Behavior of Antarctic krill (<i>Euphausia superba</i>): schooling, foraging, and antipredatory behavior

Abstract

Aspects of the behavior of pelagic euphausiids are reviewed, emphasizing the behavioral biology of Antarctic krill (Euphausia superba). Euphausia superba makes an abrupt behavioral transition after the last larval molt from an individualistic, planktonic lifestyle to that of a highly social, nektonic juvenile. Then and throughout the rest of its life, most aspects of krill behavior are expressed within the context of highly organized, polarized schools. A krill school is an integrated whole that displays properties greater than the sum of its parts. Emergent attributes of the aggregate evolve in response to a suite of positive and negative selective factors that act on entire schools as well as individuals. We evaluate the individual advantages and disadvantages of living within large schools of conspecific euphausiids primarily for foraging, antipredator behavior, and epidemiology. We review the history of research on krill behavior, comment on the current state of knowledge, and suggest new avenues for future investigations.