Krill ( Euphausia superba ) density, proportional and absolute recruitment and biomass in the Elephant Island region (Antarctic Peninsula) during the period 1977 to 1997

Abstract

The Elephant Island region (Antarctic Peninsula) was selected as a long-term monitoring site to describe the interannual variability of important krill stock parameters. The analysis reviewed and updated krill density and proportional recruitment indices. Krill absolute recruitment and biomass from net sampling surveys are introduced as additional indices from this time series. New survey results from the past two seasons indicate a very successful 1994/1995 year-class and slightly below average proportional recruitment of the 1995/1996 krill year-class. Absolute recruitment of the 1995/1996 year-class was high compared to preceding years, because total stock size was relatively high in 1996/1997. After a period of low krill density and biomass in the area for almost a decade, krill density and biomass have increased. Caution is expressed as to whether this observed increase represents a long-term recovery of the stock.