Aspects of Diel Vertical Migration in Zooplankton, and Its Enigma Variations

Abstract

Several theories concerning the adaptive significance of die! vertical migration are reviewed, and the view adopted that the commonly advanced predator avoidance theory is neither complete in itself nor universally applicable. Reverse migration is considered as a real phenomenon and reviewed with respect to both inland and marine waters. It is concluded that diel vertical migration should be treated as having multiple causation and different major adaptive functions in different situations.