Understanding krill growth and aging: the contribution of experimental studies

Abstract

Krill have been viewed as difficult animals to examine experimentally. Consequently, most information on growth and age of these pelagic crustaceans has come from demographic studies on preserved specimens. Only one species of krill, Euphausia superba, has been intensively studied in the laboratory, but the experimental findings on growth and age from these studies have fundamentally altered our perceptions of the population biology of this species. Most other species of krill remain in the preexperimental phase of understanding; thus, there remain considerable uncertainties regarding their growth and longevity. Unfortunately, these uncertainties are often ignored in ecological studies. In this paper, I have examined the role that experimental studies have played in increasing knowledge of the population biology of krill, particularly in the fields of growth and aging. I have indicated where discrepancies exist between field-based and experimental approaches and I outline some approaches for exploring these discrepancies and suggest some potentially fruitful areas for future research.