CS39B Zooplankton - Community Dynamics
Date: Wednesday, June 12, 2002
Time: 11:00:00 AM
Location: Sidney
 
BranstratorDK, University of Minnesota Duluth, Duluth, USA, dbranstr@d.umn.edu
Tanner, C, J, Utah State University, Logan, USA, 
Horin, V, , DePaul University, Chicago, USA, 
Holl, C, M, Georgia Tech University, Atlanta, USA, 
 
SPATIAL POSITIONING OF LEPTODORA KINDTI IN RELATION TO FOOD AND PREDATION RISK
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We studied the spatial positioning of Leptodora kindti in relation to food and predation risk (Chaoborus and fish) in a small eutrophic lake in northern Illinois with maximum depth 10m. Adults (>5 mm length) descend to the hypoxic hypolimnion daily and ascend nightly whereas juveniles (<5 mm length) remain distributed throughout the water column except for the smallest individuals (<3 mm length) which show reverse migration. Despite their extreme transparency, juvenile Leptodora are eaten readily by fish (based on gut analysis), except for the smallest juveniles (<3 mm length) which are taken less frequently than their occurrence. While adult Leptodora would appear to be avoiding fish, the smallest Leptodora are migrating in response to other factors.