Complete mitochondrial genome of Brachionus rubens from wuhu, China (Rotifera, Brachionidae).

The complete mitochondrial genome of Brachionus rubens was sequenced using primers design, clone culture, DNA extraction, LONG-PCR amplification, purification and clone sequencing. We found that it is composed of two circular chromosomes, designated mtDNA I (11,398 bp) and mtDNA II (12,820 bp). The gene content of the B. rubens mitochondrial genome was similar to that of the previously reported mitochondrial genome of B. plicatilis. It contained 22 tRNA genes, 2 rRNA genes and 12 protein-coding genes (PCGs). Four of the 12 PCGs had an incomplete stop codons, TA（cob, atp6, nd3）or T(cox3). The A + T content of B. rubens mitochondrial genome was apparently higher (mtDNA-I 70.2% and mtDNA II 70.4%) than that of the mitochondrial genome of B. plicatilis (mtDNA-I 63.9% and mtDNA-II 62.9%).

Influences of local habitat, tributary position, and dam characteristics on fish assemblages within impoundments of low-head dams in the tributaries of the Qingyi River, China.

Low-head dam impoundments modify local habitat and alter fish assemblages; however, to our knowledge, the pattern of how fish assemblages in the impoundments relate to local habitat, tributary position, and dam characteristics is still unclear. We used data collected in 62 impoundments created by low-head dams in headwater streams of the Qingyi River, China, to examine relationships between fish assemblages and local habitat, tributary position, and dam characteristics. We also assessed the relative importance of the three groups of factors in determining fish species richness and composition. Linear regression models showed that fish species richness was related to substrate heterogeneity, confluence link, and dam number upstream. Redundancy analysis showed that fish species compositions were influenced by substrate heterogeneity, confluence link, dam height, dam numbers upstream and downstream. Overall, dam characteristics were more important in affecting fish species richness but less important in determining fish species composition than local habitat (i.e., substrate heterogeneity) and tributary position. Our results suggest that low-head dam may affect fish species richness in impoundments by modifying local habitat and constraining fish movement, and the relative abundances of those fish species may depend more on species habitat presences and stream size than on impoundment size and number.

The complete mitochondrial genome of the Zacco platypus, Huangshan, China (Cypriniformes: Cyprinidae, subfamily Daninninae).

The mitochondrial genome of Zacco platypus (Cypriniformes: Cyprinidae, subfamily Daninninae) is a circular molecule of 16,611 bp in length, containing 37 typical animal mitochondrial genes: 13 protein-coding genes (PCGs), 2 ribosomal RNAs, 22 transfer RNAs and a D-loop region. Its gene order and arrangement are identical to the common type found in most fish mitogenomes. All PCGs start with a typical ATG codon except for COI which use GTG as start codon; all PCGs terminate in the common stop codon TAA or TAG, except for the COII which use single T as stop codon. The D-loop region is 928 bp long, located between tRNAPro and tRNAPhe genes. It contains some structures of repeated motifs and microsatellite-like elements characteristic of the Cyprinidae.

The complete mitochondrial genome of the Acrossocheilus fasciatus (Cyprinidae, Barbinae).

The mitochondrial genome of Acrossocheilus fasciatus (Cyprinidae, Barbinae) is a circular molecule of 16,589 bp in length, containing 37 typical animal mitochondrial genes: 13 protein-coding genes (PCGs), 2 r RNAs, 22 t RNAs and a non-coding D-loop region. Its gene order and arrangement are identical to the common type found in most fish mitogenomes. All PCGs start with a typical ATG codon except for COI which use GTG as a start codon; all PCGs terminate in the common stop codon TAA or TAG, except for the ND2, ND3, ND4, COII, Cytb and COIII which use single T or TA as a stop codon. The non-coding D-loop region is 938 bp long, located between tRNAPro and tRNAPhe genes. It contains some structures of repeated motifs and microsatellite-like elements characteristic of the Cyprinidae.

Influence of a large dam on the longitudinal patterns of fish assemblages in Qingyi Stream.

Using seasonally collected data (2009-2010) from 15 sampling sites that represent first- to fifth-order streams within the Qingyi watershed, we examined the spatio-temporal patterns of fish assemblages along two longitudinal gradients to explore the effects of a large dam on fish assemblages at the watershed scale. No significant variation was observed in either species richness or assemblage structure across seasons. Species richness significantly varied according to stream order and gradient. Dam construction appeared to decrease species richness upstream substantially, while a significant decrease between gradients only occurred within fourth-order streams. Along the gradient without the large dam, fish assemblage structures presented distinct separation between two neighboring stream orders, with the exception of fourth-order versus fifth-order streams. However, the gradient disrupted by a large dam displayed the opposite pattern in the spatial variation of fish assemblages related with stream orders. Significant between-gradient differences in fish assemblage structures were only observed within fourth-order streams. Species distributions were determined by local habitat environmental factors, including elevation, substrate, water depth, current discharge, wetted width, and conductivity. Our results suggested that dam construction might alter the longitudinal pattern in fish species richness and assemblage structure in Qingyi Stream, despite the localized nature of the ecological effect of dams.

[Spatial and temporal patterns of stream fish assemblages in the Qiupu Headwaters National Wetland Park].

Identifying and clarifying how stream fish assemblage patterns vary spatially and temporally are basic measures for the conservation and management of fish species. Based on data collected from 24 wadeable reaches within the Qiupu Headwaters National Wetland Park between May and October 2012, we examined the spatial and temporal patterns of the assemblage structures and diversities, collecting a total of 29 fish species belonging to four orders and ten families. The results of our survey showed influences of local habitat and tributary spatial position variables on fish assemblages. Fish diversity showed significant variations across stream-orders and seasons, which were higher in the second-order streams than in first-order streams and higher in October than in May. Habitat factors such as substrate coarseness and heterogeneity, water temperature and water depth, as well as tributary position factor-link, showed significant effects on fish diversity. Fish assemblages fitted the nested pattern that upstream assemblages presented as a nested subset of downstream assemblages. Fish assemblage structures did not vary significantly across seasons but did across stream-orders; fish assemblages between first- and second-order streams showed significant differences despite some overlap. These spatial differences mainly resulted from spatial variations of the relative abundance of Cobitis rarus, Ctenogobius sp., Zacco platypus, Phoxinus oxycephalus, Rhodeus ocellatus and Vanmanenia stenosoma, among which P. oxycephalus had higher abundance in first-order than in second-order streams but the other five species were more abundant in second-order streams. Fish assemblage structures were significantly related to substrate heterogeneity, water depth, stream order, link and C-link.