Survey of Intersex (Testicular Oocytes) in Black Crappie Collected from the Illinois River Waterway

Mark W. Fritts, Andrea K. Fritts, Richard M. Pendleton, Todd D. VanMiddlesworth, Levi E. Solomon, Jason A. DeBoer, Andrew F. Casper

Research output: Contribution to journalReview articlepeer-review


Researchers have documented intersex (testicular oocytes) in male fishes in many species worldwide and prevalence of the condition is strongly related to exposure to endocrine-disrupting compounds in aquatic ecosystems. There is no available knowledge about the incidence of intersex in Black Crappie Pomoxis nigromaculatus, an important North American sport fish. The objective of this survey was to investigate the prevalence and distribution of the intersex condition in Black Crappie collected from portions of the Illinois River waterway. We collected and examined 83 Black Crappie. We observed testicular oocytes in 22 individuals (27% intersex), representing the first documentation of intersex condition in wild Black Crappie. The number of oocytes that we observed in intersex Black Crappie ranged from 1 to 67. We documented intersex in individuals collected from all habitats, but there were no significant differences in the prevalence of the condition (Kruskal-Wallis P = 0.56) or the number of oocytes present (P = 0.25) in intersex males from the different habitats. Permutational multivariate analysis of variance indicated that morphometric parameters varied significantly among locations (P = 0.0001), but did not vary significantly between intersex and normal males. We have little information about the current distribution of endocrine-disrupting compounds in the specific regions where we collected Black Crappie for our study. However, we believe our study represents a valuable effort to detect the condition in an important sport fish and lays a foundation for future research.
Original languageEnglish (US)
Pages (from-to)659-665
Number of pages7
JournalJournal of Fish and Wildlife Management
Issue number2
StatePublished - Dec 2018


  • INHS
  • Black Crappie
  • Illinois River
  • Intersex

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology
  • Nature and Landscape Conservation
  • Ecology


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