We investigated the growth of hydromycoflora on the eggs of Atlantic salmon (Salmo salar L.) in the river water of different eutrophication levels. The investigated eggs were collected from 60 females caught during their spawning migration in the Wieprza River (Darłowo), in Świbno on the Vistula River, and from those bred in fresh water in hatcheries at Miastko. The water for the experiments was collected from three different rivers: Biała (most), Krasna (middle) and Supraśl (low eutrophication). Forty four species of straminipilous organisms were identified on the eggs of sixty females of Atlantic salmon.  Saprolegnia parasitica and Achlya polyandra were found on the eggs of most females. We have observed 23 straminipilous species on eggs in   the water from the Biała, 36 in water from the Krasna, and 24 in water from river Supraśl. 36 straminipilous organisms were found on the eggs of females from Darłowo, while only 27 and 26 were observed on the eggs of females from Miastko and Świbno. The following rare fungi were found: Saprolegnia semihypogyna and Pythium monospermum.