An investigation into the growth of 0‐group roach, (Rutilus rutilus L.) with special reference to temperature

The growth of 0‐group roach in a chalk‐fed river is traced over six seasons and the growth compared to that in a nearby gravel pit. The growth rate, the daily weight increase and the condition of the fish are all highest during the summer, falling to a minimum over the winter period and rising again in the spring. Considerable yearly variation in the growth of roach in the river was observed and correlated with water temperatures above 14° C. It is suggested that water temperature, acting through the food supply, is the dominant factor governing growth. The hot summer of 1976 appears to have resulted in excellent growth of roach in both habitats.