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Increasing numbers of Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis (commonly called "bigheaded carp") in the Illinois River have led to concerns about the impact that their invasion has on native food web dynamics. Bigheaded Carp recruited in large numbers in the LaGrange Reach of the Illinois River during the summer of 2014. This provided an opportunity to determine whether native piscivorous fish prey upon invasive carp when they are abundant. Using electrofishing and fyke nets in the LaGrange Reach (August 1–November 8, 2014), we sampled native predatory fish (n = 1,472) for stomach content analysis. Fish community data from the Upper Mississippi River Restoration Program's Long‐Term Resource Monitoring was used to quantify prey abundance (fish < 100 mm) in the study area and indicated that bigheaded carp represented 9% of available prey. Stomach content analysis revealed that the frequency of occurrence of juvenile bigheaded carp was greater than 15% in Shortnose Gar Lepisosteus platostomus, White Bass Morone chrysops, Black Crappie Pomoxis nigromaculatus, Channel Catfish Ictalurus punctatus, Smallmouth Bass Micropterus dolomieu, Largemouth Bass Micropterus salmoides, White Crappie Pomoxis annularis, Yellow Perch Perca flavescens, Flathead Catfish Pylodictis olivaris, Freshwater Drum Aplodinotus grunniens, and Yellow Bass Morone mississippiensis. Predators sampled in August and September foraged more heavily on juvenile bigheaded carp than those sampled in October and November. Electivity analysis suggested that juvenile bigheaded carp were selected over native forage by White Bass, Black Crappie, and Shortnose Gar, as these predators continued consuming them even as availability declined. Our results imply that native piscivores in the Illinois River consume and sometimes prefer juvenile bigheaded carp as prey. These results suggest that native predators might play a role in regulating bigheaded carp recruitment and that negative impacts to predators in areas of dense carp populations might be somewhat mitigated by the consumption of juvenile bigheaded carp. [ABSTRACT FROM AUTHOR]

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) that affects cervid species throughout North America. We evaluated gene expression in white‐tailed deer collected by Illinois Department of Natural Resource wildlife managers during annual population reduction (e.g., sharpshooting) and disease monitoring efforts throughout the CWD‐endemic area of northcentral Illinois. We conducted comparative transcriptomic analysis of liver and retropharyngeal lymph node tissue samples between CWD‐positive (n = 5) and CWD‐not detected (n = 5) deer. A total of 74,479 transcripts were assembled, and 51,661 (69.36%) transcripts were found to have matched proteins in NCBI‐NR and UniProt. Our analysis of functional categories showed 40,308 transcripts were assigned to at least one Gene Ontology term and 37,853 transcripts were involved in at least one pathway. We identified a total of 59 differentially expressed genes (DEGs) in CWD‐positive deer, of which 36 and 23 were associated with liver and retropharyngeal lymph node tissues, respectively. Functions of DEGs lend support to previous relationships between misfolded PrP and cellular membranes (e.g., STXBP5), and internal cellular components. We identified several genes that suggest a link between CWD and retroviruses and identified the gene ADIPOQ that acts as a tumor necrosis factor (TNF) antagonist. This gene may lead to reduced production of TNF and impact disease progression and clinical symptoms associated with CWD (i.e., wasting syndrome). Use of candidate genes identified in this study suggests the activation of endogenous processes in CWD‐positive deer, which in turn may enable earlier detection of the disease. [ABSTRACT FROM AUTHOR]