Survey of Intersex Occurrence in Largemouth Bass (Micropterus salmoides) from the Upper Illinois River Waterway

Basin-scale patterns of common carp physiological condition associated with EDC exposure in a large Anthropocene river

“…Literature reviews suggest that different types of EDCs found in the water column that largemouth bass and black crappie are exposed to may trigger a different physiological response than the EDCs found in the sediment that common carp and channel catfish are exposed to (Windsor et al 2018). The contrasting results of pelagic versus benthic feeders between the upper and lower portions of Illinois River (Fritts et al 2016; this study) support the idea of speciesspecific associations between trophic position or habitat preference and EDC accumulation noted by other authors (Müller et al 2020;Fan et al 2019;Windsor et al 2018).…”

“…We expected that common carp would show similar intersex prevalence to largemouth bass and black crappie from the same reaches of the Illinois River, because common carp are susceptible to intersex from EDC exposure (Goodbred et al 1997;Hinck et al 2009;Solé et al 2003;Devlin and Nagahama 2002;Gimeno et al 1998). Previous studies from the Illinois River showed that 41% of male largemouth bass (n = 51) and 27% of male black crappie (n = 22) exhibited intersex (Fritts et al 2016;. In contrast, we found that only 4% (n = 6) of male common carp exhibited intersex, although this prevalence is greater than other broad-scale studies that included common carp (e.g., Schmitt et al 2005;Hinck et al 2009).…”

“…The suite of biomarkers we used in this study did not differ between intersex and non-intersex male common carp. This is similar to previous largemouth bass and black crappie studies in the Illinois River (Fritts et al 2016(Fritts et al , 2018. However, we did observe sex-specific differences in the spatial patterns of most of the biomarkers we investigated.…”

“…Although the Illinois River has had substantial cumulative concentration of a variety of potent EDC for decades (Starrett 1972;Sparks et al 1993;White et al 1994;Denier et al 2009;Mehler et al 2010;Duncker et al 2020), prevalence of intersex condition in common carp in this river appears to be no different than the 5% natural background rate for other wild populations of this species (Komen et al 1989). Despite the evidence of intersex in largemouth bass and black crappie from the same Illinois River locations (Fritts et al 2016(Fritts et al , 2018, we conclude that it is unlikely that EDC leading to intersex condition is contributing to the declining common carp population in this river (Gibson-Reinemer et al 2017a). Ultimately, it is important to continue monitoring the reproductive health of common carp and other socially and economically valuable species.…”

“…Moreover, because EDCs 1 3 such as estrogenic compounds like phenols, phthalates, and heavy metals are largely untreated even in modern facilities, aquatic organisms are thought to be at ongoing risk (Denier et al 2009;White et al 1994; U.S. EPA 2015). As early as the 1940s, intersex was documented in the Illinois River in important sportfish species like largemouth bass (Micropterus salmoides Lacépède) and black crappie (Pomoxis nigromaculatus Valenciennes) (James 1946;Fritts et al 2016Fritts et al , 2018. The extensive literature on EDCs in the Illinois River means we can confidently assume the fish assemblage, including common carp, is exposed (Barber et al 2015;Battaglin et al 2020).…”