Reproductive health and endocrine disruption in smallmouth bass (Micropterus dolomieu) from the Lake Erie drainage, Pennsylvania, USA

Heather L Walsh,Sean D Rafferty,Stephanie E Gordon,Vicki S Blazer

doi:10.1007/s10661-021-09654-2

Heather L Walsh, Sean D Rafferty + Show 2 more

Open Access

https://doi.org/10.1007/s10661-021-09654-2

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Abstract

Smallmouth bass Micropterus dolomieu were sampled from three sites within the Lake Erie drainage (Elk Creek, Twentymile Creek, and Misery Bay, an embayment in Presque Isle Bay). Plasma, tissues for histopathological analyses, and liver and testes preserved in RNALater® were sampled from 30 smallmouth bass (of both sexes) at each site. Liver and testes samples were analyzed for transcript abundance with Nanostring nCounter® technology. Evidence of estrogenic endocrine disruption was assessed by the presence and severity of intersex (testicular oocytes; TO) and concentrations of plasma vitellogenin in male fish. Abundance of 17 liver transcripts associated with reproductive function, endocrine activity, and contaminant detoxification pathways and 40 testes transcripts associated with male and female reproductive function, germ cell development, and steroid biosynthesis were also measured. Males with a high rate of TO (87–100%) and plasma vitellogenin were noted at all sites; however, TO severity was greatest at the site with the highest agricultural land cover. Numerous transcripts were differentially regulated among the sites and patterns of transcript abundance were used to better understand potential risk factors for estrogenic endocrine disruption. The results of this study suggest endocrine disruption is prevalent in this region and further research would benefit to identify the types of contaminants that may be associated with the observed biological effects.

Highlights

Smallmouth bass (SMB) Micropterus dolomieu are apex predators and important sportfish throughout both native and introduced ranges (Noble, 2002)
The results of this study suggest endocrine disruption is prevalent in this region and further research would benefit to identify the types of contaminants that may be associated with the observed biological effects
Misery Bay (MB) had the smallest drainage size (76.6 km2), the greatest amount of developed landcover (72%) and the least amount of agricultural landcover (3.1%) which was dominated by pasture (2.9%)

Summary

Introduction

Smallmouth bass (SMB) Micropterus dolomieu are apex predators and important sportfish throughout both native and introduced ranges (Noble, 2002) They are native to the Great Lakes region, including the Lake Erie drainage, where angling is economically important and brings in roughly $40.6 million in revenue annually, providing more than $13 million in income for local residents (Graefe et al, 2018). Health issues, including mortality events of young-of-year (Smith et al, 2015; Walsh et al, 2018), as well as skin lesions (Blazer et al, 2020), a high prevalence of intersex (testicular oocytes; TO), and other signs of exposure to endocrine disrupting contaminants in adults (Blazer et al, 2014a) have been observed there These have raised concerns of resource managers and the public but have been associated with population declines (Schall et al, 2018a; Smith et al, 2015). No single cause for the health anomalies has been identified; rather, poor water quality, complex mixtures of contaminants, and various pathogens and parasites have been identified as potential risk factors (Boonthai et al, 2018; Schall et al, 2018b; Walsh et al, 2018)

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