Surveying the occurrence of hermaphrodite roach (Rutilis rutilis)
British studies have revealed that a large proportion of roach found in waters close to municipal sewage works are hermaphrodite.
SLU researchers are now making a similar survey of roach in Swedish waters.
"We collect roach from lakes, rivers and streams, and along the Baltic coast, and examine their sexual organs. In particular, we are looking for egg cells in the testicle tissue of male fish. Substances such as pesticides, medicines and flame retardants resemble natural sexual hormones such as oestrogen, and may cause hermaphrodism. The survey will provide information as a basis for decision making by municipalities and government agencies," says Leif Norrgren, who is heading the project.
Writer:
Karin Nilsson
Published:
2011-05-11
Roach (Rutilis rutilis). Photo: Henrik Kettunen/kuvaus.fi