The study was aimed at determining effects of catastrophic floods of 1997 and 2001 on survival and growth rate of parr (0⁺ and 1⁺) of the brown trout in two tributaries of the Kamienica Nawojowska (the River Dunajec system, southern Poland). The survival rate of parr was studied, after stocking in the rocky-bed stream of Homrzyska, was lower than that of the fry stocked into the stream of Kamionka, characterised by alluvial bed. The passage of flood waves in 1997 and 2001 in the Kamionka resulted in a more than 15- and a more than 10-fold reduction in the survival rates of the 0⁺ and 1⁺ parr respectively, compared to survival levels observed in years without catastrophic floods (1998–2000). None of the brown trout parr stocked in the Homrzyska survived the catastrophic floods. The growth rate of the 0⁺ and 1⁺ parr was, in the flood years, half and one-third of the rates recorded in the years without catastrophic floods, respectively.

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