excessive fishing, not low genetic diversity, has caused the decline in H. taimen populations. However, this species should be protected from further declines in genetic diversity.