EN
Eelpout Zoarces viviparus has been used as a bioindicator organism to monitor mercury pollution in waters of the Western part of the Gulf of Gdańsk since 1986. The concentration of mercury in the muscle tissue of the eelpout between 1986 and 1994 was found to be almost constant, which points to a steady-state condition of mercury pollution in the investigated area. Muscle tissue mercury concentration of eelpout correlated with eelpout body length and weight. The correlation was not evident in all cases, and this seems to imply seasonal variations.