PARENT SESSION

3A - Biomarker/Biomonitoring
Hall 8
8:30 AM - 12:30 PM, Tuesday, 29 April 2003
Chair: Garrigues, Ph.¹, ¹

(TU8/4) Disorders of eelpout (Zoarces viviparus) gonadal development in German Baltic coastal waters.

Gercken, Jens¹, Sordyl, Holmer¹, ¹ Institut für Angewandte Ökologie, Rostock/Broderstorf, Mecklenburg-Vorpommern, Germany

ABSTRACT- Field surveys were carried out to assess the presence of reproductive disorders in eelpout (Zoarces viviparus) living in coastal waters in the eastern part of the German Baltic Sea (Mecklenburg-Western Pomerania). During late spring, at time of advanced gonadal development, eelpout were caught at a number of coastal locations between Wismar Bay and the Darss peninsula. Histological examination of the testis revealed the presence of intersex males. The intersex condition was defined by the simultaneous presence of female gametes within the testis tissue which contained predominantly normal male gametes at late stages of spermatogenesis. Specimens with a severe form of intersexuality exhibited large strands of oocytes in the testicular lobules. Fish with intersex condition were observed at contaminated locations as well as at a place were pollution is regarded as comparatively low. The incidence of intersexuality ranged from 0% at a outer coastal site to about 30% at a inner coastal site. The presence of intersex suggests that affected fish were exposed to hormonally active substances in the environment. In the ovaries of females a degeneration of vitellogenic oocytes, a process also known as follicular atresia, was observed. As demonstrated by histology this alteration begins with a degeneration of the egg shell and proceeds until the oocyte is completely shrunken. Advanced atretic follicles were clearly visible macroscopically. Atresia was most pronounced at contaminated sites when compared to a less polluted station. In summary the results of the eelpout field surveys indicate that gonadal alterations like intersex and atresia seem to be suitable biomarkers to detect the effect of reprotoxic stressors in the coastal environment.

Key words: eelpout, Baltic Sea, intersex, atresia