Details:

Journal Title:
Environmental Toxicology and Chemistry
Personal Author:
Kadlec, Sarah M. ; Blackwell, Brett R. ; Blanksma, Chad A. ; Johnson, Rodney D. ; Olker, Jennifer H. ; ... More +
Kadlec, Sarah M. ; Blackwell, Brett R. ; Blanksma, Chad A. ; Johnson, Rodney D. ; Olker, Jennifer H. ; Schoff, Patrick K. ; Mount, David R. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; Sea Grant
OAR (Oceanic and Atmospheric Research) ; Sea Grant Less -
Sea Grant Program:
MINNU (Minnesota Sea Grant)
Description:
Testicular oocytes in wild adult bass (Micropterus spp.) are considered a potential indication of exposure to estrogenic compounds in municipal, agricultural, or industrial wastewater. However, our ability to interpret links between testicular oocyte occurrence in wild fish species and environmental pollutants is limited by our understanding of normal and abnormal gonadal development. We previously reported low-to-moderate testicular oocyte prevalence (7%–38%) among adult male bass collected from Minnesota waters with no known sources of estrogenic compounds. In the present study, two experiments were conducted in which smallmouth bass (Micropterus dolomieu) fry were exposed to control water or 17-α-ethinylestradiol (EE2) during gonadal differentiation, then reared in clean water for an additional period. Histological samples were evaluated at several time points during the exposure and grow-out periods, and the sequence and timing of gonadal development in the presence of estrogen were compared with that of control fish. Testicular oocytes were not observed in any control or EE2-exposed fish. Among groups exposed to 1.2 or 5.1 ng/L EE2 in Experiment 1 or 3.0 ng/L EE2 in Experiment 2, ovaries were observed in 100% of fish up to 90 days after exposure ceased, and approximately half of those ovaries had abnormal characteristics, suggesting that they likely developed in sex-reversed males. Groups exposed to 0.1, 0.4, or 1.0 ng/L in Experiment 2 developed histologically normal ovaries and testes in proportions not significantly different from 1:1. These findings suggest that, while presumably able to cause sex reversal, juvenile exposure to EE2 may not be a unique cause of testicular oocytes in wild bass, although the long-term outcomes of exposure are unknown. Environ Toxicol Chem 2022;00:1–13. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
Keywords:
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Histology, Pathological Smallmouth Bass
Source:
Environmental Toxicology and Chemistry, Early View
DOI:
https://doi.org/10.1002/etc.5320
Document Type:
Journal Article
Funding:
Grant no. NA10OAR4170069
Rights Information:
Public Domain
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:ded0be019abdab0ba86ecbf13a43bbd3a10d8789a4af29113286a99a2f7b368b
Download URL:
https://repository.library.noaa.gov/view/noaa/40158/noaa_40158_DS1.pdf
File Type:

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