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Effects of Current Velocity and Suspended Debris on the Drift Feeding of Arctic Grayling
Author(s) -
OˈBrien W. J.,
Showalter J. J.
Publication year - 1993
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1993)122<0609:eocvas>2.3.co;2
Subject(s) - debris , grayling , predation , arctic , streams , current (fluid) , environmental science , fishery , hydrology (agriculture) , ecology , geology , biology , oceanography , geotechnical engineering , computer network , computer science
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.