Effects of Current Velocity and Suspended Debris on the Drift Feeding of Arctic Grayling
- 1 July 1993
- journal article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 122 (4) , 609-615
- https://doi.org/10.1577/1548-8659(1993)122<0609:eocvas>2.3.co;2
Abstract
We videotaped Arctic grayling Thymallus arcticus feeding on large Daphnia middendorffiana drifting at different water velocities in an experimental stream with and without stream debris. The angle and distance at which fish first located each prey was determined from the videotapes. Both measures were affected by stream velocity and added debris. Location distance was unchanged at the lower velocities (11.6 and 32.3 cm/s) but declined at higher velocities. However, prey encounter rate increased up to water velocities of 45.8 cm/s, and thus water velocity compensated for reduced search area. Added debris always shortened location distance and decreased location angle. These findings have implications for position choice in streams and search strategies.Keywords
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