Movement likelihood (A), distance covered by moving individuals (B) and local activity (C) of juvenile and adult Astacus astacus within three-hour tracking intervals at different times of day. Asterisks indicates significant differences in behavioural metrics between juvenile and adult crayfish during particular times of day. Different letters indicate significant differences between dawn, daytime, dusk and night intervals among juvenile and adult crayfish, respectively. Levels of local activity were determined during 1-min time periods by counting the number of variations in signal strength as an index of activity according to Robinson et al. (2000): 0 (no variation), 1 (one to two variations) and 2 (more than two variations). The extent of level 2 (high) local activity is indicated in particular columns as a black bar.