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Acipenser baerii is one of the most important sources of caviar production. However, the population of the A. baerii is constantly being reduced in recent years due to dam construction, overfishing, and water pollution. Insufficient molecular markers have limited the effective conservation and management of this species; In the present study, we reported the isolation and characterization of 34 SNP markers in A. baerii; The minor allele frequency ranged from 0.050 to 0.483. The observed heterozygosity varied from 0.100 to 0.933, while the expected heterozygosity ranged from 0.097 to 0.508. Polymorphic information content ranged from 0.090 to 0.375. Seven loci showed significant deviations from the HWE after Bonferroni correction; The novel polymorphic SNPs will be helpful for the future study on molecular-aided breeding, population conservation, and construction of genetic linkage map for this species. [ABSTRACT FROM AUTHOR]

We report here the first application of the Spatially Referenced Regressions on Watershed Attributes (SPARROW) model to China, a country naturally and culturally distinct from previous SPARROW applications. The Songhuajiang River Basin (556,700 km) empties into the Tongjiang monitoring section, a shared water resource of great import for both Chinese and Russian citizens. The model was calibrated to annual loads of total nitrogen (TN) at 102 sites and total phosphorus (TP) at 65 sites. We assessed the rates of delivery and loss of nutrients from diffuse sources and also provided reach-level predictions of the percentage of nutrient loads delivered from upstream subbasins to Tongjiang monitoring section. The results indicated that farmland and pasture land were responsible for about 70 % of nutrient inputs to the Tongjiang monitoring section. Point source inputs were not statistically significant sources of TN or TP. We presented evidence that rice paddies delivered less TN to streams per area than other types of cropland. The locations responsible for the highest TN and TP inputs to the Tongjiang monitoring section tended to be located near the mainstream, though the areas of highest TN delivered yield did not correspond to the areas of highest TP delivered yield. This suggests that different management priorities may be needed in different parts of the Songhuajiang River Basin. [ABSTRACT FROM AUTHOR]

Elongate loach ( Leptobotia elongata (Bleeker)), an endemic fish species to China, is a famous ornamental freshwater fish. Here, a comparative study of mtDNA control region (D-loop) (835 bp) sequences was performed to analyze its wild population structure and evaluate the genetic diversity for 110 individuals from five locations in the upper reaches of the Yangtze River, China. A total of 49 polymorphic sites and 45 haplotypes yielded high haplotype diversity ( h = 0.952), but low nucleotide diversity ( π = 0.00454) as that of many fish species. Sequence divergences between haplotypes ranged from 0.0033 ± 0.0011 to 0.0050 ± 0.0012 in intra-groups, and from 0.0037 ± 0.0.0011 to 0.0050 ± 0.0012 between groups. Significant values of Tajima's D (−1.86383, P < 0.01) and Fu's F (−25.93, P < 0.01), together with uni-modal mismatch distribution, indicated a recent genetic bottleneck or population expansion of the species. Analysis of molecular variance (AMOVA) indicated a small amount of differentiation among groups (1.7%); most of the total variation occurred within groups (98.3%). Also, there was no significant population structure ( F = 0.017, P > 0.05), and estimates of gene flows among groups were extremely high ( Nm = 28.88), suggesting low genetic divergence between populations in the species. The lack of genetic differentiation among groups is most likely due to the combined gene flow from the downstream movement of eggs and larvae with currents and the upstream or downstream migration of adults throughout the distribution. These groups of L. elongata distributed in upper reaches of the Yangtze River should be considered as a single management unit. [ABSTRACT FROM AUTHOR]