Witkowski A., Błachuta J., Olesińska J., 1989. Age and growth-rate of grayling Thymallus thymallus (L.) in the rivers of Pomerania (NW Poland). Acta Ichthyol. Piscat. 19 (2): 3-19.

The studies were carried out on the material of 308 individuals from 18 upland river of moraine character, in north-western Poland. The growth rate, growth intensity, condition factor and the dependence between body weight and total length were estimated. It has been found that the graylings from north-western Poland live longer and grow quicker than those from mountain rivers in southern regions of the country, and also in other parts of Europe.