Chemical contamination monitored by the elevation of 7-ethoxyresorufin O-deethylase (EROD) in early life stages of Arctic charr (Salvelinus alpinus L.) incubated in Lake Geneva tributaries

EROD activity was measured in early life stages of Arctic charr Salvelinus alpinus L. incubated in eight Lake Geneva tributaries. Eggs were placed into incubators that were transferred into bottom substrate of studied streams. Eleutheroembryos were collected two months later. Results showed that EROD activities varied significantly between streams and that EROD activity measured in eleutheroembryos incubated in one tributary was significantly higher than in control eleutheroembryos incubated in the hatchery. Data suggest that elevated EROD activities could result from induction by dioxin-like compounds. Further chemical analysis will be necessary to substantiate this hypothesis. This study confirms the usefulness of EROD activity as an early warning system of contamination by CYP1A inducers and demonstrates that early life stages of salmonids can be used for in-situ monitoring.