Diana Papoulias, , Columbia Environmental Research Center, 4200 New Haven Road, Columbia, MO 65201; 573-876-1902;

Co-Authors: Mark L. Wildhaber (1), Aaron J. Delonay (1), Mandy L. Annis (1), Steven Krentz (2), Donald E. Tillitt (1)

1 U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO

2 U.S. Fish and Wildlife Service, Bismarck, ND

Sturgeon are gonochoristic and hermaphroditism is not a normal mode of reproduction in these fishes. Nevertheless, there have been occasional reports of individual sturgeon with both male and female gametes. We collected adult shovelnose sturgeon (Scaphirhynchus platorynchus) monthly from May 2001 through June 2002 from the Lower Missouri River. Abnormal hermaphroditism was observed in some of the collected fish during September, December, January, February, and April.  Gross observation indicated that gonadal tissues were mostly testicular. Ova at various developmental stages were embedded in the testicular tissue and not uniformly distributed. Ovigerous folds were observed in some areas of some testes. The proportion of hermaphroditic males ranged from 5% to 35% with the greatest percentage occurring in February. Although the conditions and factors causing abnormal hermaphroditism in sturgeons and other gonochoristic species are not known, there is some experimental evidence that altered or degraded environmental conditions may be responsible. Furthermore, it is not known if the reproductive biology of the shovelnose or the co-occurring and related endangered pallid sturgeon (Scaphirhynchus albus) may be impaired by the intersex condition. Further investigation must be completed before these observations of abnormal hermaphroditism in shovelnose sturgeon can be applied to our understanding of pallid sturgeon biology.

BIO: Diana Papoulias is a Research Fisheries Biologist. She has spent the last several years studying the effects of contaminants on fish reproduction. Diana received a Ph.D from the University of Missouri-Columbia.