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It is critical to investigate the tissue distribution and maternal transfer of poly- and perfluorinated compounds (PFCs) in wild fish for assessing potential effects on ecosystems. Concentrations of 23 PFCs in nine organs and egg were measured in 16 17- to 25-year-old female Chinese sturgeon (Acipenser sinensis, an anadromous fish), that died during propagation. Three polyfluorinated amides were detected in stomach, intestine, and gills and 7:3 FTCA was specifically accumulated in liver. The greatest total concentration of PFCs in egg was 35.1 +/- 10.4 ng/g ww and was predominated by perfluorooctane sulfonate (PFOS) and perfluorotridecanoate acid (PFTriDA). The longer-chain C(11)-C(14) and C(16) perfluorinated carboxylates were more accumulated in Chinese sturgeon than PFOS, partly due to the increasing trends of PFCAs with fish age. Maternal transfer ratios of PFCs expressed as ratios of concentrations in the egg to those in the liver ranged from 0.79 (perfluorooctanoate) to 5.5 (PFTriDA), depending on their carbon chain lengths or protein-water coefficients. The PFOS equivalent of PFC mixtures, calculated by multiplying the relative potency factor of each PFC to PFOS by the corresponding concentration, ranged from 90.6 to 262 ng/g. The hazard quotient was 0.20, implying potential reproductive effects of PFCs on Chinese sturgeon.

Sturgeons and paddlefishes (Acipenseriformes) occupy the basal position of ray-finned fishes, although they have cartilaginous skeletons as in Chondrichthyes. This evolutionary status and their morphological specializations make them a research focus, but their complex genomes (polyploidy and the presence of microchromosomes) bring obstacles and challenges to molecular studies. Here, we generated the first high-quality genome assembly of the American paddlefish (Polyodon spathula) at a chromosome level. Comparative genomic analyses revealed a recent species-specific whole-genome duplication event, and extensive chromosomal changes, including head-to-head fusions of pairs of intact, large ancestral chromosomes within the paddlefish. We also provide an overview of the paddlefish SCPP (secretory calcium-binding phosphoprotein) repertoire that is responsible for tissue mineralization, demonstrating that the earliest flourishing of SCPP members occurred at least before the split between Acipenseriformes and teleosts. In summary, this genome assembly provides a genetic resource for understanding chromosomal evolution in polyploid nonteleost fishes and bone mineralization in early vertebrates.

The anadromous Chinese sturgeon (Acipenser sinensis) is endangered and listed among the first class of protected animals in China. The possible causes for the decline of this species are the effects of synthetic chemicals, and loss of critical habitat. Chinese sturgeon in the Yangtze River have accumulated triphenyltin (TPT) to 31-128 ng/g wet weigh (ww) in liver, which is greater than the concentrations of tributyltin (<1.0 ng/g ww). Maternal transfer of TPT has resulted in concentrations of 25.5 ؎ 13.0 ng/g ww in eggs of wild Chinese sturgeon, which poses a significant risk to the larvae naturally fertilized or hatched in the Yangtze River. The incidence of deformities in fry was 7.5%, with 1.2% of individuals exhibiting ocular abnormal development, and 6.3% exhibited skeletal/morphological deformations. The incidences of both ocular and skeletal/morphological deformations were directly proportional to the TPT concentration in the eggs of both the Chinese sturgeon and the Siberian sturgeon (Acipenser baerii) in controlled laboratory studies. The rates of deformities in the controlled studies were consistent with the rates caused at the similar concentrations in eggs collected from the field. Thus, TPT is the causal agent to induce the malformation of larvae of Chinese sturgeon. The incidence of deformed larvae of Chinese sturgeon is an indicator of overall population-level effects of TPT on Chinese sturgeon, because TPT at environmentally relevant concentrations can result in significantly decrease both quality and quantity of eggs and spawning frequency of fish.teratogenesis ͉ fish ͉ triphenyltin ͉ Yangtze River

BackgroundThe Chinese sturgeon (Acipenser sinensis) is endangered through anthropogenic activities including over-fishing, damming, shipping, and pollution. Controlled reproduction has been adopted and successfully conducted for conservation. However, little information is available on the reproductive regulation of the species. In this study, we conducted de novo transcriptome assembly of the gonad tissue to create a comprehensive dataset for A. sinensis.ResultsThe Illumina sequencing platform was adopted to obtain 47,333,701 and 47,229,705 high quality reads from testis and ovary cDNA libraries generated from three-year-old A. sinensis. We identified 86,027 unigenes of which 30,268 were annotated in the NCBI non-redundant protein database and 28,281 were annotated in the Swiss-prot database. Among the annotated unigenes, 26,152 and 7,734 unigenes, respectively, were assigned to gene ontology categories and clusters of orthologous groups. In addition, 12,557 unigenes were mapped to 231 pathways in the Kyoto Encyclopedia of Genes and Genomes Pathway database. A total of 1,896 unigenes, potentially differentially expressed between the two gonad types, were found, with 1,894 predicted to be up-regulated in ovary and only two in testis. Fifty-five potential gametogenesis-related genes were screened in the transcriptome and 34 genes with significant matches were found. Besides, more paralogs of 11 genes in three gene families (sox, apolipoprotein and cyclin) were found in A. sinensis compared to their orthologs in the diploid Danio rerio. In addition, 12,151 putative simple sequence repeats (SSRs) were detected.ConclusionsThis study provides the first de novo transcriptome analysis currently available for A. sinensis. The transcriptomic data represents the fundamental resource for future research on the mechanism of early gametogenesis in sturgeons. The SSRs identified in this work will be valuable for assessment of genetic diversity of wild fish and genealogy management of cultured fish.

Freshwater capture fisheries are globally essential for food security and aquatic biodiversity conservation. The Yangtze River Basin is the third longest and one of the most human-influenced drainage basins worldwide. Since the founding of P. R.China in 1949, this large river system has suffered increasing human perturbation and its sustainable development is now severely challenged. Meta-analysis showed that Yangtze River fisheries have experienced an extraordinary process of utilization-over-exploitation-protection during the past 70 years, to an extent that other globally important rivers may never have encountered. Its fisheries appear to have collapsed over the past four decades, with yield decreasing to only 25% of an historical peak of 400,000 metric tonnes in the late 1950s. Endemic, migratory and rare fishes have been highly threatened with obvious changes in fish community structure and aquatic biodiversity. Anthropogenic activities, including impoundment of water in dams, discharge of pollutants and riverine modification for vessel navigation, have caused large decreases in fisheries yields. Projections from surplus production modelling showed potential for improvement under fishing ban scenarios, but without any prospect for full recovery to historical stock status. This study revealed that the change in fisheries resources was dominated by the social-ecological watershed system, and an integrated approach to river basin management is warranted. Better management of freshwater ecosystems to integrate food security with biodiversity conservation is urgently needed throughout the world, and the changes evident in the Yangtze River fish populations can serve as an informative global reference. K E Y W O R D Sbiodiversity conservation, China, fishing ban, food security, human impact, inland fishery