Spawning movements of European grayling Thymallus thymallus in the River Aisne (Belgium)

peer reviewed ; In three consecutive years (1998 to 2000), 20 adult grayling Thymallus thymallus (L.) (FL +/- SD: 326 +/- 43 mm) were radio-tracked during circum reproduction period (February to May) in the River Aisne, Belgium. Before the spawning period, grayling remained consistently in the pool-riffle sequence in which they had been captured. Pre-spawning migration time extended from 7 to 29 March. Distances travelled during the spawning migration ranged from 70 to 4980 in (mean +/- S.E.: 1234 +/- 328 m). Spawning migrations stalled under conditions of decreasing water level and increasing... Mehr ...