Distribution and population dynamics of Euphausia superba:: summary of recent findings

Antarctic krill, Euphausia superba, has been studied since the early 1920s including distribution, life cycle and behavioural biology. Quantitative aspects of distribution, biomass and demography were becoming more important since the late 1970s when a rapidly developing krill fishery started to exploit this unique resource. Since then, opinions have sometimes changed even on the appraisal of basic features such as small and large scale distribution or dispersion as well as on seasonal and interannual changes in biomass. Finally, the stability and size of the entire population had to be revised, which was believed to be relatively stable in a stable environment. Recent work has shown that the krill stocks are undergoing long-term changes and proximate and ultimate causes are still under discussion. Hence, it seems timely to review the current status of the discussion of sometime diverging interpretation of the results on krill distribution and stock dynamics for various spatial and temporal scales.