Evaluating the potential role of bioactive chemicals on the distribution of invasive Asian carp upstream and downstream from river mile 278 in the Illinois waterway

Why the Stall? Using metabolomics to define the lack of upstream movement of invasive bigheaded carp in the Illinois River

“…More importantly, Jeffrey et al (2019) [ 43 ] also found that silver carp collected from Rock Run Rookery at the leading edge displayed upregulation of three members of the ATP-binding cassette proteins, commonly referred to as ABC transporters, which are highly conserved transmembrane transport proteins that confer multixenobiotic-resistance allowing organisms to survive in polluted environments [ 69 – 71 ]. Thus, it is likely that the reduced concentrations of eicosanoyl glycerol acid and campesterol seen in bigheaded carp livers sampled from the leading edge of the population resulted from increased energy use and contaminant exposure due to detoxification, consistent with previous transcriptomics work and environmental monitoring [ 42 , 43 ]. It should be noted that there are other alternative explanations that should also be investigated.…”

“…Previous water quality assessments performed in the Illinois River by Battaglin et al (2020) [ 42 ] found concentrations of contaminants and bioactive chemicals (e.g., volatile organic compounds (VOCs), pharmaceuticals, wastewater indicators, hormones and metal) were elevated in samples collected upstream of Rock Run Rookery (i.e., the leading edge of bigheaded carp), with concentrations of many bioactive chemicals declining in downstream locations [ 42 ]. In addition, a previous investigation by Jeffrey et al (2019) [ 43 ] found that the gene expression patterns in livers from silver carp collected from Rock Run Rookery showed signatures of increased energy use, and decreased activity of cellular protective mechanisms, relative to silver carp collected from two downstream populations.…”

“…Despite this variation in food resources, both across seasons and across locations, silver carp and bigheaded carp have been shown to exhibit little temporal variation in nutritional indices when sampled across different regions [ 78 ], and previous work showed that silver carp at the leading edge of the Illinois River population were not experiencing impaired nutritional status compared to downstream locations [ 43 ], indicating that food resources do not appear to be limiting in these species across either time or space. Water in the upper reaches of the Illinois River contains higher concentrations of containments and flux of bioactive chemicals compared to downstream sites [ 42 ], and the plankton and suspended particles that carp feed on can accumulate bioactive chemicals from the water [ 79 – 81 ]. The one exception to this trend is that the 10 fish captured from the Starved Rock in the downstream location on May 22 nd showed a puzzling difference in metabolomics signatures.…”

“…The leading edge site at Rock Run by its very nature, has lower numbers of fish compared to the more established populations downstream [ 43 ], and the intent of this study was to collect fish from as far upstream as possible. Collections from areas farther downstream would have likely increased sample sizes, but would not have reflected the true leading edge of the population, and would not have occurred in areas of previously shown to contain elevated water contaminants [ 42 ]. Following capture, fish were euthanized via cerebral percussion then total length (TL), mass, and sex were recorded.…”

“…The movement of fish away from areas of degraded habitat or due to noxious stimuli has been well documented [ 38 – 40 ], and is believed to occur as fish ‘choose’ to avoid inhabiting water with sub-optimal quality and avoid costly upregulation of the stress response [ 40 , 41 ]. Work by Battaglin et al (2020) [ 42 ] showed that a number of pollutants in the Illinois River, including wastewater indicators, metals, hormones and pharmaceuticals, have a higher concentration upstream of the leading edge of carp relative to downstream, and, based on this abrupt change in water quality upstream of the leading edge of carp, Battaglin et al (2020) [ 42 ] suggested that the presence of contaminants “could represent a barrier to carp range expansion”. Additionally, Jeffrey et al (2019) [ 43 ] used a transcriptomics approach to show that silver carp at the upstream edge in the Illinois Waterway had an upregulation of genes related to contaminant exposure and energy use in livers relative to fish in two downstream populations, again suggesting that contaminants “may represent a non-permanent barrier to silver carp range expansion”.…”