M. Nykanen et al., Seasonal changes in the habitat use and movements of adult European grayling in a large subarctic river, J FISH BIOL, 58(2), 2001, pp. 506-519
In late summer (13 August-13 September 1998), at water temperatures of 12.0
-15.7 degrees C, grayling (n=14) stayed mainly in the riffle-section where
they were captured in a large regulated river in northern Finland, moving l
ittle between consecutive days. In autumn (2-30 October 1998), at 1.7-6.7 d
egrees C, the fish (n=16) migrated to potential overwintering sites 0-14 km
up- or downstream by mid October. moving mainly short distances thereafter
. The daily movement rates, and the total ranges covered by the fish in lat
e summer and autumn were 54 +/- 32 m (mean +/- s.d.) and 1053 +/- 1636 m, a
nd 190 +/- 168 m and 3135 +/- 1850 m, respectively. In autumn the fish used
deeper habitats (most suitable range 150-400 cm) with lower current veloci
ties (20-80 cm s(-1)) and finer bottom substrata (mainly sand) than in late
summer (depth 100-325 cm, velocity 30-110cm s(-1), and cobble-boulder subs
trata). (C) 2001 The Fisheries Society of the British Isles.