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Changes in movement, range and habitat preferences of adult grayling from late summer to early winter
Author(s) -
Nykänen M.,
Huusko A.,
Lahti M.
Publication year - 2004
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.0022-1112.2004.00403.x
Subject(s) - grayling , riffle , biology , range (aeronautics) , fish <actinopterygii> , ecology , fishery , arctic , habitat , zoology , materials science , composite material
Radio‐tagged adult grayling Thymallus thymallus ( n = 22), monitored from mid August to mid December 1999 in the River Kuusinkijoki, Finland, shifted by the end of September (water temperature 10·0–14·5° C) from riffle sites to deeper and slower pool sites 0·7–1·6 km up‐ or downstream. In early winter ( c . 0° C water temperature), eight of 13 fish still under study made a further shift into new pool sites, possibly triggered by ice formation. The summer range of grayling in the riffles was smaller (mean ± s . d . length: 75 ± 146 m) than the autumn range (99 ± 46 m) in the pools, but gross daily movements were equally short in both the seasons (18 ± 34 m and 15 ± 7 m, respectively). In late summer, adult grayling preferred water depths 80–120 cm and mean velocities >40 cm s −1 . In autumn, the preferred ranges were 100–240 cm and <30 cm s −1 , respectively. Substratum was mainly boulders in the summer sites, and gravel or pebbles in the autumn sites.