The effect of whole-lake fish community manipulations on Daphnia migratory behavior

A four-summer study of vertical migration by Daphnia was conducted in two neighboring lakes during a two-stage fish community manipulation. This manipulation produced discrete periods of low and high planktivory by fish. The migration pattern was variable and weak during the low predation stage, but became consistent and intense within weeks of the change to high levels of predation, confirming the pre-eminence of predation avoidance among several extant hypotheses.